In desert regions like the Middle East (ME), dust has a profound impact on the environment,
climate, air quality, and solar devices. The size of dust particles determines the extent of these
effects. Dust deposition (DD) measurements show that coarse dust particles with geometric
radius r > 10 μm comprise most of the deposited mass. Still, these particles are not represented in
the current models that are tuned to fit the observed aerosol visible optical depth (AOD). As a
result, the existing models and reanalysis products underestimate DD and dust emission (DE)
almost three times. This is the first study to constrain the dust simulations by both AOD and DD
measurements to quantify the effect of coarse and fine dust using the WRF-Chem model. We
found that, on average, coarse dust contributes less than 10% to dust shortwave (SW) radiative
forcing (RF) at the surface but comprises more than 70% of DE. Annual mean net RF over the
Arabian Peninsula and regional seas locally reaches -25 W m-2. Airborne fine dust particles
with radii r < 3 μm are mainly responsible for the significant dimming (5-10%) of solar
radiation, cooling the surface and hampering solar energy production. However, dust mass
deposition is primarily linked to coarse particles, decreasing the efficiency of Photovoltaic panels
by 2-5% per day. Therefore, incorporating coarse dust in model simulations and data assimilation
would improve the overall description of the dust mass balance and its impact on environmental
systems and solar devices.