The document provides an overview of thermal remote sensing. It discusses key concepts like the thermal infrared spectrum, atmospheric windows and absorption bands, fundamental radiation laws, thermal data acquisition using sensors, and applications in mapping forest fires, urban heat islands, volcanoes, and military purposes. Thermal remote sensing allows measuring the true temperature of objects and detecting features not visible in optical remote sensing. It has advantages like temperature measurement but maintaining sensors at low temperatures can be challenging.

1. Remote Sensing II (SSC-604)
Presented to: Mr. Shahid Pervaiz
Presented by: Mr. Farhan Mustafa, Rahat Tufail, Fatima Tanveer, Fatima Mushtaq
Department of Space Science, University of the Punjab, Lahore

2. Contents:
 Introduction
 Atmospheric Window & Absorption Band
 Fundamental Radiation Laws
 Atmospheric Effects
 Thermal Data Acquisition
 Applications
 Advantages & Disadvantages

3. Thermal Remote Sensing:
 Thermal Infrared Radiation refers to electromagnetic waves with a wavelength
of between 3 to 20 micrometers.
 Most remote sensing applications make use of 3-5 & 8-14 micrometer range.
(Due to absorption bands)
 The main difference between the thermal infrared and near infrared is that
thermal infrared is emitted energy and near infrared is reflected energy similar
to light.

4. Optical Remote Sensing:
 Examine abilities of objects to reflect the solar radiations. (Visible & Near IR)
Emissive Remote Sensing:
 Examine abilities of objects to absorb shortwave visible & near-IR radiations
and then to emit this energy at longer wavelengths. (Mid-IR & Microwave)

5. Thermal Infrared Spectrum:
Thermal IR
 Near IR: 0.7-1.3 μm
 Mid IR: 1.3 – 3.0 μm
 Thermal IR: 3 – 14 μm

6. Atmospheric Window & Absorption Bands:

7. Atmospheric Effects:
 The atmospheric intervention between the thermal sensor and the ground can
modify the apparent level of radiations coming from ground depending on
degree of atmospheric absorption, scattering and emission.
 Atmospheric absorption & scattering make the signal appear colder and
atmospheric emission make the object to be detected as warmer.
 There are some factors on which both of these effects depend upon given by:
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8.  Atmospheric path length
 Meteorological conditions
 Site
 Altitude
 Local weather condition

9. Atmospheric Effects:
Sun
Incident
Absorbed
Transmitted
Reflected
target radiance
Emitted
path radiance
Emitted
target radiance
Reflected
path radiance

10. Fundamental Radiation Laws:
The following laws are obeyed in this phenomenon:
 Planck’ Radiation (Blackbody Law)
 Wein’s Displacement Law
 Stefan-Boltzman Law

11. Planck’s Radiation Law:
 Blackbody: A hypothetical body that completely absorbs all radiant energy
falling upon it, reaches some equilibrium temperature, and then reemits that
energy as quickly as it absorbs it.
 Planck explained the spectral-energy distribution of radiation emitted by a
blackbody.
 For a blackbody at temperatures up to several hundred degrees, the majority
of the radiation is in the infrared radiation region.

12. Stefan Boltzman Law:
 Stefan Boltzman Law gives the energy of a blackbody.
 The area under the Planck’s curve represents
the total energy emitted by an object at a
given temperature.
 “The amount of energy emitted from an
object is primarily a function of its
temperature”.
E = σT4

13. Wein’s Displacement Law:
 Wein calculated relationship b/w true temperature of blackcody (T) in degree
kelvins and its peak spectral extiance or dominant wavelength (λmax).
λmax = k/T and k=2898 μm k
How Wein’s Displacement Law is applicable in
Thermal Remote Sensing ?

14. Emissivity:
 The is no blackbody in nature.
 All natural objects are gray-bodies, they emit a fraction of their maximum
possible blackbody radiation at given temperature.
 Emissivity is the ratio b/w actual radiance emitted by a real world selected
radiating body (Mr) and a blackbody at the same thermodynamic temperature
(Mb)
ε = Mr/Mb
 If the emissivity of an object varies with wavelength, the object is said to be a
selective radiant. Continue

15.  A graybody has ε<1 but is constant at all wavelengths.
 A selectively radiating bodies have emissivity ranging 0 ≤ 1.
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16.  Emissivity depends upon the following factors:
• Color
• Surface Roughness
• Moisture Content
• Compaction
• Field of View
• Viewing Angle

17. Thermal Image Acquisition:
 Many multispectral
(MSS) systems sense
radiations in the thermal
infrared as well as the
visible and reflected
infrared portions of the
spectrum.

