About Remote Sensing
Introduction To Precipitation
Forms of Precipitation
Measurement & Measuring Methods of Precipitation
Outcomes of Extreme Precipitation
this is my presentation of hydraulic and water resources engineering. I have discussed in this ppt about network density for given rain gauge and calculations and index of witness.
About Remote Sensing
Introduction To Precipitation
Forms of Precipitation
Measurement & Measuring Methods of Precipitation
Outcomes of Extreme Precipitation
this is my presentation of hydraulic and water resources engineering. I have discussed in this ppt about network density for given rain gauge and calculations and index of witness.
The term precipitation is also used to refer all forms of falling moisture viz., rainfall, snowfall, sleet, hail etc. Rainfall occurs in the form of a pattern. Atmospheric Precipitation is a wonderful process for the whole globe to use. This module explains it in general.
Definition, Forms of precipitation, Types of Precipitation, FACTORS ON WHICH
PRECIPITATION DEPENDS UPON, FACTORS AFFECTING PRECIPITATION, VARIABILITY OF PRECIPITATION, Measurement of Precipitation, IMPACT OF CLIMATE CHANGE ON
RAINFALL,
Hydrology means science of water.
It is the science that deals with the occurance, circulation and distribution of water on the earth.
Hydrology is a broad subject of an inter-disciplinary nature drawing support from allied sciences.
Brief description of Hydrology, various spheres of Hydrology, applications and utilities of Engineering Hydrology and understanding possibilities of flood.
WATER PRESENT AT OUR EARTH IN THE FORM OF CONDENSATION ,LIQUID AND PROVIDE RAINFALL INTENSITIES AFTER VARIABLE PERIODS OF TIME CAN BE ANALYSED BY VARIOUS METHODS ,GIVEN AND SHOWN IN THIS PPT
The term precipitation is also used to refer all forms of falling moisture viz., rainfall, snowfall, sleet, hail etc. Rainfall occurs in the form of a pattern. Atmospheric Precipitation is a wonderful process for the whole globe to use. This module explains it in general.
Definition, Forms of precipitation, Types of Precipitation, FACTORS ON WHICH
PRECIPITATION DEPENDS UPON, FACTORS AFFECTING PRECIPITATION, VARIABILITY OF PRECIPITATION, Measurement of Precipitation, IMPACT OF CLIMATE CHANGE ON
RAINFALL,
Hydrology means science of water.
It is the science that deals with the occurance, circulation and distribution of water on the earth.
Hydrology is a broad subject of an inter-disciplinary nature drawing support from allied sciences.
Brief description of Hydrology, various spheres of Hydrology, applications and utilities of Engineering Hydrology and understanding possibilities of flood.
WATER PRESENT AT OUR EARTH IN THE FORM OF CONDENSATION ,LIQUID AND PROVIDE RAINFALL INTENSITIES AFTER VARIABLE PERIODS OF TIME CAN BE ANALYSED BY VARIOUS METHODS ,GIVEN AND SHOWN IN THIS PPT
Tugboat operator Harbor Star Shipping Services, Inc. has secured the Maritime Industry Authority approval to register its newly acquired tugboat. In a disclosure to the Philippine Stock Exchange on Wednesday, the listed company said the new tugboat MT Reda will support the domestic expansion of the operator. Harbor Star was incorporated in 1988 mainly to engage in harbor assistance (docking and undocking), ship salvage, towage or lighterage, specialized cargo handling operations, and other marine services. “Harbor Star took delivery of MT Reda at the Port of Batangas last December 2016. The 2,956 BHP, 40-ton bollard pull tugboat will augment the continuous domestic expansion of Harbor Star,” the listed operator said in its regulatory filing. MT Reda is the third tugboat imported by Harbor Star in 2016. Harbor Star now manages 41 tugboats in the Philippines and Malaysia. Harbor Star announced last December that it received board approval to raise as much as P1 billion through a follow-on offering to fund its international fleet expansion, domestic feeder vessel services and renewable energy project. It will call for a stockholders’ meeting this quarter to secure the approval of its stockholders. It also secured a $2.5-million loan facility from a company based in the British Virgin Islands to fund its expansion plans and operations
The AMAZING Success of Indian Immigrants in America!Richard Herman
This is the powerpoint presentation that I am delivering today, 9/13, as part of the Onam Ponnonam celebration hosted by the Kerala Association of Ohio.
