关键词: 天津市, 极端气候指数, 变化趋势

Abstract: Based on the daily temperature and precipitation data from 1951 to 2009 in Tianjin, a series of extreme climatic indices were calculated. Variation characters of 11 main extreme climatic indices were discussed. The results indicate that the variation trends of warm days and cold nights are contrary. Warm days increase and cold nights decrease significantly, and the variation amplitude of cold nights is larger than that of warm days from 1951 to 2009. Continuous warm stage and frost days increase, while continuous cold stage decreases significantly. Five extreme precipitation indices including continuous five days precipitation index, daily precipitation intensity index, strong precipitation rate, extreme strong precipitation rate and continuous humid days are in decreasing trends, while continuous arid days increase. It suggests that drought trend is obvious in Tianjin. The abrupt changes of extreme indices correlated with temperature occur around 1993, but their cycles characters are not significant. The abrupt changes of extreme indices associated with precipitation do not exist, while their cycles are significant and are usually 10 years and 4 years.

Key words: Tianjin, Extreme climatic indices, Variation trend