Evaluation of tropical anvil cirrus in high-resolution DYAMOND simulations

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Abstract

Employing a resolution of 5 km or less, DYAMOND models resolve much of the cloud relevant dynamics and better simulate cloud structure and diurnal cycle of precipitation. Nevertheless, DYAMOND simulations show us that cloud properties can vary significantly even in high-resolution simulations. We focus on evaluating impact of tropical convection on UT ice clouds in high-resolution DYAMOND simulations as the tropics is an area that should particularly benefit from the increased resolution because deep convection is mostly resolved and controls the tropical upper tropospheric water budget. We analyse the horizontal distribution of total ice water path (IWP), the partitioning of total IWP and precipitation, cloud phase and cloud vertical structure as they are crucial to the Earth’s radiation budget. Even though deep convection is mainly resolved in DYAMOND models, tropical total IWP is generally underestimated, while the precipitation is overestimated compared to active and passive remote sensing data. In order to understand better those differences, we analysed the connection between the simulated vertical velocity and IWP. While the PDF of tropical vertical velocity simulated by the different models is quite similar, the total IWP connected with those vertical velocities varies strongly. In most models, high vertical velocities are connected with a significantly higher IWP than the liquid water path (LWP), except in the ICON model, which simulates comparably large increases in IWP and LWP. Differences in cloud phase are connected to different vertical distributions of the condensate, with NICAM ice water content (IWC) reaching higher atmospheric levels than in other models. In most models, CTH and IWC are underestimated compared to DARDAR and METEOSAT data. We analyse the variability of CTH depending on convective strength.

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• Evaluation of tropical anvil cirrus in high-resolution DYAMOND simulations. (deposited 12 Jan 2023 07:18) [Currently Displayed]