thermal remote sensing

2. AIM
TO ACQUINT THE CLASS WITH CONCEPTS
OF THERMAL REMOTE SENSING

3. CONTENTS
INTRODUCTION
PRINCIPLES OF THERMAL REMOTE SENSING
THERMAL SENSORS
APPLICATIONS

4. INTRODUCTION

5. REMOTE SENSING
Remote sensing is an art and science of
acquiring info about an object of interest
without coming in physical contact with it.

6. THERMAL REMOTE SENSING
Thermal remote sensing is based on the
measuring of EM radiation in the infrared
region of spectrum.
Most commonly used intervals are 3-5
micro-meter and 8-14 micro-meter

7. Thermal IR and atmospheric window
Landsat 7
Band 7
Landsat 7
Band 6
Global Warming!
Thermal energy emitted from the Earth is trapped by CO2, H2O, and O3.

8. CERES—Cloud-Earth Radiant
Energy System

9. PRINCIPLES OF
THERMAL REMOTE
SENSING

10. Electromagnetic Radiance (EMR)
EMR – Energy emitted by the objects of
which absolute temperature is above zero.
The magnitude and spectral range of the
emitted EMR are governed by the
material’s:
Temperature, and
Emissivity

11. Review of Radiation Laws
All objects at temperature above absolute 0oK emit (273.59oC, -459.67oF)
Stefan-Boltzmann law: W = T4
W-total emitted radiation
-a constant,
T-temperature in oK
The total emitted radiation from a blackbody is
proportional to the fourth power of its absolute
temperature

12. Radiation Laws
► Wien's displacement law: = 2,897.8/T
-peak wavelength, T-temperature in oK
► As temperature of objects increases, the
wavelength of peak emittance becomes shorter

14. Radiation Laws
► Emissivity: e = M/Mb
e-emissivity
M-emittance of a given object
Mb-emittance of blackbody
e = 1 (blackbody)
e = 0 (whitebody, perfect reflector)
► The ratio between the emittance of a given
object and that of blackbody at the same
temperature

15. Emissivity of Common Materials
Clear water 0.98-0.99
Wet snow 0.98-0.99
Human skin 0.97-0.99
Rough ice 0.97-0.98
Vegetation 0.96-0.99
Wet soil
0.95-0.98
Asphalt concrete 0.94-0.97
Brick
0.93-0.94
Wood
0.93-0.94
Basalt rock 0.92-0.96
Dry mineral soil 0.92-0.94
paint
0.90-0.96
Dry vegetation 0.88-0.94
Dry snow
0.85-0.90
Granite rock 0.83-0.87
Glass
0.77-0.81
Sheet iron (rusted) 0.63-0.70
Polished metals 0.16-0.21
Aluminum foil 0.03-0.07
Highly polished gold 0.02-0.03

16. Water, Ice and Snow
Water, ice, and snow generally have a high emissivity, 0.94 to 0.99, across
the thermal infrared region.
Snow is unusual in that it has a high reflectance in the solar (visible)
region where most of the downwelling energy is during the day, and a
very high emissivity in the thermal region.
Water
Ice
Snow

17. Soil and Minerals
Soil, rocks, and Minerals show strong spectral
features between 8 and 10 microns that depend on
the grain size.
Soil signature in the 3 to 5μm region depends on the
water and organic content. The dryer, purer soils
have lower emissivities in this region.

18. Vegetation
Green vegetation typically has a very high emissivity because
it contains water.
Senescent (dry) vegetation has a more variable emissivity,
especially in the 3 to 5μm region, which depends on the type
and structure of the cover type, the dryness, etc.

19. Man-made material
Manmade materials such as polished metals have among
the lowest emissivity values, can be made less than 0.01
(better than 99% reflecting).
“Rocky” materials such as asphalt and brick are high and
range from 0.90 to 0.98

20. (Wikipedia – Infrared)

21. Thermal sensors

22. THERMAL SENSORS
TIROS (Television IR Operational Satellite), launched in 1960
GOES (Geostationary Operational Environmental Satellite), TIR
at 8km spatial resolution, full-disk of Earth, day and night
HCMM (Heat Capacity Mapping Mission), launched in 1978600m spatial resolution, 10.5 – 12.6 micron range
CZCS (Coastal Zone Color Scanner) on Nimbus 7, launched in
1978, for SST (sea surface temperature).
AVHRR (Advanced Very High Resolution Radiometer), 1.1 and 4
km TIR bands
TIMS (Thermal Infrared Multispectral Scanner), Airborne, 6
bands
ATLAS (Airborne Terrestrial Applications Sensor), 15 bands
Landsat 4,5,7; Band 6- 10.4 – 12.5 m, 120 m (4,5), 60 m (7).
ASTER (Advanced Spaceborne Thermal Emission and Reflection
Radiometer) on Terra, 5 bands 8.125-11.65 micron range (14
total)

23. Applications

24. Application Areas
Surface temperature detection
Camouflage detection
Fire detection and fire risk mapping
Evapotranspiration and drought monitoring
Estimating air temperature
Oil spill monitoring
Water quality monitoring
Volcanic activity monitoring
Urban heat island analysis

25. Mars Hematite
detected by TES

26. Typical IR imagery of Heat Loss in Residential Structures
43.0°F
40
35
Furnace
Vent
Vent
Duct
30
25
24.0°F

27. Energy Gain (Floor Leak)
Missing Insulation in
Vaulted Ceiling Area
Heat Loss
Moisture
Heat Loss

28. Typical Institutional Building Heat Loss
46.6°
50.9°F
50
48
46
44
42
40
38
37.7°F
Typical
Air Leak
Patterns
37.3°
5

29. *>64.4°F
60.0
55.0
50.0
45.0
Air Leakage
from noninsulated areas
and window
frames.

30. Processing thermal images
Major issues
Moisture absorption in atmosphere
Mixed ground objects
Some visualization techniques
False color composite
Level slicing

31. Sea-surface temperature, June 22,
2000

32. Ocean surface temperature from MODIS
47

33. QUESTIONS PLEASE !!

34. Thank You

35. Thank You