Drought and effect of vegetation on aeolian transport in the Aralkum

Abstract

This study focusses on the effects of the desiccation of the Aral Sea, which occurred ~50 years ago. The desiccation of the Aral Sea began a shift in climate and transformed the Aral Sea. The Aral sea that once was the livelihood of many changed into the Aralkum, a dessert which to this day destroys the lives of many. This study focusses on the shift in climate that occurred due to the desiccating of the Aral Sea, the dust storms originating from the Aralkum, and vegetation strategies that can limit the magnitude of these dust storms. This study used precipitation data and satellite imagery to analyse the shift in the meteorological climate and the resulting changes in vegetation. Using the Aerosol optical depth and local wind speed data, the temporal variation of dust storms and high wind events were analysed and linked. The effect of different types of vegetation on reducing wind erosion in the form of suspension and saltation was modelled using a cellular automaton approach. The climate has shifted into a wetter but warmer climate. The regions affected by this are the rangelands in proximity(0-500 km) to the Aral sea, which experienced soil salination and a significant loss in vegetation density. The dust storms occur mainly in spring when high wind events are present. The modelling showed that to stop the erosion entirely, dense vegetation is required. Sparse vegetation will help reduce erosion, yet very sparse vegetation will create higher shear stress on the soil due to the formation of wakes increasing the erosion. Grass patches can protect the soil without creating wakes, making them the best option if possible. These storms have plagued the agriculture sector and massively increased respiratory problems in the general population of Uzbekistan jeopardising public health. Vegetation will play a key role in reducing salt and dust storms in Uzbekistan.