On the Structure and Dynamics of the Martian Middle
Atmosphere
Semi-Stationary Waves Masquerading as Stationary Waves in the
Martian AtmosphereTamara McDunn1
Advisor: David Kass1
1Jet Propulsion Laboratory, California Institute of
Technology
JPL Postdoc Seminar, June 27, 2013CL#13-1687(c) 2013 California
Institute of Technology. Government sponsorship acknowledged.
1Outline6/27/132/28Background on stationary waves at MarsMars
Climate Sounder datasetTraditional analysis and its limitation
Behavior of wavenumber-2 semi-stationary waves at Mars
ConclusionsFuture Work2Background6/27/133/28Waves are a fundamental
feature of an atmosphere on a rotating body; they drive atmospheric
behavior and can be used as a diagnostic of that behavior
7 martian years of nearly-continuous lower-atmosphere (surface
to ~50 km) observations
Seasonal behavior of large-scale (planetary) waves has been
well-explored using orbital observations; short-timescale behavior
has not
3Stationary Waves6/27/134/28Waves with zero temporal frequency
in the zonal direction (W-E)
Forced by flow over topography and zonal inhomogeneities in
thermal forcing
Phase is approximately constant with height and season
On Earth they often generate clouds
4Effects of Stationary Waves on Earth6/27/135/28Redistribute
heat from low to high latitudes
Reduce atmospheric stability (resistance to vertical motion)
Deposit momentum at high altitudes leading to
acceleration/deceleration of the mean flow
5Behavior of Stationary Waves at Mars6/27/136/28Amplitudes peak
during local fall and winter
Amplitudes peak at mid-latitudes (edge of circumpolar jet)
Dominant zonal wavenumber is driven by form of topography at jet
latitudes
Track edge of polar vortex (move poleward with height)
Same effects as stationary waves on Earth6Example6/27/137/28
7Model: Mars Climate Database6/27/138/28Suite of simulations
from a general circulation model [Lewis et al. 1999]
Horizontal resolution: 3.75 x 5.625
Vertical resolution: variable (12 layers in lowest scale height,
~1/3 scale height to scale height above that)
Forced with moderate solar input
Forced with climatological distribution of suspended dust (TES
year 1)8Outline6/27/139/28Background on stationary waves at
MarsMars Climate Sounder datasetTraditional analysis and its
limitation Behavior of wavenumber-2 semi-stationary waves at Mars
ConclusionsFuture Work9ParameterProperty / Performance
Instrument TypeFilter RadiometerSpectral Range & Channels0.3
to 50.0 m in nine spectral channelsTelescopesTwo identical, 4cm
aperture, f/1.6 telescopesDetectorsNine, 21-element, linear
thermopile arrays at 300 KFields-of-ViewDetector IFOV:3.6 x
6.2mrad5.0 x 8.6 km(At Limb)Instrument IFOV:75 x 75mrad105 x
105km(At Limb)Instrument ArticulationTwo-axis
azimuth/elevationRange/Resolution:Azimuth:270/0.1
degreesElevation:270/0.1 degreesOperation ModesSingle Operating
Mode, 2 s signal integration periodObservation StrategyLimb
Staring; Limb, nadir & off-nadir scanningIn-track, Cross-track,
and Off-track viewing6/27/1310Mars Climate Sounder (MCS) Instrument
Description
ThermalBlanketsTelescopesSolar
TargetAzimuthActuatorElevationActuatorAzimuthYokeBlackbodyTargets
LimbNadir10MCS Spectral Channel
CharacteristicsTelescope/BandpassBandMeasurement FunctionChannel
#cm-1 Center - mA1595 - 61516.5Temperature 0-20 kmA2615 -
64515.9Temperature 20-40 km, PressureA3635 - 66515.4Temperature
40-80 km, Pressure A4820 - 87011.8Dust and Condensate (D&C)
extinction 0-80 kmA5400 - 50022.2D&C extinction 0-80 kmA63300 -
330001.65Polar Radiative BalanceB1290 - 34031.7Surface Temperature,
D&C extinction 0-80 kmB2220 - 26041.7Water Vapor 0-40 km,
D&C extinction 0-80 kmB3230 - 24542.1Water Vapor 0-40 km,
D&C extinction 0-80 km6/27/1311/2811MCS DatasetRetrieved
profiles: p, T, water ice, dustSurface to 80-90 km (5 km
resolution)Sun-synchronous, fixed, high-inc., polar orbit3 am and 3
pmT uncertainty ~ 2 K
6/27/1312/28
McCleese et al., 2007; Kleinbhl et al., 2009; 2011
0 30 60 90 120 150 180 210 240 270 300 330 360Areocentric
Longitude of the Sun (Ls) -
Degrees9.59.08.58.07.57.06.56.09.59.08.58.07.57.06.56.09.59.08.58.07.57.06.56.09.59.08.58.07.57.06.56.0Pressure
mbar Pressure mbar Pressure mbar Pressure mbarMCS Investigation
Timeline13Outline6/27/1314/28Background on stationary waves at
MarsMars Climate Sounder datasetTraditional analysis and its
limitation Behavior of wavenumber-2 semi-stationary waves at Mars
ConclusionsFuture Work14Traditional AnalysisStep 1: Compute Tavg
