Simulation of Surface-Moisture Effects on the Great Plains Low-Level Jet

Abstract Convective precipitation and severe weather episodes in the central United States commonly have diurnal oscillations with maximum amplitudes at night. Observations suggest that the timing of some convective events may be driven by diurnal changes in the atmospheric boundary-layer convergence and vertical-motion fields resulting from a nocturnal, low-level jet over the southern Great Plains. Recent planetary boundary-layer models have attempted to simulate the strong boundary-layer forcings and dissipations that may be partly responsible for these low-level flows. This research attempts to determine the effects of soil moisture and evaporation on the Great Plains nocturnal jet. Soil moisture determines surface evapotranspiration, latent beating, and soil thermal capacity and thereby plays an important role in the stratification and buoyancy of the boundary layer. Soil moisture should, therefore, be significant to this nocturnal, boundary-layer phenomenon. This hypothesis is evaluated by embedding ...