1960—2020年内蒙古自治区沙尘天气的时空演变特征及驱动因素

Spatial-temporal Evolution Characteristics and Driving Factors of Sand-dust Weather for Inner Mongolia Autonomous Region During 1960—2020

[目的]分析1960—2020年内蒙古自治区沙尘天气的时空演变特征及其驱动因素,科学认识气候变化背景下区域沙尘天气变化规律,为生态治理提供理论依据。[方法]利用内蒙古自治区119个气象站点1960—2020年逐日浮尘、扬沙、沙尘暴资料,采用趋势分析、M—K检验、相关分析等方法,对内蒙古自治区沙尘天气的时空演变特征及驱动因素进行分析。[结果](1)1960—2020年内蒙古自治区的各等级沙尘日数及沙尘强度指数均呈极显著的下降趋势(p<0.01),浮尘日数和扬沙日数均在1990年前后发生由多到少的突变,沙尘暴日数和沙尘强度指数无明显突变点;(2)沙尘天气的空间变化趋势表现为,西部地区发生频率高且强度较大,高值中心出现在阿拉善盟的中部及西部与乌海市交界地区,向东迅速减弱,地区间差异明显;1960—2020年,沙尘天气减弱程度西部地区较东部地区更为明显;(3)1960—2020年,内蒙古自治区沙尘天气减弱,既与增温背景下的大风日数减少(10.1 d/10 a,p<0.01)及冬春季节降水增多(2.65 mm/10 a,p<0.01)有关,也与持续多年的大规模生态治理下,NDVI明显增加(0.036/10 a,p<0.01),生态环境显著改善有关。[结论]沙化土地治理是抑制沙尘天气发生频率和强度的有效手段,必须持续推进生态环境建设,尽可能减少沙尘源;同时,做好气候变化背景下水资源的开发和利用,促进生态环境的良性循环,达到减轻沙尘危害的目的。

[Objective]The spatial and temporal evolution characteristics and driving factors of sand-dust weather in Inner Mongolia Autonomous Region from 1960 to 2020 were analyzed in order to scientifically understand the changes in regional sand-dust weather under the background of climate change and to provide a theoretical basis for ecological governance.[Methods]Daily data for floating dust,blowing sand,and sandstorms from 119 meteorological stations within the Inner Mongolia during 1960—2020 were analyzed to determine the spatial-temporal variation characteristics of sand-dust weather for this region using trend analysis,the M—K test,wavelet analysis,etc.[Results]①The number and intensity of sand-dust storm days at each level exhibited a very significant(p<0.01)downward trend in the Inner Mongolia Autonomous Region from 1960 to 2020.There was an abrupt decreasing point around 1990 for both the number of floating dust days and blowing sand days.There was no obvious change point in either the number of sand-dust storm days or the sand dust intensity index.②The frequency and intensity of sand-dust weather was high in the western part of the region,and the high-value center was at the junction of the central and western parts of Alxa League and Wuhai City.The influence of sand-dust weather quickly weakened to the east,and regional differences were great.The weakening degree of sand-dust weather was significantly greater in the western region than in the eastern region.③The reduction in number of sand-dust days for the Inner Mongolia Autonomous Region resulted from(a)the decreasing number of windy days(10.1 d/10 yr,p<0.01)and the increasing amount of precipitation in winter and spring(10.1 d/10 yr,p<0.01)caused by significant warming,and from(b)increasing NDVI(0.036/10 yr,p<0.01)and a better ecological environment owing to the government’s large-scale ecological governance.[Conclusion]Desertified land control is an effective way to suppress the frequency and intensity of sand-dust weather.It will be necessary to continuously promote the construction of the ecological environment and to minimize the sources of sand and dust.Moreover,we increase efforts to effectively develop and utilize water resources under the background of climate change,thereby promoting a virtuous cycle of ecological environment and reducing the harm caused by sand-dust weather.