标题：Differences in snow-induced radiative forcing estimated from satellite and reanalysis surface albedo datasets over the Northern Hemisphere landmass for the overlapping period of 1982–2012
摘要：The snow-induced radiative forcing (SnRF) measures the instantaneous perturbation to Earth's shortwave radiation at the top of the atmosphere (TOA) caused by the presence of snow cover. Land surface albedo (as) is a key parameter in estimation of SnRF. Previous studies have focused on using satellite or reanalysis as data in SnRF quantifications. However, their spatial and temporal differences remain unclear. In this study, SnRF over the Northern Hemisphere (NH) estimates from two satellite and four reanalysis as datasets were compared for the overlapping period of 1982–2012. The 31-year annual-mean SnRF was estimated at −1.81 to −1.59 W m−2 from satellite as datasets, with a peak of −4.01 W m−2 and Standard Deviation (SD) of 1.54 W m−2 in April. The comparable SnRF from reanalysis as was −1.48 to −2.30 W m−2, with a peak of −4.77 W m−2 and SD of 0.81 W m−2 in the same month. In the seasonal cycle, SnRF from satellite as displayed lower values from October to January, but higher values from February to July, compared with SnRF using reanalysis as. Moreover, the annual-mean SnRF declined by 0.39–1.25 W m−2 during 1982–2012 from satellite as datasets, which is much smaller than the results using reanalysis as datasets. Furthermore, changes in monthly-mean SnRF from satellite as displayed an enhance trend in snow accumulation seasons, which are largely different with the comparable changes from reanalysis-based SnRF, indicating that there are large interannual and intra-annual biases between SnRF estimates from satellite and reanalysis as datasets. Based on above results, we conclude that the large discrepancies between SnRF estimations from satellite and reanalysis as should be considered in evaluating the response and feedback of snow cover to Earth climate change in future studies, especially in radiation budget anomalies.
关键词：snow cover; land surface albedo; Northern Hemisphere; energy budget; radiative forcing
