Abstract: By using the NCEP/NCAR reanalysis data and the station-observed haze days and precipitation data in Jiangsu Province during 1961-2010, decadal variability characteristics of haze days in autumn in recent 50 years were discussed and explained from the influencing aspects of climatological background. Results indicate that the atmospheric circulation and vapor transportation during the low incidence period of haze were in favor of the transfer and dilution of pollutants; and in the high incidence period the haze observably increased, the climatological background field played a more active role in the generation of haze weather compared with the low incidence period. Besides, the frequency of air cleaning reduced remarkably in 1961-2010. SST was closely related to the decadal variability of haze. When the haze days increased continuously, the SST became higher from the Indian Ocean to the South China Sea, giving rise to the convergence/divergence in the low-lever wind field over the sea surface/ the middle latitude area with the same longitude (East Asia) by forming a Hadley-like cell, which is conducive to the formation of haze weather in Jiangsu Province.

Key words: Jiangsu Province, haze days, decadal variability, circulation variation, SST variation