The discussion focuses on the amazing contributions of immigrants to America, with a special emphasis on immigrants from India.
The data demonstrates that immigration is America's secret weapon in the hyper-competitive global economy, and that the long-standing immigration reform debate is improperly framed and ultimately undermines the nation's economic and national security.
Immigrants from all countries contribute mightily to the country's economic development, job creation and innovation.
Immigrants from India stand-out from the pack.
I was quoted in this recent article from International Business Times (referring to a quote in Forbes):
”It’s not a surprise that we’re seeing Indians rise in corporate ranks,” said Richard Herman, co-author of a book entitled "U.S., Immigrant Inc.," to Forbes. "Of all the immigrant groups coming in today, Indians are head-and-shoulders above others, and this is partly because of their English-language skills and also the advanced education that many of them are bringing to the U.S.”
http://www.ibtimes.com/rise-indian-americans-u-s-business-infographic-1560450
America needs to understand the job-creation benefits of welcoming immigrants, integrating the foreign-born, and passing comprehensive immigration reform.
Delay on this front is jeopardizing America's future.
Webinar - Immigration Legislation in 2011 and 2012mbashyam
This powerpoint reviews significant immigration legislation introduced by Congress in 2011, and immigration attorneys at Bashyam Spiro provide their thoughts on what lies ahead for immigration legislation in 2012.
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chapter 2.ppt ,hydrological study of ethi0mulugeta48
hydrology ,A programme of groundwater investigations is to obtain information on the resource through systematic collection, synthesis, interpretation and compilation of data.
It seeks information on its occurrence, movement, storage, recharge, discharge, quality & quantity.
It includes the study of its geological, environmental, as well as the hydrologic and hydraulic aspects of its flow system.
Geologic Methods
A geologic investigation begins with the collection, analysis, and hydrogeologic interpretation of existing topographic map, aerial photographs, geologic maps and logs, and other pertinent records.
This should be supplemented, when possible, by geologic field reconnaissance and by evaluation of available hydrologic data on: stream flow and springs; well yields; groundwater recharge & levels; and water quality
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Safalta Digital marketing institute in Noida, provide complete applications that encompass a huge range of virtual advertising and marketing additives, which includes search engine optimization, virtual communication advertising, pay-per-click on marketing, content material advertising, internet analytics, and greater. These university courses are designed for students who possess a comprehensive understanding of virtual marketing strategies and attributes.Safalta Digital Marketing Institute in Noida is a first choice for young individuals or students who are looking to start their careers in the field of digital advertising. The institute gives specialized courses designed and certification.
for beginners, providing thorough training in areas such as SEO, digital communication marketing, and PPC training in Noida. After finishing the program, students receive the certifications recognised by top different universitie, setting a strong foundation for a successful career in digital marketing.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Digital Tools and AI for Teaching Learning and Research
" Precipitation" by Engr Rehan Zeb Khan PMAS-AAUR Rawalpindi
1. by Engr REhan Zeb Khan PMAS-AAur
“ Precipitation ”
By
Engr Rehan Zeb Khan
Deportment of Land and Water Conservation
Engineering
PMAS –Arid Agriculture University Rawalpindi
2. Contents
1.Introduction
2.Forms of Precipitation
3.Factor Influencing precipitation formation
4.Classification based on lifting mechanism
Convectional Precipitation
Orographic Precipitation
Cyclonic Precipitation
5.Measurement of Precipitation
Non Recording Gauges
Recording Gauges
Measurement by Radar
Rain Gauge Network
by Engr REhan Zeb Khan PMAS-AAur
3. Contents
6.Analysis of Precipitation Data
Point Data Analysis
Estimation of Missing Record
Consistency of Precipitation
Areal Precipitation Data Analysis
Arithmetic Mean Method
Thiessen Polygon Method
Isohyetal Method
7.Intensity of Precipitation
Depth Area Relationship
Mass Curve
Depth Area Duration Curves
by Engr REhan Zeb Khan PMAS-AAur
4. Inroduction
Precipitation is any product of the condensation of atmospheric water
vapour that falls under gravity. The main forms of precipitation
include drizzle, rain, sleet, snow, glaze, snowflake and hail.
