报告开始:2023年05月07日 08:55(Asia/Shanghai)
报告时间:10min
所在会场:[13B] 13B、大气物理与气象气候 [13B-1] 13B-1 大气物理和大气探测
Not only total solar irradiance (TSI) but also spectral solar irradiance (SSI) matter for our climate. Different
surfaces can have different reflectivity for the visible (VIS) and near-infrared (NIR). The recent NASA Total and Spectral
Solar Irradiance Sensor (TSIS-1) mission has provided more accurate SSI observations than before. The TSI observed by
TSIS-1 differs from the counterpart used by climate models by no more than 1Wm22. However, the SSI difference in a
given VIS (e.g., 0.44–0.63 mm) and NIR (e.g., 0.78–1.24 mm) band can be as large as 4Wm22 with opposite signs. Using the
NCAR CESM2, we study to what extent such different VIS and NIR SSI partitions can affect the simulated climate. Two
sets of simulations with identical TSI are carried out, one with SSI partitioning as observed by the TSIS-1 mission and the
other with what has been used in the current climate models. Due to different VIS-NIR spectral reflectance contrasts
between icy (or snowy) surfaces and open water, the simulation with more SSI in the VIS has less solar absorption by the
high-latitude surfaces, ending up with colder polar surface temperature and larger sea ice coverage. The difference is more
prominent over the Antarctic than over the Arctic. Our results suggest that, even for the identical TSI, the surface albedo
feedback can be triggered by different SSI partition between the VIS and NIR. The results underscore the importance of
continuously monitoring SSI and the use of correct SSI in climate simulations.
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2023
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2023
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