Based on the high-and low-resolution Community Earth System Model, version 1(CESM1), and corresponding simulations from phase 6 of the Coupled Model Intercomparison Project(CMIP6), we compare the interannual variabili...Based on the high-and low-resolution Community Earth System Model, version 1(CESM1), and corresponding simulations from phase 6 of the Coupled Model Intercomparison Project(CMIP6), we compare the interannual variability of the East Asian summer monsoon(EASM). The EASM interannual variability is characterized by the anomalous western North Pacific anticyclone(WNPAC) circulation and the dipole rainfall pattern with a negative southern lobe over the western North Pacific and a positive northern lobe along the Meiyu–Baiu region, which is better reproduced by the highresolution models. The reason for the improvement in the high-resolution models has been attributed to the better simulation of the warm temperature advection from the wind anomalies on the climatological temperature gradient. Positive sea surface temperature(SST) anomalies over the tropical Indian Ocean are the key to the improved wind anomalies featuring a WNPAC in the high-resolution models. The warm SST anomalies over the tropical Indian Ocean strengthen the WNPAC by triggering a Kelvin-wave response to the enhanced heat release induced by the increased precipitation. Based on the mixed-layer heat budget analysis, the warm SST anomalies over the western Indian Ocean in the high-resolution CESM1 are tied to the anomalous easterly wind along the equator, which reduces surface evaporation and upwelling.Therefore, the better simulations of air–sea feedback and the oceanic mesoscale eddy over the western Indian Ocean are the key for the improved simulation of the EASM interannual variations in the high-resolution CESM1.展开更多
How tropical cyclone(TC)activity varies in response to a changing climate is widely debated.The accumulated cyclone energy(ACE)is one of the indicators of TC activity and has attracted considerable attention because o...How tropical cyclone(TC)activity varies in response to a changing climate is widely debated.The accumulated cyclone energy(ACE)is one of the indicators of TC activity and has attracted considerable attention because of its close relationship with the damages caused by TCs.Previous studies have focused on detecting long-term trends in global ACE;however,the results are inconclusive.Here,it is revealed that the global ACE demonstrates a striking interdecadal variation over the past four decades,with a historical peak occurring in the 1990s.A close relationship between the interdecadal variability of the global ACE and the Interdecadal Pacific Oscillation(IPO)is also identified,with a Pearson correlation coefficient of 0.75(P<0.01).When the IPO is in its positive phase,more TCs with a longer lifetime occur owing to greater coverage of weak vertical wind shear(VWS)conditions over the tropics.The coverage of weak VWS conditions can be verified by either prescribing the observed sea surface temperature in atmospheric models or the observed IPO in coupled models,indicating the significant role of the IPO.Our findings show that the IPO affects the interdecadal variability of global TC activity through moderating atmospheric circulations.展开更多
The Yangtze River Basin(YRB;27°N-36°N,100°E-123°E)enters its main rainy season,known as Meiyu[1,2],normally from mid-June to mid-July,along with the northward seasonal march of East Asian monsoon p...The Yangtze River Basin(YRB;27°N-36°N,100°E-123°E)enters its main rainy season,known as Meiyu[1,2],normally from mid-June to mid-July,along with the northward seasonal march of East Asian monsoon precipitation.The seasonal evolution of the YRB rainfall is closely tied to the location of subtropical westerlies relative to the Tibetan Plateau.The mechanical forcing of westerlies impinging on the large-scale topography can generate meridional wind convergence downstream,inducing rainfall over the downstream regions[3,4].From spring to summer,the westerlies core undertakes a notable northward migration,moving from the south of the plateau to directly above the plateau[5].Correspondingly,the downstream convergence and moisture supply gradually intensify,leading to the northward migration of the rain belt and the onset of Meiyu[4,5].The YRB rainfall is fundamentally governed by the evolution of moisture and atmospheric circulation.Under global warming,both dynamical effects associated with circulation changes and thermodynamic effects affected by moisture changes can substantially modulate the Meiyu onset.展开更多
