Climatology of the simulated Great Plains low-level jet and its contribution to the continental moisture budget of the United States

Abstract

The Great Plains region of the United States is characterized by some of the most frequent and regular occurrences of a nocturnal low-level jet (LLJ). A two-month, springtime simulation with the Goddard Earth Observing System (GEOS-1) atmospheric general circulation model (AGCM) has produced a Great Plains LLJ with a vertical and temporal structure, directionality, and climatological distribution that compare favorably with observations. The diurnal cycle of the low-level flow is dramatic and coherent over a subcontinental area that includes much of the western United States and northern Mexico. This cycle can be interpreted as the nightly intrusion of the anticyclonic, subtropical gyre (associated with the Bermuda high) into the North American continent as surface friction decreases. -from Authors