atmospheric correction

[nemish murawat]

Greetings all,

I am currently doing a project on atmospheric correction of satellite images using Seadas-7.5 and Py6S.

I had some few questions regarding the same.

1)What do we give as the input to the class Py6S.AtmosCorr?

2)Is it the surface radiance or the at-sensor radiance?

3)If it is the at-sensor radiance what is the significance of apparent radiance?

4)If at-sensor radiance and apparent radiance are same,isn't the surface radiance/reflectance retrieval the main idea behind atmospheric correction?So why is these two value changing?





Urgent Help Required.

Thank You for hearing me!!


[Robin Wilson]

Hi,

Your email managed to slip through my filters - sorry for the delay in responding.

If you are atmospherically correcting images then I suggest you use ARCSI (https://www.arcsi.remotesensing.info/) which is based on Py6S, but has the extra infrastructure required to easily process images. In terms of the questions you asked, see below:

1)What do we give as the input to the class Py6S.AtmosCorr?

You call this class using one of its classmethods, to set the radiance or reflectance to use as input to the atmospheric correction. For example:

s.atmos_corr = AtmosCorr.AtmosCorrLambertianFromRadiance(150)

will set the atmospheric correction to correct an at-sensor radiance of 150 W/m2/sr.

2)Is it the surface radiance or the at-sensor radiance?

It is at-sensor radiance - the whole point of atmospheric correction is to take measurements from the sensor (at-sensor radiance or at-sensor reflectance) and calculate the surface radiance or reflectance.

3)If it is the at-sensor radiance what is the significance of apparent radiance?

Apparent radiance and at-sensor radiance are the same.

4)If at-sensor radiance and apparent radiance are same,isn't the surface radiance/reflectance retrieval the main idea behind atmospheric correction?So why is these two value changing?

I'm afraid I don't understand this question, sorry.

Robin