Validating Model Freezing Level Heights for West Lafayette, Indiana using Purdue University Radiosonde Data

The atmospheric freezing level height is necessary for radar hydrometeor classification algorithms to discriminate liquid or frozen precipitation. This study aimed to validate the freezing level height data from BUFKIT in the Lafayette, IN area using temperature data from 32 education-grade radiosondes (Windsonds) launched from Purdue’s West Lafayette campus from 2017 to 2023. Freezing level heights in meters were extracted from BUFKIT soundings closest to the same dates, times, and grid points as radiosonde launches from Purdue’s West Lafayette campus. The data were further split by meteorological season, numerical weather prediction (NWP) model used, and also by proximity to surface fronts. Overall, strong correlation was found between the freezing level heights of BUFKIT and those measured by radiosondes launched from West Lafayette (r=0.96). For the data subsets, the correlation coefficients fell between 0.85 to 0.97, which are still exceptionally strong. The highest correlation coefficient was found for the fall months (0.97), and the lowest was for the summer months (0.86). These findings demonstrate that BUFKIT freezing level heights are representative for West Lafayette, IN within +/- 350 m.