remote sensing of land surface temperature

Remote sensing of land surface temperature

Lecture 8

Thermal infrared of EM spectrum

0.7 m

3.0 m

100 m

All objects have a temperature above absolute zero (0 K) emit EM energy (in 3.0-100 µm). Human being has normal

98.6 ºF (37 ºC) Our eyes are only sensitive to

visible energy (0.4-0.7 µm). Human sense thermal energy through touch. while detectors (sensors) are sensitive to all EM spectrum.

All objects (vegetation, soil, rock, water, concrete, etc) selectively absorb solar short-wavelength energy and radiate thermal infrared energy.

Details about thermal remote sensing refers to another lectureFor this lecture and lab, we focus on MODIS LST processing and application

Brightness temperature, and physical (surface) temperature

Through radiance recorded by a remote sensor, if we use the Planck equation, we can get a temperature, which we call brightness temperature Tb, which is less than the real physical (or surface) temperature T.

)1(2),(

)1(2),( )/5

2

)/5

2

kThckThcb e

hcTBe

hcTLb

)1ln( / bTkhcekhcT

h, Planck’s constant =6.626 x 10-34 Ws2

T, Kelvin (K)c, 3 x 108 m/sk, Boltzmann’s constant=1.38 x 10-23 Ws/K

L or B, radiance (Wm-2μm-1)c1=2πhc2=3.74 x 10-16 Wm2

c2=ch/k=0.0144 mK

MODIS land surface temperature and emissivity product led by Dr. Wan

http://www.icess.ucsb.edu/modis/modis-lst.html

Wan et al. 2002

The accuracy of temperature is better than 1 K, Wan (2008)

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)

X Profile Y Profile NW-SE NE-SW

Xie and Ytuarte, 2005

Urban Heat Island of San Antonio downtown area detected by MODIS temperature product1:30 am, July 15, 2004

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Black areas are no date, due to cloud cover. So this image should not use

The Delaunay triangulation method is available under ENVI, at Topographic/Replace Bad Values

David Prado thesis, 2010

Source: Jeff Dozier

Active fire detection:MODIS fire and thermal anomalies products

Image caption: Fires in the Bahamas, Florida and Cuba (03 April 2004, 18:30 UTC) identified using MODIS Aqua and outlined in red on the MODIS 1km corrected reflectance product

http://modis-fire.gsfc.nasa.gov/index.asp