三峡库区高温气候特征及其预测试验

Climatic Characteristics of High Temperature in the Three Gorges Area and Its Forecasting Test

根据三峡库区及其周围35个气象站1961—2008年的逐日最高气温资料,分析了库区高温的时空变化特征;采用经验模态分解方法,探讨了近48年来三峡库区年均高温日数和日平均最高气温序列的振荡模态结构特征;利用均生函数模型作均值生成函数延拓,借助BP神经网络构建了一个新的预测模型,对三峡库区高温日数和最高气温进行了预测。结果表明,过去48年间,三峡库区年均高温日数为24.07天,高温日的平均最高气温为36.69℃,以3～5a和16a为显著振荡周期,在20世纪80、90年代为弱负距平,而在其他时期都为正距平。三峡库区高温日数分布呈北部多、东南部少的特征,高温日的平均最高气温以东南部较低,东北部较高。模型预测值与实际值的对比分析表明,该预测模型具有一定的实用性,不仅能够较好地拟合三峡库区高温的历史实况,而且对未来5～10年的演变趋势也具有一定的预报能力;对偶发极端气候事件的预测尚有待进一步提高。

Based on the daily maximum surface air temperature data of 35 stations during 1961-2008 in the Three Gorges area,the climatic characteristics of high temperature are analyzed.Using the empirical mode decomposition,we have discussed the mean annual high temperature days as well as the vacillation mode structure characteristics of the mean daily highest temperature during annual high temperature days in the Three Gorges area in recent 48 years,and we constructed a new prediction model by using function extension of mean value generated by generating function model as well as BP nerve net.The prediction model made the projection of the mean annual high temperature days and the mean daily highest temperature. The results show that the mean annual high temperature days were 24.07 and the mean daily highest temperature during annual high temperature days was 36.69℃in the past 48 years.Meanwhile,the mean annual high temperature days were negative anomaly in the 1980s and 1990s,but positive anomaly in the other periods of time,oscillating with a cycle of about 3-5 and 16 years.The mean annual high temperature days were more in the northern part,but less in the southeast part of the Three Gorges area.The mean daily highest temperature during annual high temperature days was lower in southeast part,but higher in northeast part of the Three Gorges area.By comparing the prediction value of the model with real value,it showed that the model not only could fit the history in the Three Gorges area,but also could predict the trend of the future 5-10 years in the Three Gorges area.However,the model should improve the prediction ability of the extreme climate events occurring occasionally.