For the first time, the Emirates Mars Infrared Spectrometer (EMIRS) instrument on board the Emirates Mars Mission (EMM) ‘Hope’, is providing us with the temperature measurements of Mars at all local times covering most of the planet. As a result, it is now possible to compare surface temperature measurements made from orbit with those from the surface by rovers during the same time period. We use data of diurnal temperature variation from the Rover Environmental Monitoring Station (REMS) suite on board the Mars Science Laboratory (MSL) ‘Curiosity’ rover, and the Mars Environmental Dynamics Analyzer (MEDA) suite on board the Mars 2020 ‘Perseverance’ rover, between June and August 2021 and compare them with EMIRS observations and estimates of the Mars Climate Database (MCD) model. We show that although the overall trend of temperature variation is in excellent agreement across missions, EMIRS measurements are systematically lower at night compared to Mars 2020. The lower spatial resolution of EMIRS compared to the rovers and consequently lower average thermal inertia of the observed regions in this particular case primarily contributed to this discrepancy, among other factors. We discuss the implications of these results in improving our understanding of the Martian climate which would lead to better modeling of local weather prediction, useful for future robotic and crewed missions.

<div>The ~55 hour orbit of the Emirates Mars Mission (EMM) or the “Hope'" orbiter enables it to achieve a near-global coverage of the planet every 4 orbits, or ~9 sols. The Emirates Mars Infrared Spectrometer (EMIRS) instrument on board EMM is used to retrieve surface temperatures. We study the geographical and temporal variation of surface temperature on diurnal and seasonal timescales. We compare these measurements with NASA’s rover measurements —  from the Rover Environmental Monitoring Station (REMS) suite on board the Mars Science Laboratory (MSL) "Curiosity" rover, and the Mars Environmental Dynamics Analyzer (MEDA) suite on board the Mars 2020 "Perseverance” rover. We also compare these measurements with the Mars Climate Database (MCD), identify anomalies in surface temperature and discuss the role of thermal inertia. We discuss other implications of these findings leading to a better understanding of temperature variation on Mars and its impact on weather and climate.  </div> <p> </p>

The Emirates Mars Infrared Spectrometer (EMIRS) instrument on board the Emirates Mars Mission (EMM) "Hope", for the first time, is providing us with the temperature measurements of Mars at all local times covering most of the planet. It is therefore possible now to compare surface temperature measurements made from orbit with those from the surface by rovers during the same time period. We use data of diurnal temperature variation from the Rover Environmental Monitoring Station (REMS) suite on board the Mars Science Laboratory (MSL) "Curiosity" rover, and the Mars Environmental Dynamics Analyzer (MEDA) suite on board the Mars 2020 "Perseverance" rover, between June and August 2021 and compare them with EMIRS observations. We also compare these measurements with estimates of the Mars Climate Database (MCD) model. We show that although the overall trend of temperature variation is in excellent agreement across missions, EMIRS measurements are systematically lower at night compared to Mars 2020. We describe a number of factors which could lead to this discrepancy. We discuss the implications of these results in improving our understanding of the Martian climate which would lead to better modeling of local weather prediction, useful for future robotic and potentially crewed missions to Mars.