Thermal tides in the Martian middle atmosphere as seen by the Mars Climate Sounder

The first systematic observations of the middle atmosphere of Mars (35–80km) with the Mars Climate Sounder (MCS) show dramatic patterns of diurnal thermal variation, evident in retrievals of temperature and water ice opacity. At the time of writing, the data set of MCS limb retrievals is sufficient for spectral analysis within a limited range of latitudes and seasons. This analysis shows that these thermal variations are almost exclusively associated with a diurnal thermal tide. Using a Martian general circulation model to extend our analysis, we show that the diurnal thermal tide dominates these patterns for all latitudes and all seasons

Impact of Gravity Waves on the Middle Atmosphere of Mars: A Non-Orographic Gravity Wave Parameterization Based on Global Climate Modeling and MCS Observations

The impact of gravity waves (GW) on diurnal tides and the global circulation in the middle/upper atmosphere of Mars is investigated using a general circulation model (GCM). We have implemented a stochastic parameterization of non‐orographic GW into the Laboratoire de Météorologie Dynamique (LMD) Mars GCM (LMD‐MGCM) following an innovative approach. The source is assumed to be located above typical convective cells ( urn:x-wiley:jgre:media:jgre21298:jgre21298-math-0001250 Pa), and the effect of GW on the circulation and predicted thermal structure above 1 Pa ( urn:x-wiley:jgre:media:jgre21298:jgre21298-math-000250 km) is analyzed. We focus on the comparison between model simulations and observations by the Mars Climate Sounder (MCS) on board Mars Reconnaissance Orbiter during Martian Year 29. MCS data provide the only systematic measurements of the Martian mesosphere up to 80 km to date. The primary effect of GW is to damp the thermal tides by reducing the diurnal oscillation of the meridional and zonal winds. The GW drag reaches magnitudes of the order of 1 m/s/sol above 10 urn:x-wiley:jgre:media:jgre21298:jgre21298-math-0003 Pa in the northern hemisphere winter solstice and produces major changes in the zonal wind field (from tens to hundreds of m/s), while the impact on the temperature field is relatively moderate (10–20 K). It suggests that GW‐induced alteration of the meridional flow is the main responsible for the simulated temperature variation. The results also show that with the GW scheme included, the maximum day‐night temperature difference due to the diurnal tide is around 10 K, and the peak of the tide is shifted toward lower altitudes, in better agreement with MCS observations

Observations of the martian atmosphere with the mars climate sounder

The Mars Climate Sounder (MCS) has obtained measurements of the Martian atmosphere for one Mars year. Onboard the Mars Reconnaissance Orbiter (MRO), MCS continues to acquire high vertical resolution profiles of temperature, dust, condensates of CO2 and H2O, and water vapor by observing the limb of the atmosphere from the surface to 80 km in the spectral intervals 0.3 – 3 ?m and 11.5 – 45 ?m [1]. This paper describes the investigation and introduces some of the observations being studied by the MCS science team. Other presentations by the team at this workshop will describe in greater detail results of ongoing research using MCS data

Structure and dynamics of the Martian lower and middle atmosphere as observed by the Mars Climate Sounder: Seasonal variations in zonal mean temperature, dust, and water ice aerosols

The first Martian year and a half of observations by the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter has revealed new details of the thermal structure and distributions of dust and water ice in the atmosphere. The Martian atmosphere is shown in the observations by the Mars Climate Sounder to vary seasonally between two modes: a symmetrical equinoctial structure with middle atmosphere polar warming and a solstitial structure with an intense middle atmosphere polar warming overlying a deep winter polar vortex. The dust distribution, in particular, is more complex than appreciated before the advent of these high (~5 km) vertical resolution observations, which extend from near the surface to above 80 km and yield 13 dayside and 13 nightside pole-to-pole cross sections each day. Among the new features noted is a persistent maximum in dust mass mixing ratio at 15–25 km above the surface (at least on the nightside) during northern spring and summer. The water ice distribution is very sensitive to the diurnal and seasonal variation of temperature and is a good tracer of the vertically propagating tide

The Exomars Climate Sounder (EMCS) Investigation

The ExoMars Climate Sounder (EMCS) investigation is developed at the Jet Propulsion Laboratory (Principal Investigator J. T. Schofield) in collaboration with an international scientific team from France, the United Kingdom and the USA. EMCS plans to map daily, global, pole-to-pole profiles of temperature, dust, water and CO2 ices, and water vapor from the proposed 2016 ExoMars Trace Gas Orbiter (EMTGO). These profiles are to be assimilated into Mars General Circulation Models (MGCMs) to generate global, interpolated fields of measured and derived parameters such as wind

Mars analysis correction data assimilation: a multi-annual reanalysis of atmospheric observations for the red planet

