This study investigated the quasi-biweekly oscillation(QBWO)of the South Asian high(SAH)center in midsummer and its possible impact on rainfall in the middle and lower reaches of the Yangtze River Basin(MLYRB),using E...This study investigated the quasi-biweekly oscillation(QBWO)of the South Asian high(SAH)center in midsummer and its possible impact on rainfall in the middle and lower reaches of the Yangtze River Basin(MLYRB),using ERA5 reanalysis data and CPC(Climate Prediction Center)Global Unified Precipitation data from 1979-2023.First,associated with the phase evolution of the QBWO of the SAH center zonally,a general systematic westward propagation of a wave train pattern along the northern margin of the SAH can be identified.Second,energy analysis indicates that this wave train pattern gains energy from the basic flow through both barotropic and baroclinic energy conversion.Compared with barotropic energy conversion,baroclinic energy conversion plays the more important role in the growth,maintenance,and propagation of the wave train pattern associated with the QBWO of the SAH center.Third,the QBWO of the SAH center leads the variation in rainfall in the MLYRB by approximately four days,and might modulate the precipitation in the MLYRB by affecting the coupling of upper-and lower-level circulation anomalies over the MLYRB.The findings of this study suggest that the QBWO of the SAH center could act as potential source of predictability of intraseasonal variation in precipitation in the MLYRB.展开更多
Using NCEP circulation data and precipitation data in China,the influences of strong/weak summer monsoon over the South China Sea (SCS) on atmospheric circulation and climate anomalies are studied.Corresponding to the...Using NCEP circulation data and precipitation data in China,the influences of strong/weak summer monsoon over the South China Sea (SCS) on atmospheric circulation and climate anomalies are studied.Corresponding to the strong (weak) SCS summer monsoon,there are not only different summer precipitation patterns in eastern China,but also different atmospheric circulation patterns in the Northern Hemisphere.The anomaly of the SCS summer monsoon will excite the EPA teleconnection (wave-train) in the Northern Hemispheric atmosphere and lead to climate anomalies not only in East Asia but also in North America.It is still shown that there is interaction between the SSTA in the South China Sea and the SCS summer monsoon;but the influence of the SCS summer monsoon on SSTA in the South China Sea may be more fundamental.展开更多
A universal in tailing wave-train generation of forced soliton generationover topography is found theoretically as the flows are at the resonant points and it is examinedwith the numerical calculation of the correspon...A universal in tailing wave-train generation of forced soliton generationover topography is found theoretically as the flows are at the resonant points and it is examinedwith the numerical calculation of the corresponding fKdV e-quatioa From the comparisons, it is shownthat theoretical and numerical results on the invariance is in good agreement and the theory givenin this paper does not include the modulus truncation, any free constant and unknown function.展开更多
The linkage between the sea ice concentration(SIC)over the Barents–Kara Seas in November–December(SIC_BKS_ND)and the stratospheric polar vortex(SPV)in subsequent January(SPV_Jan)is investigated.It is found that SIC_...The linkage between the sea ice concentration(SIC)over the Barents–Kara Seas in November–December(SIC_BKS_ND)and the stratospheric polar vortex(SPV)in subsequent January(SPV_Jan)is investigated.It is found that SIC_BKS_ND is positively(negatively)correlated with SPV_Jan for the period 1979–1995(1996–2009).Further analyses reveal that,during 1979–1995(1996–2009),SIC_BKS_ND is relatively higher(lower),accompanied by smaller(larger)interannual variability with its center shifting northwest(southeast).Meanwhile,the polar front jet waveguide is relatively stronger(weaker).The simultaneous anomalous eastward-propagating Rossby waves excited by anomalously low SIC_BKS_ND are stronger(weaker),which results in the stronger(weaker)negative–positive–negative wave-train structure of geopotential height anomalies over Eurasia,with the location of these anomalous height centers shifting remarkably westward(eastward).Such changes tend to enhance(suppress)vertically propagating tropospheric planetary waves into the lower stratosphere at high-latitude via constructive(destructive)interference of anomalous tropospheric wave-train structure with the climatological planetary waves,subsequently weakening(strengthening)SPV_Jan.However,in conjunction with anomalously high SIC_BKS_ND,the interference of the tropospheric wave-train structure anomalies and their climatologies shows an opposite distribution to that of low SIC_BKS_ND anomalies,which leads to a strong(weak)SPV_Jan anomaly during 1979–1995(1996–2009).展开更多
