Modeling time series of microwave brightness temperature at Dome C, Antarctica, using vertically resolved snow temperature and microstructure measurements
Abstract : Time series of observed microwave brightness temperatures at Dome C, East Antarctic plateau, were modeled over 27 months with a multilayer microwave emission model based on dense-medium radiative transfer theory. The modeled time series of brightness temperature at 18.7 and 36.5 GHz were compared with Advanced Microwave Scanning Radiometer-EOS observations. The model uses in situ high-resolution vertical profiles of temperature, snow density and grain size. The snow grain-size profile was derived from near-infrared (NIR) reflectance photography of a snow pit wall in the range 850-1100 nm. To establish the snow grain-size profile, from the NIR reflectance and the specific surface area of snow, two empirical relationships and a theoretical relationship were considered. In all cases, the modeled brightness temperatures were overestimated, and the grain-size profile had to be scaled to increase the scattering by snow grains. Using a scaling factor and a constant snow grain size below 3 m depth (i.e. below the image-derived snow pit grain-size profile), brightness temperatures were explained with a root-mean-square error close to 1 K. Most of this error is due to an overestimation of the predicted brightness temperature in summer at 36.5 GHz.
https://hal-insu.archives-ouvertes.fr/insu-00646667 Contributor : Aurore GayraudConnect in order to contact the contributor Submitted on : Tuesday, November 23, 2021 - 1:32:34 PM Last modification on : Tuesday, November 23, 2021 - 1:32:38 PM Long-term archiving on: : Thursday, February 24, 2022 - 7:32:29 PM
L. Brucker, G. Picard, L. Arnaud, J.M. Barnola, M. Schneebeli, et al.. Modeling time series of microwave brightness temperature at Dome C, Antarctica, using vertically resolved snow temperature and microstructure measurements. Journal of Glaciology, International Glaciological Society, 2011, 57 (201), pp.171-182. ⟨10.3189/002214311795306736⟩. ⟨insu-00646667⟩