Terrain variables improve modeling of Richardson numbers less than unity in the lower atmosphere

Occurrences of turbulence based on a critical Richardson number, obtained using data from nine rawinsonde stations for the years 1971-1975, are compared to show evidence of mountain induced effects in the lower atmosphere. The nine stations were selected since they could be divided into three groups by latitude. Two of the stations in each group are located in the Midwestern Plains and the third in the Western Mountain Region. Results from these comparisons led to the creation of a variable to indicate station terrain type for inclusion in an existing regression model. The improved model employing stepwise multiple regression techniques uses terrain, location, and seasonal information.