阿拉善地区沙尘暴发生的时空变化规律探讨

Spatio-temporal variation characteristics of dust-storm in Alaxan region of Inner Mongolia Autonomous region

统计分析阿拉善地区1961—2003年43 a的沙尘暴发生的空间分布特征,月际、年际和年代际的时间变化特征及其原因。结果表明:阿拉善地区沙尘暴天气在空间分布上以拐子湖为中心向外辐射减少,且北部、东部区域沙尘暴发生多,西部、南部区域发生少;在季节变化上呈现出沙尘暴春夏多发、秋冬少发的分布规律,年际间沙尘暴发生时间(以d计)高于多年平均发生时间的年份少,年代际间则以20世纪70年代沙尘暴发生时间最多,之后表现为逐渐减少趋势;沙尘暴出现时间是该地区特定气候、地理和生态环境等条件的反映,沙尘暴发生时间与大风发生时间呈正相关,与当年气温、上年降水量呈负相关,且月均沙尘暴发生时间与月均大风发生时间呈紧密的线性正相关关系,相关系数达0.988 5。研究结果可为阿拉善地区沙尘暴的防治提供科学依据。

Based on the observed dust-storm data of Alaxan region of Inner Mongolia from 1961 to 2003, the spatial distribution characteristics, seasonal and yearly and decadal temporal variation characteristics and the cause of dust storm were analyzed. The results showed as followed： The dust-storm-days radiation decreased from Guaizi lake as center to other area all around in spatial, and the dust storm occurred frequently in the north and east and less in the west and south of this region; the days of dust storm took on more in spring and summer, but less in autumn and winter, the years which was more than average days of dust storm occurring was few in yearly during 43 years, the dust-storm-days occurring was most in 20 century 70＇ s, and it had trend to decline after 70＇ s. The variation of the dust-storm-days is in response to some special climate variation, geographical situation and environment, the relationship between dust-storm-days and strong-wind- days has been positive correlation, and the intensity of dust-storm-days negatively correlated with the air temperature and precipitation of last year, further more, the linear relation was accorded with between average monthly days of dust-storm and average monthly strong-wind-days, the correlation coefficient is 0.988 5. The result can provide science gist to preventing and controlling the dust-storm for Alaxan region.