Warming Trend and Seasonal Variation in Hangzhou from 1961 to 2012
Chen Kechen;Yuhang Meteorological Bureau of Zhejiang Province;
In order to clarify the seasonal variation characteristics of Hangzhou under the background of the climate warming and the influence from the temperature variation to the seasonal variation, using the daily temperature data of the Hangzhou station from 1961 to 2012, according to the newest delineation standard of climatic season, the length and beginning date of four seasons were divided. The variation features of the temperature and the length and beginning date of four seasons in recent 52 years and the correlations among them were investigated with the modern statistical diagnostic methods, such as climatic trend rate, correlation analysis, and abrupt detection. The results showed that: summer was the longest season in Hangzhou, while autumn was the shortest season. Meanwhile the summer was becoming longer significantly at a rate of 5.33 d/ 10 a, and the winter was getting shorter obviously at a rate of-3.62 d/10 a. The lengthening of the summer was influenced by the advancing of the beginning date of the summer and the delaying of the beginning date of the autumn. The shortening of the winter was influenced by the advancing of the beginning date of the spring and delaying of the beginning date of the winter, furthermore the influence of former was more than that of the latter. The summer length becoming longer, the spring and summer beginning date advancing, and the autumn beginning date delaying occurred at the same abrupt change time of the early of the 1990s. The air temperature of Hangzhou had increased clearly with the climatic rate 0.35℃/10 a in recent 52 years. The yearly mean air temperature had relationship with the length and beginning date of the four seasons. It mainly showed that when the air temperature increased, the beginning date of the spring and summer advanced and the two seasons lengthened, and the beginning date of the autumn and winter delayed and the two seasons shortened.