Description and climatology of a new general circulation model of the Martian atmosphere

Abstract

[1] The paper presents a new grid point global general circulation model (GCM) for the Martian atmosphere with the vertical domain extending from the surface into the lower thermosphere (around 130 km). The model contains the comprehensive physical parameterizations relevant to this altitude range, including a novel CO 2 15 mm band radiation scheme for the non-LTE. The performance of the model is shown in the zonal mean fields simulated for several seasons. The comparison demonstrates a good agreement with the temperature measurements by the Thermal Emission Spectrometer below 40 km and an overall agreement with the results from other Martian GCMs. The model was used to demonstrate that the global meridional transport during solstices is forced primarily by eddies and that the ability of the model to simulate the winter polar warming depends on the ability to resolve the longitudinal disturbances, both topographically and radiatively generated.

On Forcing the Winter Polar Warmings in the Martian Middle Atmosphere during Dust Storms

“…1b, d, the areas of strong wave forcing coincide with the areas of enhanced meridional transport in the middle atmosphere. It was shown in Hartogh et al (2005) that the former forces the latter to a large degree. The horizontally transported air descends in high winter latitudes.…”

“…The vertical distribution of the aerosol mixing ratio was prescribed as Q ¼ Q 0 expf0:01½1 À ðp 0 =pÞg, where Q 0 , p 0 and p are the reference dust mixing ratio (that depends on the optical depth, e.g., 6.2 ppm of mass for t ¼ 1:0), pressures at the reference (600 Pa) and any given level, respectively. This formula is a simplified version of the representation commonly used in Martian GCMs (Forget et al 1999;Hartogh et al 2005). It corresponds to a roughly uniform mixing ratio up to @ 35 km, and to strong decays above.…”

The Atmospheric Chemistry Suite (ACS) of Three Spectrometers for the ExoMars 2016 Trace Gas Orbiter

“…Such capability of observing most gases during the same acquisition is a critical feature, which enables the estimation of the oxidation rate and the lifetime of chemical species controlled by both homogeneous and heterogeneous processes. Regions of active release, if present, will be localized using the observed concentration patterns that will be further refined by the application of the three-dimensional (3-D) models developed in our team (Forget et al 1999;Lefèvre et al 2004;Hartogh et al 2005). Depending on the gases observed, or through ratios with isotopologues, fundamental information on the nature of the source (biogenic vs. abiotic) will be deduced.…”

The RAW Filter: An Improvement to the Robert–Asselin Filter in Semi-Implicit Integrations

“…Traditionally, however, the preferred strategy has been to apply a Robert-Asselin filter (Robert 1966;Asselin 1972) after each leapfrog step. Although in wide use (e.g., Schlesinger et al 1983;Tandon 1987;Ford 1994;Caya and Laprise 1999;Griffies et al 2001;Bartello 2002;Cordero and Staniforth 2004;Fraedrich et al 2005;Hartogh et al 2005;Williams et al 2009), the Robert-Asselin filter is associated with some counterintuitive behavior (e.g., Déqué and Cariolle 1986;Robert and Lépine 1997) and a reduction to first-order accuracy. Williams (2009) proposed a simple modification to the Robert-Asselin filter, designed to preserve the secondorder accuracy in leapfrog integrations.…”