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
Quantitative assessment of natural internal variability and externally forced responses of Northern Hemisphere(NH)temperatures is necessary for understanding and attributing climate change signals during past warm and...Quantitative assessment of natural internal variability and externally forced responses of Northern Hemisphere(NH)temperatures is necessary for understanding and attributing climate change signals during past warm and cold periods.However,it remains a challenge to distinguish the robust internally generated variability from the observed variability.Here,largeensemble(70 member)simulations,Energy Balance Model simulation,temperature ensemble reconstruction,and three dominant external forcings(volcanic,solar,and greenhouse gas)were combined to estimate the internal variability of NH summer(June–August)temperatures over the past 2000 years(1–2000 CE).Results indicate that the Medieval Climate Anomaly was predominantly attributed to centennial-scale internal oscillation,accounting for an estimated 104%of the warming anomaly.In contrast,the Current Warm Period is influenced mainly by external forcing,contributing up to 90%of the warming anomaly.Internal temperature variability offsets cooling by volcanic eruptions during the Late Antique Little Ice Age.These findings have important implications for the attribution of past climate variability and improvement of future climate projections.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This work was jointly funded by the National Natural Science Foundation of China(Grant Nos.41888101 and 42077406)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB26020000)+1 种基金the Key Research Program of the Institute of Geology&Geophysics,CAS(No.IGGCAS-201905)Feng Shi is funded by the Youth Innovation Promotion Association CAS.
文摘Quantitative assessment of natural internal variability and externally forced responses of Northern Hemisphere(NH)temperatures is necessary for understanding and attributing climate change signals during past warm and cold periods.However,it remains a challenge to distinguish the robust internally generated variability from the observed variability.Here,largeensemble(70 member)simulations,Energy Balance Model simulation,temperature ensemble reconstruction,and three dominant external forcings(volcanic,solar,and greenhouse gas)were combined to estimate the internal variability of NH summer(June–August)temperatures over the past 2000 years(1–2000 CE).Results indicate that the Medieval Climate Anomaly was predominantly attributed to centennial-scale internal oscillation,accounting for an estimated 104%of the warming anomaly.In contrast,the Current Warm Period is influenced mainly by external forcing,contributing up to 90%of the warming anomaly.Internal temperature variability offsets cooling by volcanic eruptions during the Late Antique Little Ice Age.These findings have important implications for the attribution of past climate variability and improvement of future climate projections.
