I have got values for Black sky albedo and white sky albedo, from MODIS imagery. What is the simplest way to calculate blue sky albedo? I want to use albedo for snow cover.

A website which has listed this formula:

Blue-sky (Actual) Albedo = White-sky Albedo * f(optical depth, solar zenith angle, aerosol type, band) + Black-sky Albedo * (1 - f(optical depth, solar zenith angle, aerosol type, band))

Now the thing is I don't have solar zenith angle, aerosol type etc..

What do I do? Please help

  • Did you find the answer to your question? I am presently facing the same problem. Even if I get optical depth, zenith angle, etc., what is the expression of the function? Arnab
    – user21438
    Aug 27, 2013 at 7:16

1 Answer 1


For solar zenith, you can use the Solar Geom Calc. Assuming you have access to the metadata for your imagery, or know the lat/long and date and time of image acquisition, you should be good to go. As far as aerosol type, You should check out the Modis site for more information.

Can you provide the link to the site where you got your formula?

  • Hi egdetti, Thanks a lot for the reply.I got it from the website listed below. now my modis product is MCD43 A3 product, I'm not sure if I have time of acquisition, I do have the date for the images however. daac.ornl.gov/MODIS/MODIS-menu/MCD43.html
    – GBh
    Oct 23, 2012 at 20:41

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.