18. Thermal Sensors:
 Thermal sensors use photo detectors sensitive to the direct contact of photons
on their surface, to detect emitted thermal radiation.
 The detectors are cooled to temperatures close to absolute zero in order to
limit their own thermal emissions.
 Thermal sensors essentially measure the surface temperature and thermal
properties of targets.
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19.  Thermal infrared remote sensor data
may be collected by:
• Across Track Thermal
Scanning
• Push broom linear area array
charged couple devices
(CCD) detectors

20. Across Track Thermal Scanner:

21. Characteristics of Photon Detectors in Common
Use
Type Abbreviation Useful Spectral
Range (um)
Mercury-doped
germanium
Ge:Hg 3-14
Indium antimonide InSb 3-5
Mercury cadmium telluride HgCdTe 8-14

22. Thermal IR Remote Sensing Based on
Multispectral Scanners:
 Daedalus DS-1268
Incorporates the Landsat Thematic
Mapper mid -IR(1.55-1.75)um and
(2.08-2.35) um.
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23.  DS-1260
records data in 10 bands including a
thermal infrared channel(8.5-13.5um).
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24.  Thermal infrared
Multispectral Scanner
(TIMS) which has six
bands ranging from (8.2-
12.2um)
 NASA ATLAS Has six
visible and near infrared
bands from (8.2-12.2um)
Continue

25. LANDSAT THERMAL
INFRARED
SENSOR(TIRS)

26. The Thermal Infrared Sensor (TIRS):
 The Thermal Infrared Sensor (TIRS) will measure land surface temperature in two
thermal bands with a new technology that applies quantum physics to detect heat.
 TIRS was added to the satellite mission when it became clear that state water
resource managers rely on the highly accurate measurements of Earth’s thermal
energy.
 TIRS uses Quantum Well Infrared Photo detectors (QWIPs) to detect long
wavelengths of light emitted by the Earth whose intensity depends on surface
temperature.
 The QWIPs TIRS uses are sensitive to two thermal infrared wavelength bands,
helping it separate the temperature of the Earth’s surface from that of the
atmosphere. Their design operates on the complex principles of quantum
mechanics.

27. TIRS Design:
 TIRS is a push broom sensor
employing a focal plane with long
arrays of photosensitive detectors.
 A refractive telescope focuses an
f/1.64 beam of thermal radiation
onto a cryogenically cooled focal
plane while providing a 15-degree
field-of-view matching the 185 km
across-track swath of the OLI.

28. TIRS Design:
 TIRS is a push broom sensor
employing a focal plane with long
arrays of photosensitive detectors.
 A refractive telescope focuses an
f/1.64 beam of thermal radiation
onto a cryogenically cooled focal
plane while providing a 15-degree
field-of-view matching the 185 km
across-track swath of the OLI.

29.  The focal plane holds three
modules with quantum-well-
infrared-photo-detector (QWIP)
arrays arranged in an alternating
pattern along the focal plane
centerline.

30.  A mechanical, two-stage cry-
cooler will cool the focal plane to
permit the QWIP detectors to
function at a required
temperature of 43 K.

32. Applications of Thermal Remote Sensing:
I. Forest Fires
II. Urban Heat Island (UHI)
III. Active Volcanoes
IV. Military Purposes

33. Thermal Remote Sensing Of Forest Fires:

34. Causes:
 Rising global temperature might cause forest fires
to occur on large scale, an more regularly.
 The emissions of greenhouse gases (GHGs) and
aerosols from fires are important climate forcing
factors, contributing on average between 25-35%
of total CO2 emissions to the atmosphere, as well
as CO, methane and aerosols.
 Detection of active fires provides an indicator of
seasonal, regional and interannual variability in fire
frequency and shifts in geographic location and
timing of fire events.

