Global climate model occultation lightcurves tested by August 2018 ground-based stellar occultation

Pluto's atmospheric profiles (temperature and pressure) have been studied for decades from stellar occultation lightcurves. In this paper, we look at recent Pluto Global Climate Model (GCM) results (3D temperature, pressure, and density fields) from Bertrand et al. (2020) and use the results to generate model observer's plane intensity fields (OPIF) and lightcurves by using a Fourier optics scheme to model light passing through Pluto's atmosphere (Young, 2012). This approach can accommodate arbitrary atmospheric structures and 3D distributions of haze. We compared the GCM model lightcurves with the lightcurves observed during the 15-AUG-2018 Pluto stellar occultation. We find that the climate scenario which best reproduces the observed data includes a N2 ice mid latitude band in the southern hemisphere. We have also studied different haze and P/T ratio profiles: the haze effectively reduces the central flash strength, and a lower P/T ratio both reduces the central flash strength and incurs anomalies in the shoulders of the central flash. •We generated model lightcurves based on the state of Pluto's atmosphere simulated with a Global Climate Model (GCM).•We used the Fourier optics method of Young (2012) to generate occultation lightcurves.•Model lightcurves are compared with ground-based observations of the Pluto stellar occultation event on 15 August 2018.•The observed central flash is consistent with GCM simulations of Pluto in which a southern hemisphere N2 ice band is present.