PLEASE DONOT FORGET SUBSCRIBE MY CHANNEL.
Land surface temperature is a measurement of how hot the land is to the touch.
It differs from air temperature (the temperature given in weather reports) because land heats and cools more quickly than air.
Obtain Landsat data (e.g., Landsat 8) from sources like the USGS Earth Explorer.
Ensure you download the required bands, typically the thermal bands (e.g., Band 10 and Band 11 for Landsat 8).
Step 1. conversion to top of atmosphere (TOA) radiance
Using the radiance rescaling factor, thermal infrared digital numbers can be converted to spectral radiance
Add band 10 to arc map
Lλ=ML+Qcal+AlOi
Lλ =0.000334*Band10+0.100000.29
Where:
Lλ =TOA spectral radiance (watts/ (m2*sr*μm))
ML =Radiance multiplicative Band 10=value=0.0003342
Qcal=quantized and calibrated standard product pixel values (DN)
Al=Radiance Add band 10=value 0.10000
Oi =correction value for Band 10 is 0.29
Step 2. Convert Radiance to Brightness Temperature(BT)
Spectral radiance data can be converted to Top of Atmosphere brightness temperature using thermal constant value in Meta data file.
Kelvin (K) to Celsius (0C) degrees BT=K2/〖(〗⁡〖/+)−.〗
BT= 1231.0789/〖(〗⁡〖(.)/"Lλ" +)−.〗
Where
BT=Top of Atmosphere brightness temperature (0C)
Lλ =TOA spectral radiance (watts/ (m2*sr*μm))
K1=constant band (No.)/value from band10
K2=constant band (No.)/value from band10
Step 3. Normalized Different Vegetation Index
Note that the calculation of the NDVI is important because, subsequently, the proportion of vegetation (PV), which is highly related to the NDVI, and emissivity (E), which is related to the Pv, must be calculated.
NDVI= (NIRRED)/ (NIR+RED)
NDVI= (Band5Band4)/ (Band5+Band4)
NDVI = Float (Band 5 – Band 4) / Float (Band 5 + Band 4) (in Arc GIS)
Where
RED =DN value from RED band
NIR=DN value from Near Infrared band
Step 4. land surface emissivity (LSE)
Land surface emissivity (LSE) is the average emissivity of an element of the surface of the earth calculated from NDVI values.
PV= ((NDVINDVImin)/ (NDVImaxNDVImin)) 2
In Arc GIS=Square((NDVINDVImin)/(NDVImaxNDVImin))
E=0.0004*PV+0.986
Where
PV=proportion of vegetation
E=land surface emissivity
0.986 is corresponds to correction value of the equation
Step 5. Land surface temperature (LST)
The land surface temperature (LST) is the radiative temperature which calculated using
Top of Atmosphere brightness temperature,
Wave length emitted radiance and
Land surface emissivity
LST= (BT/ (1+ (λ*BT/C2)*〖(〗⁡)))
Where:
Boltzmann constant (C2)=14388μmk
The value of λ (lambda) for Landsat 8 for band 10 is 10.8 and for band 11 is 12.0
Where
BT =Top of atmosphere brightness temperature (0C)
λ= wavelength of emitted radiance for band 10=10.8
E= land surface emissivity
C2=h*c/s=1.4388*102mk=14388μmk,boltzmann constant
H=plank’s constant=6.626*1034 js