This document discusses precipitation and methods of measuring precipitation. It defines precipitation as moisture falling from the atmosphere in any form. The key forms of precipitation are liquid (rain, drizzle) and frozen (snow, hail, sleet). Precipitation is measured using various devices like rain gauges and satellites. Rain gauges include non-recording and recording types like tipping bucket gauges. Methods to calculate average precipitation over an area include arithmetic averages, Thiessen polygons, and isohyetal mapping. Factors influencing precipitation amounts are also examined.
Short power point made by AS/A Level students with the aim of explaining Storm Hydrographs and the foundations of the Drainage Basin Hydrological Cycle.
The document provides an introduction to hydrology, including:
- Defining hydrology as the science studying the water cycle and flows between the atmosphere, land, and oceans.
- Describing the key elements of the water cycle, including precipitation, infiltration, evaporation, and the spatial and temporal scales involved.
- Noting that the water cycle sustains life on Earth, shapes its surface, and regulates the climate.
An introduction to the emerging branch of Hydro-informatics Engineering.The presentation tries to highlight the salient points of this new specialization which involve contribution from various engineering ,science and management disciplines for the single objective of optimizing the utilization of water or water power resources.Various soft computation tools and techniques are generally used to achieve this objective.That is why, the knowledge of the subjects as well as the techniques are required to become an expert or professional from this stream.
This document discusses different types of precipitation including rain, snow, hail, sleet, and freezing rain. It explains the formation processes of each type. There are five main types of precipitation:
1. Rain, which develops when cloud droplets become too heavy to remain suspended and fall to the surface. It can also form when snowflakes melt while falling through warmer air.
2. Snow, which is formed from ice crystals that develop directly from water vapor in clouds.
3. Hail, which forms when raindrops are carried by updrafts into extremely cold areas of the atmosphere where they freeze into clumps that fall to earth.
4. Sleet, which is frozen
This document describes Arc SWAT, an ArcGIS extension tool for watershed modeling using SWAT. It can be used for developing inflow-outflow models, estimating water resources, managing check dams, and quantifying impacts of land use change. The document provides details on how Arc SWAT works, including delineating watersheds and subbasins, defining land use/soil/slope data, determining hydrologic response units, and running SWAT simulations. It then presents a case study applying ArcSWAT to model the Poondi sub-watershed in India.
El documento presenta información sobre un curso de técnicas invernales que incluye temas como el ciclo del agua, la formación de la nieve, los tipos de cristales de nieve, el manto nivoso, el metamorfismo de la nieve y las transformaciones de la nieve debido al viento. Explica conceptos clave como evaporación, condensación, solidificación y otros procesos del ciclo del agua. También describe las características del manto nivoso incluyendo tamaño de grano, contenido de agua
Continuous condensation causes cloud droplets to grow until, unable to resist gravity, they fall from clouds as precipitation like rain, snow, or hail. Rain consists of water drops over 0.5mm, snow falls as tiny ice crystals below 0°C, and hail forms when water droplets pass through cold layers and freeze into ice pellets before reaching the ground.
This document discusses precipitation and methods of measuring precipitation. It defines precipitation as moisture falling from the atmosphere in any form. The key forms of precipitation are liquid (rain, drizzle) and frozen (snow, hail, sleet). Precipitation is measured using various devices like rain gauges and satellites. Rain gauges include non-recording and recording types like tipping bucket gauges. Methods to calculate average precipitation over an area include arithmetic averages, Thiessen polygons, and isohyetal mapping. Factors influencing precipitation amounts are also examined.
Short power point made by AS/A Level students with the aim of explaining Storm Hydrographs and the foundations of the Drainage Basin Hydrological Cycle.
The document provides an introduction to hydrology, including:
- Defining hydrology as the science studying the water cycle and flows between the atmosphere, land, and oceans.
- Describing the key elements of the water cycle, including precipitation, infiltration, evaporation, and the spatial and temporal scales involved.
- Noting that the water cycle sustains life on Earth, shapes its surface, and regulates the climate.
An introduction to the emerging branch of Hydro-informatics Engineering.The presentation tries to highlight the salient points of this new specialization which involve contribution from various engineering ,science and management disciplines for the single objective of optimizing the utilization of water or water power resources.Various soft computation tools and techniques are generally used to achieve this objective.That is why, the knowledge of the subjects as well as the techniques are required to become an expert or professional from this stream.
This document discusses different types of precipitation including rain, snow, hail, sleet, and freezing rain. It explains the formation processes of each type. There are five main types of precipitation:
1. Rain, which develops when cloud droplets become too heavy to remain suspended and fall to the surface. It can also form when snowflakes melt while falling through warmer air.
2. Snow, which is formed from ice crystals that develop directly from water vapor in clouds.
3. Hail, which forms when raindrops are carried by updrafts into extremely cold areas of the atmosphere where they freeze into clumps that fall to earth.
4. Sleet, which is frozen
This document describes Arc SWAT, an ArcGIS extension tool for watershed modeling using SWAT. It can be used for developing inflow-outflow models, estimating water resources, managing check dams, and quantifying impacts of land use change. The document provides details on how Arc SWAT works, including delineating watersheds and subbasins, defining land use/soil/slope data, determining hydrologic response units, and running SWAT simulations. It then presents a case study applying ArcSWAT to model the Poondi sub-watershed in India.
El documento presenta información sobre un curso de técnicas invernales que incluye temas como el ciclo del agua, la formación de la nieve, los tipos de cristales de nieve, el manto nivoso, el metamorfismo de la nieve y las transformaciones de la nieve debido al viento. Explica conceptos clave como evaporación, condensación, solidificación y otros procesos del ciclo del agua. También describe las características del manto nivoso incluyendo tamaño de grano, contenido de agua
Continuous condensation causes cloud droplets to grow until, unable to resist gravity, they fall from clouds as precipitation like rain, snow, or hail. Rain consists of water drops over 0.5mm, snow falls as tiny ice crystals below 0°C, and hail forms when water droplets pass through cold layers and freeze into ice pellets before reaching the ground.
The document defines key terms related to watersheds and runoff. It explains that a watershed is an area of land that drains into a common body of water, while a river basin is made up of many watersheds draining into a river and its tributaries. Runoff is defined as the portion of precipitation that flows overland as surface runoff or subsurface flow instead of infiltrating the soil. The factors that affect the amount of runoff are described, including precipitation characteristics, catchment shape and size, topography, geology, meteorology, land use, and storage features.
Environmental hydrology involves the study of precipitation, which is a key input in hydrology. Precipitation occurs through various processes including cooling of air masses, condensation of water vapor, and growth of water droplets. It takes different forms such as rain, snow, hail, and sleet. Precipitation data is important for applications in agriculture, water resources management, and design of hydraulic structures. It is analyzed using techniques like consistency checks using double mass curves and estimation of missing data.
This document provides an overview of the field of hydrology. It defines hydrology as the study of the occurrence, circulation, distribution, and properties of water on Earth. The document then discusses the history of hydrology, highlighting early civilizations that developed irrigation systems, and scientists throughout history who contributed to understanding of hydrologic processes. It also outlines the main branches and applications of hydrology, and provides details on key hydrologic concepts like the water cycle, watersheds, and global patterns of water distribution and availability.
A drainage basin is an area of land where surface water converges to a single point, usually the exit of the basin. There are several types of drainage systems that form depending on the terrain and geology, including dendritic, parallel, rectangular, trellis, radial, and annular systems. Stream ordering schemes classify streams in a hierarchy based on how they join together. Quantitative analysis of drainage basins uses metrics like bifurcation ratio, length ratio, and drainage density to characterize aspects of the basin.
Precipitation occurs when atmospheric moisture condenses and falls to the earth's surface. The main forms of precipitation are rain, snow, hail, drizzle and dew. Precipitation is measured using rain gauges and satellite imagery. There are various types of precipitation depending on what causes the air to lift and cool, such as convection, orographic lifting, and cyclonic storms. Data from rain gauges needs to be quality controlled to ensure accuracy by checking for consistency using methods like double mass curves and adjusting records when inconsistencies are found.
Hydrographs show variations in a river's discharge over time, usually during a rainstorm. The shape of a hydrograph is influenced by factors like land use, precipitation amounts, geology, and soil. A hydrograph has a rising limb as discharge increases and a falling limb as it decreases. Lag time is the delay between peak rainfall and peak discharge as water from precipitation moves through the landscape into the river. Urbanization can increase flooding risk by preventing water infiltration into paved surfaces.