Precipitation occurs when a portion of the atmosphere becomes
saturated with water vapour, so that the water condenses and
"precipitates".
by Engr REhan Zeb Khan PMAS-AAur
5. Forms of Precipitation
Drizzle:
Drizzle is a light liquid precipitation consisting of
liquid water drops smaller than those of rain – generally
smaller than 0.5 mm (0.02 in) in diameter.
Rain:
Rain is the form of precipitation in which the size of drops
is more then 0.5mm and less than 6.25mm in diameter
by Engr REhan Zeb Khan PMAS-AAur
6. Forms of Precipitation
Glaze:
Glaze is the ice coating formed on drizzle or rain drops when it
comes in contact with cold surface
Sleet:
Sleet is the frozen rain drops cooled to the ice stage while
falling through air at subfreezing temperature.
Snow:
Snow is precipitation in the form of ice crystals resulting from
sublimation.
Snowflake:
A snow flake is made up of a number of ice crystals fused
togather.
by Engr REhan Zeb Khan PMAS-AAur
7. Forms of Precipitation
Hail:
Hail is the precipitation in the form of small balls or
lumps usually
consisting of concentric layers of clear ice and compact
snow.
Hail varies from 0.5 to 5 cm in diameter and can be
damaging crops and small buildings
by Engr REhan Zeb Khan PMAS-AAur
8. Factor Influencing precipitation formation
Mechanism of Cooling
The pressure reduction when air ascends from near
the surface to upper levels in the atmosphere is
the only mechanism capable of producing the
degree and rate of cooling needed to account for
heavy rainfall. Cooling Lowers the capacity of a
given volume of air to hold a certain amount of
water vapour.
Condensation of Water Vapor
Condensation of water into cloud droplets takes
place on hygroscopic nuclei which are small
particles having an affinity for water. The source
of these condensation nuclei are the particles of
sea salt or products of combustion of certain
sulfurous and nitrous acid and carbon dioxide.
There are always sufficient nuclei present in the
atmosphere. by Engr REhan Zeb Khan PMAS-AAur
9. Factor Influencing precipitation
formation
Growth of Cloud Droplet
Growth of droplets is required if the liquid water
present in the cloud is to reach the ground. The
two processes regarded as most effective for
droplet growth are:
Coalescence of droplets through collision due to
difference in speed of motion between larger and
smaller droplets.
Co-existence of ice crystals and water droplets.
Co-existence effect generally happens in the
temperature range from 100 to 20 °F.
by Engr REhan Zeb Khan PMAS-AAur
10. Factor Influencing precipitation
formation
Accumulation of Moisture
Heavy Rainfall amount over a river basin exceeds
by far the amount of the water vapor at
atmospheric volume vertically. Thus there must be
a large net horizontal inflow of water vapor into
the atmosphere above the basin area . This
Process is called Convergence.
by Engr REhan Zeb Khan PMAS-AAur
11. Classification based on lifting mechanism
Convectional precipitation:
Convectional precipitation results from the heating of the earth's
surface. The warm ground heats the air over it. As the air warms, the
air molecules begin to move further apart. With increased distance
between molecules, the molecules are less densely packed. Thus, the
air becomes “lighter” and rises rapidly into the atmosphere. As the air
rises, it cools. Water vapour in the air condenses into clouds and
precipitation.
by Engr REhan Zeb Khan PMAS-AAur
12. Orographic Precipitation
Orographic precipitation results when warm moist
air moving across the ocean is forced to rise by
large mountains. As the air rises, it cools. Cold air
cannot hold as much moisture as warm air. As air cools, the water
vapour in the air condenses and water droplets form. Clouds forms and
precipitation (rain or snow) occurs
Classification based on lifting
mechanism
by Engr REhan Zeb Khan PMAS-AAur
13. Cyclonic Precipitation
Cyclonic precipitation results when the leading edge
of a warm, moist air mass (warm front) meets a cool and
dry air mass (cold front). The molecules in the cold air are
more tightly packed together (i.e., more dense), and thus, the
cold air is heavier than the warm air. The warmer air mass
is forced up over the cool air. As it rises, the warm air cools,
the water vapour in the air condenses, and clouds and precipitation
result.
