Xiao Ma, Yanping Li, Zhenhua Li (2022). Investigation of the climatology of low-level jets over North America in a high-resolution WRF simulation. Proceedings of the GWF Annual Open Science Meeting, May 16-18, 2022.

The Low-level Jet (LLJ) is an important atmospheric phenomenon over North America and significantly impacts on local weather and climate. In this study, we use a 4-km convection-permitting Weather Research Forecasting (WRF) simulation over 13 years (2000-2013) to investigate the climatological features of LLJs. A high-resolution model better represents orography and the underlying surface that strongly affect winds in the boundary layer. The simulation domain covers the continental US and the neighboring portions of Canada and Mexico. The study characterizes the spatial distribution and seasonal and diurnal fluctuations of northerly/southerly LLJs' frequencies. Our algorithm successfully identified the previously well-known large-scale features of North American LLJs like southerly Great Plain LLJs and summer northerly Pacific Coast LLJs. Besides, the high-resolution simulation also provides new climatic characteristics of weaker and smaller-scale LLJs near complex terrains. Wintertime northerly Rockies LLJs were confined in limited foothill regions.

First Author: Xiao Ma, University of Saskatchewan
Additional Authors: Yanping Li, University of Saskatchewan; Zhenhua Li, Global Institute for Water Security