近54年博州地区低云量变化特征及影响因素分析

Analysis on the Change Characteristics and Influencing Factors of Low Cloud Cover in Bozhou Area in Recent 54 Years

选取新疆博州地区4个气象站1960—2013年逐月的气象数据,通过线性拟合、Mann-Kendall突变检验、小波分析、相对贡献率和敏感系数分析方法,分析近54年来该地区的低云量变化特征及与其他气候因子的关系。结果表明,近54年博州地区低云量呈明显上升趋势,上升幅度约为1.2%/10 a,多年平均值为22.57%,且序列的正持续性较强;夏季的低云量最低,为20.47%,春季最高,为24.17%;全年低云量从在2001年发生突变性增加;春季和夏季低云量均值不存在突变性增加,秋季和冬季低云量分别于1999和1989年发生突变性增加;低云量演变过程中存在着8～9和25～26年尺度的周期变化规律;8年的时间尺度是低云量变化的第1主周期,14年的时间尺度为低云量变化的第2周期;相对湿度对低云量具有最高的相对贡献率,达51.3%,而降水量对低云量的相对贡献率最小,仅为6.1%,降水量与低云量的相关性最高,相关系数达0.67(P<0.01),平均气温的相关系数最低,仅为0.29(P<0.05)。

The meteorological data of 4 meteorological stations in Bozhou area of Xinjiang from1960 to2013 were selected,the characteristics of low cloud cover and itsrelationship with other climatic factors in the past 54 years were analyzed by linear fitting,Mann-Kendall mutation test,wavelet analysis,relative contribution rate and sensitivity coefficient analysis method.The resultsshowed that the low cloud cover in Bozhou area had shown an obvious upward trend in the past 54 years,with an increase of about1.2%/10 a,with an average of22.57% for many years,and the sequence had a strong positive sustainability;the lowest amount of low cloudiness in summer was20.47%,and the highest amount in spring was24.17%.The annual low cloud volume increased from2001;there was no increase in the mean value of low cloud cover in spring and summer,and the increase in the amount of low cloud in autumn and winter increased in1999 and1989,respectively;During the evolution of low cloud quantity,there were periodic variations of 8-9 and25-26 years;the 8-year time scale was the1st main cycle of low cloud cover change,and the14- year time scale is the second period of low cloud cover change;relative humidity had the highest relative contribution rate to low cloud amount,reaching 51.3%,while the relative contribution rate of precipitation to low cloud amount was the smallest,only 6.1%.The correlation between precipitation and low cloud cover was the highest,the correlation coefficient was 0.67 ( P< 0.01),and the correlation coefficient between average temperature and low cloud cover was the lowest,only 0.29 ( P <0.05).