宁夏大风日数气候变化及其对沙尘天气的影响

Changes of Gale Days and Its Impacts on Dust Weathers in Ningxia

本文利用宁夏23个气象台站1961—2004年共44a的大风日数、沙尘暴日数、扬沙日数资料,统计分析了宁夏大风日数的空间分布和时间分布特征,结果表明:近44a来宁夏存在2个大风中心———北部的惠农和东部的麻黄山,西南部的隆德大风日数最少,春季是宁夏各站大风日数最多的季节;20世纪60、70年代是宁夏大风日数明显偏多期,80、90年代是偏少期,21世纪初期比20世纪80、90年代略有增加;大风日数气候倾向率16个站为负值,7个站为正值;大武口———石炭井一带、麻黄山、兴仁、泾源是大风日出现的沙尘暴次数占其沙尘暴出现总次数的百分率高值区,陶乐———盐池一带、中卫是低值区,且大风中心区与沙尘暴频发区不重合;惠农、麻黄山是大风日出现的扬沙次数占扬沙出现总次数的百分率高值区,陶乐、永宁、盐池、中卫是低值区;年平均大风日数、年大风日出现沙尘暴次数及扬沙次数均呈减少趋势,时间曲线变化趋势也相同。

The gale days, dust-storm days and blowing sand days data of 23 meteorological observatories in Ningxia from 1961 to 2004 were used in this text to statistically analyze the spatial and temporal distribution of gale days. The results showed that Ningxia had 2 gale centers in the recent 44a ： Huinong in the north and Mahuang mountain in the east; Longde which is in the southwest had the least gale days, and Spring was the season which in all the stations in Ningxia having the most gale days; In Ningxia gale days were obviously more in the 1960s and 1970s, less in 1980s and 1990s, and little increased in the 21st century （compare to 1980s and 1990s）; The climate trend rate of gale days were negative in 16 stations and positives in 7 stations; To the percentage the dust-storm times occurred in gale days occupied the total dust-storm times, the strip from Dawukou to Huinong, Mahuang mountain, Xinren, Jingyuan were the higher percentage zones, the strip from Taole to Yanchi and Zhongwei were the lower zones, and the gale centers were not the same to the dust-storm frequency zones; To the blowing sand times occurred in gale days occupied the total blowing sand times, Huinong and Mahuang mountain were the higher percentage zones, Taole, Yongning, Yanchi and Zhongwei were the lower percentage zones; The annual mean gale days, annual dust-storm and blowing sand times occurred in gale days were all increasing, and the changing trend of the temporal curve was the same.