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)...'

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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GCM simulations of the martian water cycle

Results from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) have long been the definitive data set for observations of the Martian water cycle (Farmer et al., 1977). The ongoing Mars Global Surveyor Thermal Emission Spectrometer (TES) observations are providing new insights into the current water cycle, with detailed longitude-latitude dependence of water vapour (Figure 1) and water cloud (Figure 2) with time, as well as information on vertical distribution of water vapour and ice cloud (Smith, 2001). The described results are derived from an ongoing project to model the currentwater cycle using the Oxford version of the European Mars General Circulation Model (MGCM) (Forget et al., 1999), which was developed in colaboration with LMD, Paris

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

Recent advances in the development of a European Mars climate model in Oxford

Since the early 1990s, efforts have been under way in Oxford to develop a range of numerical weather and climate prediction models for various studies of the Martian atmosphere and near-surface environment. Early versions of the Oxford model were more in the way of 'process models', aimed at relatively idealised studies e.g. of baroclinic instability[1] and low-level western boundary currents in the cross-equatorial solsticial Hadley circulation[2]. Since the mid-1990s, however, the group in Oxford have worked closely with the modelling group at LMD in Paris to develop a joint suite of more sophisticated and comprehensive numerical models of Mars' atmosphere. This collaboration, partly sponsored in recent years by the European Space Agency in connection with the associated development of a climate database for Mars[3], culminated in a suite of global circulation models[4], in which both groups share a library of parametrisation schemes, but in which the Oxford team use a spectral representation of horizontal fields (in the form of spherical harmonics) and the LMD group use a grid-point finite difference representation. These models were described in some detail by Forget et al.[4], and their preliminary validation and use in the construction of first versions of the European Mars Climate Database by Lewis et al.[3]. In the present report, we will review further developments which have taken place since the latter papers were published. Aspects of these developments which are common to both the LMD and Oxford groups will also be covered in the companion contribution by Forget et al. in this meeting, and so will only be touched on briefly here. Instead, we will concentrate on those advances which are more specific to the Oxford version of the model. In the following sections, we outline the main new developments to the model formulation since 1999. Subsequent sections then describe some recent examples where the new model is being utilised to advance a diverse range of studies of Mars atmospheric science

Towards a global model of the martian atmosphere

In an effort to continuously improve the capabilities of the Martian atmospheric predictions at LMD, the GCM has been extended into thermospheric heights thus creating the first model to self-consistently couple the lower and upper regions of the Martian atmosphere. The behaviour of the Martian thermosphere is strongly influenced by lower atmospheric processes and has complex dynamics. Such a fully coupled model will certainly aid in the preparation of future missions and on the analysis of future high altitude data, as well as serve as a base for the simulation of ionospheric processes, escape, etc