Results on dust storms and stationary waves in three Mars years of data assimilation

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Breeding vectors and predictability in the Oxford Mars GCM

A breeding vectors approach is used to study the intrinsic predictability of the Martian atmosphere using the Oxford Mars General Circulation Model (MGCM). The approach, described in detail below, is first tested using a terrestrial general circulation model, the United Kingdom Meteorological Office's Unified Model (UM), and results show growing modes of instability at mid to high latitudes on spatial scales of less than ~1,000km, in qualitative agreement with previous studies performed using terrestrial models. For the Martian atmosphere, and in the absence of radiatively active dust transport (so using a typical background dust distribution for each time of year), the technique reveals model states with approximately zero growth factors, and modes of instability on relatively large (up to ~5,000km) spatial scales. The implications of this for the predictability of the Martian atmosphere and for the usage of ensemble forecasting methods on Mars are also discussed

Data assimilation for Mars: an overview of results from the Mars Global Surveyor period, proposals for future plans and requirements for open access to assimilation output

Abstract not available. From the introduction: 'The Thermal Emission Spectrometer (TES) aboard Mars Global Surveyor (MGS) has produced an extensive atmospheric data set, both during the initial aerobraking hiatus and later from the scientific mapping phase of the mission which lasted almost three complete Martian seasonal cycles. Thermal profiles for the atmosphere below about 40 km, and total dust and water ice opacities, have been retrieved from TES spectra (Conrath et al., 2000, Smith et al., 2000)...'

On the assimilation of Martian total ozone retrievals

The technique of data assimilation gives us an opportunity to further our understanding of important photochemical processes in the Martian atmosphere, through the creation of a reanalysis product that can be used to investigate the temporal and spatial agreement between model and observations and determine any possible causes of identified differences. In this study [1], we have assimilated, for the first time, total ozone retrievals into a Mars Global Circulation model (GCM) to study the ozone cycle

The Low Adhesion Problem due to Leaf Contamination in the Wheel/Rail Contact: Bonding and Low Adhesion Mechanisms

Autumn leaves often cause low adhesion problems for train operations, leading to station overruns and signals passed at danger (SPADS). The aim of this paper was to review operational data and research methods to assess the current understanding of the problem and formulate hypotheses for the causes. Incident analysis showed the relatively high possibility of incidents between the hours of 05:00 – 10:00 and 20:00 – 24:00, suggesting the dew effect was important. This result corresponds to the knowledge that wet leaves in the contact area produce very low friction coefficients, below 0.1. Current mitigation methods, such as sanding, seem inadequate to remove the leaf films completely. To explain the bonding mechanism between the leaf film and the rail, a laboratory-based model and a field-based model were developed based on previous studies. Moreover, key parameters for a strong bond formation were identified, which are iron oxide, temperature, pressure and leaf material. The research gaps were identified by a paper grading method, and several hypotheses for bonding mechanisms and low adhesion mechanisms were proposed, such as sub- or super critical water and pectin gel

Climatology on Mars: interannual variability of mean fields

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Dust cycles and storms in a Mars GCM

A number of different dust lifting parameterizations have been used to model the injection of dust from the Martian surface into the atmosphere, and the form of the resulting dust cycles and dust storms produced are found to be highly dependent on the precise form of the parameterization used, provided that it includes some threshold dependence, and particularly where radiatively active dust transport is employed. This talk will review the most interesting results from previous work. We have recently altered a key factor which particularly affects the dust lifting due to near-surface wind stress, however, so we will also present results using the new dust lifting formulation, and make some comparisons

Atmospheric predictability of the martian atmosphere: from low-dimensional dynamics to operational forecasting?

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MGS accelerometer data analysis with the LMD GCM

Mars Global Surveyor aerobreaking phases, required to achieve its mapping orbit, have yielded vertical profiles of thermospheric densities, scale heights and temperatures covering a broad range of local times, seasons and spatial coordinates [Keating et al. 1998, 2001]. Phase I covered local times from 11 to 16 h (assuming 24 "martian hours” per martian day or sols), with a latitude coverage of approximately 40deg to 60deg N. Seasons observed during this phase were centered around winter solstice and altitudes of periapsis range from 115 to 135 km. The altitudes for Phase II were lower, with a minimum around 100 km and a maximum around 120. Martian spring was the season covered during this phase and the local time was between 15 and 16 h. The latitude covered by Phase II, however, was more extense than that seen during Phase I, with a coverage from 60deg N to basically the South Pole