CR 50:171-185 (2011)  -  DOI: https://doi.org/10.3354/cr01045

Circulation patterns of regional mean daily ­precipitation extremes over the middle and lower reaches of the Yangtze River during the boreal summer

Zhaoyong Guan*, Jie Han, Minggang Li

Province-Ministry Established Key Laboratory for Meteorological Disasters, Nanjing University of Information Science and Technology, Nanjing 210044, PR China

ABSTRACT: By employing the composite analysis and using daily data from the National Center for Environmental Prediction/National Center for Atmospheric Research reanalysis and precipitation records at 743 stations in China, the anomalous circulation patterns for the regional mean daily precipitation extreme (DPE) events over the middle and lower reaches of Yangtze River (MLRYR) in June, July and August of the boreal summer during the period from 1979 to 2008 were investigated. This analysis determined that there have been 93 DPE events in the past 30 yr. Two types of anomalous circulation patterns were revealed in association with these DPE events. A Type I circulation pattern demonstrates an anomalous cyclone over MLRYR and an anomalous anticyclone in the South China Sea (SCS) and tropical northwestern Pacific Ocean (NWP) in the lower troposphere. An anomalous anticyclone in the upper troposphere exists in the region south of the MLRYR. The water vapor is transported not only from the Bay of Bengal, the SCS and the NWP, but also from areas northwest of the MLRYR. The apparent heating anomalies are favorable for intensifying the anomalous vertical meridional circulations in East Asia. The pattern of sea ­surface temperature anomalies (SSTAs) in the Indo-Pacific sector looks similar to the SSTA pattern during the maturing and decaying phases of El Niño episodes. Of the 93 DPE events 16 were induced by a Type II circulation pattern. This pattern looks largely different from the Type I ­pattern in aspects of distributions of anomalous winds, divergence, water vapor sources, thermal forcings and SSTAs. These results will help us understand the occurrences of DPE events in the MLRYR.


KEY WORDS: Daily precipitation extremes · Circulation patterns · Diabatic heating · Yangtze River · China · Boreal summer


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Cite this article as: Guan Z, Han J, Li M (2011) Circulation patterns of regional mean daily ­precipitation extremes over the middle and lower reaches of the Yangtze River during the boreal summer. Clim Res 50:171-185. https://doi.org/10.3354/cr01045

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