pyPI (v1.3): Tropical Cyclone Potential Intensity Calculations in Python

• Published in: Geoscientific Model Development Vol. 14; no. 5; pp. 2351 - 2369
• Main Author: Gilford, Daniel M.
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 03.05.2021; Copernicus Publications
• Subjects: Algorithms; Atmospheric boundary layer; Atmospheric models; Climatology; Computation; Cyclones; Efficiency; Heat; Heat engines; Hurricanes; Meteorological research; Missing data; Oceanographic conditions; Storm winds; Storms; Temperature; Tropical climate; Tropical cyclone intensities; Tropical cyclones; Wind speed
• ISSN: 1991-9603; 1991-962X; 1991-959X; 1991-9603; 1991-962X
• DOI: 10.5194/gmd-14-2351-2021

Potential intensity (PI) is the maximum speed limit of a tropical cyclone found by modeling the storm as a thermal heat engine. Because there are significant correlations between PI and actual storm wind speeds, PI is a useful diagnostic for evaluating or predicting tropical cyclone intensity climatology and variability. Previous studies have calculated PI given a set of atmospheric and oceanographic conditions, but although a PI algorithm – originally developed by Kerry Emanuel – is in widespread use, it remains under-documented. The Tropical Cyclone Potential Intensity Calculations in Python (pyPI, v1.3) package develops the PI algorithm in Python and for the first time details the full background and algorithm (line by line) used to compute tropical cyclone potential intensity constrained by thermodynamics. The pyPI package (1) provides a freely available, flexible, validated Python PI algorithm, (2) carefully documents the PI algorithm and its Python implementation, and (3) demonstrates and encourages the use of PI theory in tropical cyclone analyses. Validation shows pyPI output is nearly identical to the previous potential intensity computation but is an improvement on the algorithm's consistency and handling of missing data. Example calculations with reanalyses data demonstrate pyPI's usefulness in climatological and meteorological research. Planned future improvements will improve on pyPI's assumptions, flexibility, and range of applications and tropical cyclone thermodynamic calculations.