Sensitivity of present and future surface temperatures to precipitation characteristics

Climate Research

Cynthia Rosenzweig¹  Leonard Druyan¹  Christian Hogrefe¹  Richard Healy¹  Barry H. Lynn¹  Patrick Kinney¹  David Rind¹  JoyceRosenthal¹  Jimy Dudhia¹  Richard Goldberg¹ 

关键词: Climate change;    Surface temperatures;    Model assessment;   

DOI  :  10.3354/cr028053

来源: Inter-Research Science Publishing

【 摘 要 】

ABSTRACT: A model simulation study shows that different diurnal cycles of precipitation are consistent with radically different present and future climate characteristics. In projected future climate scenarios, divergence in the time of day and type ofprecipitation had very divergent impacts on the radiation balance and consequently on surface temperatures. The relationship between the diurnal cycle of precipitation versus the present and future climate was examined using the GISS-MM5 (GoddardInstitute for Space Studies Mesoscale Model 5) regional climate modeling system with 2 alternative moist convection schemes. June-August (JJA) mean surface temperatures of the 1990s, 2050s, and 2080s were simulated over the eastern US on a doublenested 108/36 km domain, with the 36 km domain centered over the eastern US. In the 1990s, one model version simulated maxima in (convective) precipitation during the early morning, while the second model simulated the hour of precipitation maxima withconsiderable spatial variability (in better agreement with observations). In the futuristic climate scenarios, differences in the time of day of precipitation had very important impacts on the radiation balance at the surface. One version gave moreprecipitation at night and fewer clouds during the day, promoting higher surface temperatures. The alternative version created more precipitation during the day, consistent with diminished absorption of solar radiation at the surface and consequentlylower surface temperatures. The results demonstrate the importance of improving cumulus parameterizations in regional mesoscale and global climate models and suggest that such improvements would lead to greater confidence in model projections of climatechange.

【 授权许可】

Unknown