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Convective boundary layer equilibrium over a tropical ocean

A one dimensional, thermodynamic model for a partially mixed, partly cloudy, convective boundary layer (CBL) is coupled to a radiation model to compute equilibrium solutions for a tropical CBL and troposphere in energy balance over the ocean. For a sea surface temperature (SST) of 300K, the model gives an equilibrium cloud-base ≈ 950mb, a CBL top ≈ 800mb and a low level Θe ≈ 347K, close to climatic values. The CBL deepens and low level Θe rises with increasing wind speed and SST. We explore the change in CBL structure and surface fluxes with external parameters on two timescales: that of the CBL (≈ 1 day); that of tropospheric radiative equilibrium (≈ 10 days). The variation in cloud-top, and the slope of the latent heat flux with increasing SST decrease with more tropospheric coupling.

This is a version of: "Betts, A.K. and W. L. Ridgway, 1989: Climatic equilibrium of the atmospheric convective boundary layer over a tropical ocean. J. Atmos. Sci., 46, 2621-2641." produced for this Indian semina and book

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Full Citation

Betts, A. K., 1990: Convective boundary layer equilibrium over a tropical ocean. Indo-US Seminar, 6-10 Aug. 1990. Published in "Physical Processes in Atmospheric Models", (Eds. D.R.Sikka and S.S.Sikka), Wiley Eastern Ltd., India, 32-59.