One Martian Year of data assimilation with the Emirates Mars Mission

The Emirates Mars Mission (EMM) will have spent just over one Martian Year (MY) of science operations by the time the EGU General Assembly begins in late April 2023, having begun its primary science phase in May 2021 or MY36 L_s = 49^o. Over this primary phase of the mission, we have been assimilating observations from EMM into the Mars Planetary Climate Model (PCM), using the Local Ensemble Transform Kalman Filter (LETKF), to understand various aspects of Mars' climate. EMM's unique high orbit and viewing geometry make it an extremely valuable source of data for assimilation, as it can observe nearly a whole hemisphere at once, monitor synoptic-scale features for several hours, and sample the whole diurnal cycle over 10 sols. This presentation will focus on the assimilation of atmospheric temperature profiles and column dust optical depth measurements, retrieved from spectral observations made by the Emirates Mars InfraRed Spectrometer (EMIRS), a thermal infrared spectrometer sensitive to 6-50 μm wavelengths on board EMM. We may also include EMIRS surface temperature measurements, and observations from Mars Climate Sounder (MCS) on board Mars Reconnaissance Orbiter (MRO) to fill in gaps in the data record. The assimilation combines EMIRS observations with a climate model in a statistically rigorous way to produce a data product consistent with the uncertainties in both. By measuring the quality of these analyses against assimilated and independent observations, we will highlight how assimilation can be used to inform the future development of our climate simulations.