The Non-local impact of Dust Storms
on Martian Atmospheric Dynamics
Luca Montabone – LMD, Paris, France (and University of Oxford, UK)

Contributors
T. (LJ) Ruan, D. Mitchell, P. L. Read - Univ. of Oxford, UK
O. Martinez-Alvarado – Univ. of Reading, UK
S. Thomson – Univ. of Cambridge, UK
S. R. Lewis - The Open University, UK
J. Wilson – GFDL, USA
A. Spiga – LMD, France
CPS workshop -6th February 2013

Outline

Objective: Impact of Martian Dust Storms on
Dynamical Phenomena “At Distance”(Non-Local)

Case Studies:1. 2001 Planet-Encircling Dust Storm (MY25,Ls~186°)
2. 2003b Regional Dust Storm (MY26, Ls~316°)

Dynamical Phenomena:• Teconnection event• Super-rotating westerly equatorial jet• Polar vortex anomaly (and “sudden polar warming”)

2001 Planet-encircling Dust Storm

31 July 2001

20 June 2001

Mars Global Surveyor spacecraft MOC camera

Synopsis of the 2001 dust storm

LS ~169°→180°Pre-storm events:
baroclinic waves

Synopsis of the 2001 dust storm

LS ~180°→187°
LMD Mesoscale Model, 50 km
horizontal resolution. Boundary
conditions from data assimilation.

Explosive growth:strong updrafts

Synopsis of the 2001 dust storm

LS ~187°→193°

What happens at this time?

Teleconnection event

Questions
1. What is the origin of such a teleconnection
event?
2. Is this a “teleconnection event”?
3. Does the advection towards the east of thedust lifted in Hesperia Planum cause thelongitudinal displacement of surface pressure
extrema?

Thermal tides

Teleconnection event

Time-11 Pa

Longitudinal anomalies ofsurface pressure:
Amplitudes of diurnal +Kelvin components
Pa

Teleconnection event

TimeUniform andconstant dust:
τ =0.4

Longitudinal anomalies ofsurface pressure:
Amplitudes of diurnal +Kelvin components
Pa

Teleconnection event

Model of the initial burst of dust inHesperia Planum
Data assimilation
Dust optical depth
at reference
pressure

Gaussian dust storm

LatitudeLongitude

Longitude

Teleconnection event

Time-14 Pa

Longitudinal anomalies of
surface pressure:
Amplitudes of diurnal +Kelvin components
PaNear surface wind stress

Data assimilation

N/m2

Gaussian model

N/m2

Partial conclusions...and further questions
 Hesperia Planum and the Tharsis region were connected at distance(“teleconnected”) at short time scale via the thermal tides during the onset ofthe 2001 planet-encircling dust storm

 Such non-local effect developed in presence of localized atmospheric forcing(initial burst of dust in Hesperia Planum) There was an effect of such a teleconnection on surface wind stress(therefore on potential dust lifting), but it can only partially explain the increaseof surface wind stress in the reanalysis.

 How important was eastward dust advection via atmospheric middle-altitudewind?
 Can we explore the attribution problem (i.e. cause-effect relationship) for the
initiation of secondary lifting in Tharsis? Effect of teleconnection vs effect ofadvection?

Westerly Equatorial Jet

Work inspired by resultsin Lewis & Read, 2003
Zonal mean, daily averages

Westerly Equatorial Jet
Local super-rotation index: MarsLatm
=s−1 > 0
Lrest

Westerly Equatorial Jet
Local super-rotation index: MarsLatm
=s−1 > 0
Lrest

Autumn (LS = 195°—225°) in MY24 and MY25

Westerly Equatorial Jet...on Earth
Local super-rotation index: EarthLatm=s−1 > 0Lrest

Westerly Equatorial Jet...on EarthMars(Past)
Earth
B. Harris (Ph.D.
thesis, 2009)

DustStormAtlas

2003b Regional Dust Storm:Impact on NH polar vortex
15 sols before
Ls~324°15 sols afterありがとうございます。!