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基于CMIP6模式的东南亚极端降水未来预估及热动力成因研究

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本文利用26个CMIP6全球气候模式,研究了21世纪末东南亚极端降水事件的变化,通过分解水汽收支方程分析降水变化的动力和热力效应.结果表明,21世纪末(2071-2100年)相对历史参考期(1985-2014年),东南亚大部分地区的气候态降水、极端降水事件的发生频率和强度均显著增加.除大于10 mm降水日数(R10mm)外,其他极端降水指数在SSP5-8.5情景下的变化幅度比SSP2-4.5情景更大.其中强降水量贡献率(R95pTOT)的增长幅度最大,在SSP2-4.5(SSP5-8.5)情景下增加22%(41%).极端降水变化对气候变暖的响应存在明显的区域性差异.加里曼丹岛将出现更短时集中的极端降水.苏门答腊岛南部的极端降水频率略有减小,且可能发生较强的持续性干旱事件.进一步分析水汽收支方程可知,SSP2-4.5(SSP5-8.5)情景下,热力作用项对P-E(降水减蒸发)的变化贡献为65%(64%),并且模式间一致性更高.而动力作用项对P-E的变化呈抵消趋势,贡献为35%(36%).这说明相比大尺度环流变化,大气比湿变化引起的水汽辐合是未来东南亚降水量增多的主要因子.
Projected changes in extreme precipitation and the roles of thermodynamic and dynamic causes over Southeast Asia:insights from CMIP6 Models
Southeast Asia,characterized by intricate topography and dense population,is highly sensitive to pre-cipitation extremes in the context of global warming,making understanding its future change characteristics essen-tial.This study utilizes 26 global climate models(GCMs)to project changes in precipitation extremes over South-east Asia by the end of the 21st century,based on the Shared Socioeconomic Pathway(SSP)scenarios 2-4.5 and 5-8.5(SSP2-4.5 and SSP5-8.5)simulations from the Coupled Model Intercomparison Project phase 6(CMIP6).By decomposing the moisture budget equation,we quantify the relative contributions of increased atmospheric specific humidity and alterations in atmospheric circulation to climatological precipitation changes.The research explores both dynamic and thermodynamic mechanisms driving these precipitation changes,rigorously evaluating the consistency and reliability of simulation outputs across a diverse range of climate models.The multi-model en-semble medians(MMM)reveal that,compared with the historical reference period(1985-2014),climatological precipitation and precipitation extremes in most of Southeast Asia will increase significantly by the end of the 21st century(2071-2100)under SSP2-4.5 and SSP5-8.5 scenarios.Precipitation extremes exhibit spatial differences,with short duration,high intensity events predicted for Kalimantan,while southern Sumatra experiences a decrease in total precipitation on wet days(PRCPTOT)and an increase in consecutive dry days(CDD).Except for heavy precipitation days(R10mm),extreme precipitation indices show more pronounced magnitudes under the SSP5-8.5 scenario than the SSP2-4.5 scenario.The contribution rate of heavy precipitation(R95pTOT)increases by 22%(41%)under SSP2-4.5(SSP5-8.5)scenario.Climatological precipitation at the end of this century exhibits an obvious increasing trend across most regions of Southeast Asia under SSP2-4.5 and SSP5-8.5 scenarios,with large increases mainly observed in Kalimantan and New Guinea Island.Spatial patterns of precipitation alterations align closely with changes in P-E(precipitation minus evaporation),with the magnitude of evaporation change being modest.This suggests that the enhancement in climatological precipitation is the dominant factor contributing to the increase in P-E.Quantitative analysis of the moisture budget equation indicates that thermodynamic and dy-namic effects mainly result in climatological precipitation changes by the end of the 21st century.The thermody-namic component,with higher inter-model consistency,contributes the most,accounting for 65%(64%)of the P-E changes under SSP2-4.5(SSP5-8.5)scenarios.However,dynamic effects counteract the changes in P-E,contributing 35%(36%).Moisture convergence caused by atmospheric-specific humidity changes is considered the dominant factor in the projected precipitation increase.This conclusion underscores the need for a thorough as-sessment of the risks associated with extreme climatic conditions in Southeast Asia and emphasizes the importance of proactive measures to mitigate the risks posed by precipitation extremes in the region.

Southeast AsiaCMIP6precipitation extremesclimate changemoisture budget equation

林芷叶、葛非、金正睿、孙雪榕

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成都信息工程大学四川省高原大气环境重点实验室/气候与环境变化联合实验室/大气科学学院,四川成都 610225

南京信息工程大学气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心/大气科学学院,江苏南京 210044

东南亚 CMIP6 极端降水事件 气候变化 水汽收支方程

国家自然科学基金成都信息工程大学青年科技创新计划四川省自然科学基金四川省青年科技创新研究团队项目

42375047U20A2097KYQN2022012024NSFSC00642024NSFTD0017

2024

大气科学学报
南京信息工程大学

大气科学学报

CSTPCD北大核心
影响因子:1.558
ISSN:1674-7097
年,卷(期):2024.47(3)
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