MARTIAN ATMOSPHERE DURING THE 2001 GLOBAL DUST STORM: OBSERVATIONS WITH SWAS AND SIMULATIONS WITH A GENERAL CIRCULATION MODEL - Advances in Geosciences - page 145

MARTIAN ATMOSPHERE DURING THE 2001
GLOBAL DUST STORM: OBSERVATIONS WITH SWAS
AND SIMULATIONS WITH A GENERAL
CIRCULATION MODEL

TAKESHI KURODA ∗ , ALEXANDER S. MEDVEDEV and PAUL HARTOGH
Max-Planck-Institute for Solar System Research
Max-Planck.Str.2, D-37191 Katlenburg-Lindau, Germany
∗ [e-mail]

The Earth-orbiting submillimeter wave astronomy satellite (SWAS) observed
the global mean surface and atmosphere temperature on Mars as a function of
the altitude. Unlike for the infrared spectrometers, the temperature retrievals
from submillimeter instruments can be performed in the presence of the atmo-
spheric dust. During the 2001 global dust storm on Mars, SWAS measured the
atmosphere and surface temperature for aerocentric longitudes from L s = 166 ◦
to 233 ◦ , and observed the temperature inversion in the lower atmosphere. We
use a recently developed general circulation model of the Martian atmosphere
to simulate the temperature and other atmospheric fields under the conditions
corresponding to those during the SWAS measurements. The model takes into
account the radiative effects of the atmospheric dust. Simulations show an over-
all agreement with the SWAS measurements. In particular, the model repro-
duces the inversion of the global mean temperature and the surface cooling
detected by SWAS. Time series of the globally averaged surface and atmo-
spheric temperature at 0.05 hPa (

49 km) are also in a good agreement with
the measurements. Without the dust, the model cannot reproduce these fea-
tures. A brief discussion of the differences between the model and observations
as well as their possible reasons is provided.

∼

1. Introduction

The June 21, 2001 Mars opposition was a good opportunity for observations
from Earth and Earth-orbiting satellites because the apparent size of the
planet was largest in more than 10 years. In addition, soon after the opposi-
tion, the rise and growth of the global dust storm were observed. It started
from smaller regional storms in and around the Hellas Basin on June 26,
2001 (aerocentric longitude, L s = 185 ◦ ), and grew to cover the entire Mars
in 2 weeks, as was recorded in the snapshots from Hubble telescope. 1

∗ Corresponding author.

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