842 The Relationship between the Summertime Great Plains Low-Level Jet and Shear-Generated Turbulence and Fluxes in the Nocturnal Stable Boundary Layer

Tuesday, 9 January 2018
Exhibit Hall 3 (ACC) (Austin, Texas)
Megan McAuliffe, University of California, Davis, CA; and K. T. Paw U

The Great Plains low level jet and corresponding conditions within the nocturnal stable boundary layer (NSBL) could play critical roles in nocturnal warm-season precipitation, but these roles are still not well understood. The Plains Elevated Convection at Night (PECAN) campaign was conducted across the United States Great Plains from 1 June to 15 July 2015. PECAN was split into 26 intensive operation periods to address four key scientific objectives: mesoscale convective systems, bores, convective initiation, and the low level jet (LLJ). Characterizing the LLJ was one of four key scientific objectives during PECAN due to its ability to have an influence on nocturnal precipitation and moisture transport. It is vital to understand because a large portion of the summertime precipitation in the Great Plains occurs at night. However, understanding the evolution and strength of the Great Plains LLJ and its relationship with turbulence and surface fluxes is a challenge. The characteristics of the LLJ can vary greatly due to changes in larger scale weather systems and diurnal heating of the gradual sloping topography of the Midwest. Analyzing these varying characteristics, which include speed, height, and depth, allow for a better understanding of the LLJ. These findings can aid in understanding and quantifying turbulence generation and subjet thermodynamic characteristics in the NSBL. Primary data from PECAN that continues to be analyzed include flux and near-surface measurements from the PECAN Integrated Sounding Arrays as well as Weather Regional Forecast Model ran coupled with the University of California Advanced Canopy-Atmosphere-Soil Algorithm. These measurements and the subsequent analyses of the characteristics of LLJ and NSBL in different locations are unique opportunities to gain better insight into this phenomenon.
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