Spatiotemporal variability in dust observed over the Sinkiang and Inner Mongolia regions of Northern China

Abstract

This study presents a detailed analysis of the spatiotemporal variability in dust observed over Sinkiang and Inner Mongolia in Northern China from 2005 to 2008. The relationships between airborne dust (observed by OMI–AI and MODIS–AOD), the normalized difference vegetation index (NDVI), monthly total precipitation (MTP) and surface wind speed (SWS) are investigated. The results show that the spatial distribution of airborne dust distinctly decreases from west to east across Northern China; this pattern is opposite to that of the NDVI and MTP. Both Sinkiang and Inner Mongolia experience high amounts of airborne dust in spring, with the highest values in April. The two regions also had different dust variabilities. In Sinkiang, three major dust regions were identified, with airborne dust mainly distributed in regions with NDVI values between 0 and 0.1, SWS values between 2 and 5m/s, and a MTP of less than 5mm. In addition, the temporal variation in airborne dust exhibits both positive and negative correlations with the NDVI, MTP and SWS. However, over Inner Mongolia, five high–dust regions were confirmed, with airborne dust generally distributed in the areas with NDVI values between 0 and 0.4, SWS values between 3 and 6m/s, and a MTP of less than 10mm. The time series of airborne dust is negatively correlated with the NDVI and MTP but strongly and positively correlated with the SWS. In addition, the temporal pattern of the AOD in Sinkiang is essentially controlled by dust activity, whereas it may be influenced by anthropogenic emissions in Inner Mongolia. Overall, the spatiotemporal variabilities in dust over Sinkiang and Inner Mongolia are not identical, although both regions are important sources of dust in East Asia.