Update on Observations/Solsticial Pause TAS-I/ESA Progress Meeting – 24th April 2012

New Dust Scenarios MY 24 through MY 30 are now available 7 years of 669 sols each MY 24 is an “hybrid” scenario, built with part of MY 25 (until Ls=105°) Each year is available in NetCDF format Zonal means of equivalent visible total dust opacity at reference pressure of 610 Pa, extracted from the dust scenario NetCDF files

Dust at Meridiani: multi-instrument observations Dust opacity extracted at Meridiani using a combination of THEMIS and MCS

Mars Solsticial Pause Background: Surface pressure observations and assimilation of temperature fields suggest a “pause” in the baroclinic waves in the range Ls = 240° - 300°, near N. winter solstice Less regional flushing storms which could affect Meridiani (See previous reports). BUT : this was not simulated in GCMs New : Theoretical explanation with LMD UK-GCM (Mulholland et al. 2012, in preparation) : This can be simulated with radiatively active clouds “altering the thermal structure of the atmosphere and decreasing the vertical shear of the westerly jet near the surface around solstice, and shifting the lower portion of the jet equatorwards”

Solstitial pause in baroclinic wave activity Mars Solsticial Pause Solstitial pause in baroclinic wave activity 62.5°N, MY24 Transient Temperature at 50 Pa, ~25 Km (TES data assimilation) Transient Surface Pressure (TES data assimilation) Lewis et al., 2012 - Mulholland et al, 2012 (in preparation)

RMS Temperature (TES data assimilation) (2.5 km altitude) Mars Solsticial Pause RMS Temperature (TES data assimilation) (2.5 km altitude)

RMS Meridional Wind (TES data assimilation) (2.5 km altitude) Mars Solsticial Pause RMS Meridional Wind (TES data assimilation) (2.5 km altitude)

Mars Solsticial Pause Background: Surface pressure observations and assimilation of temperature fields suggest a “pause” in the baroclinic waves in the range Ls = 240° - 300°, near N. winter solstice Less regional flushing storms which could affect Meridiani (See previous reports). BUT : this was not simulated in GCMs New : Theoretical explanation with LMD UK-GCM (Mulholland et al. 2012, in preparation) : This can be simulated with radiatively active clouds “altering the thermal structure of the atmosphere and decreasing the vertical shear of the westerly jet near the surface around solstice, and shifting the lower portion of the jet equatorwards”

Theoretical confirmation of solsticial pause : Near surface baroclinic waves activity in LMD/UK GCM (RMS of Temperature at 2.5 km) Mulholland et al. 2012 Non active clouds Active clouds tau = 0.2 MY 24 Scenario

Upcoming : work combining datasets from various instruments to better characterize dust activity Moc Wide Angle Camera, MRO/MARCI etc… making use of new database at : Arizona State University's Mars Space Flight Facility Ashima Research (Pasadena) Ls: 244.72 Mars year: 24 1999-11-15