The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal ...The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late1980 s.During the latter period,the weak(strong)EAT corresponds to a strong and large-scale anomalous anticyclone(cyclone)over the East Asia-Northwest Pacific region.The EAT-related anomalous southerlies(northerlies)dominate eastern SWC,leading to significant upward(downward)motion and moisture convergence(divergence)over the region,providing favorable(unfavorable)dynamic and moisture conditions for extreme precipitation over eastern SWC.In contrast,during the former period,the EAT-related circulation anomalies are weak and cover a relatively smaller region,which cannot significantly affect the moisture and dynamic conditions over eastern SWC;therefore,the response in extreme precipitation over eastern SWC to EAT is weak over the period.The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability.The large(small)variability of the EAT is associated with significant(insignificant)changes in spring extreme precipitation over eastern SWC during the latter(former)period.展开更多
基金jointly supported by the National Natural Science Foundation of China[grant number 41825010]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA23090102]。
文摘The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late1980 s.During the latter period,the weak(strong)EAT corresponds to a strong and large-scale anomalous anticyclone(cyclone)over the East Asia-Northwest Pacific region.The EAT-related anomalous southerlies(northerlies)dominate eastern SWC,leading to significant upward(downward)motion and moisture convergence(divergence)over the region,providing favorable(unfavorable)dynamic and moisture conditions for extreme precipitation over eastern SWC.In contrast,during the former period,the EAT-related circulation anomalies are weak and cover a relatively smaller region,which cannot significantly affect the moisture and dynamic conditions over eastern SWC;therefore,the response in extreme precipitation over eastern SWC to EAT is weak over the period.The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability.The large(small)variability of the EAT is associated with significant(insignificant)changes in spring extreme precipitation over eastern SWC during the latter(former)period.
