地球系统模式CESM1．0对太阳辐射和温室气体的敏感性差异研究

DIVERGENT SENSITIVITY OF EARTH SYSTEM MODEL CESM 1.0 TO SOLAR RADIATION VERSUS GREENHOUSE GASES

利用通用地球系统模式CESM1．0的全强迫试验和单因子敏感性试验结果，初步探讨了CESM模拟的地表气温、降水率对太阳辐射和温室气体的敏感性差异，以便更好地认识自然和人为因子对全球气候变化的贡献。结果表明：地球系统模式CESM1．0对温室气体变化的敏感性比对太阳辐射的敏感性高，温室气体含量变化引起相当于1W／m2的辐射强迫增加会导致全球平均温度上升0．51℃，而太阳辐射变化1W／m。时全球平均温度仅上升0．27％；在太阳辐射单因子敏感性试验中，地表气温每升高1qc降水量增加2．91％，要高于温室气体单因子敏感性试验的增量2．22％。另外，自然和人为因子所导致的地表气温空间变化特征也不相同，在太阳活动影响下，气温首先在北欧区域明显升高，赤道西太平洋暖池区域随着总太阳辐射量的增加而明显变暖，但在白令海峡和格陵兰岛区域则出现明显降温；而在温室气体影响下，地表气温则在北半球高纬区域显著增加，赤道东太平洋区域随着温室气体浓度的增加呈现出类似El Nifio的分布型态。

The global climate changes induced by natural and anthropogenic forcings over the past 2000 years has been a hot and difficult issue at the frontier of climate change research. Due to the short period of the observation and the low spatial and temporal resolution of reconstruction for the past 2000 years, Earth system modeling became a useful tool. The sensitivity of Earth system model to solar radiation versus greenhouse gases is the key of exploring divergent global climate changes induced by natural versus anthropogenic forcing, but has remained less explored so far. In this study, the Community Earth System Model （CESM 1.0） is used to do historical climate modeling for the past 2000 years. Three 2000-year simulations have been completed, namely the all forcing experiment, the solar radiation sensitivity experiment and the greenhouse gas sensitivity experiment. Based on the three experiments, we examined the sensitivity of CESM to solar radiation versus greenhouse gases preliminary. Firstly, we compared the climatology of the global temperature and the precipitation derived from the all forcing experiment to the reanalysis data, in order to verify the model performance. The characteristics of the temperature and precipitation simulated by the CESM 1.0 show similarity to the reanalysis data. The outputs of surface air temperature and precipitation from the solar radiation sensitivity experiment and greenhouse gas sensitivity experiment are compared to discuss the different sensitivity of CESM to solar radiation versus greenhouse gases. The results show that the sensitivity of CESM to greenhouse gases is larger than that to solar radiation. From the solar radiation sensitivity experiment, the global precipitation would increase 2.91% （0. 078mm/day/~C ） for I^C temperature increase, which is higher than 2.22% （O.052mm/dayPC） increase in the greenhouse gas sensitivity experiment. The spatial evolution characteristics induced by solar radiation and greenhouse gases are also different. Under the influence of solar activity, the temperature increases significantly in the northern Europe, but obvious cooling is shown in Greenland and Bering Strait. The temperature in the warm pool of equatorial western Pacific becomes higher significantly with the increase of solar radiation. However, under the influence of greenhouse gases, the temperature increases obviously in high latitude of the Northern Hemisphere. The warming strengthens gradually from north to south and an E1 Nino-like pattern appears in the eastern equatorial Pacific as the increase of greenhouse gas concentrations and then extended to a global warming pattern.