Status of surface processes in the LLNL zonally symmetric model

• Main Author: Gleckler, P.J. )
• Language: unknown
• Published: 2020
• Subjects: 54 ENVIRONMENTAL SCIENCES; ATMOSPHERIC CIRCULATION; MATHEMATICAL MODELS; CLIMATES; COMPUTERIZED SIMULATION; SURFACES; ATMOSPHERIC PRECIPITATIONS; EARTH ATMOSPHERE; GLOBAL ASPECTS; SIMULATION; Sea ice
• Online Access: http://www.osti.gov/servlets/purl/7256214; https://www.osti.gov/biblio/7256214; https://doi.org/10.2172/7256214

A surface package has been developed for use in the LLNL zonally symmetric model (ZSM). Surface energy balances are computed for both land and ocean. The ocean is modeled as a well-mixed slab, the land as a single layer with constant thermal conductivity. A land surface moisture budget includes rain, evaporation, sublimation, snowfall, snowmelt and runoff. There is a highly simplified parameterization of surface albedo for freezing oceans and snow covered land. Land and sea air is instantly mixed' by averaging pertinent land and sea surface variables (weighted by their respective areas in each zone) before use in subsequent atmospheric computations. Initial tests have demonstrated that the surface package is working properly. It has been demonstrated that the model produces a reasonable annually averaged' climate. There are some aspects of ZSM which need to be improved, most notably that of cloud cover. The next stage in the development is to test the model in seasonal mode. An improved treatment of surface albedo is currently being coded. When ZSM has been tested in seasonal mode, a sea ice routine will be added to the surface package. There are also plans to implement a method which accounts for the interaction between land and sea air. 5 refs., 15 figs.