35. Why we use Thermal Remote Sensing in
forest fires?

36. NASA's Ikhana Unmanned Research Aircraft Recorded Image of Fire Near Lake
in Southern California:
 The 3-D processed image is a colorized
mosaic of images draped over terrain,
looking east.
 Active fire is seen in yellow, while hot,
previously burned areas are in shades
of dark red and purple.
 Unburned areas are shown in green
hues.

37. Aster Image Of Wildfire in Northeast of Durango, Colorado:

38. Study area of Rujigou Coal Field:
 (a) shows the location and direction of
study area in Northwest China.
 (b) shows the Rujigou Coal Field
located in the Rujigou district, in
Shizuishan city.
 (c) is a 3-D FCC (False Color
Composite) image (generated by
coding ETM+6/4/2 in R/G/B) based on
Landsat ETM+ data.

39. Landsat 8 Images of California:
In NIR & MIR In TIR

40. Current Event:

41. Aster Image of Sulfur Plant Industry (Iraq):
Disaster in Iraq

42. Deschutes National Forest:
False Color Composite Thermal Image

43. September 11, 2001 (9/11):
 Through data one can make and send
emergency responders a thermal image
showing firefighters where fires were still
burning deep in the debris. In some areas,
temperatures were over 1300°F.
 The USGS team provided this information to
emergency response agencies on September
18, 2001.
 Another flyover on September 23 revealed
that by that date most of the hot spots had
been eliminated or reduced in intensity.

44. Thermal Remote Sensing of UHI:

45. Urban Heat Island (UHI):

46. Factors Affecting UHI:

47. Why we Thermal Remote
Sensing in urban Areas?

48. Surface UHI Measurements:
 Thermal remote sensing –uses non-contact
instruments that sense longwave or thermal
infrared radiation to estimate surface
temperature.
 Clear weather limitation (for satellites).
 Spatial view of the urban surface.
 Relative temperature measurement –for
comparison between images may require
correction for atmospheric and surface
effects.

49. Canopy Layer Urban Heat Island:

50. Day & Night Thermal Infrared:

51. MEAN AIR TEMPERATURE IN PARIS, FRANCE:

52. Volcanism in Thermal Remote Sensing:

53. Why we need Thermal remote sensing in active
volcanoes ???
 Active volcanoes exhibit many difficulties in being studied by in situ techniques.
 For example, during eruptions, high altitude areas are very hard to be accessed because of volcanic
hazards.
 We use thermal remote sensing techniques in mapping and monitoring the evolution of volcanic
activity.

54. Temperature Of Volcanoes:
 As Wien’s Law:
λmax = k/T where k=2898 μm k
Where T=700 k
So,
λmax =2898/700=4.27 μm
Hence, it’s a thermal infrared range. So we use Thermal remote sensing for active volcanoes.

55. Aster Image:
 Size: 7.5 x 7.5 km
 Orientation: North at top
 Image Data: ASTER bands.

56. Chiliques volcano, Chile:
True Color Image Thermal Image

57. Landsat Image:
 Size: 5km x 5km
 Orientation: North at the top
 Image Data: landsat bands

58. Paluweh volcano:
True Color Image Thermal Image

59. Most Active Volcanoes:
True Color Image Thermal Image

60. Thermal remote sensing in Military:

61. Thermal remote sensing in Military:

63. Advantages & Disadvantages:
Advantages
 We can detect true temperature
of objects.
 Feature cannot be detected by
optical RS may be detected with
Thermal IR.
Disadvantages
 It is pretty difficult to maintain
the sensors at required
temperatures.
 Image interpretation of thermal
image is difficult.

64. References:
 “Remote Sensing of the Environment ” , John. R Jensen, Edition 6th.
 “Remote Sensing and Image Interpretation ” , Thomas M. Lillisand, Ralph W. Kiefer, Jonathan W.
Chipman, Edition 6th.
 www.geog.ucsb.edu/~jeff/.../remote_sensing/thermal/thermalirinfo.html
 www.crisp.nus.edu.sg/~research/tutorial/infrared.htm
 earth.esa.int/landtraining09/D1Lb3_Su_SEBBasics.pdf
 en.wikipedia.org/wiki/Remote_sensing
 en.wikipedia.org/wiki/Thermal_infrared_spectroscopy

65. Thanks 