Abstract:

 Based on the observation data from 83 meteorological stations and radiosounde stations at Nanchang and Ganzhou of Jiangxi province during 1980-2011, the climate characteristics of haze days and its relationship with meteorological elements were analyzed. The results show that the haze days are in an upward trend in the past 32 years and have significant inter-annual and inter-decadal variations. A larger number of haze days occur in autumn and winter with the maximum number in December and smaller number appears in spring and summer with the minimum number in July, respectively. There are significant 4-year and 8-year cycles for annual haze days and 15-year cycle for inter-decadal variation. The spatial distributions of haze days are inhomogeneous in Jiangxi province with a larger number in the north and smaller in the south and mountain area. It is found that the low wind speed, temperature inversion, high pressure, high humidity and less rainfall are favourable conditions to the occurrence of haze. Conversely, the high wind speed, low pressure, low humidity and abundant rainfall are not favourable.

Key words: Haze, Wavelet analysis, Meteorological conditions, Temperature inversion