Spatial and temporal evolution of soil wind erosion in the Beijing-Tianjin sandstorm sources

Abstract

<p indent="0mm">Dust emissions due to soil wind erosion and its transport are the most important natural sources of inhalable particulate matter in the atmospheric environment of sandstorm sources and the regions where sandstorms occur. To control the impact of dust emissions caused by soil wind erosion on the atmospheric environment in the Beijing-Tianjin resources, the Chinese government implemented a strategic significance ecological governance project in the Beijing-Tianjin sandstorm sources at the beginning of this century. However, there is still much controversy about soil wind erosion in the Beijing-Tianjin sandstorm sources and the resulting dust emissions. Based on field surveys, laboratory tests, remote sensing images and meteorological data, this paper calculated soil wind erosion in the Beijing-Tianjin sandstorm sources under three conditions, including the typical years of 2000, 2005, 2010, and 2015, land-use change conditions (land use in 2000, 2005, 2010, and 2015 but other factors with 2015), and climate change conditions (land use in 2015 but other factors with 2000, 2005, 2010, and 2015), by using the specified soil wind erosion model in the National Plan for Dynamic Monitoring of Soil and Water Loss from 2018 to 2022 and the Technical Regulations for Dynamic Monitoring of Regional Soil and Water Loss (Trial Version). In 2000, 2005, 2010, and 2015, the fluctuation in wind erosion modulus in the Beijing-Tianjin sandstorm sources decreased. Wind erosion modulus gradually decreased from northwest to southeast, and the value in desert or sandy land was higher than that in the surrounding areas. With the advancement of governance projects in the Beijing-Tianjin sandstorm sources, the distribution of wind erosion modulus changed significantly. Wind erosion modulus in the desert steppe was the largest and was approximately 2.67–2.98 times that of the Beijing-Tianjin sandstorm sources. Wind erosion modulus in the Hetao Plain and Hunshandake Sandy Land, were roughly the same as that in the Beijing-Tianjin sandstorm sources. Wind erosion modulus in other subregions was 42.69% of that in the Beijing-Tianjin sandstorm sources. Wind erosion area and variability in the above years in the Beijing-Tianjin sandstorm sources were <sc>385800–464500 km²</sc> and −9.35%–9.14%, respectively. The area of ​​mild and moderate wind erosion accounted for 91.56%. Overall, wind erosion area in the northwestern Beijing-Tianjin sandstorm sources was large, and its area proportion was high, followed by that in the middle area, and the southeast area had the smallest area. The wind erosion area in ​​desert steppe accounted for the largest proportion, with a value of 25.88%, and that in the southern part of the Greater Khingan Mountains was only 3.18%. Intense and extremely intense soil wind erosion was concentrated in the desert steppe and the western part of the Hetao Plain. Intense soil wind erosion was mainly distributed in the Kubuqi Desert and Hunshandake Sandy Land. Moderate and mild erosion involved each subregion in the Beijing-Tianjin sandstorm sources. There were obvious differences in the changes in the wind erosion area and intensity in each subregion during 2000–2005, 2005–2010, and 2010–2015. Climate change and land-use change had important impacts on soil wind erosion in the Beijing-Tianjin sandstorm sources. The variability of the wind erosion modulus and the area affected by climate change was equivalent to the corresponding variability of the year but greater than the influence of land-use change. In addition, the area of wind erosion under land-use change generally decreased, especially from 2010 to 2015, which had a decrease of 4.10%, indicating that the Beijing-Tianjin sandstorm source control project played an important role. These results provide a scientific basis for the evaluation of the benefits of the Beijing-Tianjin sandstorm source control project and the optimization of its layout.