Cloud-Top Entrainment Instability Observed in AMTEX

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  • 1 Department of Atmospheric Sciences, Oregon State University, Corvallis, 97331
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Abstract

Aircraft data collected at the top of a cloud-topped mixed layer during the Air Mass Transformation Experiment are analyzed. Entrainment instability due to evaporation of liquid water is found to occur intermittently. This instability and upward heat flux occur frequently at the downstream edge of cloudy mixed-layer motions which have penetrated upward into the faster moving dry air of the inversion layer. Such circulations appear to occur mainly on scales of the order of 100 or 200 m. At the level of the aircraft at the mixed-layer top, the net heat flux is upward in cloudy regions and downward in the driest regions.

Abstract

Aircraft data collected at the top of a cloud-topped mixed layer during the Air Mass Transformation Experiment are analyzed. Entrainment instability due to evaporation of liquid water is found to occur intermittently. This instability and upward heat flux occur frequently at the downstream edge of cloudy mixed-layer motions which have penetrated upward into the faster moving dry air of the inversion layer. Such circulations appear to occur mainly on scales of the order of 100 or 200 m. At the level of the aircraft at the mixed-layer top, the net heat flux is upward in cloudy regions and downward in the driest regions.

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