This study analyzed the spatial differences of the precipitation variations in the mid-latitude Asia and their possible physical mechanisms during 1960–2009.The annual precipitation showed an opposite variations betw...This study analyzed the spatial differences of the precipitation variations in the mid-latitude Asia and their possible physical mechanisms during 1960–2009.The annual precipitation showed an opposite variations between the westerlies-dominated arid Central Asia(ACA)and monsoon-dominated North China(NC)during the study period.Given the different contributions of seasonal precipitation to annual total precipitation in ACA and NC,the atmospheric circulation anomalies during the major precipitation seasons(winter in ACA/summer in NC)were analyzed.In winter,negative North Atlantic Oscillation may cause negative height anomalies over the north side and positive anomalies over the south side of the ACA.Together,the enhanced pressure gradient and anomalous westerly wind brings more water vapor to ACA,and leaves less precipitation in NC.In summer,the low-pressure anomalies in Northeast China,along with a weaker summer monsoon and negative height anomalies in Eastern Europe together contribute to reduced(excessive)summer precipitation in NC(ACA).The interactions between ENSO and NAO may result in the opposite precipitation variations between ACA and NC.A significant 2–3-year cycle is identified in ACA,which is linked to the variations of westerly circulation in the middle troposphere.展开更多
基金supported by the National Basic Research Program of China (2012CB955303)the Program for New Century Excellent Talents in University (NCET-09-0439)+2 种基金the National Natural Science Foundation of China (41021091 and 41130102)the Program of Introducing Talents of Discipline to Universities (B06026)the Fundamental Research Funds for the Central Universities (lzujbky-2012-k45)
文摘This study analyzed the spatial differences of the precipitation variations in the mid-latitude Asia and their possible physical mechanisms during 1960–2009.The annual precipitation showed an opposite variations between the westerlies-dominated arid Central Asia(ACA)and monsoon-dominated North China(NC)during the study period.Given the different contributions of seasonal precipitation to annual total precipitation in ACA and NC,the atmospheric circulation anomalies during the major precipitation seasons(winter in ACA/summer in NC)were analyzed.In winter,negative North Atlantic Oscillation may cause negative height anomalies over the north side and positive anomalies over the south side of the ACA.Together,the enhanced pressure gradient and anomalous westerly wind brings more water vapor to ACA,and leaves less precipitation in NC.In summer,the low-pressure anomalies in Northeast China,along with a weaker summer monsoon and negative height anomalies in Eastern Europe together contribute to reduced(excessive)summer precipitation in NC(ACA).The interactions between ENSO and NAO may result in the opposite precipitation variations between ACA and NC.A significant 2–3-year cycle is identified in ACA,which is linked to the variations of westerly circulation in the middle troposphere.
