Open AccessThree‐dimensional modeling of ozone on Mars
Author(s) -
Lefèvre Franck,
Lebonnois Sébastien,
Montmessin Franck,
Forget François
Publication year - 2004
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004je002268
Subject(s) - middle latitudes , atmospheric sciences , latitude , altitude (triangle) , ozone , polar vortex , mars exploration program , environmental science , diurnal cycle , climatology , atmosphere (unit) , physics , troposphere , meteorology , geology , astrobiology , geometry , mathematics , astronomy
We present the first three‐dimensional model simulations of ozone on Mars. The model couples a state‐of‐the‐art gas‐phase photochemical package to the general circulation model developed at Laboratoire de Météorologie Dynamique (LMD). The results do not contradict the classical picture of a global anticorrelation between the ozone (O 3 ) and water vapor columns. However, the quantitative approach shows significant departures from this relationship, related to substantial orbital variations in the O 3 vertical distribution. Over the period L s = 180°–330°, low‐latitude to midlatitude O 3 is essentially confined below 20 km, has a weak diurnal cycle, and is largely modulated by topography. During the rest of the year ( L s = 330°–180°) the model predicts the formation of an O 3 layer at 25–70 km altitude, characterized by nighttime densities about one order of magnitude larger than during the day. Throughout the year, high‐latitude O 3 peaks near the surface and reaches maximum integrated amounts (∼40 μm‐atm) in the winter polar vortex, with considerable (30 to 50%) dynamically induced day‐to‐day variations. The most stringent comparison to date with O 3 observational data reveals contrasted results. A good quantitative agreement is found in the postperihelion period ( L s = 290°–10°), but the model fails to reproduce O 3 columns as large as those measured near aphelion ( L s = 61°–67°). Current uncertainties in absorption cross sections and gas‐phase kinetics data do not seem to provide credible explanations to explain this discrepancy, which may suggest the existence of heterogeneous processes.