Dynamic pathway linking Pakistan flooding to East Asian heatwaves

Dynamic pathway linking Pakistan flooding to East Asian heatwaves

24 April 2024 | Zheng-Hang Fu, Wen Zhou, Shang-Ping Xie, Ruhua Zhang, Xudong Wang
This study investigates the dynamic pathway linking Pakistan flooding to East Asian heatwaves, which occurred simultaneously in July-August 2022. Using observations and atmospheric model experiments, the authors find that convective heating over Pakistan induces a barotropic anomalous anticyclone (AAC) over eastern China, leading to persistent heatwaves. This dynamic connection is intrinsic to the Asian summer monsoon system and is largely independent of global sea surface temperature (SST) forcing. The upper-tropospheric divergent flow associated with convective heating produces a negative Rossby wave source (RWS) near the subtropical westerly jet, which further enhances the AAC over eastern China. This feedback mechanism is most active during July-August, when convective variability is high over Pakistan. The study highlights the importance of atmospheric internal variability in linking Pakistan flooding and East Asian heatwaves, providing insights for improving subseasonal prediction of extreme events in East Asia.This study investigates the dynamic pathway linking Pakistan flooding to East Asian heatwaves, which occurred simultaneously in July-August 2022. Using observations and atmospheric model experiments, the authors find that convective heating over Pakistan induces a barotropic anomalous anticyclone (AAC) over eastern China, leading to persistent heatwaves. This dynamic connection is intrinsic to the Asian summer monsoon system and is largely independent of global sea surface temperature (SST) forcing. The upper-tropospheric divergent flow associated with convective heating produces a negative Rossby wave source (RWS) near the subtropical westerly jet, which further enhances the AAC over eastern China. This feedback mechanism is most active during July-August, when convective variability is high over Pakistan. The study highlights the importance of atmospheric internal variability in linking Pakistan flooding and East Asian heatwaves, providing insights for improving subseasonal prediction of extreme events in East Asia.
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