Classification of 3h extreme precipitation spatial patterns and their
influencing factors in Guangdong Province, China
Abstract
Extreme precipitation events (EPEs) on a sub-daily scale are an
important factor in triggering urban flooding and flash flooding.
However, corresponding studies on the spatial patterns of sub-daily
extreme precipitation in Guangdong Province are lacking. We objectively
classified the spatial patterns of extreme precipitation (EPSPs) in
Guangdong Province, calculated the importance of influencing factors on
EPSPs, and finally analyzed the weather background corresponding to
various EPSPs and explained the causes of extreme precipitation. We have
found that the incidence of most EPSPs has tended to increase
significantly over this 40-year period, and the increase has been
particularly pronounced since the 21st century. The Pacific Decade
Oscillation (PDO) was the main influence on EPEs in Yangjiang, Maoming
and Shanwei, and the weakening of PDO has contributed to the occurrence
of EPEs in these areas. Urbanization is the main factor contributing to
the increase in EPEs in the PRD, Zhanjiang and coastal areas of
Guangdong Province. The cause of the EPSP in central Guangdong Province
was the southwest jet stream and topographic uplift. The extreme
precipitation in Yangjiang, the PRD, Maoming and Shanwei was mainly
triggered by the convergent shear of the southwesterly winds. The cause
of the EPSP over Zhanjiang was the low vortex in western Guangdong and
the influx of large amounts of water vapour over land from the south
over the ocean.