[A-AS10] General Meteorology

[AAS10-02] Influence of Satellite-observed Solar Spectral Irradiance on the Modeled High-Latitude Surface Climate

*Xianwen Jing¹, Xianglei Huang² (1.College of Urban and Environmental Sciences, Hubei Normal University, 2.Department of Climate and Space Sciences and Engineering, University of Michigan)

Keywords:Solar radiation, Climate sensitivity, Climate change, Sea ice, Energy budget, Surface albedo

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 1 W m22 . 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 4 W m22 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 (see the attached figure). 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.