Dust aerosols above the south polar cap of Mars as seen by OMEGA

The time evolution of atmospheric dust at high southern latitudes on Mars has been determined using observations of the south seasonal cap acquired in the near infrared (1–2.65 μm) by OMEGA/Mars Express in 2005. Observations at different solar zenith angles and one EPF sequence demonstrate that the reflectance in the 2.64 μm saturated absorption band of the surface CO2 ice is mainly due to the light scattered by aerosols above most places of the seasonal cap. We have mapped the total optical depth of dust aerosols in the near-IR above the south seasonal cap of Mars from mid-spring to early summer with a time resolution ranging from one day to one week and a spatial resolution of a few kilometers. The optical depth above the south perennial cap is determined on a longer time range covering southern spring and summer. A constant set of optical properties of dust aerosols is consistent with OMEGA observations during the analyzed period. Strong variations of the optical depth are observed over small horizontal and temporal scales, corresponding in part to moving dust clouds. The late summer peak in dust opacity observed by Opportunity in 2005 propagated to the south pole contrarily to that observed in mid spring. This may be linked to evidence for dust scavenging by water ice-rich clouds circulating at high southern latitudes at this season.

[1]  Jean-Pierre Bibring,et al.  Recovery of surface reflectance spectra and evaluation of the optical depth of aerosols in the near-IR using a Monte-Carlo approach: Application to the OMEGA observations of high latitude regions of Mars , 2007 .

[2]  Mark T. Lemmon,et al.  Properties of dust in the Martian atmosphere from the Imager on Mars Pathfinder , 1999 .

[3]  David E. Smith,et al.  Two Mars years of clouds detected by the Mars Orbiter Laser Altimeter , 2003 .

[4]  S. Douté,et al.  South Pole of Mars: Nature and composition of the icy terrains from Mars Express OMEGA observations , 2007 .

[5]  J. Gooding.  Martian dust particles as condensation nuclei: A preliminary assessment of mineralogical factors , 1986 .

[6]  O. Korablev,et al.  Vertical Structure of Martian Dust Measured by Solar Infrared Occultations from the Phobos Spacecraft , 1993 .

[7]  Gabriele Arnold,et al.  A Model of Spectral Albedo of Particulate Surfaces: Implications for Optical Properties of the Moon , 1999 .

[8]  Stephen R. Lewis,et al.  Modeling the Martian dust cycle, 1. Representations of dust transport processes , 2002 .

[9]  P. Drossart,et al.  Perennial water ice identified in the south polar cap of Mars , 2004, Nature.

[10]  G. Piccioni,et al.  Water clouds and dust aerosols observations with PFS MEX at Mars , 2005 .

[11]  M. Mishchenko,et al.  Reprint of: T-matrix computations of light scattering by nonspherical particles: a review , 1996 .

[12]  M. Smith.  TES ATMOSPHERIC TEMPERATURE, AEROSOL OPTICAL DEPTH, AND WATER VAPOR OBSERVATIONS 1999-2004 , 2006 .

[13]  Mark T. Lemmon,et al.  Constraints on dust aerosols from the Mars Exploration Rovers using MGS overflights and Mini‐TES , 2006 .

[14]  Mark I. Richardson,et al.  A first look at dust lifting and dust storms near the south pole of Mars with a mesoscale model , 2002 .

[15]  Mars Exploration Rover Atmospheric Imaging: Dust Storms, Dust Devils, Dust Everywhere , 2006 .

[16]  Oleg Korablev,et al.  Open questions on optical properties of dust and the opacity of the Martian atmosphere , 2002 .

[17]  Stephen R. Lewis,et al.  Improved general circulation models of the Martian atmosphere from the surface to above 80 km , 1999 .

[18]  M. J. Wolff,et al.  An intercomparison of ground-based millimeter, MGS TES, and Viking atmospheric temperature measurements: Seasonal and interannual variability of temperatures and dust loading in the global Mars atmosphere , 2000 .