BRIEF REVISION - HYDROLOGY - 01. EVAPORATION AND EVAPOTRANSPIRATIONGeorge Dumitrache
Evaporation is the process by which liquid water is transformed into water vapor through exposure to solar energy. It is an essential part of the water cycle. Evapotranspiration involves both evaporation from open water and transpiration through plant stomata, and is the total amount of moisture removed from vegetated land surfaces. Potential evapotranspiration represents the maximum amount that could be evaporated or transpired given sufficient available water, and is directly related to temperature conditions.
This document provides an overview of rivers and drainage basins. It defines a river, describes the water cycle and precipitation that feeds rivers. It explains the four types of river origins and stages of river development. Key river characteristics like width, depth, velocity and discharge are outlined. The hydrological cycle and its major components are described. Drainage basins are defined as the catchment area that feeds a river system, and key basin features like the source, mouth, tributaries and confluence are identified. Four characteristics of drainage basins are described: drainage patterns, drainage density, stream ordering, and vegetation and climatic hydrologic factors.
This document provides an overview of hydrology and related concepts. It defines hydrology as the study of water on Earth, describes the hydrologic cycle of evaporation, precipitation, and runoff, and identifies the major sources and components of water. Measurement tools like rain gauges and types of precipitation such as orographic, convective, and cyclonic are explained. Factors affecting rainfall and important hydrologic terminology are also defined.
This presentation will provide you basic knowledge on Darcy's law, its application and limitation. In addition ground water contamination and remediation also have been discussed here.
Hydrological cycle- Meteorological measurements – Requirements, types and forms of Precipitation-Rain Gauges-Spatial analysis of rainfall data using Thiessen and Isohyetal methods Infiltration-Infiltration Index-Interception-Evaporation, Watershed, catchment and basin - Catchment characteristics - factors affecting runoff – Runoff estimation using empirical
The document discusses groundwater and the water cycle. It describes how (1) water moves among oceans, atmosphere, Earth and biosphere in the water cycle through processes like infiltration, transpiration and precipitation; (2) there is a balance in the water cycle as annual precipitation equals evaporation globally; and (3) groundwater is water located underground in the saturated zone below the water table, where it moves slowly through pores and fractures in rock and soil.
Introduction global water resource,global water uses,hydrological cycle (water cycle),common hydrological units,component of hydrological cycle,water budget, methods for measuring precipitation.like arithematic average method,thessen ploygon method and isohytel method.
This document provides information on measuring precipitation. It discusses various types of rain gauges used to measure precipitation, including non-recording gauges, tipping bucket gauges, and weighing bucket gauges. It also discusses methods to estimate average rainfall over a watershed area, including the arithmetic mean method, Thiessen polygon method, and isohyetal method. Additionally, it covers depth-area-duration curves and the frequency of rainfall events.
Precipitation occurs when moisture in the atmosphere condenses and falls to the surface. The main types of precipitation are rain, snow, hail, fog, dew, mist, glaze, rime, sleet. Precipitation is measured using rain gauges, snow gauges, radars, and satellites. Rain gauges include non-recording and recording types like tipping bucket, weighing, and float gauges. Recording gauges provide rainfall duration and intensity data in addition to total amounts.
The document discusses the main factors that affect runoff from a catchment area. It lists seven factors: 1) precipitation characteristics like intensity and duration, 2) the shape and size of the catchment, 3) topography such as slope, 4) geological characteristics of the surface and subsurface, 5) meteorological characteristics like temperature and humidity, 6) the character of the catchment surface such as whether it is cultivated or drained, and 7) the storage characteristics of the catchment including natural depressions or artificial reservoirs. Each of these factors can increase or decrease the amount of runoff from a catchment area depending on the specific characteristics.
The document discusses India's water crisis and climate change. It notes that many parts of India do not have adequate access to safe water for daily needs. This is due to over-pumping of groundwater, population growth, pollution from industry and sewage, and increasingly erratic weather patterns due to global warming. Climate change is affected by both natural factors like variations in solar output and volcanic eruptions, as well as human activities such as deforestation, air pollution, and changes to atmospheric gas composition and evaporation rates. Actions are suggested to conserve water usage and prevent pollution of rivers and groundwater sources to mitigate the water crisis, as well as activities to reduce greenhouse gas emissions and plant more trees to help address climate
Groundwater occurs beneath the Earth's surface in pore spaces and fractures in rocks and sediments. It originates from rainfall and snowmelt percolating into the ground. Groundwater is found everywhere but is usually within 750 meters of the surface. It makes up about 1% of the total water on Earth but 35 times the amount of water in streams and lakes. Groundwater flows through the hydrologic cycle, entering the ground as precipitation and eventually emerging in streams, lakes, or oceans.
CLIMATE CHANGE IMPACT ASSESSMENT ON MELTING GLACIERS USING RS & GISAbhiram Kanigolla
Remote sensing and GIS techniques are effective methods for mapping and monitoring glaciers and the impacts of climate change. Two case studies are summarized in the document. The first case study monitors the Gangotri glacier in India using satellite imagery and finds a 6% reduction in glacier area between 1962 and 2006. The second case study analyzes satellite images of Mount Suphan glacier in Turkey and determines that the glacier area decreased from 1.2 km2 to 0.33 km2 between 1977 and 2000, with climatic factors like increasing minimum temperatures contributing to the recession.
Hydrology is the study of water on Earth. The key concepts discussed include:
1. The hydrological cycle which describes the continuous movement of water on, above, and below the surface of the Earth.
2. Drainage basins which are areas of land where water from rain or snowmelt drains into a body of water.
3. Factors that influence storm hydrographs such as rock types, basin characteristics, precipitation levels, temperature, and vegetation cover.
This document discusses remote sensing and GIS applications for studying glaciers and snow cover. It describes different types of glaciers, snow cover, and cryosphere regions like the Arctic and Antarctica. MODIS instruments on Terra and Aqua satellites are used to map global snow cover monthly and observe changes in Arctic sea ice extent over time. GIS tools can integrate satellite imagery with digital elevation models to analyze glacier changes and snow melt runoff. Monitoring snow and glaciers is important for assessing climate change impacts and managing water resources in regions like the Himalayas.
The document summarizes the activities of the Platform Water Management in the Alps over the past two years and outlines its planned activities for the next period. It discusses workshops held on sediment management, hydropeaking, and hydropower that brought together administrators, practitioners, and stakeholders. It also describes dissemination of guidelines on small hydropower and platform meetings. Going forward, the document outlines three planned workshops on local adaptation to climate change, flood risk prevention, and river management, as well as a conference on water in the Alps. The goals are to address EU directives in an alpine context and local adaptation to climate change.
The document defines key terms related to watersheds and runoff. It explains that a watershed is an area of land that drains into a common body of water, while a river basin is made up of many watersheds draining into a river and its tributaries. Runoff is defined as the portion of precipitation that flows overland as surface runoff or subsurface flow instead of infiltrating the soil. The factors that affect the amount of runoff are described, including precipitation characteristics, catchment shape and size, topography, geology, meteorology, land use, and storage features.
Environmental hydrology involves the study of precipitation, which is a key input in hydrology. Precipitation occurs through various processes including cooling of air masses, condensation of water vapor, and growth of water droplets. It takes different forms such as rain, snow, hail, and sleet. Precipitation data is important for applications in agriculture, water resources management, and design of hydraulic structures. It is analyzed using techniques like consistency checks using double mass curves and estimation of missing data.
This document provides an overview of the field of hydrology. It defines hydrology as the study of the occurrence, circulation, distribution, and properties of water on Earth. The document then discusses the history of hydrology, highlighting early civilizations that developed irrigation systems, and scientists throughout history who contributed to understanding of hydrologic processes. It also outlines the main branches and applications of hydrology, and provides details on key hydrologic concepts like the water cycle, watersheds, and global patterns of water distribution and availability.
A drainage basin is an area of land where surface water converges to a single point, usually the exit of the basin. There are several types of drainage systems that form depending on the terrain and geology, including dendritic, parallel, rectangular, trellis, radial, and annular systems. Stream ordering schemes classify streams in a hierarchy based on how they join together. Quantitative analysis of drainage basins uses metrics like bifurcation ratio, length ratio, and drainage density to characterize aspects of the basin.
