The impact of tropical Indo-Pacific ocean sea surface temperature anoma-lies on high temperature anomalies in the middle and lower reaches of the Yangtze River basin in the summer of 2022
Using NCEP/NCAR reanalysis data,ERSST v5 sea surface temperature data,and an atmospheric cir-culation model,we analyzed the mechanisms and relative contributions of tropical Indo-Pacific ocean SST anoma-lies to the high-temperature event in the middle and lower reaches of the Yangtze River basin during the summer of 2022.The study shows that the summer of 2022 recorded the highest temperatures in the middle and lower rea-ches of the Yangtze River basin in the past 40 years,with an area mean anomalous temperature of 1.52 ℃.The spatial distribution of positive temperature anomalies in this region was highly uneven,with the maximum anoma-lies located to the west of the Henan-Hubei border.This positive temperature anomaly event was influenced by both La Nina and the negative phase of the IOD.After removing the ENSO and IOD signals,the anomalous tem-peratures in the middle and lower reaches of the Yangtze River were 1.23 and 1.37 ℃,respectively.When both ENSO and IOD signals were removed,the temperature anomaly was 1.13 ℃,indicating that tropical Indian Ocean and Pacific SST anomalies contributed 25.66％to the summer high-temperature anomalies in this region.The atmospheric Matsuno-Gill response to the La Nina event caused an anticyclonic circulation anomaly from the middle and lower reaches of the Yangtze River to the Northwest Pacific region.The negative phase IOD event en-hanced the subtropical high in the western Pacific by strengthening the easterly anomalies over the Maritime Con-tinent.The strengthened western Pacific subtropical high favored maintaining anomalous subsidence motion in the middle and lower reaches of the Yangtze River basin,facilitating the occurrence of the high-temperature event.These results provide a scientific basis for understanding the extreme high-temperature events in the middle and lower reaches of the Yangtze River basin during summer.
the summer of 2022middle and lower reaches of theYangtze River basinanomalous high tempera-turetropical Indo-Pacific oceanSST anomaly
万方数据
维普