基金supported by the National Natural Science Foundation of China [Grant Nos.42275018 (L.D.) and 42175029 (F.S.)]the Shandong Provincial Natural Science Fund for Excellent Young Scientists Fund Program (Overseas) [Grant No.2022HWYQ-065 (L.D.)]+3 种基金the Taishan Scholars Program of Shandong Province [Grant No.tsqn202211068 (L.D.)]the Fund of Laoshan Laboratory [Grant Nos.LSKJ202202602 (L.D.) and LSKJ202202201 (F.S.)]financially supported by Laoshan Laboratory (Grant No.LSKJ202300302)supported by the Office of Science, U.S.Department of Energy (DOE) Biological and Environmental Research through the Water Cycle and Climate Extremes Modeling (WACCEM) scientific focus area funded by the Regional and Global Model Analysis program area。
文摘Based on the high-and low-resolution Community Earth System Model, version 1(CESM1), and corresponding simulations from phase 6 of the Coupled Model Intercomparison Project(CMIP6), we compare the interannual variability of the East Asian summer monsoon(EASM). The EASM interannual variability is characterized by the anomalous western North Pacific anticyclone(WNPAC) circulation and the dipole rainfall pattern with a negative southern lobe over the western North Pacific and a positive northern lobe along the Meiyu–Baiu region, which is better reproduced by the highresolution models. The reason for the improvement in the high-resolution models has been attributed to the better simulation of the warm temperature advection from the wind anomalies on the climatological temperature gradient. Positive sea surface temperature(SST) anomalies over the tropical Indian Ocean are the key to the improved wind anomalies featuring a WNPAC in the high-resolution models. The warm SST anomalies over the tropical Indian Ocean strengthen the WNPAC by triggering a Kelvin-wave response to the enhanced heat release induced by the increased precipitation. Based on the mixed-layer heat budget analysis, the warm SST anomalies over the western Indian Ocean in the high-resolution CESM1 are tied to the anomalous easterly wind along the equator, which reduces surface evaporation and upwelling.Therefore, the better simulations of air–sea feedback and the oceanic mesoscale eddy over the western Indian Ocean are the key for the improved simulation of the EASM interannual variations in the high-resolution CESM1.
基金supported by the National Natural Science Foundation of China(41961144014,and 42175029)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2023QNRC001).
文摘How tropical cyclone(TC)activity varies in response to a changing climate is widely debated.The accumulated cyclone energy(ACE)is one of the indicators of TC activity and has attracted considerable attention because of its close relationship with the damages caused by TCs.Previous studies have focused on detecting long-term trends in global ACE;however,the results are inconclusive.Here,it is revealed that the global ACE demonstrates a striking interdecadal variation over the past four decades,with a historical peak occurring in the 1990s.A close relationship between the interdecadal variability of the global ACE and the Interdecadal Pacific Oscillation(IPO)is also identified,with a Pearson correlation coefficient of 0.75(P<0.01).When the IPO is in its positive phase,more TCs with a longer lifetime occur owing to greater coverage of weak vertical wind shear(VWS)conditions over the tropics.The coverage of weak VWS conditions can be verified by either prescribing the observed sea surface temperature in atmospheric models or the observed IPO in coupled models,indicating the significant role of the IPO.Our findings show that the IPO affects the interdecadal variability of global TC activity through moderating atmospheric circulations.
基金jointly supported by the National Natural Science Foundation of China(42175029,42475029 and 92358302)Laoshan Laboratory(LSKJ202300302).
文摘The Yangtze River Basin(YRB;27°N-36°N,100°E-123°E)enters its main rainy season,known as Meiyu[1,2],normally from mid-June to mid-July,along with the northward seasonal march of East Asian monsoon precipitation.The seasonal evolution of the YRB rainfall is closely tied to the location of subtropical westerlies relative to the Tibetan Plateau.The mechanical forcing of westerlies impinging on the large-scale topography can generate meridional wind convergence downstream,inducing rainfall over the downstream regions[3,4].From spring to summer,the westerlies core undertakes a notable northward migration,moving from the south of the plateau to directly above the plateau[5].Correspondingly,the downstream convergence and moisture supply gradually intensify,leading to the northward migration of the rain belt and the onset of Meiyu[4,5].The YRB rainfall is fundamentally governed by the evolution of moisture and atmospheric circulation.Under global warming,both dynamical effects associated with circulation changes and thermodynamic effects affected by moisture changes can substantially modulate the Meiyu onset.
