Remote Sensing for Meteorology

1. DEPARTMENT OF GEOGRAPHY
SOUTH EASTERN UNIVERSITY OF SRILANKA.

2.  What is Remote sensing
 Field of Application
 What is meteorology
 Why Meteorological Satellites?
 Types of Weather Satellite Images
 Meteorological Satellites
 Weather Radars
 Advantages of Satellite weather forecasting
 Disadvantages of Satellite weather forecasting

3.  “It is the art, science and technology of
obtaining reliable information about
physical objects and the environment,
through the process of recording,
measuring and interpreting imagery and
digital representations of energy patterns
derived from non contact sensor systems”
(Coldwell, 1997)

4. Passive RS
systems
Active RS
systems
• Energy source: Passive/Active
• Atmosphere
• Target
• Recording devices
• Transmission/reception/processing
• Interpretation
• Application
Receiving stations
Final product
Application
Interpretation

6.  Meteorology is the science that studies atmospheric phenomena,
especially those that relate to weather.
 Meteorologists who forecast the weather rely on thousands of weather
stations located around the world, both on land and at sea.
 At each station, measurements are taken of such things as air pressure
and temperature, wind speed, cloud cover, and precipitation.
 Meteorological satellites can be used to keep track of weather systems
days before they come close to an area.
 This is particularly useful in monitoring severe weather systems like
tropical cyclones.
 The very basic application of meteorological satellite is in identification
of clouds.

7.  Clouds can be broadly classified into three categories according to the
cloud base height, namely, low, medium and high clouds. Some clouds,
such as cumulonimbus (a type of thundery clouds), span the three layers.
 Sensors onboard meteorological satellites are pointing towards the
ground, enabling them to have bird eye view of the globe from the space.
 There are two types of meteorological satellites characterized by their
orbits.
 They are geostationary satellites and polar-orbiting satellites. As the
name suggests, a geostationary satellite is stationary relative to the
earth.
 That is, it moves above the equator at the same rate as the earth's
rotation so that all the time it is above the same geographical area on the
earth.

8.  In this manner, it is capable of taking cloud images of the same
area continuously, 24 hours a day.
 As it is some 35,800 kilometers from the earth, it is capable of
taking cloud pictures covering part of the whole globe.
 These satellites together provide full coverage of the earth.
 Polar-orbiting satellites are low-flying satellites circling the
earth in a nearly north-south orbit, at several hundred
kilometers above the earth.
 Most of them pass over the same place a couple of times a day.

9.  Satellite data have considerably improved
weather prediction, in part because of the
information they provide over data-sparse
areas.
 This includes the oceans, which cover almost
three-quarters of the earth's surface and
most of the Southern Hemisphere.

10.  Environmental satellites provide data in several different formats.
 The most commonly used channels on weather satellites used are
the visible, infrared, and water vapor satellites.
 Visible (~0.6 μm) ,Infrared or IR (10 to 12 μm), Water vapor (6.5 to
6.7 μm)
 Each of these channels on the satellite sensors is sensitive to
energy (electromagnetic energy) at a particular range of
frequencies, therefore each type provides a different view of the
Earth, its atmosphere, and its oceans.
 Researchers rely on all three types of data, and often use them
together to better understand the interactions between the
atmosphere, oceans, and the Earth's surface.

12.  Radar is a ground-based and active remote sensing
equipment.
 It emits microwave radiation from a fixed location
into the atmosphere and receives the reflected
radiation called echoes from water droplets in the
air.
 Microwave is not intense in the solar radiation and
the earth's emission spectrum.
 Therefore the background radiation level in the
microwave frequencies is not high and it usually
does not affect the operation of the radar.

13.  Microwave frequencies can be divided into a
number of frequency bands.
 Many weather radars operate in the S and C
bands.
 While weather radar can measure the distance of
rain areas, there is a limit to the effective range
of detection of weather radar.
 The reason is as follows: weather radar transmits
a pulse of microwave and waits for the pulse to
return to determine the distance to a rain area.

14. We can get the weather information accurately
for using weather satellite.
 we can observation the atmosphere conditions
in every second..
 When we get bad weather .. That time also we
can get the weather information in reliability
and accurately.
 Uneducated People also know about the
weather information through the
communication..(Television and Radio)

15.  It is high Expensive.
 It is depend in trained People.