Abstract for presentation at 14th IUAPPA World Congress

Since the release of TAPM V3, several enhancements have been made to the model. This paper focuses on two new options for the representation of land surface processes, including an improved scheme for radiation and soil in TAPM, and the inclusion of the CABLE V0 land surface scheme. The first option improves upon the old scheme in TAPM by using a vegetative canopy overlaying the soil and a 15-level numerical solution of the heat diffusion equation for soil temperature and Richards’ equation for soil moisture content. This approach allows a more interactive calculation of radiation and surface fluxes than the old scheme and allows soil temperature and moisture to vary with depth and to evolve over time in response to changes in surface fluxes, rainfall, and soil and vegetation processes. Compared to the above scheme, CABLE includes a 6-level soil scheme, a snow scheme, and uses a more comprehensive approach for the vegetative canopy, but at this stage it does not include an urban scheme. Two new global datasets of soil type and monthly-varying Leaf Area Index have also been connected to TAPM. The new scheme has been run for a number of past verification studies, with statistical results showing improved wind and temperature predictions. The CABLE scheme has also been run for some of these datasets for comparative purposes. A more comprehensive comparison of the new options against data, with a focus on light wind and stable conditions, will be done in Part 2 of this series of papers.