摘要
采用与全球海气耦合模式(NCC/IAPT63)嵌套的区域气候模式(RegCM2_NCC),对东亚区域进行了30年的气候积分(1961—1990年),作为控制试验的气候背景场,在此基础上,在IPCC第三次评估报告SRES排放情景A2下对我国未来30年(2001—2030年)的气候变化趋势进行了预估,重点分析了我国东部季风区夏季降水的变化趋势及区域特征。结果显示:未来30年夏季平均降水量在北部地区呈现增加的趋势,以降水量距平代表的夏季主要雨带转到长江以北地区,且北方地区降水量增加主要以对流性降水量增加为主,长江以南地区降水量有所减少,特别是华南地区降水量减少较为明显,据此预测结果,未来30年华北地区夏季干旱可能有所缓解。未来30年夏季低层空气湿度也将发生明显变化,主要表现为中高纬度地区湿度增大,较低纬度地区湿度减小,东亚夏季风有所增强,特别是西南气流明显加强,有利于暖湿空气向北方地区输送。由于预估结果的可信度取决于全球模式和区域模式的模拟性能以及温室气体排放浓度的准确性,因此还需要更多的试验及进一步的综合比较,以减少未来气候变化趋势预估的不确定性。
By using the nested regional climate model (NCC/IAP T63-RegCM_NCC), climate change over China during the past 30 years(1961-1990) is simulated as the control run of the climatic background. Based on it, under the IPCC SRES A2 emission scenario, projection is made over East Asia with the aim of examining climate change scenarios for the future 30 years (2001-2030). The changes of summer precipitation are analyzed, with the key focus on the eastern China monsoon regions. The results show that, due to the effect of greenhouse gas increase, the summer mean precipitation presents increasing trend over northern regions but decreasing over southern regions. The summer rain belts expressed by rainfall departure are expected to shift to the North of Yangtze River. Furthermore, the increase of the total precipitation over northern regions is mainly caused by the increase of convective precipitation, with non-convective precipitation unchanged. With regard to the climate field of 1961-1990, annual mean precipitation in North China (35°-40°N,110°-120°E) shows less increase by 2%-3% in the next 30 years, but summer mean precipi tation is expected to increase remarkably with the maximum precipitation variability of about 19%. Based on the projection, drought over North China in summer is expected to be relieved to some extent in the next 30 years. Summer mean air moisture (especially in lower-layers) is also expected to change obviously in the future, with the atmosphere becoming wetter in mid-high latitude but drier in low latitude regions. East Asian summer monsoon will be much intensive during 2001 2030. The southwesterly airflow is expected to be enhanced in eastern monsoon regions, which would lead to more warm and wet moisture transporting to the regions of northern China and then increasing the precipitation over that region. Considering the reliability of the projection mainly lies on the capability of the global and regional models as well as the reliability of greenhouse gases concentration, further experiments and integrated comparisons need to be done in the future. Based on the constant improvement of the GCM and RCM, the optimized schemes and the appropriate emission scenarios relative to the different research aim are needed to be chosen. Furthermore, other kinds of the greenhouse gases and aerosols also should be included in the model to decrease the uncertainties in the future climate projection.
出处
《应用气象学报》
CSCD
北大核心
2008年第6期770-780,共11页
Journal of Applied Meteorological Science
基金
科技部国际合作项目"区域气候变化的监测
模拟和影响研究"(2005DFA20940)项目
国家科技支撑计划"全球环境变化应对技术研究与示范"项目01课题"气候变化的检测和预估技术研究"(2007BAC03A01)
国家重点基础研究发展规划项目(2006CB403404)共同资助
关键词
CO2增加
我国东部季风区
降水变化趋势
CO2 increasing
eastern China monsoon regions
precipitation change trend