461 / 2026-03-17 14:22:26

Extending a dry-environment convection parameterization to couple with moist turbulence and a baseline evaluation in the GRIST model

convection parameterization, physical process, global modeling

主题1 天气、气候、全球变化、行星大气 > 专题1.23 对流多尺度相互作用的数值模拟与基础理论

This study presents an extension of a dry-environment convection scheme (Tiedtke–Bechtold) to couple with a boundary-layer moist turbulence scheme. The deep and shallow convective updraught is modified to develop in a moist environment and the large-scale budget ofcloud condensate takes account ofthe influence of compensation subsidence. An ambiguous layer is introduced in the sub-cloud layer transport ofshallow convection to mimic the non-local transport that is ignored in the moist local turbulence scheme. Long-term global simulation suggests that the modified convection and moist turbulence improve low cloud and short-wave cloud radiative forcing. This includes a more realistic climatological structure of stratocumulus-to-cumulus transition and ameliorated biases in liquid water path. For short to mid-term hindcasts in June 2021, the modified convection coupled with moist turbulence mitigates some regional over-forecasts of precipitation. They improve the forecast ability for light and moderate precipitation. Themodifiedmodel still retains the capability to capture the diurnal features of continental rainfall.