Surface Energy Fluxes and Temperatures at Jezero Crater, Mars

Abstract

Diurnal ground surface and air temperatures (Tg, Ta) and the five major surface energy budget fluxes are displayed as derived from M2020 mission observations and from column model simulations in two extreme cases (low and high diurnal Tg-variation) along the Perseverance rover track in the Jezero crater. In both cases the fluxes and Tg are well modeled when using diurnally variable apparent ground thermal inertia I derived via a Fourier series method from the hourly observations. Hence the measurements, the diagnostic method and the model results are consistent with high- and low-I nonhomogeneous terrain in the field-of-view (FOV) of the thermal infrared and solar sensors. In contrast less extreme values of I consistent with THEMIS retrievals are necessary for good simulations of observed Ta. We deduce that the measured Tg for the small ∼3 m2 FOV may not always be representative for the larger region around the rover, which controls the near-surface atmospheric temperature profile.Plain Language SummaryWe present comparisons of hourly surface and air temperatures and solar and thermal (atmospheric) radiation as measured by Perseverance during quite low and quite high noon temperature. We also compare the observed values to those produced by a numerical model. It appears that the model can produce excellent simulations of radiation and the ground surface temperature, if the small measurement spot for the latter is assumed to be a thermally extreme and nonhomogeneous mixture of sand and rocks (models usually assume homogeneous ground). Less extreme soil properties, such as measured by satellites, are needed instead for good air temperature predictions at 1.5 m height, as air temperatures are controlled by larger areas of surface temperatures around the rover. These results are important to better interpret local measurements by Perseverance and to provide ground-truth to satellite observations with a much greater spatial resolution.Key PointsMEDA-observed radiative fluxes and ground temperatures Tg are compared to model simulations during weak and strong diurnal variation in TgRadiation and Tg are best modeled with use of diurnally variable apparent thermal inertiasAir temperatures are best modeled with less extreme area-averaged thermal inertias