Analysis of Changing Dust Concentrations and Circulation in West Africa using WRF-CHEM, 2010-2100

Abstract - Airborne dust particles play a significant role in influencing the climate of West Africa, but it is unclear how climate change may alter this. WRF-CHEM Version 4.5 with the GOCART module was used to analyze several meteorological variables, most importantly dust concentrations, across West Africa between the periods of 1981-2010, 2041-2060, and 2081-2100. The Max Planck Institute Earth System Model (MPI-ESM) provided lateral boundary conditions for WRF-CHEM. The simulations were carried out using both SSP126 and SSP585. While both runs indicate changes in dust concentrations across the domain, changes in dust concentrations are higher across the SSP585 runs in both mid- and late-century runs. According to these runs, changes in areas of lower level convergence and divergence will result in higher dust concentrations in the vicinity of the Western Sahara, especially during JJA, in both mid-century and late-century runs. This will in turn result in areas of lower dust concentrations along the coastal regions and just offshore in the vicinity of Western Sahara. In the mid-century, these effects will be confined near the coast and during the summer months. During the 2081-2100 period, a greater amount of dust loading is found across the domain, with most of West Africa experiencing at least a 10 μg m^-3 increase in total dust loading. This is despite lower dust concentrations from the Bodélé Depression (except during JJA). The causes of the distribution of dust events will be explored further in the conference.