Validation and application of the monitoring method for degraded land-area-based on a dust erodibility in eastern Asia

Abstract

ABSTRACTArid regions are very sensitive to climate change and human activity, two critical drivers of change that are degrading environmental conditions. Part of the world’s drylands lie in eastern Asia, including China and Mongolia, where the problems of desertification, drought, and Asian dust events (ADEs) are frequent. To help prevent economic damage from these problems, an early warning and monitoring system based on numerical models, remote sensing, and weather forecasts is needed. I define a degraded land area as ‘the area where dust can easily occur’ and make exclusive use of satellite data to identify land that meets certain conditions of vegetation and aridity. I then validate this definition against a dust erodibility map and occurrences of ADEs over Japan, which was closely related to the extent and severity of dust areas in Mongolia and parts of China, especially in March (coefficient of determination R2 = 0.856). The yearly change of degraded land area indicates a clear decreasing trend in China (R2 = 0.210), but an overall negative trend in Mongolia (R2 = 0.010). Years of major droughts in China and Mongolia correspond well to large positive deviations in degraded land area.