Atmospheric Physics Building,Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Dr Brett McKim, Laboratoire de Météorologie Dynamique (LMD), Paris
Andrea Simpson - andrea.simpson@physics.ox.ac.uk
Abstract
Clouds are composed of condensates. Their vertical distribution helps set a number of important quantities including precipitation efficiency, cloud fraction, and cloud optical depth, but our understanding remains limited. Here, we examine profiles of liquid condensate in shallow convection and ice condensate in deep convection collected from in-situ and satellite-based observations. We find a striking resemblance between the two types of profiles, which suggests they might be controlled by the same underlying physical processes. We develop a simple analytical theory for these profiles based on condensation, entrainment, and conversion to precipitation. When given a few input parameters, the theory quantitatively reproduces observed and simulated profiles of liquid and ice condensate. We then outline how the theory could be used to 1) provide analytical estimates of liquid and ice water path and cloud fraction; 2) interpret the transition from shallow to deeper convection by specifying the relationship between cloud base width and cloud depth; and 3) most speculatively, to anticipate whether exoplanets with hydrological cycles can sustain clouds.