Precipitation occurs when atmospheric moisture condenses and falls to the earth's surface. The main forms of precipitation are rain, snow, hail, drizzle and dew. Precipitation is measured using rain gauges and satellite imagery. There are various types of precipitation depending on what causes the air to lift and cool, such as convection, orographic lifting, and cyclonic storms. Data from rain gauges needs to be quality controlled to ensure accuracy by checking for consistency using methods like double mass curves and adjusting records when inconsistencies are found.
Hydrographs show variations in a river's discharge over time, usually during a rainstorm. The shape of a hydrograph is influenced by factors like land use, precipitation amounts, geology, and soil. A hydrograph has a rising limb as discharge increases and a falling limb as it decreases. Lag time is the delay between peak rainfall and peak discharge as water from precipitation moves through the landscape into the river. Urbanization can increase flooding risk by preventing water infiltration into paved surfaces.
BRIEF REVISION - HYDROLOGY - 01. EVAPORATION AND EVAPOTRANSPIRATIONGeorge Dumitrache
Evaporation is the process by which liquid water is transformed into water vapor through exposure to solar energy. It is an essential part of the water cycle. Evapotranspiration involves both evaporation from open water and transpiration through plant stomata, and is the total amount of moisture removed from vegetated land surfaces. Potential evapotranspiration represents the maximum amount that could be evaporated or transpired given sufficient available water, and is directly related to temperature conditions.
This document provides an overview of rivers and drainage basins. It defines a river, describes the water cycle and precipitation that feeds rivers. It explains the four types of river origins and stages of river development. Key river characteristics like width, depth, velocity and discharge are outlined. The hydrological cycle and its major components are described. Drainage basins are defined as the catchment area that feeds a river system, and key basin features like the source, mouth, tributaries and confluence are identified. Four characteristics of drainage basins are described: drainage patterns, drainage density, stream ordering, and vegetation and climatic hydrologic factors.
This document provides an overview of hydrology and related concepts. It defines hydrology as the study of water on Earth, describes the hydrologic cycle of evaporation, precipitation, and runoff, and identifies the major sources and components of water. Measurement tools like rain gauges and types of precipitation such as orographic, convective, and cyclonic are explained. Factors affecting rainfall and important hydrologic terminology are also defined.
This presentation will provide you basic knowledge on Darcy's law, its application and limitation. In addition ground water contamination and remediation also have been discussed here.
Hydrological cycle- Meteorological measurements – Requirements, types and forms of Precipitation-Rain Gauges-Spatial analysis of rainfall data using Thiessen and Isohyetal methods Infiltration-Infiltration Index-Interception-Evaporation, Watershed, catchment and basin - Catchment characteristics - factors affecting runoff – Runoff estimation using empirical
The document discusses groundwater and the water cycle. It describes how (1) water moves among oceans, atmosphere, Earth and biosphere in the water cycle through processes like infiltration, transpiration and precipitation; (2) there is a balance in the water cycle as annual precipitation equals evaporation globally; and (3) groundwater is water located underground in the saturated zone below the water table, where it moves slowly through pores and fractures in rock and soil.
Introduction global water resource,global water uses,hydrological cycle (water cycle),common hydrological units,component of hydrological cycle,water budget, methods for measuring precipitation.like arithematic average method,thessen ploygon method and isohytel method.
This document provides information on measuring precipitation. It discusses various types of rain gauges used to measure precipitation, including non-recording gauges, tipping bucket gauges, and weighing bucket gauges. It also discusses methods to estimate average rainfall over a watershed area, including the arithmetic mean method, Thiessen polygon method, and isohyetal method. Additionally, it covers depth-area-duration curves and the frequency of rainfall events.
Precipitation occurs when moisture in the atmosphere condenses and falls to the surface. The main types of precipitation are rain, snow, hail, fog, dew, mist, glaze, rime, sleet. Precipitation is measured using rain gauges, snow gauges, radars, and satellites. Rain gauges include non-recording and recording types like tipping bucket, weighing, and float gauges. Recording gauges provide rainfall duration and intensity data in addition to total amounts.
The document discusses the main factors that affect runoff from a catchment area. It lists seven factors: 1) precipitation characteristics like intensity and duration, 2) the shape and size of the catchment, 3) topography such as slope, 4) geological characteristics of the surface and subsurface, 5) meteorological characteristics like temperature and humidity, 6) the character of the catchment surface such as whether it is cultivated or drained, and 7) the storage characteristics of the catchment including natural depressions or artificial reservoirs. Each of these factors can increase or decrease the amount of runoff from a catchment area depending on the specific characteristics.
The document discusses India's water crisis and climate change. It notes that many parts of India do not have adequate access to safe water for daily needs. This is due to over-pumping of groundwater, population growth, pollution from industry and sewage, and increasingly erratic weather patterns due to global warming. Climate change is affected by both natural factors like variations in solar output and volcanic eruptions, as well as human activities such as deforestation, air pollution, and changes to atmospheric gas composition and evaporation rates. Actions are suggested to conserve water usage and prevent pollution of rivers and groundwater sources to mitigate the water crisis, as well as activities to reduce greenhouse gas emissions and plant more trees to help address climate
Groundwater occurs beneath the Earth's surface in pore spaces and fractures in rocks and sediments. It originates from rainfall and snowmelt percolating into the ground. Groundwater is found everywhere but is usually within 750 meters of the surface. It makes up about 1% of the total water on Earth but 35 times the amount of water in streams and lakes. Groundwater flows through the hydrologic cycle, entering the ground as precipitation and eventually emerging in streams, lakes, or oceans.
CLIMATE CHANGE IMPACT ASSESSMENT ON MELTING GLACIERS USING RS & GISAbhiram Kanigolla
Remote sensing and GIS techniques are effective methods for mapping and monitoring glaciers and the impacts of climate change. Two case studies are summarized in the document. The first case study monitors the Gangotri glacier in India using satellite imagery and finds a 6% reduction in glacier area between 1962 and 2006. The second case study analyzes satellite images of Mount Suphan glacier in Turkey and determines that the glacier area decreased from 1.2 km2 to 0.33 km2 between 1977 and 2000, with climatic factors like increasing minimum temperatures contributing to the recession.
Hydrology is the study of water on Earth. The key concepts discussed include:
1. The hydrological cycle which describes the continuous movement of water on, above, and below the surface of the Earth.
2. Drainage basins which are areas of land where water from rain or snowmelt drains into a body of water.
3. Factors that influence storm hydrographs such as rock types, basin characteristics, precipitation levels, temperature, and vegetation cover.
This document discusses remote sensing and GIS applications for studying glaciers and snow cover. It describes different types of glaciers, snow cover, and cryosphere regions like the Arctic and Antarctica. MODIS instruments on Terra and Aqua satellites are used to map global snow cover monthly and observe changes in Arctic sea ice extent over time. GIS tools can integrate satellite imagery with digital elevation models to analyze glacier changes and snow melt runoff. Monitoring snow and glaciers is important for assessing climate change impacts and managing water resources in regions like the Himalayas.
The document summarizes the activities of the Platform Water Management in the Alps over the past two years and outlines its planned activities for the next period. It discusses workshops held on sediment management, hydropeaking, and hydropower that brought together administrators, practitioners, and stakeholders. It also describes dissemination of guidelines on small hydropower and platform meetings. Going forward, the document outlines three planned workshops on local adaptation to climate change, flood risk prevention, and river management, as well as a conference on water in the Alps. The goals are to address EU directives in an alpine context and local adaptation to climate change.
An evapotranspiration (ET) bed uses evaporation and plant transpiration to treat wastewater. It consists of storage trenches filled with crushed stone or other media, surrounded by loamy soil and planted with grass. Wastewater flows from the septic tank into the distribution pipes in the trenches. The water then evaporates or is absorbed by plant roots and transpired out of their leaves. Proper maintenance of the grass cover and diversion of rainfall runoff are needed for the system to function effectively.
A sensitivity Analysis of Eddy Covariance Data Processing Methods for Evapotr...Troy Bernier
The document discusses sensor errors found in a microclimate station in the Florida Everglades wetlands that could lead to inaccurate water budget calculations. Errors up to 22.34% were found in rainfall and evapotranspiration sensors, which could result in water budgets being off by over 7 inches in a year. Such large errors from sensors in small watersheds can create seriously inaccurate water budgets that could cause problems like perceived drought conditions or poor infrastructure planning.
