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關(guān)鍵詞: 氣候變暖, 極端氣溫指數(shù), 變化趨勢, 北京, climate warming, extreme temperature indices, trend, Beijing

Abstract: Using the homogenized temperature data series in the period 1960-2008, the characteristics of climate warming and variations of extreme temperature indices in Beijing were analyzed. Results indicate that the increase rate of annual mean temperature were 0.39℃/10a, and the mean maximum and minimum temperatures changed asymmetrically, indicating that the climate warming were mainly caused by minimum temperature increasing. The climate base state indices of frost days (FD) and extreme temperature range (ETR) declined, warm nights (TN90) and heat wave duration index (HWDI) increased, and most of extreme temperature indices exhibited high variability except for the ETR index. Morlet wavelet transform shows that the main periods for mean annual temperature and extreme temperature indices were about 21, 15-17, and 10 years. There were a close correlation between annual mean temperature and extreme temperature indices. Since 1980, extreme high temperature, and high temperature days have increased more in urban areas than in suburbs and exurbs, while extreme low temperature and low temperature days have decreased more in urban areas and suburbs than in exurbs. The above results suggest that the variations in extreme temperatures in Beijing have been obviously affected by its urbanization process.