In Situ UV Measurements by MSL/REMS: Dust Deposition and Angular Response Corrections

Measurements by the REMS/UV sensor onboard the MSL Curiosity rover constitute the first in situ dataset of UV radiation flux at the surface of Mars. Due to its position on the Curiosity deck, the UV sensor has been directly exposed to dust deposition. Inaccuracies in the original angular response calibration functions have led to discrepancies between measured and physically-expected UV fluxes when the solar zenith angle ( θ ) relative to the rover frame is between 20^∘ and 55^∘ . Here we present a methodology to correct UV fluxes when θ < 55^∘ for both effects, and show results of the corrected data set for the first 2003 sols (∼3 Martian Years, MY) of the MSL mission, from L _s∼ 151^∘ in MY 31 to L _s∼ 149^∘ in MY 34. Close to noon, when θ values are typically < 30^∘ , relative differences between corrected and original UV fluxes are ∼35 – 40