Diurnal Variations in the Aphelion Cloud Belt as Observed by the Emirates Exploration Imager (EXI)

International audienceObservations by the Emirates eXploration Imager (EXI) on-board the Emirates Mars Mission are used to characterize the diurnal, seasonal, and spatial behavior of aphelion cloud belt during Mars Year 36 LS ∼ 30°-190°. Building from previous work with the Mars Color Imager (MARCI) onboard the Mars Reconnaissance Orbiter, we retrieve water ice extinction optical depth (τice) with an uncertainty ±0.0232 (excluding particle size effects). We connect EXI and MARCI using radiance and τice. Zonal and meridional diurnal trends are analyzed over 6-18 hr Local True Solar Time. The retrievals show large morning-evening asymmetries about a minimum near 12 hr. The latitudinal distributions in early morning are extensive and particularly striking near mid-summer. Comparisons to the Mars Planetary Climate Model show reasonable agreement with basic diurnal behavior, but noticeable departures include too much water ice in early morning, the general latitudinal extent, and behavior at smaller scales like the volcanoes and other topographically distinct features

Emirates Mars Mission Characterization of Mars Atmosphere Dynamics and Processes

International audienceThe Emirates Mars Mission (EMM) - Hope Probe - was developed to understand Mars atmospheric circulation, dynamics, and processes through characterization of the Mars atmosphere layers and its interconnections enabled by a unique high-altitude (19,970 km periapse and 42,650 km apoapse) low inclination orbit that will offer an unprecedented local and seasonal time coverage over most of the planet. EMM has three scientific objectives to (A) characterize the state of the Martian lower atmosphere on global scales and its geographic, diurnal and seasonal variability, (B) correlate rates of thermal and photochemical atmospheric escape with conditions in the collisional Martian atmosphere, and (C) characterize the spatial structure and variability of key constituents in the Martian exosphere. The EMM data products include a variety of spectral and imaging data from three scientific instruments measuring Mars at visible, ultraviolet, and infrared wavelengths and contemporaneously and globally sampled on both diurnal and seasonal timescale. Here, we describe our strategies for addressing each objective with these data in addition to the complementary science data, tools, and physical models that will facilitate our understanding. The results will also fill a unique role by providing diagnostics of the physical processes driving atmospheric structure and dynamics, the connections between the lower and upper atmospheres, and the influences of these on atmospheric escape