This slide was prepared for the course Applications of GIS and RS for water resources in Mekelle University, Institute of Geo-information and earth observation Science(I-GEOS) by Mr. Esayas Meresa.

1. Mekelle University
Institute of Geo-information and Earth Observation Sciences(I-
GEOS)
Department of GEOS – NRM
Course: RS and GIS Applications for Water Resources
Title: Remote Sensing of Aerosols Parameters, Water Vapor Parameters
and Cloud Parameters
Prepared by: Esayas Meresa
Id-Pr-001/08
Submitted to Dr. Govindu V.
Academic year – 2008e.c.
Mekelle, Tigray, Ethiopia

2.  Presentation Outline
 Applications of GIS and RS for Water resources
 Remote Sensing of Aerosols Parameters
 Water Vapor Parameters
 Cloud Parameters

3.  Applications of GIS and RS for Water resources
 Our water supply is finite. From areas of abundance to places struck with
drought, ensuring access to a clean, reliable source of water is critical. With
Esri technology, you can protect water supplies and their integrity by
understanding how human behaviors impact the natural system.
 Document water sources and quantify their capacity based on current and
historic data. Then share the story of the water system through engaging
maps so everyone can see how today’s actions affect tomorrow’s water
system.
 Accurate, adequate and contemporary information on the state of water
resources is must for planning & water resources management strategy .
Increasing public awareness elevates the importance of water information &
enlighten public involvement in water management / decisions.
 Satellite Remote Sensing & GPS for temporal, multi - scale information
generation at country level Geographic information system (GIS) is an
effective tool for storing, managing, analyzing , displaying and dissemination
of spatial data. Some RS and GIS applications in H2O resources:
 Basin – wise water resources assessment • Groundwater Budgeting •
Development of Decision support systems for WR Management • Flood
forecasting and flood inundation modeling • Real time Irrigation
management.

4.  To address challenges in water sector the ultimate
requirement is an information system having four elements:
(1) data input / collection system
(2) data storage, analysis, and transformation into "user-friendly“ information
(3) interactive system to geo - visualization & for decision making
(4) information dissemination system in public domain
 RS and GIS is a good tool for planning and management of water
resources.
 Remote sensing and GIS specifically in monitoring water quality
parameter such as suspended matter, phytoplankton, turbidity, and
dissolved organic matter.
 Potential application and management is identified in promoting concept
of sustainable water resource management.
 The integration of remote sensing and GIS techniques has enabled
assessments of NPS pollution, aquatic vegetation growth, salt marsh quality
and floodplain disturbances over time.
 Modeling water resources amount for the future…..etc.

5.  Remote Sensing of Aerosols Parameters
 What are Aerosols:
 Aerosols are bright particles that reflect Sunlight back to space reducing the amount of
solar radiation that can be absorbed by the surface below (Kahn, 1999). The magnitude
of this effect depends on the size and composition of the aerosols, and in the reflecting
properties of the underlying surface.
 Aerosol particles may be solid or liquid and range in size from 0.01 micrometers to
several tens of micrometers. Cigarette smoke particles are in the middle of this size
range ; typical cloud drops are 10 or more micrometers in diameter.
 Aerosol particles scatter and absorb radiation, and thus modify the radiation in the
atmosphere. Satellite sensors measure the TOA radiance, which is a
reflected by the aerosol optical properties. Passive satellite remote sensing analyzes the
TOA radiance to extract the aerosol optical properties. Clouds will have a very large
impact on the TOA radiance. Aerosol retrieval is not possible when clouds are present.
 To model and understand the forces modifying the Earth’s global climate system (Kahn,
1999)= NASA Earth Science Enterprise scientists:
 The amount and type of atmospheric particles (aerosols), including those formed by
nature and by human activities.
 The amount, type, and height of clouds; and
 The distribution of land-surface cover, including vegetation canopy structure.

6.  Remote Sensing for Aerosols Parameters
 The aerosol particles are characterized by their shape, size, chemical
composition, and total concentration, which in turn determine the aerosol
optical properties. The typical range for the aerosol optical depth, the single
scattering albedo, and the scattering coefficient, direction of the scattered
light.
 Remote sensing aerosols, clouds, and aerosol–cloud interactions is a hot
topic of modern atmospheric remote sensing studies. Both aerosols and
clouds influence climate and weather.
 Optical and thermal infrared remote sensing of aerosols and clouds is a
mature research field with a long history. Great progress has been achieved
(especially in the last 40 years) using both ground-based and satellite
instrumentation. The main parameters of interest are aerosol/cloud optical
and microphysical properties, concentration, and aerosol/cloud geometrical
characteristics (e.g., the altitudes, thickness and spatial extent).


7.  Satellite sensors for Aerosol retrieval

8.  Water Vapor Parameters
 It is well established that water vapor from the environment can be
absorbed into the bulk structure of amorphous solids of pharmaceutical
interest, such as drugs, sugars, polymers, and proteins, in addition to being
adsorbed on the surface. The amount of water taken up depends on
environmental conditions, such as relative humidity and temperature, as
well as the relative polarity of the solid A fundamental understanding of the
mechanisms giving rise to various types of isotherms can therefore be
helpful in understanding the effects sorbed water might have on the
physical and chemical properties of such solids.
 Water vapor is essential for precipitation. It is possible to detect and map
water vapor by sensing in water vapor absorption bands. Several
wavelengths can be used, but the most common is centered around 6.7µm.


