Environmental Engineering Reference
In-Depth Information
Table 3.1
Salient features of IRS-P4
Payloads
Ocean colour monitor
Swath 1,420 km
Field of view 360 m
Spectral bands 8 (from 400 to 885 nm)
Multifrequency scanning microwave radiometer
Frequency
features. Data can be used for coastal zone
management and erosion prevention.
Ocean applications: monitor ocean circulation
and current systems, measure ocean tempera-
ture and wave heights and track sea ice. Data
can be used to understand the health of ocean
water and manage marine biodiversity.
Hazard assessment:
track hurricanes, earth-
6.6, 10.65, 18 and 21 GHz
quakes, erosion and
ooding. Data can be used
to assess the impacts of a natural disaster and
create preparedness strategies to be used
before and after a hazardous event.
fl
Swath
1,360 km
Table 3.2
Scanner specication of IRS-P4
Salient features
Orbit
Natural resource management: monitor land
use, map wetlands and wildlife habitats. Data
can be used to minimize the damage that urban
growth has on the environment and help for-
mulate policies to conserve natural resources.
For understanding the basics of remote sens-
ing and its working, few terminologies are
essential to understand, which are discussed here
in brief.
Polar sun-synchronous circular
Altitude
720 km
Inclination
98.28
°
Period
99.31 min
Local time of
equator crossing
12 noon
Repetitivity cycle
2 days
Size
2.8 m
×
1.98 m
×
2.57 m
Mass at lift-off
1,050 kg
Length when
fully deployed
11.67 m
3.1.1 Electromagnetic Energy
Altitude and orbit
control
Three-axis body-stabilized using
reaction wheels, magnetic
torquers and hydrazine thrusters
The EM spectrum is the continuous range of EM
radiation, extending from gamma rays (highest
frequency and shortest wavelength) to radio
waves (lowest frequency and longest wave-
length) and including visible light. The EM
spectrum can be divided into seven different
regions such as gamma rays, X-rays, ultraviolet,
visible light, infrared, microwaves and radio
waves (Fig.
3.1
).
Remote sensing involves the measurement of
energy in many parts of the EM spectrum. The
major regions of interest in satellite sensing are
visible light, re
9.6 m
2
solar array generating
750 W; two 21 Ah Ni
-
Cd
batteries
Power
Mission life
5 years
NOAA AVHRR
5 spectral bands 1.1 km spatial
resolution
1-day repeat cycle
Landsat TM
7 spectral bands 30 m spatial resolution 16-day
repeat cycle
ected and emitted infrared and
the microwave regions. The measurement of this
radiation takes place in what are known as
spectral bands.
fl
MODIS
Multi-spectral bands 250
1,000 m spatial res-
olution (band dependent) 1-day repeat cycle
-
IKONOS
4 spectral bands 4 m spatial resolution 5-day
repeat cycle.
Remote sensing has a wide range of applica-
tions in many different
3.1.2 Spectral Band
elds:
A spectral band is de
ned as a discrete interval of
the EM spectrum. For example, the wavelength
range of 0.4
Coastal applications: monitor shoreline chan-
ges, track sediment transport and map coastal
-
0.5
μ
m(
μ
m = micrometers or
