Meiyu is the main rainy season in the middle and lower reaches of the Yangtze River basin.However,the mechanism and predictability of atypical Meiyu are not clear.In 2022,an atypical“hot-and-dry”Meiyu occurred in th...Meiyu is the main rainy season in the middle and lower reaches of the Yangtze River basin.However,the mechanism and predictability of atypical Meiyu are not clear.In 2022,an atypical“hot-and-dry”Meiyu occurred in the lower Yangtze River basin(LYRB).By taking the 2022 Meiyu as an example,causes of the atypical Meiyu are diagnosed from the perspective of subseasonal evolution,and its predictability is further evaluated with ECMWF and NCEP Climate Forecast System version 2(CFSv2)forecast models.The 2022 atypical Meiyu featured an early onset and a three-stage back-and-forth swing through LYRB,with two sudden meridional rainband shifts,i.e.,a southward withdrawal in early June and a northward leap in late June.Influenced by the active phases of the boreal summer intraseasonal oscillation(BSISO)and the“cold vortex-heat dome(CVHD)”pattern in northern East Asia,the Meiyu rainband was suppressed and retreated southward to South China in early June.A northwestward expansion of western Pacific subtropical high(WPSH)and an abrupt northward leap of the rainband terminated Meiyu near early July due to a sudden northward displacement of the East Asian summer westerly jet and the BSISO2(10-30 day BSISO)-modulated anomalous cyclone in the subtropics.Two eastward-propagating intraseasonal wave trains along the polar front and subtropical westerly jets that are responsible for the jet displacement played crucial roles in triggering the CVHD pattern and forming an enormous upper-tropospheric anomalous anticyclone over western East Asia.Both ECMWF and CFSv2 models exhibited lower prediction skills on extratropical intraseasonal oscillations(ISOs)than on tropical ISOs.The models well predicted the rainband position in the first and third stages,but overestimated the LYRB rainfall in the second stage,which was caused by poor representation of the two intraseasonal wave trains and the CVHD pattern.These results highlight the cooperative effects of tropical and extratropical intraseasonal variabilities on atypical Meiyu events.展开更多
A record-breaking extreme Meiyu rainfall occurred along the Yangtze River valley(YRV)in 2020 since 1961,persisting from 11 June to 31 July with the largest amount and the highest intensity.From the aspect of water vap...A record-breaking extreme Meiyu rainfall occurred along the Yangtze River valley(YRV)in 2020 since 1961,persisting from 11 June to 31 July with the largest amount and the highest intensity.From the aspect of water vapor,the causes of its formation are revealed in this study.The 2020 Meiyu rainfall amount is directly attributed to the greatly enhanced vertically integrated water vapor transport(IVT)convergence,which is in turn primarily determined by the mean circulation dynamic(MCD)contribution associated with anomalous East Asian summer monsoon(EASM)and the thermodynamic component(TH)contribution due to water vapor anomaly.The MCD contribution is mainly responsible for the extreme Meiyu rainfall amount and abundant water vapor convergence in the YRV,whereas the TH contribution tends to shift Meiyu rain belt northward to the Yangtze-Huaihe River valley,extending the Meiyu rainfall coverage area.Furthermore,the excessive moist static energy(MSE)associated with the largest water vapor anomaly could substantially increase the atmospheric instability,favoring the extreme 2020 Meiyu rainfall intensity.In terms of the tremendous IVT to the YRV from both the South China Sea and Bay of Bengal during the 2020 Meiyu period,the low-level anticyclone anomalies over the western North Pacific(WNP)and Bay of Bengal provide appropriate atmospheric circulation conditions,and they are generated by the super suppressed WNP convective activities as a Matsuno-Gill type response,which are further attributed to the combined warm SST anomalies in both the tropical western Indian Ocean(TWIO)and tropical Atlantic Ocean(TAO)eventually.展开更多
This erratum is to report a figure misplacement in Wang et al.(2021)entitled“Contribution of Water Vapor to the Record-Breaking Extreme Meiyu Rainfall along the Yangtze River Valley in 2020.”In Wang et al.(2021),Fig...This erratum is to report a figure misplacement in Wang et al.(2021)entitled“Contribution of Water Vapor to the Record-Breaking Extreme Meiyu Rainfall along the Yangtze River Valley in 2020.”In Wang et al.(2021),Fig.2b should be switched with Fig.2d(note that the labels on top of Figs.2b and 2d need not change).The correct figure as a whole is given here(Fig.2).展开更多
基金Supported by the National Natural Science Foundation of China(42175056)China Meteorological Administration(CMA)Joint Research Project for Meteorological Capacity Improvement(23NLTSQ006)+4 种基金Shanghai Sailing Program(23YF1440100)Natural Science Foundation of Shanghai(21ZR1457600)CMA Innovation and Development Project(CXFZ2022J009)CMA Youth Innovation Group Program(CMA2024QN06)CMA Key Innovation Team Project(CMA2023ZD03).
