Atmospheric Boundary Layers (ABLs) in California

The summertime flow throughout the Great Central Valley of California is characterized by a strong mountain-valley circulation. Up-valley flow during the day driven by strong solar heating creates divergence that promotes mesoscale subsidence ultimately supressing the growth of the atmospheric boundary layer in the valley and foothills. The gradual slope of the mountains furthermore creates a small component of the geostrophic wind aloft which further compresses the ABL. 

Trade wind boundary layers over the ocean

Over the tropical oceans a two layer system develops with a well mixed lower boundary layer in contact with the ocean below an intermittently turbulent cloud (or buffer) layer. The upper layer can act like a temprorary reservoir of chemical species for the lower marine boundary layer.

Coupled Ocean/Atmosphere Boundary Layers

The Pacific High drives strong alongshore winds during late spring to early autumn. The strong and steady winds at the continental margin, reinforced by the strong land-sea thermal gradients, impels the California Current equatorward. The consequent Ekman transport offshore pulls cold, nutrient rich deep water to the surface. The results are atmospheric downwelling under the High and oceanic upwelling which creates two adjacent, shallow planetary boundary layers filled with great biological productivity due to the deep water nutrient injection from the dynamically induced upwelling.