摘要
借助第五次国际耦合模式比较计划(Coupled Model Intercomparison Project Phase 5,CMIP5)多模式集合数据及英国气候研究所(Climatic Research Unit Time-Series version 4.0,CRU TSv4.0)的格点降水资料,分析了多模式集合平均降水在亚洲的偏差分布特征,检验了三种偏差订正统计方法,并且预估了2021~2050年亚洲降水的可能变化。结果表明,在CMIP5历史气候模拟中,多模式集合降水在亚洲存在明显偏差,北方降水偏多,南方偏少,其中在青藏高原、内蒙古、蒙古国等地明显偏多达30%~40%,南亚偏少30%~40%,在越南和华南沿海偏少20%~30%等。2006~2015年预估降水偏差型与历史气候模拟相似,具有准定常性,可以通过二者之差将其消去。偏差订正检验表明,单纯除去模式气候漂移后的降水距平太小,尽管距平符号一致率较高。在暖季(5~10月),一元对数回归偏差订正结果在北方略优于一元差分回归,在冷季(11月至次年4月)与此相反,二者结合可以构成区域组合回归偏差订正法。最后,用组合订正法订正了RCP4.5情景下20个CMIP5模式集合2021~2050年亚洲降水预估偏差,又利用某些区域的去除模式漂移后的订正结果对其盲区进行了补充订正。结果表明,相对于1976~2005年气候平均,在暖季,中国南方、南亚东北部、中亚南部、阿拉伯半岛东北部等地降水可能减少10%~20%;从中国的三江源区到淮河流域带降水会增加约20%,东北南部的降水会增加约10%;新疆北部降水增加约10%,南部约20%;华北和东北大部降水减少约10%~20%;中南半岛北部降水增加约10%;亚洲高纬度地带降水也略有增加。在冷季,亚洲降水呈现北方增加,南方减少的格局,其中南亚降水减少最明显,达-10%左右,中国西南部减少约-5%;中国西部降水增加幅度为20%~40%,华北和东北增加约5%;亚洲高纬度降水增加约为10%~40%。因此,随着气候暖化,未来30年中国的淮河流域、长江和黄河上游�
This study focuses on the bias of the multimodel ensemble mean in the precipitation simulated using models of the fifth phase of the Coupled Model Intercomparison Project(CMIP5)compared with the precipitation data using Climatic Research Unit Timeseries version 4.0(CRU TS v4.0).Three bias correction methods are tested,and a precipitation projection with the correction is made for the coming 30 years(2021-2050)based on the selected 20 CMIP5 models.Results show that the precipitation in the CMIP5 historical simulation is overestimated in northern Asia and underestimated in the south for 1960-2005 with 30%-40% more precipitation than that observed in the Tibetan Plateau,Inner Mongolia,and Mongolia;20%-30% less in the South China Coast and Vietnam;and 30%-40% less in South Asia than that of the observation.The bias pattern of the projected precipitation for 2006-2015 under the Representative Concentration Pathway(RCP)4.5 scenario is found to be similar to that from the CMIP5 historical climate simulation,implying that the bias pattern is almost stationary and should belong to the model climate drift that can be removed using the difference between the period-mean projection and historical simulation.However,this bias correction leads to a much small magnitude of the precipitation anomaly,although it has a good anomaly rate compared with the observation.The bias correction test confirms that the performance of the bias correction using logarithm regression(LR)is better in northern Asia compared with the year-to-year increment regression(YYIR)during the warm season(May-October).Meanwhile,the YYIR is better than the LR in southern Asia in this season.Nevertheless,the LR is better in the south,and YYIR is better in the north during the cold season(November throughout next April).Therefore,combining the two regression methods can form a regional combination bias correction.The regional combination method is applied in the bias correction for the 2021-2050 precipitation projection of the Asian continent under the RCP4.5 sc
作者
杨阳
戴新刚
汪萍
YANG Yang;DAI Xingang;WANG Ping(Key Laboratory of Regional Climate-Environment for Temperate East Asia,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029;School of Atmospheric Sciences,Sun Yat-sen University,Zhuhai 519082;Key Laboratory for Atmospheric Chemistry,Institute of Atmospheric Composition and Environment Meteorology,Chinese Academy of Meteorological Sciences,Beijing,100081;College of Atmospheric Sciences,Lanzhou University,Lanzhou 730000)
出处
《大气科学》
CSCD
北大核心
2022年第1期40-54,共15页
Chinese Journal of Atmospheric Sciences
基金
国家自然科学基金项目41675087、42061144015
国家重点研发计划项目2016YFA0600404、2016YFA0601901。
关键词
亚洲季风
降水预估
CMIP5
偏差订正
旱涝趋势
Asian monsoon
Precipitation projection
CMIP5
Bias correction
Drying and flooding
