The Asian summer monsoon(ASM)is the most energetic circulation system.Projecting its future change is critical for the mitigation and adaptation of billions of people living in the region.There are two important compo...The Asian summer monsoon(ASM)is the most energetic circulation system.Projecting its future change is critical for the mitigation and adaptation of billions of people living in the region.There are two important components within the ASM:South Asian summer monsoon(SASM)and East Asian summer monsoon(EASM).Although current state-of-the-art climate models projected increased precipitation in both SASM and EASM due to the increase of atmospheric moisture,their circulation changes differ markedlyÐA robust strengthening(weakening)of EASM(SASM)circulation was projected.By separating fast and slow processes in response to increased CO_(2) radiative forcing,we demonstrate that EASM circulation strengthening is attributed to the fast land warming and associated Tibetan Plateau thermal forcing.In contrast,SASM circulation weakening is primarily attributed to an El Niño-like oceanic warming pattern in the tropical Pacific and associated suppressed precipitation over the Maritime Continent.展开更多
Tropical rainfall is important for regional climate around the globe.In a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally en...Tropical rainfall is important for regional climate around the globe.In a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally enhanced.Here,we analyze an idealized CO_(2) removal experiment from the Carbon Dioxide Removal Model Intercomparison Project(CDRMIP)and show that the tropical rainfall change features a stronger pattern during CO_(2) ramp-down than ramp-up,even under the same global mean temperature increase,such as the 2℃ goal of the Paris Agreement.The tropical rainfall during CO_(2) ramp-down increases over the equatorial Pacific with a southward extension,and decreases over the Pacific intertropical convergence zone and South Pacific convergence zone.The asymmetric rainfall changes between CO_(2) ramp-down and ramp-up result from time-varying contributions of the fast and slow oceanic responses to CO_(2) forcing,defined as the responses to abrupt CO_(2) forcing in the first 10 years and thereafter,respectively,in the abrupt-4xCO_(2) experiment.The fast response follows the CO_(2) evolution,but the slow response does not peak until 60 years after the CO_(2) peak.The slow response features a stronger El Niño-like pattern,as the ocean dynamical thermostat effect is suppressed under stronger subsurface warming.The delayed and stronger slow response leads to stronger tropical rainfall changes during CO_(2) ramp-down.Our results indicate that returning the global mean temperature increase to below a certain goal,such as 2℃,by removing CO_(2),may fail to restore tropical convection distribution,with potentially devastating effects on climate worldwide.展开更多
基金supported by the National Natural Science Foundation of China (42088101)the National Key Research & Development Program of China (2017YFA0603802)US National Science Foundation (AGS-2006553)
文摘The Asian summer monsoon(ASM)is the most energetic circulation system.Projecting its future change is critical for the mitigation and adaptation of billions of people living in the region.There are two important components within the ASM:South Asian summer monsoon(SASM)and East Asian summer monsoon(EASM).Although current state-of-the-art climate models projected increased precipitation in both SASM and EASM due to the increase of atmospheric moisture,their circulation changes differ markedlyÐA robust strengthening(weakening)of EASM(SASM)circulation was projected.By separating fast and slow processes in response to increased CO_(2) radiative forcing,we demonstrate that EASM circulation strengthening is attributed to the fast land warming and associated Tibetan Plateau thermal forcing.In contrast,SASM circulation weakening is primarily attributed to an El Niño-like oceanic warming pattern in the tropical Pacific and associated suppressed precipitation over the Maritime Continent.
基金supported by the National Key Research&Development Program of China(2019YFA0606703)the National Natural Science Foundation of China(41975116 and 42105027)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202025)the China Postdoctoral Science Foundation(BX20200329 and 2020M680646)the Special Research Assistant Project of Chinese Academy of Sciences。
文摘Tropical rainfall is important for regional climate around the globe.In a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally enhanced.Here,we analyze an idealized CO_(2) removal experiment from the Carbon Dioxide Removal Model Intercomparison Project(CDRMIP)and show that the tropical rainfall change features a stronger pattern during CO_(2) ramp-down than ramp-up,even under the same global mean temperature increase,such as the 2℃ goal of the Paris Agreement.The tropical rainfall during CO_(2) ramp-down increases over the equatorial Pacific with a southward extension,and decreases over the Pacific intertropical convergence zone and South Pacific convergence zone.The asymmetric rainfall changes between CO_(2) ramp-down and ramp-up result from time-varying contributions of the fast and slow oceanic responses to CO_(2) forcing,defined as the responses to abrupt CO_(2) forcing in the first 10 years and thereafter,respectively,in the abrupt-4xCO_(2) experiment.The fast response follows the CO_(2) evolution,but the slow response does not peak until 60 years after the CO_(2) peak.The slow response features a stronger El Niño-like pattern,as the ocean dynamical thermostat effect is suppressed under stronger subsurface warming.The delayed and stronger slow response leads to stronger tropical rainfall changes during CO_(2) ramp-down.Our results indicate that returning the global mean temperature increase to below a certain goal,such as 2℃,by removing CO_(2),may fail to restore tropical convection distribution,with potentially devastating effects on climate worldwide.
