Retrieval of CO Relative Column Abundance in the Martian Thermosphere From FUV Disk Observations by EMM EMUS

Carbon monoxide (CO) is a sensitive tracer of the thermal profile and winds in Mars' middle atmosphere chemistry that balances CO2 whole Mars. The Emirates Ultraviolet Spectrometer (EMUS) onboard Mars Mission Hope probe images at ultraviolet wavelengths from approximately 100 to 170 nm. ?CO/CO2, column density ratio CO carbon dioxide, provides measure relative variability within Martian thermosphere. Derived heritage ?O/N2 used Earth, ?CO/CO2 algorithm uses emission Fourth Positive Group band system derive abundance above ?70 km. We describe EMUS algorithm, review Level 3 data product, discuss preliminary validation algorithm. produces ratios characterize spatial structure