The document discusses the measurement and representation of hydrological quantities. It notes that hydrological data has complex trends that are nonlinear and influenced by many factors. Statistical tools must be used to describe hydrological quantities given their spatiotemporal variability. Examples of typical problems in measuring quantities like precipitation, river flows, and soil moisture are provided.
The document discusses various hydrological measurement quantities and instruments. It describes 8 main hydrological quantities of interest: temperature, humidity, precipitation, radiation, wind, pressure, wetting, and evapotranspiration. It then explains principles and instruments for measuring temperature, humidity, and soil moisture, including thermometers, hygrometers, psychrometers, lysimeters, tensiometers, and instruments measuring electrical conductivity, thermal conductivity, and dielectric constants.
TIME INTEGRATION OF EVAPOTRANSPIRATION USING A TWO SOURCE SURFACE ENERGY BALA...Ramesh Dhungel
This dissertation presents a two source surface energy balance model called BATANS that uses NARR reanalysis weather data and satellite-based METRIC data to simulate evapotranspiration. BATANS partitions surface energy fluxes at satellite overpass times and time integrates evapotranspiration between overpasses. It estimates soil moisture in the surface and root zone layers using a Jarvis-type canopy resistance model. An irrigation module simulates irrigation when soil moisture falls below a threshold. The model was applied to an area in southern Idaho and results showed good agreement between simulated and METRIC surface fluxes and temperatures for most agricultural lands, though agreement was lower for desert areas. Daily evapotranspiration estimates from BATANS compared reasonably
This document discusses peak river flows and flow hydrology. It introduces the concept of a peak flow, shows a graph of discharge over time as an example, and discusses precipitation patterns and the calculation of effective precipitation. It also discusses the instantaneous unit hydrograph method for summing surface runoff over a basin to determine discharge at the basin outlet.
Daily evapotranspiration by combining remote sensing with ground observations...CIMMYT
This document discusses combining remote sensing data with ground observations to estimate daily evapotranspiration (ET) for agricultural water management. It summarizes using remote sensing to model spatial land surface temperature and vegetation cover hourly, integrating them to compute daily ET. It also describes using wireless sensors at an experimental cotton field in Maricopa, Arizona to monitor crops and irrigation as part of an integrated monitoring system for irrigation scheduling. The goal is to provide reasonably accurate and cost-effective daily ET estimates at resolutions useful to growers.
Crop Et And Implications For Irrigationcarterjfranz
Crop coefficient studies were conducted at the Tal Amara Research Station in Lebanon's Bekka Valley to determine optimal irrigation volumes for sunflowers, soybeans, wheat, and corn. Deficit irrigation experiments on sunflowers found that yield was reduced by 25% during early flowering but only 14% during mid-flowering. Seed yield actually increased with deficit irrigation during seed formation. The studies provide crop water use data and coefficients to inform sustainable irrigation planning for farmers in the water-stressed Bekka Valley region.
Python IDLE (Integrated Development and Learning Environment) for remote sens...Ramesh Dhungel
The document discusses using Python IDLE (Integrated Development and Learning Environment) for developing complex algorithms for remote sensing, hydrological, and meteorological applications. It provides examples of how to import modules, write equations, perform conditional statements, loops, and monitor pixel values during algorithm simulation in Python IDLE. Python IDLE allows integrating algorithms with ArcGIS and performing tasks like iterative processes and complex modeling that can be difficult in other environments like ENVI or ERDAS Imagine.
Session I: Water Consumption – Evapotranspiration (ET) Case Study TunisiaNENAwaterscarcity
Workshop on Operationalizing the Regional Collaborative Platform to Address ‘Water Consumption, Water Productivity and Drought Management’ in Agriculture, 27 - 29 October 2015, Cairo, Egypt
The document discusses water and energy budgets. It explains that a budget represents the variation of a given quantity within a control volume over a time interval, and is the algebraic sum of inputs and outputs. It provides examples of water budgets for soil volumes and atmospheric layers, accounting for precipitation, evapotranspiration, runoff and other fluxes. It also discusses the components of an energy budget, including net radiation, heat conduction, heat of vaporization and more.
This document summarizes a study analyzing land cover types within non-urbanized areas (NUA) in the Catania metropolitan region of Italy. The study used aerial imagery and field surveys to classify land cover patches within various land use types. The analysis found that residential areas had the highest proportion of tree cover, while abandoned farmland had the most shrub cover. The results were used to develop a land use suitability model to guide planning and climate change adaptation strategies for NUA, such as environmental protection, leisure activities, urban agriculture, and local green services. Further work will explore weighting land cover types by their evapotranspiration potential and comparing manual vs. automated land cover extraction methods.
This introduces the Open Source GIS JGrass. Other useful tools are the udig Walkthrough -1 and 2 from the udig site, and obviously the main resources are on www.jgrass.org. Other presentations about JGrass are available from slideshare. Serach them!
Time integration of evapotranspiration using a two source surface energy bala...Ramesh Dhungel
This document provides an outline for a dissertation on developing methodologies and models to estimate evapotranspiration (ET) using a two-source surface energy balance model. The objectives are to extrapolate ET between satellite overpass dates using gridded weather data and Landsat-based ET data. A resistance-based two-source surface energy balance model is developed that incorporates a soil water balance model. The model is tested against ET estimates from the METRIC model to estimate ET at higher temporal resolutions than satellite overpasses.
A look at the factors of winter weather and the challenges of a changing climate. Many of the notes refer to MN, but are true across the northern landscape
Winter ecology notes frost, snow, and icemikelink45
The basic aspects of winter revolve around water and how it freezes and how our bodies try to prevent its freezing. In the exterior world ice, frost, snow are expressions of the winter season.
The document discusses a major snowstorm that hit Colorado in March 2003, causing significant snow accumulation and roof damage. It provides details on snow load calculations, typical snow densities, building code requirements, and analyses of specific roof failures during the storm. Insured property damage from the 2003 storm totaled over $93 million in Colorado. The document is a technical report analyzing the storm impacts and snow loads on structures.
The document summarizes a major ice storm that hit eastern Canada and the northeastern United States in January 1998. Temperatures dropped to as low as -36 degrees Celsius in some areas, bringing heavy snowfall, winds up to 60 mph, and snowdrifts over 15 feet deep. In Canada, rain fell as supercooled droplets that instantly froze on surfaces like power lines, leaving over 3 million people without electricity by January 9th. The storm caused school closures and hazardous black ice on roads.
LISTEX Summer Exchange Snow-Forecast season 2017/18 reviewCH_1982
The LISTEX Summer Exchange on 2 May at The Snow Centre saw Snow-Forecast.com take us through the snow conditions for season 2017/18. The highs of the season and the ski resorts making snowfall history.
Antarctica is the coldest, windiest, and highest continent on Earth. It is also the driest, classified as an official desert due to the small amounts of rain and snow. The continent is covered by a thick ice sheet composed of compressed snow and ice. Slow moving glaciers and large floating ice shelves attached to land are also present. As winter approaches, sea ice begins to form, initially breaking into small pancake-shaped pieces before freezing entirely into a thick pack ice covering. Icebergs break off from glaciers and ice shelves that extend into the ocean. The document outlines the various types of ice found in Antarctica and how they differ in appearance and formation throughout the seasons.
This document discusses how paleoclimatologists use borehole data to study past climates. Boreholes provide a vertical timeline of temperature, precipitation, atmospheric composition, volcanic activity, and wind patterns from locations around the world. They do not provide information about past organisms. Boreholes are created by drilling into the ground or ice caps. Annual layers in ice cores can be analyzed to infer past temperature and atmospheric conditions. Temperature changes at different borehole depths are used to calculate past surface temperatures and climate trends, though local conditions can introduce uncertainties.
A glacier forms over many years in places where snow falls but does not melt, accumulating in layers that compress into ice. As glaciers move into warmer areas, melting occurs at the glacier's snout or front. Glaciers advance when accumulation exceeds melting and retreat when melting exceeds accumulation. Factors influencing this balance include climate cycles, volcanic eruptions, and human-caused global warming, which is currently causing many glaciers to retreat rapidly.
Comprehensive powerpoint on features of Glacial Erosion.
