Reanalysis and extension of namias's climatological isentropic analysis: Detection and evaluation of monsoonal, severe storm, drought, and flood events

This study revisits, updates, and evaluates the climatological isentropic analysis method pioneered by Jerome Namias in the 1930s. Early researchers including Namias noted many advantages to the use of constant potential temperature surfaces, or isentropic analysis, over constant pressure charts (e.g., barometric heights) but aviation needs for constant pressure charts caused climatological isentropic research to wane after World War II. We employ modern data to verify and update Namias's original identification of the North American monsoon. Given this verification, we extend his analyses to other seasons. Importantly, we identify a springtime prominent "isentropic inverted wave" over the Great Plains that corresponds to severe storm and tornadic activity. We also verify isentropic analysis in the detection of drought using modern drought indexes. Fundamentally, we demonstrate that Namias's climatological isentropic analysis is still notably applicable to climate forecasting concerns. In a larger perspective, we demonstrate the usefulness of reexamining past research in the context of new data and methods.