TOWARDS ICE FORMATION CLOSURE IN MIXED-PHASE BOUNDARY LAYER CLOUDS DURING ISDAC
Abstract
Mixed-phase stratus clouds are ubiquitous in the Arctic during the winter and transition seasons. Despite their important role in various climate feedback mechanisms they are not well understood and are difficult to represent faithfully in cloud models. In particular, models of all types experience difficulties reproducing observed ice concentrations and liquid/ice water partitioning in these clouds. Previous studies have demonstrated that simulated ice concentrations and ice water content are critically dependent on ice nucleation modes and ice crystal habit assumed in simulations. In this study we use large-eddy simulations with size-resolved microphysics to determine whether uncertainties in ice nucleus concentrations, ice nucleation mechanisms, ice crystal habits and large-scale forcing are sufficient to account for the difference between simulated and observed quantities. We present results of simulations of two case studies based on observations taken during the recent Indirect and Semi-Direct Aerosol Campaign (ISDAC) on April 8 and 26, 2008. The model simulations are evaluated through extensive comparison with in-situ observations and ground-based remote sensing measurements.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.A43A0176A
- Keywords:
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- 0320 ATMOSPHERIC COMPOSITION AND STRUCTURE / Cloud physics and chemistry