RCP4.5情景下中国未来干湿变化预估  

Projected Changes in the Dry/Wet Climate of China under the RCP4.5 Scenario

作　　者：刘珂[1,2] 姜大膀[1,3] 

机构地区：[1]中国科学院大气物理研究所,北京100029 [2]中国科学院大学,北京100049 [3]中国科学院气候变化研究中心,北京100029

出　　处：《大气科学》2015年第3期489-502,共14页Chinese Journal of Atmospheric Sciences

基　　金：国家重点基础研究发展计划(973计划)项目2012CB955401;公益性行业(气象)科研专项GYHY201006022;国家自然科学基金项目41375084

摘　　要：本文采用国际耦合模式比较计划第五阶段（CMIP5）中21个气候模式的试验数据,利用土壤湿度以及由其他8个地表气象要素计算所得的干旱指数,预估了RCP4.5 （Representative Concentration Pathway 4.5）情景下21世纪中国干湿变化.结果表明：全球气候模式对1986～2005年中国现代干湿分布具备模拟能力,尽管在西部地区模式与观测间存在一定的差异.在RCP4.5情景下,21世纪中国区域平均的标准化降水蒸散发指数和土壤湿度均有减小趋势,与之对应的是短期和长期干旱发生次数增加以及湿润区面积减小.从2016到2100年,约1.5％～3.5％的陆地面积将从湿润区变成半干旱或半湿润区.空间分布上,干旱化趋势明显的区域主要位于西北和东南地区,同时短期和长期干旱发生次数在这两个地区的增加幅度也最大,未来干旱化的发生时间也较其他地区要早;只在东北和西南地区未来或有变湿倾向,但幅度较小.在季节尺度上,北方地区变干主要发生在暖季,南方则主要以冷季变干为主.造成中国干旱化的原因主要是由降水与蒸散发所表征的地表可用水量减少.This study projects changes in China＇s dry/wet climate in the 21st century using datasets from 21 climate models from the Coupled Model Intercomparison Project Phase 5 （CMIP5） under the RCP4.5 （Representative Concentration Pathway 4.5） scenario through soil moisture levels and a drought index, with the latter being calculated using eight surface meteorological variables. Results show that the models can reproduce the basic characteristics of the climatological dry/wet climate in China during 1986-2005, although there are some differences between the models and observations for the spatial pattern of dry climate over western China. Under the RCP4.5 scenario, the standardized precipitation evapotranspiration index and soil moisture levels would generally decrease across the whole of China, corresponding to an upward trend in the frequency of short- and long-term droughts, and a downward trend in the wet climate region. From 2016 to 2100, approximately 1.5 to 3.5 percent of the land area of China would change from a humid to semi-humid or semi-arid climate. With respect to the geographical distribution, the most obvious dryness would occur in northwestern and southeastern China where short- and long-term drought frequencies would increase remarkably, and the dryness would be detectable earlier than in other regions. Wetness would only occur in northeastern and southwestern China, but would be very weak. Seasonally, there would be warm season dryness in northern China and cold season dryness in southern China. The dryness trend of China would be primarily due to the decrease of available surface water as determined by precipitation and evapotranspiration levels.

关 键 词：RCP4.5 干湿气候 土壤湿度 标准化降水蒸散发指数 预估 

分 类 号：P467[天文地球—大气科学及气象学]