TY - JOUR
T1 - Physical processes of summer extreme rainfall interannual variability in eastern China: Part I — Observational analysis
AU - Tian, Fangxing
AU - Li, Sihan
AU - Dong, Buwen
AU - Klingaman, Nicholas P.
AU - Freychet, Nicolas
AU - Sparrow, Sarah
N1 - Funding Information:
This work and its contributors were supported by the UK-China Research and Innovation Partnership Fund through the Met Office Climate Science for Service Partnership (CSSP) China EERCH project as part of the Newton Fund. BD is supported by the U.K. National Centre for Atmospheric Science (NCAS) at the University of Reading. NPK was also supported by the ACREW programme of NCAS, part of the Global Challenges Research Fund (GCRF) administered by the Natural Environment Research Council. The authors would like to thank anonymous reviewers for their constructive comments on the earlier version of the paper.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/1/20
Y1 - 2022/1/20
N2 - Extreme precipitation can have catastrophic effects in China by triggering floods, landslides, and other natural disasters. We measure extreme precipitation over eastern China by the maximum of five-day precipitation amount (Rx5day) in June, July, and August (JJA), which contributes more than 20% of the climate mean of JJA regional total precipitation. Based on the empirical orthogonal teleconnection (EOT) method, this work identifies four dominant regions of observed Rx5day interannual variability in eastern China: north-eastern China (EOT1), the southern lower reaches of the Yangtze valley (EOT2), southern China (EOT3) and the northern lower reaches of the Yangtze valley (EOT4). EOT1 extreme precipitation is related to a strong East Asian Summer Monsoon (EASM), a weak monsoon front and a northward displaced upper-tropospheric westerly jet. EOT2 and EOT4 extreme precipitation are related to an enhanced and stable monsoon front and a strong western North Pacific subtropical high (WNPSH). The WNPSH associated with EOT4 is stronger than that associated with EOT2, which pushes the monsoon front further north. EOT3 represents extreme precipitation that is related to anomalous southerlies around the western ridge of the WNPSH. The southerlies transport warm and moist air to southern China and increase precipitation there. The four key regions and the related mechanisms are not sensitive to the EOT technique, as the EOT-based extreme precipitation patterns and circulation anomalies are confirmed using Self-Organising Maps (SOMs).
AB - Extreme precipitation can have catastrophic effects in China by triggering floods, landslides, and other natural disasters. We measure extreme precipitation over eastern China by the maximum of five-day precipitation amount (Rx5day) in June, July, and August (JJA), which contributes more than 20% of the climate mean of JJA regional total precipitation. Based on the empirical orthogonal teleconnection (EOT) method, this work identifies four dominant regions of observed Rx5day interannual variability in eastern China: north-eastern China (EOT1), the southern lower reaches of the Yangtze valley (EOT2), southern China (EOT3) and the northern lower reaches of the Yangtze valley (EOT4). EOT1 extreme precipitation is related to a strong East Asian Summer Monsoon (EASM), a weak monsoon front and a northward displaced upper-tropospheric westerly jet. EOT2 and EOT4 extreme precipitation are related to an enhanced and stable monsoon front and a strong western North Pacific subtropical high (WNPSH). The WNPSH associated with EOT4 is stronger than that associated with EOT2, which pushes the monsoon front further north. EOT3 represents extreme precipitation that is related to anomalous southerlies around the western ridge of the WNPSH. The southerlies transport warm and moist air to southern China and increase precipitation there. The four key regions and the related mechanisms are not sensitive to the EOT technique, as the EOT-based extreme precipitation patterns and circulation anomalies are confirmed using Self-Organising Maps (SOMs).
KW - East Asian Summer Monsoon
KW - Empirical orthogonal teleconnection (EOT)
KW - Extreme precipitation
KW - Moisture budget
KW - Monsoon front
KW - Rx5day
KW - Self-Organising Maps (SOM)
KW - Upper-tropospheric westerly jet
KW - Western North Pacific subtropical high (WNPSH)
U2 - 10.1007/s00382-021-06123-x
DO - 10.1007/s00382-021-06123-x
M3 - Article
SN - 0930-7575
VL - 59
SP - 201
EP - 217
JO - Climate Dynamics
JF - Climate Dynamics
IS - 1-2
ER -