[19]  F. Lefévre,et al.  Global distribution of total ozone on Mars from SPICAM/MEX UV measurements , 2006 .

[20]  Hugh H. Kieffer,et al.  CO2 jets formed by sublimation beneath translucent slab ice in Mars' seasonal south polar ice cap , 2006, Nature.

[21]  Y. Langevin,et al.  Martian aerosol properties from the Phobos/ISM experiment , 1991 .

[22]  Jimmy D Bell,et al.  Atmospheric Imaging Results from the Mars Exploration Rovers: Spirit and Opportunity , 2004, Science.

[23]  H. Kieffer.  H2O grain size and the amount of dust in Mars' Residual north polar cap , 1990 .

[24]  C. Rice,et al.  Structure of the catalytic domain of the hepatitis C virus NS2-3 protease , 2006, Nature.

[25]  Dale P. Cruikshank,et al.  Comparison between the Shkuratov and Hapke scattering theories for solid planetary surfaces: Application to the surface composition of two Centaurs , 2002 .

[26]  Bruce A. Cantor,et al.  Martian dust storms: 1999 Mars Orbiter Camera observations , 2001 .

[27]  Jean-Pierre Bibring,et al.  A mapping of martian water sublimation during early northern summer using OMEGA/Mars Express , 2005 .

[28]  R. Todd Clancy,et al.  Mars aerosol studies with the MGS TES emission phase function observations: Optical depths, particle sizes, and ice cloud types versus latitude and solar longitude , 2003 .

[29]  F. Montmessin,et al.  Stellar Occultations at UV Wavelengths by the SPICAM Instrument: Retrieval and Analysis of Martian Haze Profiles , 2006 .

[30]  S. Erard,et al.  Martian Aerosols: Near-Infrared Spectral Properties and Effects on the Observation of the Surface , 1994 .

[31]  R. Todd Clancy,et al.  Constraints on the size of Martian aerosols from Thermal Emission Spectrometer observations , 2003 .

[32]  Jean-Pierre Bibring,et al.  No signature of clear CO2 ice from the ‘cryptic’ regions in Mars' south seasonal polar cap , 2006, Nature.

[33]  Michael D. Smith.  Interannual variability in TES atmospheric observations of Mars during 1999–2003 , 2004 .

[34]  Pascal Rannou,et al.  Origin and role of water ice clouds in the Martian water cycle as inferred from a general circulation model , 2004 .

[35]  F. Forget,et al.  Modeling the Martian dust cycle 2. Multiannual radiatively active dust transport simulations , 2002 .

[36]  Robert M. Haberle,et al.  Modeling the Martian dust cycle and surface dust reservoirs with the NASA Ames general circulation model , 2006 .

[37]  Jimmy D Bell,et al.  Absorption and scattering properties of the Martian dust in the solar wavelengths. , 1997, Journal of geophysical research.

[38]  K. Evans.  The Spherical Harmonics Discrete Ordinate Method for Three-Dimensional Atmospheric Radiative Transfer , 1998 .

[39]  Retrieval of Surface Lambert Albedos and Aerosols Optical Depths Using OMEGA Near-IR EPF Observations of Mars , 2007 .

[40]  S. Douté,et al.  Observations of the south seasonal cap of Mars during recession in 2004–2006 by the OMEGA visible/near‐infrared imaging spectrometer on board Mars Express , 2007 .

[41]  Hugh H. Kieffer,et al.  Mars south polar spring and summer behavior observed by TES: Seasonal cap evolution controlled by frost grain size , 2000 .

[42]  Y. Langevin,et al.  Summer Evolution of the North Polar Cap of Mars as Observed by OMEGA/Mars Express , 2005, Science.

[43]  F. Montmessin,et al.  New insights into Martian dust distribution and water‐ice cloud microphysics , 2002 .

[44]  P. Drossart,et al.  Post‐Phobos model for the altitude and size distribution of dust in the low Martian atmosphere , 1995 .