柴达木盆地北部风速对尘暴事件降尘的影响

通过系统监测柴达木盆地北部冷湖地区的月降尘通量以及尘暴事件降尘量,发现该地区月降尘通量变化在0.57×103～18.12×103 μg·cm–2·month–1之间,并且与月极大风速（Vextr）具有较好的正相关性（r2=0.60, n=23）;该区年内主要粉尘堆积时段为春季和初夏;尘暴事件发生期间的降尘量不仅与尘暴持续期间10 min平均风速具有良好的正相关关系（r2=0.60, n=16）,而且降尘量与10 min风速变化幅度有关:强劲稳定的风力条件在监测地点产生较少的降尘量,强劲且变率较大的风力条件产生较多的降尘量。监测结果显示,风速的变化对粉尘的释放、输送和沉降有重要的影响,有助于理解地质记录所揭示的冰期-间冰期不同的大气粉尘沉降速率。

Impact of Wind Velocity on Dustfall during Dust Storm Events in Northern Qaidam Basin, China

The monthly dustfall flux and modern dust storm events were monitored in the northern Qaidam Basin on Qinghai-Tibetan Plateau, which is regarded as an important dust source area. The monthly dustfall flux varied between 0.57×103 and 18.12×103 g5cm-2 month-1, and was well correlated with the monthly extreme wind velocity (Vextr) (r2=0.60, n=23). Sand-dust was mainly deposited in spring and early summer in the study area. The amount of settled sand-dust collected during dust storm events exhibited a significant positive correlation with the mean 10 min wind velocity (r2 =0.60, n=16) of the same time, and was related to fluctuations of the 10 min wind velocity. Most of the fine-grained particles were lifted and transported to far from the source regions by strong and stable winds. Changes in wind velocity thus had an important impact on dust emission, transportation, and deposition; and this knowledge could be helpful in understanding the different rates of atmospheric dust deposition during glacial and interglacial periods.