The Red Sea (RS) has a high evaporation rate, exceeding 2 m of water per year. The water vapor is transported from the shorelines by sea breezes as far as 200 km landward. Relative humidity in the vicinity of the RS exceeds 80% in summer. Nevertheless, precipitation is scarce in most of the Arabian RS coastal plain. In this work we use the Weather Research and Forecasting (WRF) regional model to assess how deliberate changes (geoengineering) in the surface albedo or convertion of bare land to wide-leaf forests over a vast coastal plain region affect precipitation over the Arabian RS coast. Our simulations show that geoengineering of land surface characteristics perturbs coastal circulation, alters temperature, moisture, and momentum exchange between the land surface and atmosphere, changes the breeze intensity, cloud cover, and eventually the amount of precipitation. We find that extended afforestation and increased surface albedo are not effective in triggering rainfall over the RS coastal plains. Conversely, decreasing surface albedo to 0.2 assuming installation of solar panels over the coastal plains, increases surface air temperature by 1-2 K, strengthens horizontal surface temperature differences between sea and land, intensifies breezes, increases water vapor mixing ratio in the boundary layer above 3 km by about 0.5 gkg −1, enhances vertical mixing within the Planetary Boundary Layer, and generates 1.5 Gt of extra rain water, equivalent to the annual consumption of five million people. Thus, this form of regional land-surface geoengineering, along with advanced methods of collection and underground storage of freshwater, provides a feasible solution to mitigation of the existing water crisis the arid coastal regions.
|Original language||English (US)|
|Journal||Journal of Hydrometeorology|
|State||Published - Nov 10 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-11-16
Acknowledged KAUST grant number(s): URF/1/2180-01-01
Acknowledgements: The research reported in this publication was supported by funding from King Abdullah University of Science and Technology (KAUST) through the Competitive Research Grant (URF/1/2180-01-01) “Combined Radiative and Air Quality Effects of Anthropogenic Air
Pollution and Dust over the Arabian Peninsula” and Belmont Forum Grant (REP/1/3963-01-01 / RFBR #20-55-75002) ”Coastal OceAn SusTainability in Changing Climate (COAST).” For computer time, this research used the resources of the Supercomputing Laboratory at KAUST.
ASJC Scopus subject areas
- Atmospheric Science