and Tdiff6/27/1315/28 Tavg = T3am + T3pm 2 Tdiff = T3am - T3pm
2e.g., Banfield et al, 2003; Lee et al, 2009 m = |s |local-time
wavenumberzonal wavenumbertemporal frequency Step 2: Take spatial
Fourier Transform15
Ls = 285, Lat = 45 N, and p = 106 Pa6/27/1316/28Result of
Traditional Analysis
Local-time wavenumber Local-time wavenumberWave Amplitude (K)
Tavg Tdiff 17/28Limitation of Traditional Analysis LT = 03 LT =
156/27/13
m = 2 iis strong on the nightside but, disappears on the
dayside
Ls = 285 LatitudeLatitudeOutline6/27/1318/28Background on
stationary waves at MarsMars Climate Sounder datasetTraditional
analysis and its limitation Behavior of wavenumber-2
semi-stationary waves at Mars ConclusionsFuture Work18Local-time
Behavior (from model)6/27/1319/28 LT = 00
Pressure (Pa)19Local-time Behavior (from model)6/27/1320/28 LT =
01
Pressure (Pa)20Local-time Behavior (from model)6/27/1319/28 LT =
02
Pressure (Pa)21Local-time Behavior (from model)6/27/1319/28 LT =
03
Pressure (Pa)22Local-time Behavior (from model)6/27/1319/28 LT =
04
Pressure (Pa)23Local-time Behavior (from model)6/27/1319/28 LT =
05
Pressure (Pa)24Local-time Behavior (from model)6/27/1319/28 LT =
06
Pressure (Pa)25Local-time Behavior (from model)6/27/1319/28 LT =
07
Pressure (Pa)26Local-time Behavior (from model)6/27/1319/28 LT =
08
Pressure (Pa)27Local-time Behavior (from model)6/27/1319/28 LT =
09
Pressure (Pa)28Local-time Behavior (from model)6/27/1319/28 LT =
10
Pressure (Pa)29Local-time Behavior (from model)6/27/1319/28 LT =
11
Pressure (Pa)30Local-time Behavior (from model)6/27/1319/28 LT =
12
Pressure (Pa)31Local-time Behavior (from model)6/27/1319/28 LT =
13
Pressure (Pa)32Local-time Behavior (from model)6/27/1319/28 LT =
14
Pressure (Pa)33Local-time Behavior (from model)6/27/1319/28 LT =
15
Pressure (Pa)34Local-time Behavior (from model)6/27/1319/28 LT =
16
Pressure (Pa)35Local-time Behavior (from model)6/27/1319/28 LT =
17
Pressure (Pa)36Local-time Behavior (from model)6/27/1319/28 LT =
18
Pressure (Pa)37Local-time Behavior (from model)6/27/1319/28 LT =
19
Pressure (Pa)38Local-time Behavior (from model)6/27/1319/28 LT =
20
Pressure (Pa)39Local-time Behavior (from model)6/27/1319/28 LT =
21
Pressure (Pa)40Local-time Behavior (from model)6/27/1319/28 LT =
22
Pressure (Pa)41Local-time Behavior (from model)6/27/1319/28 LT =
23
Pressure (Pa)42Daily Maximum and Minimum(from
model)6/27/1320/28
Pressure (Pa) (K)Daily Maximum m = 2 Amplitude Daily Minimum m =
2 Amplitude LT = 00 am LT = 11 amLs = 285 4321/28Latitudinal
Behavior (from MCS) T3am , Ls = 285
T3am m = 2 peaks at mid-latitudes and is vertically confined to
p ~ 80-150 Pa44
Seasonal Behavior (from MCS)Latitude = 30-40 NLatitude = 40-50
NT3am m = 2 at higher latitudes is greater at local fallT3am m = 2
at lower latitudes is greater at local winter 6/27/1322/28
45Interannual Behavior (from MCS)MY 29MY 30Spatial extent
varies, but m = 2 exists during all 3 Mars Years23/286/27/13
MY 28
46Associated with negative phase of Meridional (S-N) Winds (from
model)24/286/27/13 Ls = 285, p = 106 Pa
LT = 00 am LT = 11 am
47Outline6/27/1325/28Background on stationary waves at MarsMars
Climate Sounder datasetTraditional analysis and its limitation
Behavior of wavenumber-2 semi-stationary waves at Mars
ConclusionsFuture Work48Semi-stationary waves are those that
exhibit Stationary behaviorTavg and Tdiff analyses consistent with
m = s = 2 wavesPeak during fall and winter Zonal form matches that
of the topography at mid-latitudesPositive phase is in the Lee of
Tharsis and Elysium mountain ranges Phase is nearly constant with
season and height (not shown)
Non-stationary behaviorLocal-time variability strongest near
local midnightweakest near local noonCorrelation with the
semidiurnal tide in the v wind fieldUnstable region aloft (not
shown)6/27/1326/28ConclusionsStorm Tracks-Positive phase correlated
with storm tracks?- Profiles through the positive phase show no
significant correlation with dust opacity
Clouds- Profiles through the negative phase show no significant
correlation with water ice opacity- But, negative phase is
correlated with increased nightside column-integrated water ice
clouds [Benson et al., 2011]
Aerosol Transport-Positive phase correlated with channels of
transport?
6/27/1327/28Future Work: Explore Implications for Atmosphere
50Thank you! 6/27/1328/[email protected]
Acknowledgement:Caltech/JPL Postdoctoral Fellowship