Low-level Jet Turbulence and Impacts on Stability in the Nocturnal Boundary Layer

A low-level jet (LLJ) is most simply defined as a strong wind speed maximum in the lower troposphere with a significant decrease in wind speed at higher altitudes. LLJ events over land typically occur at night and are confined to the lowest kilometer of the atmosphere. These events impact meteorology and air quality by transporting atmospheric constituents hundreds of kilometers and by generating significant wind shear mixing near the surface. This presentation will focus on Great Plains LLJs observed during the Plains Elevated Convection at Night (PECAN) field campaign. The strong LLJs in this region induce significant turbulence throughout the lowest several hundred meters of the atmosphere. This mechanically created bulk shear turbulence has impacts on nocturnal stability, eradicating the common stable boundary layer model and approaching an isothermal boundary layer. The research shown here utilizes active and passive remote sensing instruments to create timeseries of these dynamic and thermodynamic phenomena with unprecedented resolution.