摘要
Based on daily maximum and minimum surface air temperature and precipitation records at 48 meteorological stations in Xinjiang, the spatial and temporal distributions of climate extreme indices have been analyzed during 1961-2008. Twelve temperature ex- treme indices and six precipitation extreme indices are studied. Temperature extremes are highly correlated to annual mean tem- perature, which appears to be significantly increasing by 0.08 ℃ per year, indicating that changes in temperature extremes reflect consistent warming. The warming tendency is clearer at stations in northern Xinjiang as reflected by mean temperature. The fre- quencies of cold days and nights have both decreased, respectively by -0.86 and -2.45 d/decade, but the frequencies of warm days and nights have both increased, respectively by ＋1.62 and ＋4.85 d/decade. Over the same period, the number of frost days shows a statistically significant decreasing trend of-2.54 d/decade. The growing season length and the number of summer days exhibit significant increasing trends at rates of ＋2.62 and ＋2.86 d/decade, respectively. The diumal temperature range has de- creased by -0.28 ℃/decade. Both annual extreme low and high temperatures exhibit significant increasing trend, with the former clearly larger than the latter. For precipitation indices, regional annual total precipitation shows an increasing trend and most other precipitation indices are strongly correlated with annual total precipitation. Average wet day precipitation, maximum 1-day and 5-day precipitation, and heavy precipitation days show increasing trends, but only the last is statistically significant. A decreasing trend is found for consecutive dry days. For all precipitation indices, stations in northwestern Xinjiang have the largest positive trend magnitudes, while stations in northern Xiniiang have the largest negative magnitudes.
Based on daily maximum and minimum surface air temperature and precipitation records at 48 meteorological stations in Xinjiang, the spatial and temporal distributions of climate extreme indices have been analyzed during 1961-2008. Twelve temperature ex- treme indices and six precipitation extreme indices are studied. Temperature extremes are highly correlated to annual mean tem- perature, which appears to be significantly increasing by 0.08 ℃ per year, indicating that changes in temperature extremes reflect consistent warming. The warming tendency is clearer at stations in northern Xinjiang as reflected by mean temperature. The fre- quencies of cold days and nights have both decreased, respectively by -0.86 and -2.45 d/decade, but the frequencies of warm days and nights have both increased, respectively by ＋1.62 and ＋4.85 d/decade. Over the same period, the number of frost days shows a statistically significant decreasing trend of-2.54 d/decade. The growing season length and the number of summer days exhibit significant increasing trends at rates of ＋2.62 and ＋2.86 d/decade, respectively. The diumal temperature range has de- creased by -0.28 ℃/decade. Both annual extreme low and high temperatures exhibit significant increasing trend, with the former clearly larger than the latter. For precipitation indices, regional annual total precipitation shows an increasing trend and most other precipitation indices are strongly correlated with annual total precipitation. Average wet day precipitation, maximum 1-day and 5-day precipitation, and heavy precipitation days show increasing trends, but only the last is statistically significant. A decreasing trend is found for consecutive dry days. For all precipitation indices, stations in northwestern Xinjiang have the largest positive trend magnitudes, while stations in northern Xiniiang have the largest negative magnitudes.
基金
supported by a special scientific research project(GYHY200706008)in the public welfare industry(meteorology)
the"Western Light"Project(RCPY200902)of the Chinese Academy of Sciences
the Oasis Scholar"Doctor"Talent Training Program(0771021) of Xinjiang Institute of Ecology and Geography