Ever-increasing numbers of atmospheric observations from orbiting spacecraft, and increasingly sophisticated numerical atmospheric models, have recently permitted data assimilation techniques to be applied to planets beyond the Earth. Mars is the first extra-terrestrial planet for which reanalyses of the atmospheric state are now available. The Thermal Emission Spectrometer (TES) on board NASA’s Mars Global Surveyor (MGS) has produced an extensive atmospheric data set during its scientific mapping phase between 1999 and 2004. Nadir thermal profiles for the atmosphere below about 40 km altitude, and total dust and water ice opacities, have been retrieved from TES spectra, covering almost three complete Martian seasonal cycles (each seasonal cycle on Mars corresponds to 668.6 mean solar days, and the Martian mean solar day is about 24 hours and 40 minutes). Note that dust on Mars plays a key role in the weather and climate, mainly through its strong absorption of short wave radiation with a short radiative relaxation timescale of 1-2 days. Assimilating dust opacities correctly is, therefore, particularly important for atmospheric data assimilation on the Red Planet. TES retrieved observations have been analysed by assimilation into a Mars general circulation model (MGCM), making use of a sequential procedure known as the Analysis Correction scheme, a form of successive corrections method which has proved simple and robust under Martian conditions, even during the less-than-ideal MGS aerobraking period. The MGCM used at the University of Oxford and at The Open University consists of a spectral dynamical solver and a tracer transport scheme developed in the UK. Its package of state-of-the-art physical parameterization routines is shared with the LMD-MarsGCM, developed by the Laboratoire de Météorologie Dynamique in Paris (France). One limitation of TES is that relatively few limb profiles are available, compared to nadir soundings. Our MGS/TES reanalysis, therefore, does not include observations of temperature above about 40 km altitude, nor 3D information on dust opacity (the vertical distribution of dust opacity is prescribed assuming a well mixed dust layer with a rapid transition to a clear upper atmosphere at a height which depends on latitude and season. In September 2006 NASA’s Mars Reconnaissance Orbiter (MRO) started its mapping phase. The Mars Climate Sounder (MCS) on board MRO is a radiometer with eight mid- and far-infrared channels and one visible channel, which takes measurements in limb and off-nadir geometries. Retrieved vertical profiles of temperature, dust and water ice opacities from MCS observations can now be assimilated using the same scheme we used for TES, with the advantage of the extension in altitude (thermal profiles can extend to above 80 km altitude, although errors become larger at greater altitudes), the increased vertical resolution (~ 5km compared to > 10km for TES nadir retrievals), and the direct information on the vertical distribution of dust and water ice. Overall, the application of our data assimilation scheme to retrieved observations from TES and MCS spans almost six complete Martian seasonal cycles. This represents a multi-annual climatology for Mars, which has the advantage of being a complete, dynamically-balanced, four-dimensional best-fit to observations for all the atmospheric variables, including those for which no direct measurements are available (e.g. wind and surface pressure) and with regions of no observations filled-in in a physically-consistent way. The reanalysis represents, therefore, a unique opportunity to study the inter-annual variability of the Martian weather and climate with respect to all its components, such as the dust cycle, the water cycle, the CO2 cycle, the atmospheric tides and other prominent waves, such as high latitude baroclinic waves. In this contribution we present the first results of a complete assimilation of both datasets, using a consistent model and data assimilation scheme, and highlight the challenges of combining TES and MCS data assimilation to produce a multi-annual climatology. Particular attention will be devoted to the inter-annual variability of the atmospheric thermal field in response to dust storm activity. We will also provide an insight into the dynamics, looking in particular at the high latitude winds, waves and polar vortices. Our data assimilation products are freely available to the community for both science- and engineering-oriented purposes. The British Atmospheric Data Centre (BADC, http://badc.nerc.ac.uk) hosts our datasets, which, for the time being, are limited to the MGS/TES reanalysis. People may contact the corresponding author in order to register their interest and be updated about the status of the project. New versions of the MGS/TES reanalysis as well as the MRO/MCS reanalysis will be made available through the BADC in future. Interested people can download the current TES reanalysis dataset by registering at the BADC and searching for the MACDA (“Mars Analysis Correction Data Assimilation”) project. The direct link to the project is provided by the following URL: http://badc.nerc.ac.uk/view/badc.nerc.ac.uk__ATOM__DE_095e8da2-cf02-11e0-8b7a-00e08147026

Mars Sample Handling and Requirements Panel (MSHARP)

In anticipation of the return of samples from Mars toward the end of the first decade of the next century, NASA's Office of Space Sciences chartered a panel to examine how Mars samples should be handled. The panel was to make recommendations in three areas: (1) sample collection and transport back to Earth; (2) certification of the samples as nonhazardous; and (3) sample receiving, curation, and distribution. This report summarizes the findings of that panel. The samples should be treated as hazardous until proven otherwise. They are to be sealed within a canister on Mars, and the canister is not to be opened until within a Biosafety Hazard Level 4 (BSL-4) containment facility here on Earth. This facility must also meet or exceed the cleanliness requirements of the Johnson Space Center (JSC) facility for curation of extraterrestrial materials. A containment facility meeting both these requirements does not yet exist. Hazard assessment and life detection experiments are to be done at the containment facility, while geochemical characterization is being performed on a sterilized subset of the samples released to the science community. When and if the samples are proven harmless, they are to be transferred to a curation facility, such as that at JSC