Retrieval of snow albedo and grain size using reflectance measurements in Himalayan basin 1Snow & Avalanche Study Establishment, Him Parisar, Sector-37A, Chandigarh 160 036, India
11 Mar 2011
2Institute of Environmental Physics, University of Bremen, O. Hahn Allee 1, 28359 Bremen, Germany
Received: 18 October 2010 – Published in The Cryosphere Discuss.: 04 November 2010 Abstract. In the present paper, spectral reflectance measurements of Himalayan seasonal
snow were carried out and analysed to retrieve the snow albedo and effective
grain size. The asymptotic radiative transfer (ART) theory was applied to
retrieve the plane and spherical albedo. The retrieved plane albedo was
compared with the measured spectral albedo and a good agreement was observed
with ±10% differences. Retrieved integrated albedo was found within
±6% difference with ground observed broadband albedo. The retrieved snow grain sizes
using different models based on the ART theory were compared for various snow
types and it was observed that the grain size model
using two channel method (one in visible and another in NIR region) can work
well for the Himalayan seasonal snow and it was found consistent with temporal changes in grain size.
This method can work very well for clean, dry snow as
in the upper Himalaya, but sometimes, due to the low reflectances (<20%) using
wavelength 1.24 μm, the ART theory cannot be applied, which is common in
lower and middle Himalayan old snow. This study is important for
monitoring the Himalayan cryosphere using air-borne or space-borne sensors.
Revised: 08 February 2011 – Accepted: 18 February 2011 – Published: 11 March 2011
Citation: Negi, H. S. and Kokhanovsky, A.: Retrieval of snow albedo and grain size using reflectance measurements in Himalayan basin, The Cryosphere, 5, 203-217, doi:10.5194/tc-5-203-2011, 2011.