9.  METEOSAT 1, lunched in 1978 by the European Space Agency, was the
first geostationary satellite to obtain images of mid to upper troposphere
water vapor in the 6.7µm region in addition to visible and 10 – 12 µm
infrared images (Kidder and Vander Haar, 1995).
 Geostationary Operational Environmental Satellite (GOES) sensor
routinely provide water vapor images obtained in the 6.7µm region. At this
wavelength, most of the radiation sensed by the satellite comes from the
atmospheric layer between 300 and 600 km, i.e., from the middle layers of
the troposphere.
 MODIS has several bands that are sensitive to atmospheric water vapor,
including band 17(890-920 nm), 18 (931-941 nm), and 19 (915-965 nm).


10.  Cloud Parameters
 Clouds play an important role in terrestrial atmospheric dynamics,
thermodynamics, chemistry, and radiative transfer and are key elements of the
water and energy cycles. Cloud properties can be modified by anthropogenic
and natural gaseous and aerosol emissions (i.e. aerosol indirect effect) and are
important for understanding climate change. Therefore, it is of a great
importance to understand cloud characteristics and their distributions on a
global scale. This can only be achieved using
satellite observations.
 On average, about 70% of the Earth’s surface is covered by clouds. cloud
fraction is a very important parameter, e.g. for the climate studies and also
for the retrievals of the vertical columns of trace gases using space-borne
instrumentation.
 A cloud may warm or cool the Earth, depending upon its thickness and height
above the surface. Low, thick clouds reflect incoming solar radiation back to
space, which cause cooling.
 High clouds trap outgoing infrared radiation and produce greenhouse
warming. Because cloud type, height, moisture content, and location are so
variable, their effect on global climate is very difficult to measure.

11.  Clouds in Visible Imagery:
 The first meteorological satellite only measured visible energy reflected
clouds (0.4-0.7µm).
 New GOES sensors provide data in both the visible and thermal infrared
portion of the spectrum.
 In the daylight hours, visible imagery provides detailed views of the cloud
patterns that closely match our visual sense, i.e., clouds usually appear
bright while land and water appear darker on the images.
 GOES was first lunched on October 16,1975. Since that time many new
GOES satellites have been parked at 35,790km in geostationary orbit to
obtain visible and infrared imagery.
 Visible imagery can only be obtained during the daytime. However,
a light – sensitive instrument onboard the Defense Meteorological
Satellite Program (DMSP) can obtain visible images at night. This is
done by recording the features illuminated at night by moonlight.

12.  The EOS Terra MISR collects stereoscopic cloud information by viewing each
cloud from nine angles previously discussed. The stereoscopic data can be
analyzed to yield three dimensional quantitative information about cloud
height, structure, thickness, shape, and roughness of cloud tops. Accurate
albedo information can also be computed.
 In general, clouds do not reflect solar radiation equally well in all directions.
Therefore, a single measurement of reflectivity from a single direction (e.g. at
nadir) makes it difficult to determine the total amount of light reflected by the
cloud (its albedo) relative to the incident energy.
 The main cloud products derived from passive optical satellite observations are:
 Cloud cover,
 Cloud thermodynamic phase,
 Cloud optical thickness,
 Cloud droplet/crystal effective radius,
 Cloud liquid/ice water path, and
 Cloud top properties (temperature, pressure/height).

13.  Clouds in thermal Infrared:
 The most common thermal infrared band used in meteorological investigations is
10–12.5µm. The atmosphere is relatively transparent to this wavelength energy
upwelling from the Earth surface and clouds. Also, thermal infrared images can be
obtained at night, so we can have a continuous 24-hour record events taking place
at night.
 Cloud-height information extracted from thermal infrared data can be used to
generate pseudo three dimensional oblique images of major storm events.
 It has been known for some time that is possible to extract information on the type
of clouds and their height using multispectral remote sensing. Visible and infrared
data can be used to differentiate between the sea, land, cumuliform clouds,
semitransparent high clouds, and convective clouds (like thunderstorms). Tall
convective cumulonimbus clouds are clod and bright. The sea and land surface are
warm and dark. The analyst extracts the pixel value in the visible and thermal
infrared bands, locates it in the diagram, and identifies the nature of the cloud under
investigation.
 The TRMM Visible Infrared Scanner (VIRS) lunched in 1997 provides high
resolution information on cloud cover age, type, and cloud top temperature using a
five channel cross track scanning radiometer.

14.  The Terra MISR (Multi-angle Imaging Spector Radiometer) sensor
collects information in only the visible and near-infrared portions of the
spectrum, while the terra Clouds and Earth’s Radiant Energy System
(CERES) sensor collects data from just one look angle, but across the entire
solar spectrum.
 CERES measures both solar reflected and Earth emitted radiation from the
top of the atmosphere to the surface. It also determine cloud properties
including amount, height, thickness, and particle size.
 Thus, the VIRS, MISR, and CERES instruments complement one another
in the collection of cloud information. Moderate Resolution Imaging
Spector radiometer (MODIS) obtain cloud top information from bands 33-
36 in the thermal infrared region from 13.185-14.385µm.