Daily global mapping of Mars ozone column abundances with MARCI UV band imaging

Since November of 2006, The Mars Color Imager (MARCI) onboard the Mars Reconnaissance Orbiter (MRO) has obtained multiple-filter daily global images of Mars centered upon a local time (LT) of 3 pm. Ultraviolet imaging bands placed within (260 nm) and longward (320 nm) of Hartley band (240-300 nm) ozone (O-3) absorption support retrievals of atmospheric ozone columns, with detection limits (similar to 1 mu m-atm) appropriate to mapping elevated O-3 abundances at low latitudes around Mars aphelion, and over mid-to-high latitudes during fall/winter/spring seasons. MARCI O-3 maps for these regions reveal the detailed spatial (similar to 1 degrees lat/long, for 8 x 8 pixel binned resolution) and temporal (daily, with substantial LT coverage at pole) behaviors of water vapor saturation conditions that force large variations in water vapor photolysis products (HOx-OH, HO2, and H) responsible for the catalytic destruction of O-3 in the Mars atmosphere. A detailed description of the MARCI O-3 data set, including measurement and retrieval characteristics, is provided in conjunction with comparisons to Mars Express SPICAM ozone measurements (Perrier, S. et al. [2006].J. Geophys. Res. (Planets) 111) and LMD GCM simulated O-3 abundances (Lefevre, F. 12004].J. Geophys. Res. (Planets) 109). Presented aspects of the MARCI ozone mapping data set include aphelion increases in low latitude O-3, dynamically evolving high latitude O-3 maxima associated with planetary waves and weather fronts during northern early spring, and distinctive winter/spring O-3 and CO increases within the Hellas Basin associated with transport of condensationenhanced south polar air mass. Comparisons of coincident MARC! measurements and LMD simulations for ice cloud and O-3 columns are considered in the context of potential heterogeneous photochemical processes (Lefevre, F. [2008]. Nature 454,971-975), which are not strongly evidenced in the MARCI observations. Modest interannual variations are exhibited, most notably a 20% reduction in aphelion low latitude O-3 columns following the 2007 perihelic global dust storm. (c) 2015 Elsevier Inc. All rights reserved.