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arXiv · 2305.02871

Steady-state supersaturation distributions for clouds under turbulent forcing

Manuel Santos Gutiérrez·Kalli Furtado
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Abstract

The supersaturation equation for a vertically moving adiabatic cloud parcel is analysed. The effects of turbulent updrafts are incorporated in the shape of a stochastic Lagrangian model, with spatial and time correlations expressed in terms of turbulent kinetic energy. Using the Fokker-Planck equation, the steady-state probability distributions of supersaturation are analytically computed for a number of approximations involving the timescale separation between updraft fluctuations and phase-relaxation, multiplicative noise simplification and droplet or ice particle size fluctuations. While the analytical results are presented in general for single-phase clouds, the calculated distributions are used to compute mixed-phase cloud properties -- mixed fraction and mean liquid water content in an initially icy cloud -- and are argued to be useful for generalising and constructing new parametrisation schemes.

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Manuel Santos Gutiérrez, Kalli Furtado. 2023-05-04. Steady-state supersaturation distributions for clouds under turbulent forcing. https://arxiv.org/abs/2305.02871

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