4.1    The Noah-MultiPhysics Land Surface Model: Description and         Comparison of Options

Barlage, Michael, Mukul Tewari, Keving Manning, Fei Chen, National Center for Atmospheric Research, Guo-Yue Niu, Biosphere 2 at The University of Arizona, Zong-Liang Yang, The University of Texas- Austin

The Noah-Multi-Physics (Noah-MP) land surface model (LSM) is a new land surface physics option available in WRF version 3.4. Noah-MP contains multiple options for key land processes and improves upon some Noah LSM limitations. Noah-MP contains a separate vegetation canopy that uses a two-stream radiation transfer approach along with three options for shading effects. Noah-MP contains a multi-layer snow pack separated from vegetation with liquid water storage and melt/refreeze capability and a snow-interception model describing loading/unloading, melt/refreeze, and sublimation of canopy-intercepted snow. Multiple options are available for surface water infiltration and runoff, and groundwater transfer and storage including water table depth to an unconfined aquifer. Vegetation can be prescribed both horizontally and vertically or can be predicted using a Ball-Berry photosynthesis-based stomatal resistance with a dynamic vegetation model that allocates carbon to vegetation (leaf, stem, wood and root) and soil carbon pools. The Noah-MP options are described, compared amongst each other, and contrasted with the analogous Noah capabilities. Results are shown demonstrating the additional processes that can be considered when using Noah-MP and situations, like the presence of snow under a vegetation canopy, where using Noah-MP results in superior land-atmosphere coupling.