太阳常数变化对冬季全球辐射强迫及气候影响的数值模拟研究
A Modeling Study of the Response of Radiative Forcing and Climate to Solar Constant Variation in Boreal Winter
中文摘要：
利用中国科学院大气物理研究所第四代大气环流模式IAP AGCM4.0，通过在模式中将太阳常数从1367W·m-2减少至1361W·m-2，探讨了太阳总辐射减弱对冬季（12—2月）全球辐射强迫及气候模拟的影响。结果表明：（1）大气顶入射太阳辐射在全球范围内平均减少1.54W·m-2，南半球中高纬地区显著减少2.15W·m-2。北美、西西伯利亚、中东以及澳洲东部大气顶与地表的净短波辐射则出现增加，这与上述地区总云量减少相对应；（2）地表温度在全球范围内平均降低约0.05oC，北美南部、南美南部、非洲东部与南部、澳洲西部以及亚欧大陆地表温度出现降低，其中亚欧大陆降温幅度达到2oC以上，北美北部、南美北部、非洲西部以及澳洲东部地表温度则为升高，其中澳洲东部平均升温幅度约为0.5oC；（3）降水在全球范围内平均减少约0.003mm·d-1，其中澳洲大陆降水平均减少约0.6mm·d-1，与该地区地表蒸散发减少、水汽源减少以及夏季风减弱有关。
中文关键词：
太阳活动，辐射强迫，地表温度，降水，大气环流模式
KeyWords：
solar variation, radiative forcing, surface temperature, precipitation, atmospheric general circulation model
Abstract：
In this paper, the impact of total solar irradiance (i.e., solar constant) variation upon global radiative forcing and climate change in winter (December - February) is investigated by using a global atmospheric general circulation model (IAP AGCM4.0). Two sets of numerical experiments are designed, with one using the default solar constant (1367W·m-2) and the other adopting the latest value (1361W·m-2). Comparisons of the model results from both experiments demonstrate that with the reduction of solar constant: (1) Incoming solar radiation decreases 1.54W·m-2 globally and 2.15W·m-2 over areas of the mid- and high-latitudes in the Southern Hemisphere. Corresponding to less total cloud cover, net solar radiation at the top of the atmosphere and the surface increases in regions such as North America, West Siberia, Middle East, and Eastern Australia; (2) Surface temperature decreases 0.05℃ globally and more than 2℃ over Eurasia, while it increases about 0.5℃ over Eastern Australia. In other regions such as Southern North-America, Southern South-America, Eastern and Southern Africa, and Western Australia, surface temperature becomes colder. Over regions including Northern North-America, Northern South-America, and Western Africa, surface temperature becomes warmer. (3) Precipitation exhibits negligible variations when averaged globally, which only drops by 0.003 mm·d-1. Owing to the combined effects of decreased surface evapotranspiration, reduced surface humidity, and weakened Australian summer monsoon, precipitation over Eastern Australia is on average reduced by about 0.6 mm·d-1.