1961—2019年柴达木盆地沙尘强度时空变化特征

Temporal and Spatial Variation Characteristics of Dust Intensity in Qaidam Basin from 1961 to 2019

基于1961—2019年柴达木盆地9个地面气象站沙尘逐月观测资料,计算沙尘指数并分析盆地沙尘强度的时空变化特征及其主要影响因素。结果表明:(1)近59 a柴达木盆地沙尘强度整体呈显著减弱趋势,减小速率为2.05 a-1;沙尘强度年代变化呈单峰型,其中1970年代最强;柴达木盆地沙尘指数突变发生在1990年;月均沙尘指数也呈单峰型分布,峰值位于春季4月,谷值位于冬季12月。(2)柴达木盆地沙尘强度整体呈腹部高、外围低的空间分布格局;近59 a除冷湖的沙尘强度呈显著增强趋势外,其余地区沙尘强度均呈显著减弱趋势,其中诺木洪和格尔木减弱速率较快;春季沙尘强度减弱速率最快。(3)近59 a柴达木盆地年均气温升高、降水增多、风速降低、大风日数减少是影响其沙尘强度变弱的重要原因。

Based on monthly dust data from 9 automatic weather stations in the Qaidam Basin from 1961 to 2019,the dust index was calculated,and the spatiotemporal variation characteristics and the main influence factors of dust intensity were analyzed.The results are as follows:(1)In recent 59 years,the intensity of dust showed a significant decrease trend with a deceleration of 2.05 a-1 in the Qaidam Basin.The annual variation of dust intensity showed a single peak distribution with the strongest in the 1970s.The mutation of dust index occurred in 1990 in the Qaidam Basin.The monthly average dust index also showed a single peak distribution to some extent,with the peak in April in spring and the valley in December in winter.(2)The dust intensity in the Qaidam Basin was high in the abdomen and low in the periphery as a whole,in recent 59 years,except for Lenghu,the dust intensity of other areas showed a significant weakening trend.The weakening rates of Nuomuhong and Golmud were faster and the weakening rate of dust intensity in spring was the fastest.(3)In recent 59 years,the annual average temperature increased,precipitation increased,wind speed decreased,windy days decreased in the Qaidam Basin,which was important reasons for the weakening of dust intensity.