Diurnal Variation in Mars Equatorial Odd Oxygen Species: Chemical Production and Loss Mechanisms

Odd oxygen (O, O(¹D), O₃) abundance and its variability in the Martian atmosphere results from complex physical and chemical interactions among atmospheric species, which are driven mainly by solar radiation and atmospheric conditions. Although our knowledge of Mars’ ozone distribution and variability has been significantly improved with the arrival of several recent orbiters, the data acquired by such missions is not enough to properly characterize its diurnal variation. Thus, photochemical models are useful tools to assist in such a characterization. Here, both the Martian ozone vertical distribution and its diurnal variation for equatorial latitudes are studied, using the JPL/Caltech one-dimensional photochemical model and diurnally-variable atmospheric profiles. The chosen equatorial latitude-region is based on the recent and future plans of NASA and other agencies to study this region by different surface missions. A production and loss analysis is performed in order to characterize the chemical mechanisms that drive odd oxygen's diurnal budget and variability on Mars making use of the comprehensive chemistry implemented in the model. The diurnal variation shows large differences in the abundance between daytime and nighttime; and variable behavior depending on the atmospheric layer. The photolysis-driven ozone diurnal profile is obtained at the surface, whilst a sharp decrease is obtained in the upper troposphere at daytime, which originates from the large differences in atomic oxygen abundances between atmospheric layers. Finally, no clear anticorrelation between ozone and water vapor is found in the diurnal cycle, contrary to the strong correlation observed by orbiters on a seasonal timescale

Effects of the MY34/2018 Global Dust Storm as Measured by MSL REMS in Gale Crater

The Rover Environmental Monitoring Station (REMS) instrument is on board NASA’s Mars Science Laboratory (MSL) Curiosity rover. REMS has been measuring surface pressure, air, and ground brightness temperature, relative humidity, and ultraviolet (UV) irradiance since MSL’s landing in 2012. In Mars Year (MY) 34 (2018) a global dust storm reached Gale Crater at Ls ~ 190°. REMS offers a unique opportunity to better understand the impact of a global dust storm on local environmental conditions, which complements previous observations by the Viking landers and Mars Exploration Rovers. All atmospheric variables measured by REMS are strongly affected albeit at different times. During the onset phase, the daily maximum UV radiation decreased by 90% between sols 2075 (opacity ~1) and 2085 (opacity ~8.5). The diurnal range in ground and air temperatures decreased by 35 and 56 K, respectively, with also a diurnal-average decrease of ~2 and 4 K respectively. The maximum relative humidity, which occurs right before sunrise, decreased to below 5%, compared with prestorm values of up to 29%, due to the warmer air temperatures at night, while the inferred water vapor abundance suggests an increase during the storm. Between sols 2085 and 2130, the typical nighttime stable inversion layer was absent near the surface as ground temperatures remained warmer than near-surface air temperatures. Finally, the frequency domain behavior of the diurnal pressure cycle shows a strong increase in the strength of the semidiurnal and terdiurnal modes peaking after the local opacity maximum, also suggesting differences in the dust abundance inside and outside Gale.Key PointsAtmospheric opacity over Gale Crater was increased by more than 8 times and disturbed all the atmospheric variables measured by REMSREMS data suggest that the nighttime near-surface atmosphere stability was reduced and its water abundance increased during the GDSThe semidiurnal mode peaked after the local opacity maximum, suggesting different dust abundance inside and outside GalePeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151294/1/jgre21177_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151294/2/jgre21177.pd

Meteorological predictions for Mars 2020 Perseverance rover landing site at Jezero crater

Correction to: Space Sci Rev (2020) 216:148 https://doi.org/10.1007/s11214-020-00763-xPeer reviewe

Secular Climate Change on Mars: An Update Using MSL Pressure Data

The South Polar Residual Cap (SPRC) on Mars is an icy reservoir of CO2. If all the CO2 trapped in the SPRC were released to the atmosphere the mean annual global surface pressure would rise by approx. 20 Pa. Repeated MOC and HiRISE imaging of scarp retreat rates within the SPRC have led to the suggestion that the SPRC is losing mass. Estimates for the loss rate vary between 0.5 Pa per Mars Deacde to 13 Pa per Mars Decade. Assuming 80% of this loss goes directly to the atmosphere, and that the loss is monotonic, the global annual mean surface pressure should have increased between approx. 1-20 Pa since the Viking mission (19 Mars years ago)

