The regional water and energy budget for different convection regimes at the SGP region

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Description

Land-surface energy and water budget is strongly influenced by the land-atmosphere interaction. Modelling and observational studies show a discrepancy on the strength of the land-atmosphere coupling at the southern Great Plains (SGP), e.g. a relatively weak (strong) signal from observation-based (model-based) studies. Previous studies of the land-atmosphere interactions in the SGP region focused on nocturnal precipitation, which is associated with eastward-propagating convection systems. To quantify the impact of dominant moisture source on locally-generated convective events at SGP, four convection regimes are classified following Zhang and Klein (2010) and the corresponding water and energy budgets are examined at the daily and sub-daily scales. In this study, 10 years (2004-2013) of the Atmospheric Radiation Measurement (ARM) continuous forcing data are used to calculate the water and energy budget components of the warm seasons (May-August). This continuous forcing data is derived by applying the constrained variational analysis (CVA, Xie et al. 2004) to observational data from the ARM comprehensive long-term network measurements. To characterize the difference in the precipitation fraction supplied by local evapotranspiration between local and non-local convective events, the recycling ratio is defined and quantified based on the dynamic recycling model. Observational analysis is further compared with data from the North American Regional Reanalysis (NARR), and modeling results from cloud-associated parameterizations testbed (CAPT) and Continental United Sates (CONUS) regional-refined model (RRM) to assess the performance of large-scale models. This study investigates the moisture recycling process at the SGP site associated with different convective regimes and improves our understanding on how “local” the local convective events are, from the perspective of their moisture sources. This work is performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-743974.