Introduction to Glaciers and Ice, plucking, abrasion and freeze-thaw, followed by descriptions and photographs of:
Corries
Aretes
Pyramidal Peaks
U-Shaped Valleys
Hanging Valleys
Truncated Spurs
Ribbon Lakes
The document discusses the environmental and economic impacts of decreasing snowfall and earlier snowmelt due to climate change. Environmentally, earlier snowmelt disrupts water supplies, increases risks of floods and forest fires, and reduces sediment transport. Economically, winter sports industries and local economies that rely on winter tourism are struggling with less reliable snow. Ski resorts have cut expenses by reducing operations and going green through initiatives like purchasing wind power and using biofuels. Athletes and resorts are raising awareness through programs like Save Our Snow to advocate for addressing climate change.
The document discusses evidence that the world is getting warmer based on various temperature records and proxy climate data:
- Instrumental records show global surface temperatures have risen 0.6°C over the past 50 years and the past few decades have been the hottest on record.
- Proxy climate data from tree rings, ice cores, corals, lake sediments, and ocean sediments extending thousands of years indicate the current warming trend is unprecedented over the last 2,000 years based on northern hemisphere temperature reconstructions.
- While some periods in the past like the Medieval Warm Period were warmer than today in some regions, the global temperature rise of the last century stands out when considering records from across the globe.
The document discusses evidence that the global climate is getting warmer. It provides temperature data from instruments over the past 200 years showing a slight warming trend. Proxy climate records using factors like tree rings, ice cores, lake sediments and coral growth extend the temperature record back thousands of years. When these multiple proxy records from around the world are combined, they indicate that the 0.6°C surface warming over the past 100 years is unprecedented over the past 2000 years and the recent warming therefore appears to be significant.
The document describes glaciers and periglacial landforms and processes. It defines different types of glaciers and explains glacial processes like formation, movement, erosion, transportation and deposition. This creates landforms like moraines, drumlins and eskers. Periglacial landscapes lacking glacial ice are also described, featuring permafrost and patterned ground. The Pleistocene epoch is summarized, noting continental glaciation, sea level changes, and paleoclimate studies of past climate variations.
Glaciation refers to the process by which glaciers shape the surrounding landscape through erosion, transportation, and deposition. During the last ice age, around 18,000 years ago, ice covered 30% of the world's landmass, including much of Britain as far south as the Bristol Channel. Glaciers erode the landscape through freeze-thaw weathering of rocks, and by plucking and abrasion as they move over the land, leaving behind characteristic features like those seen today in the Lake District.
in this presentation I will discus about the glacier, different type of glacier, formation of glacier and its movement from height toward lower area and supply water to our rivers
The document summarizes impacts of climate change including rising global temperatures, sea levels, and shifts in ecosystems. Continued carbon emissions are expected to lead to more warming, melting of ice sheets and glaciers, and sea level rise of several meters over centuries. This poses risks to coastal cities and islands. Certain tipping points such as thawing permafrost and collapse of the West Antarctic ice sheet could have irreversible consequences if crossed. Urgent action is needed to reduce carbon emissions according to the IPCC.
This document discusses the use of satellite soil moisture data for hydrological applications. It summarizes research validating satellite soil moisture products against in situ observations across different scales. It also describes a method called SM2RAIN that estimates rainfall from satellite soil moisture observations by inverting the soil water balance equation. Initial tests of SM2RAIN show good agreement between estimated and observed rainfall.
This contains the lecture about how to read data from the console. And obviously it contains also other information: about UML, about TextIO class and other stuff. See also http://abouthydrology.blogspot.it/2013/07/java-for-hydrologists-101.html for more information and for the other slides
The document discusses a Java program that solves linear equations. It begins by outlining objectives and analyzing the problem of solving for one variable in an equation of the form "ax + b = 0". It then shows the initial coding of a simple program to solve a specific case. The document goes on to discuss improving the program by making it more general and introducing object-oriented programming concepts like classes, methods and information hiding. It provides annotated code and explanations for a class called LinearEquationSolver that takes parameters to solve any linear equation, unless the coefficient of x is 0.
This is the implementation with explanations of a Hello World simple program. It is useful to document keyword and Java modifiers, as well as how to execute a program.
The document provides an introduction to using the Eclipse Java IDE for beginners learning Java. It recommends first understanding basic Java concepts by reading introductory books before using an IDE. It then directs the reader to an external website that provides instructions on installing and using Eclipse's basic features. The document stresses the importance of self-practice and mentions several other tools like Git, Ant, and Maven that programmers should learn but doesn't provide details as the author is also still learning.
This document provides an introduction to solar radiation and its role in powering the water cycle. It discusses the composition and structure of the Sun, and how it produces radiation through nuclear fusion. While solar radiation is generally constant, it exhibits variations in the form of solar spots and an 11-year activity cycle. The amount of radiation emitted by any body is determined by the Stefan-Boltzmann law, which relates radiation to the body's temperature and emissivity.
The document provides an introduction to geographic information systems (GIS) and land information systems. It defines GIS as a set of tools for collecting, modeling, manipulating, analyzing and presenting spatially referenced data. GIS allows for the overlay of different data layers to gain a better understanding of the factors that characterize an area. The document discusses the history of GIS, its components and functions, as well as how it represents spatial data through raster files, vector files, and other methods.
This document provides an introduction to concepts related to delineating a hydrographic catchment from a digital elevation model. It discusses how a DEM is discretized into a grid with elevation values for each cell. Primary topographic attributes that can be derived from the DEM like altitude, slope, gradient, and curvature are described. It explains how drainage directions and hydrographic networks can be determined from the DEM and how this allows delineation of contributing areas and hydrographic catchments. The objectives are to introduce these concepts and lay the groundwork for subsequent lectures on using software like JGrass to perform catchment delineation.
This document provides information on style and notation for "Real Books". It discusses:
- What a Real Book is and the layout of the slides
- How to write and comment on formulae
- Explaining the different parts of individual slides
- Examples of commenting equations term-by-term
- Use of symbols and providing their definitions
- Including references and bibliography
The document aims to establish clear and consistent notation for presenting technical concepts through a series of example slides. It outlines stylistic choices for formatting, commenting equations, and inserting relevant citations and resources.
The document discusses The Real Book, which refers to collections of lead sheets that contain standard jazz songs. It provides background on the original Real Book from the 1970s, which was compiled illegally by students at Berklee College of Music. The document then explains that the title "Real Book" is being used for this collection of hydrology lecture slides, which provide systematic knowledge about the topic beyond textbooks. It aims to direct students towards further resources while communicating information.
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
How to Setup Warehouse & Location in Odoo 17 InventoryCeline George
In this slide, we'll explore how to set up warehouses and locations in Odoo 17 Inventory. This will help us manage our stock effectively, track inventory levels, and streamline warehouse operations.
ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
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Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
2. 2
Yes, still the snow
...
What will be of the snow, of the garden,
what will be of free will and of destiny
and of those who have lost their way in the snow
....
Andrea Zanzotto (La beltà, 1968)
Snow, Ice, Permafrost
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
3. Goals:
•To introduce the phenomenon of snowfalls
•To describe the characteristics of snow on the ground and its
metamorphism
•To introduce the difference between snow and ice and introduce some
elements of glacial hydrology
•To introduce the thematics relative to frozen soils and permafrost
3
Snow, Ice, Permafrost
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
4. 4
Snow
Snowfalls are an important element of the water cycle: in arctic and alpine
catchments they can contribute over 95% of the hydric balance and cause
over 50% of floods, when melting.
Snow modifies the energy balance of the Earth’s surface in an essential way,
with relevant consequences on climate and ecosystems.