Classification based on lifting
mechanism
by Engr REhan Zeb Khan PMAS-AAur
14. Measurement of Precipitation
Amount of Precipitation
The amount of precipitation means the vertical height of water that wuld
accumulate on a level surface
Intensity or Rate of precipitation
Amount of precipitation per unit time is called the intensity or Rate of
Precipitation.
by Engr REhan Zeb Khan PMAS-AAur
Precipitation is measured by rain gauges. There are two
types of rain gauges.
1, Recording Gauges
2,Non Recording Gauges
15. Measurement of Precipitation
Non Recording Gauges
Non-recording rain gauges are commonly used. They do not record the data and
collect only rain and this collected rain is then measured in a graduated
cylinder.
The standard gauge of U.S. Weather Bureau has a collector of 200 mm diameter
and 600 mm height. Rain passes from a collector into a cylindrical measuring
tube inside the overflow can.
The snow collected in the outer container or overflow can is melted, poured
into the measuring tube and then measured. This type of rain gauge is one of
the most commonly used rain gauges.
by Engr REhan Zeb Khan PMAS-AAur
16. Measurement of Precipitation
Recording Gauges
Float recording gauges
by Engr REhan Zeb Khan PMAS-AAur
This type of rain gauge also has a receiver and a float chamber along with
some recording mechanism or arrangement. In this type the rain is led
into a float chamber containing a light, hollow float. The vertical
movement of the float as the level of water rises is recorded on a chart
with the help of a pen connected to float. The chart is wrapped around a
rotating clock driven drum. To provide a continuous record for 24 hours
the float chamber
has either to be very large, or some
automatic means are provided for
emptying the float chamber quickly
when it becomes full, the pen then
returning to the bottom of the chart.
17. Measurement of Precipitation
Recording Gauges
Weighing type gauges:
It consists of a storage bin, which is weighed to
record the mass. It weighs rain or snow which falls
into a bucket, set on a platform with a spring or
lever balance. The increasing weight of the bucket
and its contents are recorded on a chart. The
record shows accumulation of precipitation.
by Engr REhan Zeb Khan PMAS-AAur
18. Measurement of Precipitation
Recording Gauges
Tipping Bucket Type:
In TBG the collector is funneled into two
compartment buckets. When one compartment of
bucket is filled with rain water it becomes over
balanced and tips such that the other
compartment takes its place beneath the funnel.
As the bucket is tipped it automatically activates
an electronic circuit. As the bucket is tipped by
each 0.25 mm of rain it actuates an electrical
circuit, causing a pen to mark on a revolving
drum.
by Engr REhan Zeb Khan PMAS-AAur
19. Measurement of Precipitation
Measurement of Precipitation by
Radar
This is a modern technique for measurement of
rainfall rate. It can also detect local movement of
areas of precipitation. The electromagnetic
energy released and received back by radar is a
measure of rainfall intensity. The measurement is
appreciably affected by trees and buildings.
However extent of rainfall can be estimated with
reasonable accuracy. Use of radar is useful where
number of rain gauges installed in an area is not
sufficient.
by Engr REhan Zeb Khan PMAS-AAur
20. Measurement of Precipitation
Rain Gauge Network
The number of rain gauges and their distribution affect the nature
of collected precipitation data. The larger the number of rain
guages the more representative will be the data collected. World
Meteorological Organization (WMO) has made following
recommendations for minimum number of rain gauges in a
catchment:
In comparatively flat regions of temperate, Mediterranean and
Tropical Zones, the ideal is at least one station for 230 – 345 sq.
miles.
In mountainous regions of Temperate, Mediterranean and Tropical
Zones, the ideal is at least one station for 35 – 95 sq. miles
In arid and polar zones, one station for 575 – 3860 sq. miles is
acceptable.
by Engr REhan Zeb Khan PMAS-AAur
22. Analysis of Precipitation Data
Point data analysis
Point precipitation data refers to precipitation of a station. This data could be form of hourly
record, daily record, monthly precipitation or annually precipitation. Due to many reasons
data may not be continuous and consistent.
