I found very inconsistent answers to this question. What is correct to use in atmospheric correction?
Dear Helena,
First of all you have to decide which Landsat to use in case of Landsat 8 the gain and Bias are found in the metadata file LC8pathrowyeardays_MTL e.g. LC81740372014140_MTL.
This example queries a Landsat metadata file for gain and bias factors. It uses these
factors to compute at-sensor spectral radiance using the following equation from
Chander, Markham, and Helder (2009):
Lλ= Grescal* Qcal + Brescale
Where:
Lλ= Spectral radiance in units of [W/(m2 * sr * µm)]
Grescale = Rescaling gain factor for each band.
Qcal = Quantized calibrated pixel value (Pixel values)
Brescale = Rescaling bias factor for each band.
Grescale (Gain) is found for each band from the RADIANCE_MULT_BAND_x field of the Landsat metadata file.
Brescale (Bias) is found for each band from the RADIANCE_ADD_BAND_x field of the Landsat metadata file.
; compute spectral radiance Lλ
FOR i=0, NumBands-1 DO BEGIN
data(*,*,i) = data(*,*,i) * gain[i] + bias[i]
ENDFOR
Chander, G., B. Markham, and D. Helder, "Summary of current radiometric calibration coefficients for Landsat MSS, TM, ETM+, and EO-1 ALI sensors," Remote Sensing of the Environment 113 (2009): 893-903.
I hope I answered your question Helena.
Hello Helena, Please go through herewith the attached file of "ENVI Metadata Tutorial" This gives you how to follow each step for your query, i think this may helpful to you
Be focus on C0 and C1 parameters for ATCOR
Ans: L=Grescal*Qcal+Brescal
Lsat=C0+C1*DN
so Grescal =C1&Brescal=C0
Grescal(Gain)=RADIANCE_MULT_BAND
Brescal(Bias)=RADIANCE_ADD_BAND
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