DonCline,1999
Snow, Ice, Permafrost
Thursday, November 18, 2010
5. 5
Snow, Ice, Permafrost
it is important to understand
•the mechanisms of precipitation and accumulation of snow
•the mechanisms of ablation and movement of snow
•the mechanisms of runoff generation
Rigon, Endrizzi, Dall’Amico
In order to understand the phenomena that have been listed
Thursday, November 18, 2010
6. 6
Snow, Ice, Permafrost
It is important to quantify
•the amount of snow that precipitates and its redistribution due to the
wind
•the amount of water in the snow cover
•the amount of snow lost through sublimation
•the quantity and timescales of melting
•the modalities of meltwater flow aggregation
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
7. 7
The formation of snowfalls
The formation of snowfalls
DonCline,1999
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
8. 8
Necessary conditions:
•Presence of water vapour
•Vapour pressure greater than equilibrium pressure
•Temperature T < 0 ºC
•Presence of condensation nuclei
Rigon, Endrizzi, Dall’Amico
The formation of snowfalls
The formation of snowfalls
Thursday, November 18, 2010
9. 9
Le montagne influenzano le precipitazioni
Versante sopravento: nubi, pioggia, neve (stau)
Versante sottovento: tempo asciutto (föhn)
DanieleCatBerro,2009
The formation of snowfalls
Mountains effect precipitations:
•Windward side: clouds, rain, snow (stau)
•Leeward side: dry weather (föhn)
Thursday, November 18, 2010
10. 10
If the condensation process is triggered
There are various formation phases:
•Nucleation
•Formation of ice crystals
•Formation of snow crystals
Crystal growth AggregationRiming
Rigon, Endrizzi, Dall’Amico
The formation of snowfalls
Thursday, November 18, 2010
13. 13
Forma di base del cristallo di neve: esagonale
135 a.C. - prime osservazioni documentate in Cina
1635 – Cartesio, primi disegni delle forme dei cristalli
1681 – Trattato “La figura della neve” del livornese Donato Rossetti
1820 – Classificazione di William Scoresby jr.
1845 – Ricerca sulle proprietà della neve di Faraday
1885 – Prima fotografia al microscopio, Wilson Bentley
(collezione al Museo delle Scienze di Buffalo, USA)
W. Bentley
www.bentley.sciencebuff.org
DanieleCatBerro,2009
On snow crystals
Snow crystals
Basis shape of the snow crystal: hexagonal
135 BC - first documented observations in China
1635 AD - Descartes, the first diagrams of snow crystal shapes
1681 - Essay “The Shape of Snow” by Donato Rossetti
1821 - Classification by William Scoresby Jr.
1845 - Studies on the properties of snow by Faraday
1885 - First microscopic photograph by Wilson Bentley
(Buffalo Science Museum collection, USA)
Thursday, November 18, 2010
15. 15
Snowfalls are linked by particular
synoptic situations
D.Cline,1999The formation of snowfalls
Thursday, November 18, 2010
16. 16
Prevedere la neve (quantità, limite nevicata): una sfida…
- Effetto valle
- Quota inferiore sul basso Piemonte
- Effetto rovesci / isotermie verticali
- Quantità difficili da prevedere in prossimità di 0 °C
DanieleCatBerro,2009
But locally it is difficult
To forecast snow (quantity, snow limit) is a challenge....
•Valley effect
•Lower altitude in southern Piedmont
•Storm effects / vertical isotherms
•Quantities difficult to forecast in proximity of 0 ºC
The formation of snowfalls
Thursday, November 18, 2010
17. 17
In hydrological modelling
Usually, the rule of the U.S. Corps of Engineers is used:
•if the temperature is below -6º C, the precipitation is all snow
•if the temperature is above 6º C, the precipitation is all liquid
•for intermediate temperatures, only a fraction is snow, the rest is liquid.
Modern models, however, use satellite data to correct the rule.
The formation of snowfalls
Thursday, November 18, 2010
19. 19
Gli spessori di neve più elevati
nel mondo e nelle Alpi italiane
1140 cm l'11 marzo 1911 a Tamarack, California (USA)
1035 cm il 28 marzo 1937 al Piccolo San Bernardo (Aosta)
850 cm il 14 marzo 1972 al Lago Valsoera (Torino)
600 cm il 13 febbraio 1951 al Lago Toggia (Verbania)
Le nevicate più abbondanti
in un giorno nel mondo e in Italia
193 cm il 15 aprile 1921 a Silver Lake, Colorado (USA)
340 cm nel dicembre 1961 a Roccacaramanico (L'Aquila),
record non omologato
198 cm il 30 dicembre 1917 a Gressoney-La Trinité
155 cm l'11 marzo 2004 a Gares (Belluno)
DanieleCatBerro,2009
The statistics of snowfalls
The greatest depths of snow recorded in the world
and in the Italian Alps
1140 cm, 11th march 1911 at Tamarack California (USA)
1035 cm, 28th March 1937 at Little Saint Bernard, Aosta (Italy)
850 cm, 14th March 1972 at Lake Valsoera, Turin (Italy)
600 cm, 13th March 1951 at Lake Toggia, Verbania (Italy)
The greatest snowfalls recorded in one day
in the world and in Italy
193 cm, 15th April 1921 at Silver Lake, Colorado (USA)
340 cm, in December 1961 at Roccacaramanico, L’Aquila (Italy)
(unapproved record)
198 cm, 30th December 1917 at Gressoney-la Trinité, Aosta (Italy)
155 cm, 11th March 2004 at Gares, Belluno (italy)
Thursday, November 18, 2010
21. 21
DanieleCatBerro,2009
There has been a drastic reduction in snowfalls since the end of
the 1980s. The winter of 2007-08 was the warmest and least
snowy on record.
The statistics of snowfalls
Thursday, November 18, 2010
22. 22
La misura della neve a Torino iniziò nel 1787,
si tratta di una tra le serie nivometriche più lunghe al mondo.
L’inverno più nevoso, il 1882-83, accumulò ben 172 cm di neve fresca.
Altri tempi… mentre fino al 1989 la media storica era di 50 cm di neve all’anno,
dal 1990 la media si è ridotta a soli 17 cm.
Torino, quantità annua neve fresca (anno idrologico) dal 1787-88 al 2008-09
0
20
40
60
80
100
120
140
160
180
200
1787
1807
1827
1847
1867
1887
1907
1927
1947
1967
1987
2007
cm
DanieleCatBerro,2009
The statistics of snowfalls
Snow measurements in Turin began in 1787, the records there represent the longest nivometric series in the world.
The snowiest winter was the winter of 1882-83 when there was a cumulative depth of 172 cm of fresh snow.
Times have changed ... up to 1989 the historical average was a cumulative depth of 50 cm per year
Since 1990, this average has been reduced to only 17 cm
Thursday, November 18, 2010
26. 26
Photographs of snow crystals
Rime on Plate Crystal Early Rounding Faceted Growth Early Sintering (Bonding)
Wind-Blown Grains Melt-Freeze with
No Liquid Water
Melt-Freeze with
Liquid Water
Faceted Layer Growth Hollow, Faceted Grain
(Depth Hoar)
Thursday, November 18, 2010
33. Seasonal trend of snow
33
Rigon, Endrizzi, Dall’Amico
and its temperature in temperate environments
Snow, Ice, Permafrost
Thursday, November 18, 2010
34. 34
in tropical areas
With current climatic conditions, snow can only accumulate at high altitudes.
This accumulation is particularly dependant on the alternation of wet and dry
seasons (for example, as a consequence of phenomena such as El Niño and La
Niña).
During the dryer seasons, snow tends to melt, while it tends to accumulate
during the wet seasons.
Seasonal trend of snow
Thursday, November 18, 2010
36. 36
DonCline,1999
Spatial Scales
Microscale
10 - 100 m
Mesoscale
100 m - 10 km
Macroscale
> 10 km
Differences in
accumulation due to
individual plants and
micro-topography
Small-scale
turbulence
Differences in
accumulation due to
vegetation cover
plants and micro-
topography
Characteristics of
the terrain
Meteorological
dynamics
Rigon, Endrizzi, Dall’Amico
Areal Distribution
Snow, Ice, Permafrost
Thursday, November 18, 2010
37. 37
DonCline,1999
Effects of topography
•Locally, snow cover increases with altitude
- in fact, the quantity of precipitation events increases
- evapotranspiration and melting decreases
•The increase varies greatly from year to year
•Other topographical factors that affect snow cover:
- slope, aspect
Rigon, Endrizzi, Dall’Amico
Snow, Ice, Permafrost
Areal Distribution
Thursday, November 18, 2010
38. 38
DonCline,1999
Effects of vegetation
•Conifers and deciduous species obviously accumulate different
amounts of snow
•Snow gathered on treetops sublimates faster than snow on the ground
Rigon, Endrizzi, Dall’Amico
Areal Distribution
Snow, Ice, Permafrost
Thursday, November 18, 2010
39. 39
Most studies show that snow accumulation occurs prevalently in open spaces
rather than within the forested areas.
The clearings are not generally subject to a great redistribution of snow due to
the wind, therefore the major factor contributing to the difference in
accumulation is sublimation, which is favoured by the heating of the tree trunks.