1. ESTIMATION OF MISSING PRECIPITATION RECORD.
Some precipitation stations may have short breaks in the records because of absence of the
observer or because of instrumental failure. It is often necessary to estimate the missing
record. There are two methods for estimation of missing data.
A. SIMPLE ARITHMETIC MEAN METHOD.
i=n
Px =1/n ∑ Pi (where ‘n’ is number of station and ‘Pi’ is precipitation at ith
i=1 station)
WHERE,
Px = (P1 +P2 +P3)/3
by Engr REhan Zeb Khan PMAS-AAur
23. Analysis of Precipitation Data
B, NORMAL RATION METHOD.
i=n
Px =1/n ∑ (Nx /Ni)Pi
i=1
Px=1/3 [Nx /N1)P1 + (Nx /N2)P2 +(Nx /N3)P3 ]
2, CONSISTANCY OF PRECIPITATION DATA OR DOUBLE MASS ANALYSIS.
Double mass curve is used when the consistency of the data is required.
Pa = (Sa/So)* Po
Pa = Adjusted precipitation.
Po = Observed Precipitation.
by Engr REhan Zeb Khan PMAS-AAur
24. Analysis of Precipitation Data
Double Mass Curve
by Engr REhan Zeb Khan PMAS-AAur
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 0.5 1 1.5 2 2.5
accumulatedannualrainfallofXstnin10^3cm
Accumulated annual rainfall of neigbouring stns in 10^3 cm
Double Mass Curve
25. Analysis of Precipitation Data
Areal Precipitation Data Analysis.
To find out runoff from a catchment and most of other hydrology
analysis, it is important to know the average precipitation of a
certain part of a catchment or for the whole of catchment area.
ESTIMATION OF AVERAGE PRECIPITATION OVER A BASIN.
Conversion of point precipitation of various gauging station into
average precipitation of that area a great skill and
experience is required.
A. Arithmetic mean method
According to this method ,
i=n
P(average) = (1/n)∑ Pi
i=1
Pav = [ P1 + P2 + P3 + …………..+Pn ]/n
by Engr REhan Zeb Khan PMAS-AAur
27. Analysis of Precipitation Data
Thiessen Polygon
Draw the given area according to a certain scale and locate the stations
where measuring devices RE installed.
Join all the according to get a network of non- intersecting systems of
triangles.
Draw the bisectors of all the lines joining the station and get a suitable
network of polygons, each enclosing one station. It is assumed that
precipitation over the area enclosed by the polygon is uniform.
Measure area of the each polygon.
Calculate the average precipitation for the whole basin by the formula
P(average)=(P1A1+P2A2+……PNAN)/A
P1=Precipitation at station enclosed by polygon of area A1
P2=Precipitation at station enclosed by polygon of area A2
And so on.
Pn=Precipitation at station enclosed by polygon of area An and A
represents the total area of catchment
by Engr REhan Zeb Khan PMAS-AAur
28. Analysis of Precipitation Data
Isohyet Method
by Engr REhan Zeb Khan PMAS-AAur
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29. Analysis of Precipitation Data
Isohyet Method
Draw the map of the area according to a certain scale.
Locate the points on map where precipitation measuring gauges are installed.
Write the amount of precipitation of stations.
Draw isohyets (lines joining points of equal precipitation).
Measure area enclosed between every two isohyets or the area enclosed by an isohyet
and boundry of the catchment.
Find the average precipitation by the formula.
P (average) = (P1A2 + P2A2 + ………..+PnAn
Where P1=Mean precipitation of two isohyets 1 and 2
A1= Area between two isohyets
P2=mean precipitation of two isoyets2 and 3
A 2=Area b/w these two isohyets
Pn=Mean precipitation of isohyets n and n+1
An=The area b/w these two isohyets. by Engr REhan Zeb Khan PMAS-AAur
30. Analysis of Precipitation Data
INTENSITY OF Precipitation.
