Dear Piyushkumar,

The common word 'albedo' actually covers a number of different concepts, and you will indeed find many products on the web called like that but calculated in different ways, so the first thing to clarify is what exactly you are looking for.

For reference, the ratio between the flux of solar radiation reflected by the cloud in the 'upper' hemisphere (from the cloud, directed away from the planet, accounting for all outgoing light, irrespective of direction) and the irradiance (from the sky, directed 'downward' towards the planet surface, accounting for all incoming light, irrespective of direction), then that is technically called the bi-hemispherical reflectance (or reflectance factor, if it is normalized by the equivalent bi-hemispherical reflectance of an ideal, lossless, Lambertian surface).

If you'd like to investigate and understand the nomenclature of albedo concepts, the key reference is

Nicodemus, F. E., Richmond, J. C., Hsia, J. J., Ginsberg, I. W. and Limperis, T. (1977) 'Geometrical Considerations and Nomenclature for Reflectance, US Department of Commerce, National Bureau of Standards, NBS Monograph No. 160, Washington, DC, USA.

You'll find a PDF (scanned) version of that seminal document here:

http://graphics.stanford.edu/courses/cs448-05-winter/papers/nicodemus-brdf-nist.pdf

To calculate this particular albedo concept, you need to integrate the outgoing and incoming (directional) radiances over their respective hemispheres before taking the ratio: this implies having multi-angular measurements, or using a couple of pyranometers, and making strong assumptions on the spatial homogeneity and anisotropy of these radiation fields.

There is a large literature on the theory and measurement of reflectance for various geophysical media, and clouds in particular. The MISR instrument on NASA's Terra platform, in particular, was designed specifically to characterize clouds and aerosols. You'll find a lot of information, including hundreds of publications, on the following JPL web site:

https://www-misr.jpl.nasa.gov/

And if you'd like to get albedo products, please visit this web site:

https://eosweb.larc.nasa.gov/project/misr/misr_table

I hope this helps. Good luck, Michel.

Thank you Mr. Michel M. Verstraete for your kind and valuable response. 

Actually, I am looking for a cloud albedo at top-of the atmosphere (TOA). 

I am trying to study the cloud albedo response during aerosl-cloud iteraction, but I don't have any clear idea that how can I calculate cloud albedo from satellite measurements of TOA flux?

Dear Piyushkumar,

As indicated earlier, the simplest albedo concept (from the user point of view, not from the computational point of view) is the bi-hemispherical reflectance factor: this is the ratio of the upward flux exiting from the top of the cloud over the downward flux (irradiance) from the Sun at the same level, place and time. When you use a satellite instrument to measure this upward flux, it is automatically 'at the Top of the Atmosphere (ToA)', of course, and the higher the altitude of the cloud top, the better the ToA measurements will represent or approximate the top of cloud values.

You'll find all the scientific and technical details about the underlying equations in the appropriate MISR Algorithm Theoretical Basis Document (ATBD), which are publicly available here:

http://eospso.gsfc.nasa.gov/atbd-category/45

See, in particular, ATBD-MISR-08. The corresponding products are available from the 'eosweb.larc.nasa.gov' web site mentioned previously.

Cheers, Michel.