南疆近60a来寒潮气候特征及其对农业生产的影响

寒潮是我区主要灾害性天气之一,南疆植被稀少,温差大,强冷空气南下,容易形成寒潮。论文利用南疆5地(州)1949-2008年间的寒潮发生频次、 持续时间及其造成的受灾农田面积、 死亡牲畜、 经济损失数据资料,对南疆寒潮空间分布、 年际变化、 季节变化、 形成原因及其对农业生产影响进行深入分析。分析得出:①近60 a来,南疆寒潮发生频次山区多于平原、 北部多于南部,而寒潮过程降温幅度天山南麓绿洲带大于北部山区;对地(州)而言,巴州发生频次最多,受灾最严重,阿克苏次于巴州,克州与和田寒潮频次与受灾最少,喀什居中。②近60 a来,寒潮发生频次年际变化幅度较大,总体上呈现略有减少趋势,特别是1999年来频次明显减少;每年9月至翌年5月是寒潮活动期,以5月和4月发生频次最高,极端最大降温以4-5月和9-10月居多。③在气候变暖背景下,虽寒潮频次总体上呈略有减少趋势,但由于4-5月寒潮较多,而且小麦返青拔节,棉花出苗蕾铃,果树生芽开花,其抗寒能力下降,遇到明显降温,就会发生冻害,加上绿洲种植面积扩大,社会经济发展,承载体单位面积的受灾成本提高,使南疆寒潮低温冻害灾害呈显著增多趋势。

Climatic Characteristics of Cold Wave and Its Impact on Agriculture in Southern Xinjiang in Recent 60 Years

The cold wave is one of the main natural disasters in Xinjiang. Because of sparse vegetation cover, large temperate difference and strong cold air mass to the south, it is easy to form cold wave. This paper analyzed the spatial distribution, seasonal and annual changes and forming reasons of the cold wave based on the data of cold wave frequency, duration and its impact on cropland, livestock and economic damage encompassing from 1949 to 2008 in five districts in southern Xinjiang. The results showed that: 1)In recent 60 years, the occurrence of cold wave in mountain areas in southern Xinjiang is more frequent than that in plain area, northern part more than southern part, and the magnitude of cold wave induced temperature drop at southern foot hills of the Tianshan Mountains is greater than in the northern mountain area. According to special distribution, the maximum frequency of the cold wave took place in Bayingolin Mongol Autonomous Prefecture, and then in Aksu Prefecture, Kizilsu Kirghiz Autonomous Prefecture and Hotan Prefecture in turns. Kashgar Prefecture is in an intermediate place. 2)In recent 60 years, annual variation of cold wave frequency is pronounced, and it displayed a decreasing trend, especially, since 1999. The cold wave is strong from September to May of the next year, April and May reach the maximum in the one year time. Decreasing of the extreme temperature happens from April to May and from September to October. 3)Although, frequency of cold wave has a decreasing trend under climate change, its damages to the agriculture are enormous. With the expansion of crop area and the development of socio-economy in southern Xinjiang, the cold wave disasters to agriculture have an increasing trend.