First Atmospheric Results from InSight APSS

NASA’s Mars InSight Spacecraft landed on Nov 26, 2018 (Ls=295°) in Elysium Planitia (~4.5°N, 136°E). InSight’s main scientific purpose is to investigate the interior structure and heat flux from Mars, but it is also equipped with instrumentation that can serve as a very capable meteorological station. To remove unwanted environmental noise from the seis- mic signals, InSight carries a very precise pressure sensor (PS) and the first magnetometer (IFG) to the surface of Mars. Additionally, to aid in removing the atmospheric pressure-induced seismic noise, and to identify periods when wind-induced seismic noise may reduce sensitivity, InSight also carries a pair of Wind and Air temperature sensors (TWINS). These three sensors comprise the Auxiliary Payload Sensor Suite (APSS) [1]. Complementing this are a radiometer in the HP3 suite to measure surface radiance, the seismic measurements of SEIS which can record interesting atmospheric phenomena, and the InSight cameras to image clouds and dust devils and estimate atmospheric opacity from dust or clouds. The Lander also carried accelerometers that can be used to reconstruct the at- mospheric structure during descent. We will discuss results drawn from atmospheric measurements on board InSight from the first months of operation, high- lighting the new perspectives permitted by the novel high-frequency, and continuous nature of the InSight data acquisition. Details on pre-landing scientific perspectives for atmospheric science with InSight are found in [2]

Mars Science Laboratory relative humidity observations : Initial results

The authors would like to express their gratitude to the MSL and REMS instrument teams in making this wonderful Mars mission come true. Ari‐Matti Harri and Hannu Savijarvi are thankful for the Finnish Academy grants 132825 and 131723.Peer reviewedPublisher PD

Pressure observations by the curiosity rover : Initial results

The authors would like to express their gratitude to the MSL and REMS instrument teams in making this wonderful Mars mission come true. Ari-Matti Harri and Hannu Savijarvi are thankful for the Finnish Academy grants 132825 and 131723.Peer reviewedPublisher PD

More than one martian year of meteorology observed by the Insight lander

InSight has been measuring atmospheric pressure, wind and temperature since December 10, 2018 (around Ls=304° of Martian Year 34), 14 sols after its landing. In particular, more than one Martian year of almost continuous measurements has been obtained in 2018-2020. InSight is located in Elysium Planitia, at 4.50238°N, 135.62345°E in planetocentric coordinates (-2614 m altitude below MOLA areoid). Hence, the geophysical lander is providing the best long-duration meteorological Mars station since Viking. In this work, we review the meteorological phenomena that characterize the pressure and wind measurements at timescales larger than 1000 seconds. A subset of the meteorological observations obtained at the beginning of the mission was previously reported in [1]. The analysis is helped by comparing the results with prediction from the LMD numerical global climate model (GCM, [2]) as re-ported before landing by [3]

Multi-model Meteorological and Aeolian Predictions for Mars 2020 and the Jezero Crater Region

Nine simulations are used to predict the meteorology and aeolian activity of the Mars 2020 landing site region. Predicted seasonal variations of pressure and surface and atmospheric temperature generally agree. Minimum and maximum pressure is predicted at Ls∼145° and 250°, respectively. Maximum and minimum surface and atmospheric temperature are predicted at Ls∼180° and 270°, respectively; i.e., are warmest at northern fall equinox not summer solstice. Daily pressure cycles vary more between simulations, possibly due to differences in atmospheric dust distributions. Jezero crater sits inside and close to the NW rim of the huge Isidis basin, whose daytime upslope (∼east-southeasterly) and nighttime downslope (∼northwesterly) winds are predicted to dominate except around summer solstice, when the global circulation produces more southerly wind directions. Wind predictions vary hugely, with annual maximum speeds varying from 11 to 19ms−1 and daily mean wind speeds peaking in the first half of summer for most simulations but in the second half of the year for two. Most simulations predict net annual sand transport toward the WNW, which is generally consistent with aeolian observations, and peak sand fluxes in the first half of summer, with the weakest fluxes around winter solstice due to opposition between the global circulation and daytime upslope winds. However, one simulation predicts transport toward the NW, while another predicts fluxes peaking later and transport toward the WSW. Vortex activity is predicted to peak in summer and dip around winter solstice, and to be greater than at InSight and much greater than in Gale crater