Evaluation of wind erosion in the Tarim Basin based on parameter localization

Abstract

Air density strongly constrains the characteristics of an airflow and the resulting flow of sand and therefore, it should not be neglected in sand transport models. Although the potential importance of air density is well known, most studies on threshold velocity, saltation trajectory, and dust emission have been conducted near sea level, at a “normal” atmospheric density. In this study, utilizing the observational data from 12 meteorological stations in the Tarim Basin (TB) from 2009 to 2018, we used air density as the basis to discuss the necessity of model parameter localization. It was found that there was a significant difference in the horizontal dust flux estimated using the normal and local air densities. Using the localized air density, we re-evaluated the temporal and spatial distribution characteristics of the threshold velocity, horizontal dust flux, and wind erosion events in the TB and further quantified their distributions in all directions. The results demonstrated that the threshold velocity gradually increased from east to west and from north to south, with the maximum value occurring in the southwestern TB. The horizontal dust fluxes and wind erosion events could be classified into three types according to the seasonal variation characteristics; however, one of the main distribution characteristics was spring > summer > autumn > winter. Tazhong, Qiemo, and Ruoqiang are sand- and dust-incident frequent zones. Taking Minfeng when passing from Tazhong to Shaya as the line of demarcation, it was found that the horizontal dust fluxes and wind erosion events in the eastern region mostly occurred in the eastern direction, whereas those in the western region primarily occurred in the western direction. The results suggested that it was extremely important and necessary to localize the parameters in sand–dust models, which would also provide a more accurate climate background for the study of sand and dust in the TB.