The rate of occurrence of precipitation is called INTENSITY OF
Precipitation. To find out intensity of a certain interval the points
on graph of accumulative precipitation Vs Time are chosen in such
a way that we get maximum difference for the given interval.
DEPTH – AREA RELATIONSHIPS.
The distribution of rainfall is usually not uniform over the area. The
precipitation is maximum at the centre of storm and decreases as
we move away from the centre of the storm. For rainfall of a
given duration, the average depth decreases with the area in an
exponential manner.
by Engr REhan Zeb Khan PMAS-AAur
31. Analysis of Precipitation Data
MASS CURVE
Precipitation recorded by a wing type and float type
recording rain gauge is in form of graph. It is a plot of
cummulative precipitation against time in
chronological order this is called mass curve of rainfall
data. Intensity of rainfall for a certain duration is
determined by the graph.
by Engr REhan Zeb Khan PMAS-AAur
32. Analysis of Precipitation Data
Mass curve of rainfall
0
10
20
30
40
50
60
0 20 40 60 80 100 120
Time, hour
accumulatedprecipitation,mm
by Engr REhan Zeb Khan PMAS-AAur
1st storm,
16 mm
2nd storm,
16 mm
33. Analysis of Precipitation Data
DEPTH – AREA – DURATION CURVES
Analysis of both the time and areal distribution of a
storm is required in many hydrological studies. Depth
area duration curves provide requisite information for
such studies. It is necessary to have information on the
maximum amount of precipitation of various durations
occurring over various sizes of areas. The development of
relationship between maximum depth area duration for a
region is called (DAD) analysis.
WHILE,
EUD is found by dividing cumulative volume by
cumulative area .
by Engr REhan Zeb Khan PMAS-AAur
34. Analysis of Precipitation Data
DEPTH – AREA – DURATION CURVES
by Engr REhan Zeb Khan PMAS-AAur
0
2
4
6
8
10
12
14
0 1 2 3 4 5 6
EUD
CUMM. AREA (X100 Km2)
DEPTH – AREA – DURATION CURVES
35. IMPORTANT POINTS
Precipitation is any product of the condensation
of atmospheric water vapour that falls under gravity.
Drizzle is a light liquid precipitation consisting of
liquid water drops smaller than those of rain
Rain is the form of precipitation in which the size of drops is
more then 0.5mm
Glaze is the ice coating formed on drizzle or rain drops when it
comes in contact with cold surface
Sleet is the frozen rain drops cooled to the ice stage while falling
through air at subfreezing temperature
Snow is precipitation in the form of ice crystals resulting from
sublimation
A snow flake is made up of a number of ice crystals fused
togather.
Hail is the precipitation in the form of small balls or lumps
by Engr REhan Zeb Khan PMAS-AAur
36. IMPORTANT POINTS
Cooling Lowers the capacity of a given volume of air to hold a
certain amount of water vapour.
Condensation of water into cloud droplets takes place on
hygroscopic nuclei which are small particles having an affinity
for water.
Growth of droplets is required if the liquid water present in
the cloud is to reach the ground.
Heavy Rainfall amount over a river basin exceeds by far the
amount of the water vapor at atmospheric volume vertically.
Convectional precipitation results from the heating of the
earth's surface. The warm ground heats the air over it.
Orographic precipitation results when warm moistair moving
across the ocean is forced to rise by large mountains
Cyclonic precipitation results when the leading edge of a
warm, moist air mass (warm front) meets a cool and dry air
mass (cold front)
by Engr REhan Zeb Khan PMAS-AAur
37. IMPORTANT POINTS
The amount of precipitation means the vertical height of water that wuld
accumulate on a level surface
Amount of precipitation per unit time is called the intensity or Rate of
Precipitation.
Non-recording rain gauges are commonly used. They do not record the
data and collect only rain
Float recording gauges
Weighing type gauges
Tipping Bucket Type
Point precipitation data refers to precipitation of a station. This data
could be form of hourly record, daily record, monthly precipitation or
annually precipitation.
Analysis of both the time and areal distribution of a storm is required in
many hydrological studies. Depth area duration curves provide requisite
information for such studies.
by Engr REhan Zeb Khan PMAS-AAur