Abstract:
Using observational daily maximum temperature of Chinese 181 stations for the period of 1957~2004, the spatiotemporal features of the climatology and decadal variability of the extreme hot event (EHE) frequency, intensity, onset date (EHEOD), and termination date (EHE_TD) are investigated. The climatological analysis indicates that southeastern China and Xinjiang are the two major domains for the EHE, and eastern China is a region with a strong interannual variability. The EHE experienced strong decadal variability in the last 48 years. The variabilities of the frequency and intensity are consistent, and the variabilities of the EHE_OD and EHE_TD are similar. Based on the EHE spatiotemporal feature, the whole China can be divided into four subregions: Southern China, central China, eastern northern China, and Northwest China. The EHE frequency is high in the 1960s and the 1980s for southern China,in the 1960s and the 1990s for central China, and in the 1990s for northern China. Further, the atmospheric circulations which are responsible for the interannual and decadal variability of the EHE in the above four sub-regions are explored. It suggests that the circulations impacting on the interannual and decadal variability are consistent. For northern China, the major circulation is the overlying geopotential height anomaly at middletoupper levels. For southern and central China, the major circulations are the overlying geopotential height anomaly at middletoupper levels and temperature advection by the meridional wind at lower levels.
