东亚地区云对地球辐射收支和降水变化的影响研究

Study on the Influence of Clouds on the Earth Radiation Budget and Precipitation Changes in East Asia Region

云覆盖地球表面约60%的区域。云通过反射太阳辐射造成地气系统变冷和通过吸收地表与云下大气的长波辐射使地气系统变暖,这两种效应显著地影响着地气系统的辐射收支平衡。同时,云通过影响大气水分输送和降水调节大气水循环,是大气中重要的水汽调节器。然而,历次政府间气候变化专门委员会(IPCC)评估报告和很多研究都指出,云是迄今为止影响气候变化和气候预测诸多因子中非常重要却又不确定性最大的因子。低云增加4%即可抵消二氧化碳浓度加倍引起的2~3℃增温,反之会扩大相应的增温效应。东亚地区处于亚洲季风区,又是温室气体和大气污染物高排放区,使得该地区的云-辐射-降水具有鲜明的区域特征。目前对东亚地区气候模拟的偏差和不确定性均与云辐射过程及其反馈有关。因此,极有必要研究东亚地区云对于辐射收支和温度的影响、揭示其与降水的关系及机制,为准确预估全球增暖情景提供科学基础。进而为国家制定保护环境和减缓全球变化的各项政策、进行国际气候变化外交谈判提供科学支撑。

Clouds covers about 60% of the Earth.They have both cooling and warming effects on the Earth-atmosphere system by reflecting solar radiation and absorbing the longwave radiation from the Earth and the atmosphere under clouds, thus influencing the radiation budget of the system significantly.At the same time, clouds play a key role in regulating the atmospheric water circula-tion by affecting the atmospheric water transport and precipitation.They are important water vapor regulator in the atmosphere.However,the previous IPCC assess-ment reports and lots of researches point out that clouds have been the most important but uncertain factor in cli-mate change and climate prediction so far.If low clouds increase by 4%,they can offset 2~3℃warming due to carbon dioxide concentration doubling.Oppositely, it will expand the corresponding warming effect.East Asi-an locates in the Asian monsoon zone,which is also the high emission zone of greenhouse gases and atmospheric pollutants,which makes the region possess distinct re-gional features in cloud-radiation-precipitation proces-ses.The current deviation and uncertainty in climate modeling in the East Asian region are all related to the process of cloud radiation and its feedback.Therefore, it＇s necessary to investigate the influence and mechanism of clouds on the radiation budget,temperature and pre-cipitation in this region, which can provide scientific basis for estimating the global warming scenarios accu-rately and then for our government to make policies on protecting the environment and mitigating global war-ming, and supporting international diplomacy negotia-tions on climate change.