A mass‐flux convection scheme for regional and global models

TLDR

The authors present a bulk mass‑flux convection parametrization for deep and shallow convection that efficiently handles numerics, moist thermodynamics, and convective downdraughts. The scheme is evaluated in single‑column, tropical deep‑convective and trade‑wind cumulus cases, and applied in global and mesoscale numerical weather‑prediction models, using a CAPE‑based closure to ensure smooth large‑scale interaction and suppress spin‑up. Results indicate the scheme yields reasonable rainfall, temperature, and moisture structures, while its theoretical and practical limits and future development directions are discussed.

Abstract

Abstract A bulk mass‐flux convection parametrization for deep and shallow convection is presented that includes an efficient and straightforward treatment of numerics, moist thermodynamics and convective downdraughts. The scheme is evaluated in a single‐column model context for a tropical deep‐convective period and a trade‐wind cumulus case. Preliminary applications in a global numerical weather‐prediction model and a mesoscale model are also discussed. The results suggest that the present scheme provides reasonable solutions in terms of predicted rainfall, and tropical temperature and moisture structures. The application of the scheme to various scales is supported by the use of a convective available potential energy convective closure that assures a smooth interaction with the large‐scale environment and efficiently suppresses conditional instability of the second kind‐like spin‐up processes on the grid‐scale. Finally, the theoretical and practical limits of the present approach are discussed together with possible future developments.