6.5 Assessing the role of land surface hydrology in the development of terrain-induced convection within the North American Monsoon

Tuesday, 21 August 2012: 9:15 AM
Priest Creek C (The Steamboat Grand)
David J. Gochis, NCAR, Boulder, CO; and E. R. Vivoni, M. Tewari, T. Xiang, and W. Yu

Land surface hydrology has been implicated as an active participant in the initiation of atmospheric convection under certain conditions. What is less clear is how terrestrial hydrologic variability, superimposed on complex terrain regions, modifies background circulation structures such as mountain valley and mountain plain flows. We present results from a series of idealized and real-world simulation experiments which attempt to define the role and context of surface hydrology on terrain induced convection. Single-column model and three-dimensional simulation domains of the Advanced Weather Research and Forecasting Model are used and model results from ‘real-world' simulations are validated using both traditional meteorological variables and recently developed land-atmosphere coupling metrics. We present the results in the context of assessing the influence of land surface hydrologic forcing versus various possible states of atmospheric conditions including a priori moisture availability and stability. Emphasis of the analyses will be placed on diagnosing key variables and threshold values for the initiation and growth of convective cloud cover and precipitation in the mountainous region of northwest Mexico. We will conclude with a set of recommendations for future observational efforts which may have the potential to reduce model initialization errors and improve forecast skill.
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