Friday, October 16, 2026 at 12:15 pm

JILA Foothills Room

Elisha Jhoti , UCLA

"Modeling the Lunar Thermal Emission Phase Function with the Diviner Lunar Radiometer"

Abstract:

The lunar thermal emission phase function (EPF) describes the anisotropic variation in observed infrared emission and brightness temperature with illumination and viewing geometry. The EPF is caused by small-scale surface roughness below the resolution of current orbital data sets. Accounting for the EPF is critical for interpreting off-nadir remote sensing data and for modeling the effect of topographic emission on surface temperatures, especially at high latitudes and polar regions where illumination conditions are more extreme. We develop a semi-analytical model that uses small-scale bowl-shaped craters to simulate daytime surface temperature distributions and directional emission. Our model is validated by the novel Diviner EPF data set, which covers a wider range of targets, illumination and viewing geometries than previous lunar thermal data sets, enabling this model to predict the EPF more accurately than previous studies. The model provides a critical correction for high- resolution 3D thermophysical models, which is essential for accurate prediction of surface temperatures in grazing illumination and volatile stability at the poles.

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