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Thermal tides during the 2001 Martian global‐scale dust storm
Author(s) -
Guzewich Scott D.,
Wilson R. John,
McConnochie Timothy H.,
Toigo Anthony D.,
Banfield Donald J.,
Smith Michael D.
Publication year - 2014
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2013je004502
Subject(s) - atmospheric sciences , martian , dust storm , extratropical cyclone , wavenumber , atmospheric tide , storm , climatology , atmosphere (unit) , atmospheric wave , atmosphere of mars , diurnal cycle , environmental science , madden–julian oscillation , forcing (mathematics) , geology , mars exploration program , geophysics , gravity wave , thermosphere , physics , meteorology , ionosphere , wave propagation , convection , astrobiology , oceanography , quantum mechanics , optics
The 2001 (Mars Year 25) global dust storm radically altered the dynamics of the Martian atmosphere. Using observations from the Thermal Emission Spectrometer onboard the Mars Global Surveyor spacecraft and MarsWRF general circulation model simulations, we examine the changes to thermal tides and planetary waves caused by the storm. We find that the extratropical diurnal migrating tide is dramatically enhanced during the storm, particularly in the southern hemisphere, reaching amplitudes of more than 20 K. The tropical diurnal migrating tide is weakened to almost undetectable levels. The diurnal Kelvin waves are also significantly weakened, particularly during the period of global expansion at L s = 200°–210°. In contrast, the westward propagating diurnal wavenumber 2 tide strengthens to 4–8 K at altitudes above 30 km. The wavenumber 1 stationary wave reaches amplitudes of 10–12 K at 50°–70°N, far larger than is typically seen during this time of year. The phase of this stationary wave and the enhancement of the diurnal wavenumber 2 tide appear to be responses to the high‐altitude westward propagating equatorial wavenumber 1 structure in dust mixing ratio observed during the storm in previous works. This work provides a global picture of dust storm wave dynamics that reveals the coupling between the tropics and high‐latitude wave responses. We conclude that the zonal distribution of thermotidal forcing from atmospheric aerosol concentration is as important to understanding the atmospheric wave response as the total global mean aerosol optical depth.