Spatiotemporal Characteristics of 1961-2020 Summer Extreme Precipitation Anomaly in Henan Province and Their Relationships with the Atmospheric Circulation and SST
The climatic characteristics and major modes of summer extreme precipitation in Henan Province from 1961 to 2020 and their relationships with atmospheric circulation and SST were analyzed based on the daily precipitation data of 125 meteoro-logical stations,ERA5 atmospheric reanalysis data and HadISST sea surface temperature data.The climatological mean of the frequency and intensity of extreme precipitation in Henan Province showed an increasing pattern from northwest to southeast,with the most extreme precipitation in the southeast,followed by the northern part of the east,and the least in the western mountain regions.The distribution of standard deviation was similar with that of the climatology,and the regions with larger mean precipitation also had larger interannual differences.Summer extreme precipitation in Henan Province presented signifi-cant interannual variation,but the linear trend was relatively weak.The first mode of EOF of summer extreme precipitation in Henan Province showed a uniform distribution overall the province,with the high-latitude Eurasian teleconnection mode condu-cive to the southward movement of high-latitude cold air,and the westward extension of the subtropical high conducive to the transport of water vapor to Henan.The simultaneous SST showed significant positive Kuroshio extension SST anomaly,La Nina pattern,the negative phase of the South Indian Ocean SST dipole and the North Atlantic SST tripole positive phase modes,and vice versa.The second mode was characterized by the inverse phase distribution with more precipitation in the northern part of Henan Province and less in the southern part of Henan Province,the blocking high over the Ural Mountains and the longwave trough in East Siberia were conducive to the southward movement of high-latitude cold air,and the westward extension of the subtropical high was conducive to the transport of water vapor to Henan.The simultaneous SST showed signif-icant La Nina pattern,but the more extreme the precipitation was,the more complex the SST anomaly signal will be,and vice versa.
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