Impacts of Saharan Mineral Dust on Air-Sea Interaction over North Atlantic Ocean Using a Fully Coupled Regional Model


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The atmosphere and oceans act as a coupled system. They interact in various ways, including via ocean-sur-face wind stresses, downward radiation fluxes, and exchanges of surface heat/energy. Professor Yu-heng Tseng and his collaborators investigate how the common Sahara dust can change the atmosphere and ocean dynamical processes using a high-resolution coupled model. The dust-induced mechanisms that are responsible for changes of sea surface temperature (SST) and latent and sensible heat fluxes (LHF/SHF) are also examined. Sensitivity experiments show that the dust significantly reduces surface downward radiation fluxes over the ocean with the maximum change of 20–30Wm-2. Over the dust plume region, the dust effect creates a low-pressure anomaly and a cyclonic circulation anomaly, which drives a positive wind stress curl anomaly, thereby reducing sea surface height and mixed layer depth. However, the SST change by dust has a great spatial variation which differs from the dust plume shape. Dust cools SST around the West African coast, except under the maximum dust plume ridge, and extends westward asymmetrically along the northern and southern edges of the dust plume. Dust unexpectedly warms SST over a large area of the western tropical North Atlantic and north of the dust plume. These SST changes are controlled by different mechanisms. Unlike the SST change pattern, the LHF and SHF changes are mostly reduced underneath the dust plume region.

Further information can be found in Prof. Tseng’s recent paper published in Journal of Geophysical Research: Atmospheres (Chen et al. 2021)

Chen, S. H., Huang, C. C., Kuo, Y. C., Tseng*, Y. H., Gu, Y., Earl, K., Chen, C-Y, Cho Y. & Liou, K. N. (2021). Impacts of Saharan mineral dust on air‐sea interaction over North Atlantic ocean using a fully coupled regional model. Journal of Geophysical Research: Atmospheres, e2020JD033586.