基金supported jointly by the National Natural Science Foundation of China(Grant No.42105039)the China Postdoctoral Science Foundation(Grant No.2024M753587)+4 种基金the Hubei Provincial Natural Science Foundation and Meteorological Innovation and development Joint Foundation of China(Grant No.2023AFD104)the Shanghai Science and Technology Development Funds(Grant No.24QB2703600)the Open Project Fund of the China Meteorological Administration Basin Heavy Rainfall Key Laboratory(Grant No.2023BHR-Y03)the Basic Research Fund of the Institute of Heavy Rain,China Meteorological Administration,Wuhan(Grant No.202314)the Open Project Fund of the Key Open Laboratory of Hydrometeorology,China Meteorological Administration(Grant No.23SWQXM018)。
文摘This study investigated the quasi-biweekly oscillation(QBWO)of the South Asian high(SAH)center in midsummer and its possible impact on rainfall in the middle and lower reaches of the Yangtze River Basin(MLYRB),using ERA5 reanalysis data and CPC(Climate Prediction Center)Global Unified Precipitation data from 1979-2023.First,associated with the phase evolution of the QBWO of the SAH center zonally,a general systematic westward propagation of a wave train pattern along the northern margin of the SAH can be identified.Second,energy analysis indicates that this wave train pattern gains energy from the basic flow through both barotropic and baroclinic energy conversion.Compared with barotropic energy conversion,baroclinic energy conversion plays the more important role in the growth,maintenance,and propagation of the wave train pattern associated with the QBWO of the SAH center.Third,the QBWO of the SAH center leads the variation in rainfall in the MLYRB by approximately four days,and might modulate the precipitation in the MLYRB by affecting the coupling of upper-and lower-level circulation anomalies over the MLYRB.The findings of this study suggest that the QBWO of the SAH center could act as potential source of predictability of intraseasonal variation in precipitation in the MLYRB.
基金State Key Project (A)-SCSMEXthe NNSF of China (No.40233033)
文摘Using NCEP circulation data and precipitation data in China,the influences of strong/weak summer monsoon over the South China Sea (SCS) on atmospheric circulation and climate anomalies are studied.Corresponding to the strong (weak) SCS summer monsoon,there are not only different summer precipitation patterns in eastern China,but also different atmospheric circulation patterns in the Northern Hemisphere.The anomaly of the SCS summer monsoon will excite the EPA teleconnection (wave-train) in the Northern Hemispheric atmosphere and lead to climate anomalies not only in East Asia but also in North America.It is still shown that there is interaction between the SSTA in the South China Sea and the SCS summer monsoon;but the influence of the SCS summer monsoon on SSTA in the South China Sea may be more fundamental.
文摘A universal in tailing wave-train generation of forced soliton generationover topography is found theoretically as the flows are at the resonant points and it is examinedwith the numerical calculation of the corresponding fKdV e-quatioa From the comparisons, it is shownthat theoretical and numerical results on the invariance is in good agreement and the theory givenin this paper does not include the modulus truncation, any free constant and unknown function.
基金Supported by the National Natural Science Foundation of China(41730964 and 42088101)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(311021001).
文摘The linkage between the sea ice concentration(SIC)over the Barents–Kara Seas in November–December(SIC_BKS_ND)and the stratospheric polar vortex(SPV)in subsequent January(SPV_Jan)is investigated.It is found that SIC_BKS_ND is positively(negatively)correlated with SPV_Jan for the period 1979–1995(1996–2009).Further analyses reveal that,during 1979–1995(1996–2009),SIC_BKS_ND is relatively higher(lower),accompanied by smaller(larger)interannual variability with its center shifting northwest(southeast).Meanwhile,the polar front jet waveguide is relatively stronger(weaker).The simultaneous anomalous eastward-propagating Rossby waves excited by anomalously low SIC_BKS_ND are stronger(weaker),which results in the stronger(weaker)negative–positive–negative wave-train structure of geopotential height anomalies over Eurasia,with the location of these anomalous height centers shifting remarkably westward(eastward).Such changes tend to enhance(suppress)vertically propagating tropospheric planetary waves into the lower stratosphere at high-latitude via constructive(destructive)interference of anomalous tropospheric wave-train structure with the climatological planetary waves,subsequently weakening(strengthening)SPV_Jan.However,in conjunction with anomalously high SIC_BKS_ND,the interference of the tropospheric wave-train structure anomalies and their climatologies shows an opposite distribution to that of low SIC_BKS_ND anomalies,which leads to a strong(weak)SPV_Jan anomaly during 1979–1995(1996–2009).