20-45%
Greater Snow
Accumulation
DonCline,1999
Rigon, Endrizzi, Dall’Amico
Effects of vegetation
Areal Distribution
Snow, Ice, Permafrost
Thursday, November 18, 2010
40. 40
Open environments
Together, vegetation distribution and topography can cause differences in snow
distribution patterns.
Rigon, Endrizzi, Dall’Amico
DonCline,1999
Areal Distribution
Snow, Ice, Permafrost
Thursday, November 18, 2010
43. 43
Blowing Snow
The transport of snow by the wind has a relevant effect on snow
distribution.
DonCline,1999
Thursday, November 18, 2010
44. 44
Blowing Snow
Four factors:
1 - Drag speed
2 - Windspeed thresholds
3 - Types of transport
4 - Rate of transport
Thursday, November 18, 2010
45. 45
Blowing Snow
Drag speed
The drag speed of the wind u* is usually calculated from the wind profile,
but it can be estimated on the basis of a single windspeed measurement
taken at 10 m from the ground:
where red. factor u∗
(u10 = 5) m/s
Antartic Ice Sheet u10/26.5 0.19
Snow-covered lake u1.18
10 /41.7 0.16
Snow-covered fallow field u1.30
10 /44.2 0.18
0
0.3750
0.7500
1.1250
1.5000
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
u*
10-m Wind Speed
Antarctic Lake Field
Thursday, November 18, 2010
46. 46
Blowing Snow
Windspeed thresholds at which transport begins.
The thresholds depend on the characteristics of the snow.
Type of snow u∗
t m s−1
Old, wind-hardened 0.25 -1
dense, or wet
Fresh, loose, dry snow 0.07-0.25
and during snowfall
Thursday, November 18, 2010
47. 47
Blowing Snow
3 types of movement
Type of movement Motion Typical Height u∗
[m] [m s−1
]
Creep Roll ≤ 0.01 ≤ 5
Saltation Bounce 0.01-0.1 5-10
Turbulent Supended 1-100 10
Diffusion
Thursday, November 18, 2010
48. 48
Blowing Snow
The transport rate depends on the conditions of the
surface of the snow but it is approximately:
∝ u3
10
By doubling the windspeed, the transport rate increases eightfold;
quadrupling the windspeed, the transport increases by a factor of 64
Thursday, November 18, 2010
49. 49
Blowing Snow
During transportation, the snow particles are more
affected by sublimation rather than if they were still.
30
25
2522
16
22
5020
Mean Annual Blowing Snow Sublimation
CANADA, 1970-1976
Loss in mm SWE over 1 km
Thursday, November 18, 2010
50. 50
Blowing Snow
Transport causes the modification of the ice crystals
- it makes them rounder
As a consequence, the snow cover that has
accumulated because of transport is denser than that
which precipitated in situ.
Snow crystals
collected after a
snowfall with
little wind
Snow crystals
collected
during
transportation
2 mm
Thursday, November 18, 2010
52. 52
The snowpack
Snow, Ice, Permafrost
Water (Liquid)
Ice
Air
Massa Volume
Vag
ViMi
Mag
The column of snow
Mw Vw
M∗
V∗
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
53. 53
The snowpack is:
- a porous medium (as shown in the preceding slide)
Generally, it is composed of different layers, which are typically
homogeneous, of different thicknesses and of different types of snow.
The layers are composed of crystals and grains that are usually bound
together by some sort of cohesion.
The snowpack
Thursday, November 18, 2010
54. 54
Basic notation
M∗ = Mag + Mw + Mi
M∗ = Mv + Mw + Mi
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
55. 54
Mass of snow
Basic notation
M∗ = Mag + Mw + Mi
M∗ = Mv + Mw + Mi
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
56. 54
Mass of snow
Mass of air
Basic notation
M∗ = Mag + Mw + Mi
M∗ = Mv + Mw + Mi
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
57. 54
Mass of liquid
water
Mass of snow
Mass of air
Basic notation
M∗ = Mag + Mw + Mi
M∗ = Mv + Mw + Mi
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
58. 54
Mass of liquid
water
Mass of vapour
Mass of snow
Mass of air
Basic notation
M∗ = Mag + Mw + Mi
M∗ = Mv + Mw + Mi
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
59. 54
Mass of liquid
water
Mass of vapour
Mass of ice
Mass of snow
Mass of air
Basic notation
M∗ = Mag + Mw + Mi
M∗ = Mv + Mw + Mi
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
60. 55
The volumes, with the same indices as the masses
V∗ = Vag + Vw + Vi
Vtw = Vv + Vw + Vi
Rigon, Endrizzi, Dall’Amico
Basic notation
Thursday, November 18, 2010
61. Ice density
56
Snow bulk density
ρi :=
Mi
Vi
Rigon, Endrizzi, Dall’Amico
ρ∗ :=
M∗
V∗
=
M∗
Vag + Vw + Vi
Basic notation
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64. 58
Typical densities of snow
Snow Type Density
[kg m−3
]
Wild snow 10-30
New snow 50-60
falling in still air
Settling snow 70-90
Average wind-toughened 280
snow
Hard wind slab 400-500
New firn snow 550-650
Thawing firn snow 600-700
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65. 59
Volume fraction of liquid water in snow
pores (dimensionless)
θw :=
Vw
Vag + Vw + Vi
Volume fraction of frozen water (ice) in snow
θi :=
Vi
Vag + Vw + Vi
Rigon, Endrizzi, Dall’Amico
Basic notation
Thursday, November 18, 2010
67. 61
Water equivalent of snow
Volume of water due to the complete melting of the snow on a
corresponding horizontal area.
h∗ =
θw + (1 − φ∗)
ρi
ρw
V∗
A
=
θw + (1 − φ∗)
ρi
ρw
hsn
hsn :=
V∗
A
h∗ :=
Vw(A) + ρi
ρw
Vi(A)
A
Rigon, Endrizzi, Dall’Amico
Basic notation
Thursday, November 18, 2010
68. 62
Qualitative characteristics
of the snowpack
Term Size θ∗
Dry Usually T ≤ 0 ◦
C 0
Little tendency for snow grain to stick together
Moist T = 0 ◦
C ≤ 0.03
Grains stick together
Wet T = 0 ◦
C 0.03 - 0.08
Water can be seen in meniscus, but not squeezed out from snow
Pendular regime
Very wet T = 0 ◦
C 0.08 - 0.15
Water can be pressed out by squeezing snow
Appreciable amount of air (funicular regime)
Slush T = 0 ◦
C ≥ 0.15
The snow is flooded with water. No air
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69. 63
Other characteristics
of the snowpack
•Shape of the grains of snow
•Size of the grains of snow
•Albedo
•Temperature
•Hardness
•Mechanical properties
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70. 64
Variation of the albedo in time
Albedo as a function of snow surface (i.e., time since last snowfall).
From U.S. Army Corps of Engineers (1956)
Thursday, November 18, 2010
71. 65
Thermal properties of snow
It is assumed that the heat flux is according to Fourier’s law:
Jh = Kh
∇T
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72. 65
Thermal properties of snow
It is assumed that the heat flux is according to Fourier’s law:
Jh = Kh
∇T
Heat flux
W m-2
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73. 65
Thermal properties of snow
It is assumed that the heat flux is according to Fourier’s law:
Jh = Kh
∇T
Heat flux
W m-2
Thermal
conductivity
W m-1 K-1
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74. 65
Thermal properties of snow
It is assumed that the heat flux is according to Fourier’s law:
Jh = Kh
∇T
Heat flux
W m-2
Thermal
conductivity
W m-1 K-1
Temperature
gradient
K m-1
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75. 66
The thermal conductivity, Kh, is a measure of the capacity of a material to transfer
heat. A good heat conductor has an elevated value of K, while an insulator has a
low value of K.
Fresh snow 0.03 (better than glass wool!)
Old snow 0.4
Ice 2.1
Jh = Kh
∇T
Snow attenuates the thermal changes of the atmosphere. For example, a
change of 1 degree in air temperature, in 15 minutes, causes a change of only
0.1 degrees at a depth of 20 cm in the snowpack and of only 0.01 degrees at
a depth of one metre.