文摘Meiyu is the main rainy season in the middle and lower reaches of the Yangtze River basin.However,the mechanism and predictability of atypical Meiyu are not clear.In 2022,an atypical“hot-and-dry”Meiyu occurred in the lower Yangtze River basin(LYRB).By taking the 2022 Meiyu as an example,causes of the atypical Meiyu are diagnosed from the perspective of subseasonal evolution,and its predictability is further evaluated with ECMWF and NCEP Climate Forecast System version 2(CFSv2)forecast models.The 2022 atypical Meiyu featured an early onset and a three-stage back-and-forth swing through LYRB,with two sudden meridional rainband shifts,i.e.,a southward withdrawal in early June and a northward leap in late June.Influenced by the active phases of the boreal summer intraseasonal oscillation(BSISO)and the“cold vortex-heat dome(CVHD)”pattern in northern East Asia,the Meiyu rainband was suppressed and retreated southward to South China in early June.A northwestward expansion of western Pacific subtropical high(WPSH)and an abrupt northward leap of the rainband terminated Meiyu near early July due to a sudden northward displacement of the East Asian summer westerly jet and the BSISO2(10-30 day BSISO)-modulated anomalous cyclone in the subtropics.Two eastward-propagating intraseasonal wave trains along the polar front and subtropical westerly jets that are responsible for the jet displacement played crucial roles in triggering the CVHD pattern and forming an enormous upper-tropospheric anomalous anticyclone over western East Asia.Both ECMWF and CFSv2 models exhibited lower prediction skills on extratropical intraseasonal oscillations(ISOs)than on tropical ISOs.The models well predicted the rainband position in the first and third stages,but overestimated the LYRB rainfall in the second stage,which was caused by poor representation of the two intraseasonal wave trains and the CVHD pattern.These results highlight the cooperative effects of tropical and extratropical intraseasonal variabilities on atypical Meiyu events.
基金Supported by the National Key Research and Development Program of China(2018YFC1505803)National Natural Science Foundation of China(41775074)Foundation for Innovative Research Groups of the National Natural Science Foundation of China(41621005)。
文摘A record-breaking extreme Meiyu rainfall occurred along the Yangtze River valley(YRV)in 2020 since 1961,persisting from 11 June to 31 July with the largest amount and the highest intensity.From the aspect of water vapor,the causes of its formation are revealed in this study.The 2020 Meiyu rainfall amount is directly attributed to the greatly enhanced vertically integrated water vapor transport(IVT)convergence,which is in turn primarily determined by the mean circulation dynamic(MCD)contribution associated with anomalous East Asian summer monsoon(EASM)and the thermodynamic component(TH)contribution due to water vapor anomaly.The MCD contribution is mainly responsible for the extreme Meiyu rainfall amount and abundant water vapor convergence in the YRV,whereas the TH contribution tends to shift Meiyu rain belt northward to the Yangtze-Huaihe River valley,extending the Meiyu rainfall coverage area.Furthermore,the excessive moist static energy(MSE)associated with the largest water vapor anomaly could substantially increase the atmospheric instability,favoring the extreme 2020 Meiyu rainfall intensity.In terms of the tremendous IVT to the YRV from both the South China Sea and Bay of Bengal during the 2020 Meiyu period,the low-level anticyclone anomalies over the western North Pacific(WNP)and Bay of Bengal provide appropriate atmospheric circulation conditions,and they are generated by the super suppressed WNP convective activities as a Matsuno-Gill type response,which are further attributed to the combined warm SST anomalies in both the tropical western Indian Ocean(TWIO)and tropical Atlantic Ocean(TAO)eventually.
文摘This erratum is to report a figure misplacement in Wang et al.(2021)entitled“Contribution of Water Vapor to the Record-Breaking Extreme Meiyu Rainfall along the Yangtze River Valley in 2020.”In Wang et al.(2021),Fig.2b should be switched with Fig.2d(note that the labels on top of Figs.2b and 2d need not change).The correct figure as a whole is given here(Fig.2).
