Abstract: ： In order to explore the variation rule and the reason of sunshine duration in Huanggang city, Hubei province, under the background of global climate change in the past 55 years, based on the daily sunshine data of nine national meteorological stations in Huanggang city from 1961 to 2015, the sunshine duration variation characteristics in Huanggang city were analyzed by using the linear trend estimation, Mann-Kendall parametric test, 5 years moving ayerage method and wavelet analysis. The results showed that, in the past 55 years, the annual sunshine duration in Huanggang city showed an obvious reduction trend, and the climate tendency rate was -41.576 h/10 a. The decrease of sunshine duration in summer was the most significant and the decrease of sunshine duration was the largest. The monthly sunshine duration in Huanggang city was the highest in August, while the lowest was in February, and the highest sunshine duration was 2.2 times of the lowest one. In August, the decrease of the sunshine duration was the most significant, followed by June and July. The annual sunshine duration of Huanggang city was abruptly changed in 1972, and the mutation was significant. In the past 55 years, there were obvious interannual and interdecadal variations of sunshine duration in Huanggang city, the sunshine duration was mainly controlled by three cycles. In terms of impact factors, the precipitation and vapor pressure were negatively correlated with sunshine duration, which was one of the reasons for the decline of sunshine duration. Although, the amount of total cloud and low cloud had a certain effect on sunshine duration, but not the main cause of sunshine declined.

Key words: sunshine duration, trend characteristics, mutation, period, Huanggang city