Thermal properties of snow
Thursday, November 18, 2010
76. 67
Jh = Kh
∇T
Kh grows with the metamorphosis of the snow. For example, Sturm, 1997 gives
the following parametric formula:
Kh = 0.138 − 1.01 ρ ∗ +3.233 ρ2
∗
Thermal properties of snow
Thursday, November 18, 2010
77. 68
Temperature
Generally two different situations are found in the snowpack:
- there is a variation of temperature between the surface and the
ground upon which the snowpack is lying: the temperature is typically
dominated by the temperature at the surface and the ground is usually
at 0ºC … unless, of course, we find ourselves in the presence of
permafrost.
- there is no temperature gradient: the snowpack is in an isothermic
state.
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78. 69
Temperature
Snow is a good thermal insulator. Large temperature gradients can be observed in
proximity of the surface.
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81. 72
The name indicates the changes to the morphology of the grains that occur
due to variations in temperature and pressure to which they are subjected
following their deposition.
Snow metamorphism changes:
•density
•porosity
•albedo
•thermal conductivity
•cohesion
Snow metamorphism
Thursday, November 18, 2010
82. Metamorphism occurs because:
•the grains have relatively large surface area with respect to their volume
and they tend towards a more stable geometric configuration (the
spherical surface is the one with minimum energy)
•the temperature, during the season, exceeds the melting point
•the pressure in the lower layers causes a compaction of the snow (and
approaches melting conditions)
73
Neve, Ghiaccio, Permafrost
Rigon, Endrizzi, Dall’Amico
Thursday, November 18, 2010
83. 74
Two categories of metamorphism can be identified:
In the presence of liquid water:
- T = 0 (usually)
In the absence of liquid water:
- T 0
- ice is in equilibrium with vapour
- prevalently determined by the flux of vapour
Metamorphism occurs because:
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84. 75
“Dry” metamorphism
It is linked to the movement of vapour in the pores
The movement of vapour is linked to the vapour pressure gradient
The pressure gradient is controlled by:
•Temperature (on the basis of what has been seen so far, the
equilibrium vapour pressure depends on the temperature according to
the Clausius-Clapeyron law)
•Local radius of curvature of the ice crystals (the Clausius-Clapeyron
law must be modified when the air-ice interface is curved. The
equilibrium vapour pressure increases with increasing radius of
curvature)
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85. 76
Destructive metamorphism
Constructive metamorphism
Two types
It occurs at constant temperature and it is due to the demolition of
the cusps of the grains. The process is particularly intense for freshly
fallen snow and brings about increases in density at rates greater
than 1% per hour. It comes to a halt when the density is of the order
of 0.25 g cm-3
Depends on the temperature from point to point. In the warmer points
sublimation of the snow occurs. The vapour then moves following the
pressure gradients.
“Dry” metamorphism
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86. 77
Destructive metamorphism
Reduces the free energy of the system to its stable state
This energy depends of the local radius of curvature of the ice crystal
Thursday, November 18, 2010
87. 77
Destructive metamorphism
Reduces the free energy of the system to its stable state
This energy depends of the local radius of curvature of the ice crystal
elevated radius of
curvature implies
greater vapour
pressure
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88. 78
Reduces the free energy of the system to its stable state
This energy depends of the local radius of curvature of the ice crystal
A negative radius
o f c u r v a t u r e
implies a lower
vapour pressure in
t h e r m o d y n a m i c
equilibrium
Destructive metamorphism
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89. 79
The difference in vapour pressure between two point implies a vapour
transfer (from “+” to “-”).
In this way there is
an excess of vapour
over the “-” point
and , consequently,
condensation.
+
-
The ideal equilibrium
configuration is a sphere.
The real equilibrium
configuration depends on
the interaction of the
single crystal with
surrounding
environment.
Destructive metamorphism
Reduces the free energy of the system to its stable state
Thursday, November 18, 2010
90. 80
The macroscopic effect of destructive
metamorphism is that of :
- reducing the surface / volume ratio of the
crystals and therefore increasing the
density of the snow (by filling the pores);
- increasing the cohesion between grains.
Destructive metamorphism
Thursday, November 18, 2010
91. 80
The macroscopic effect of destructive
metamorphism is that of :
- reducing the surface / volume ratio of the
crystals and therefore increasing the
density of the snow (by filling the pores);
- increasing the cohesion between grains.
Destructive metamorphism
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92. 81
“dry” but dictated by the temperature gradient
It can be very efficient if the gradient is at least 10 ºC/m and the snow
density is low (less than 350 kg/m3)
It creates faceted grains with weak reciprocal bonds
It tends to reduce the density
Destructive metamorphism
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93. 82
Melting metamorphism
or “wet” metamorphism
It occurs in the presence of water and, therefore, in proximity of T=0 ºC
There are two main mechanisms:
•surface melting followed by percolation of the meltwater
•an acceleration of the “dry” processes which brings about the formation of
large, rounded grains.
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The first of these mechanisms is caused by surface melting or by the
introduction of rainwater which freezes within the snowpack at lower
temperature. In this way a layer of compact ice can form within the
snowpack, which can extend even over large distances.
The freezing of water within the snowpack causes the liberation of
latent heat, which contributes to the generation of vapour and the
acceleration of its transfer.
Melting metamorphism
or “wet” metamorphism
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95. 84
T h e s e c o n d m e t a m o r p h i c
process that accompanies
melting processes is the rapid
disappearance of the smaller
grains and the formation of
larger grains, which occurs in the
presence of liquid water. Because
of this phenomenon, a snowpack
that is melting is formed by an
aggregation of grains with
diameters of 1-2 millimetres
(Colbeck, 1978).
Melting metamorphism
or “wet” metamorphism
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96. 85
The energy balance of snow
It occurs by:
• radiation (energy transfer by means of electromagnetic waves)
• conduction (heat transfer by direct contact between molecules)
• convection (sublimation and transfer of sensible heat due of atmospheric
turbulence)
• advection (due to mass transfer: precipitation, vapour, meltwater)
Thursday, November 18, 2010
97. 86
Factors contributing to the energy exchange
• The Wind (it is the manifestation of atmospheric turbulence that controls
the transfer of sensible and latent heat at the surface)
• The presence of water vapour (its gradients control the transfer of
sensible heat)
• The amount of radiation (across the spectrum)
• The energy content of rainwater which alters the state of the snow
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102. 91
The radiative balance of snow
SNOW, T = 0oC
CLEAR DRY AIR, T = 0oC
Net Energy Loss
From Snow Pack No Net Energy Loss
From Snow Pack
a ≈ 0.6 − 0.7
w,i,∗ ≈ 0.92 − 0.97
R = σ T4
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104. 93
On rainy and cloudy days, exchanges of sensible and latent heat dominate
the balance.
However, these exchanges are always important due to the high albedo of
snow which does not allow for large storage of radiative energy, except
maybe in the summertime.
Generally, a large-scale melting of snow requires that the “turbulent”
exchanges of energy be rather intense.
Turbulent fluxes
The energy balance of snow
Thursday, November 18, 2010
105. 94
Stable atmospheric conditions reduce turbulence and, therefore, the turbulent energy
transfer. Vice versa, atmospheric instability increases the transfers.
Aerodynamic roughness
length
INSTABILITY
ln(z-d0)
STABILITY
q-qs
Turbulent fluxes
The energy balance of snow
Thursday, November 18, 2010
106. 95
The theory that describes this process is known by the name of its authors:
Monin-Obukhov
Turbulent fluxes
The energy balance of snow
Thursday, November 18, 2010
107. 96
Over snow it is easy for stable atmospheric conditions to prevail: it is a
feedback effect caused by the elevated albedo of the snow.
Therefore, the same condition that minimises radiative storage also
minimises the turbulent energy transfers.
Turbulent fluxes
The energy balance of snow
Thursday, November 18, 2010
108. 97
However, given that snow cover is not uniform across the landscape, and that
vegetation constitutes an element that absorbs and emits energy with great
efficiency, there are parts of the landscape where snowmelt is greater than in
others.
Turbulent fluxes
The energy balance of snow
Thursday, November 18, 2010
110. 99
SW radiation tends to zero when the sky is cloudy
Accumulation season - the Tonale Pass
The energy balance of snow
Thursday, November 18, 2010
111. 100
Latent and sensible heat:
• there are increases when
windspeed is high.
• they increase and decrease in
antiphase, except that...
• they both increase when it rains
or there is high humidity in the
atmosphere
Accumulation season - the Tonale Pass
The energy balance of snow
Thursday, November 18, 2010