Climatic Characteristics of Regional Persistent Heat Event in the Eastern China During Recent 60 Years

Abstract

Regional persistent heat event is extensively studied and its intensity is normally investigated from the view of regional average. Climatic characteristics of persistent heat event in 4 regions in the eastern China are analyzed on the basis of distinguishing historical persistent heat event in the South China, the Yangtze River, the Huanghuai and the North China, using the daily maximum temperature data of 2407 stations in China during 1961-2019. The definition index of regional persistent heat event is established, in which the proximity of high temperature stations, the spatial range, the temporal consistency, the regional climate characteristics and the universality of methods are synthesized. Average times of regional persistent heat event in the South China, the Yangtze River, the Huanghuai and the North China are 3.3, 2.8, 2.2 and 0.8 per year respectively, with an average duration of 5.1 d, 6.4 d, 5.0 d and 3.9 d for per event, and the average annual cumulative days in climatology are 16.8 d, 17.8 d, 11.0 d, 3.1 d. Both the duration and the average annual cumulative days of persistent heat event are the longest in the Yangtze River, indicating that the persistent heat event in the Yangtze River is the most serious in climatology among these regions. The average annual cumulative days of persistent heat event in the North China are the least, and it usually ends at the end of July or before. There is a significant linear growing trend in the persistent heat event index in the South China, the North China, and the Yangtze River. There are only 4 non-summer persistent heat events in the Huanghuai in recent 20 years. The difference in strength of the persistent heat event index between the Yangtze River and the South China has significant inter-decadal trends. The index in the Yangtze River is obviously stronger than that in the South China during the first period of 1961-1978, while the index in the South China is slightly stronger than that in the Yangtze River during the second period of 1979-2019. The difference of persistent heat event between these two regions changes by nearly 10 d over these years.

Keywords

• persistent heat event
• variation characteristics