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9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Atmospheric Waves WorkshopScott Osprey1, Corwin Wright2
Evidence of atmospheric gravity waves and their effects from satellite data
1AOPP, University of Oxford; 2Laboratoire de Physique des Oceans, Universite de Bretagne Occidental
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Gravity Waves Above the Indian Ocean
source: MISR (NASA)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Lenticular Clouds, Amsterdam Island
MODIS, December 2005
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Sandwich Islands, South Atlantic, January 2004
Source MODIS on AQUA (NASA)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Outline• Radio-occultation retrievals of gravity waves• Limb-sounding instruments:
– NASA A-Train– S-Transform
• High Resolution Dynamics Limb Sounder (HIRDLS)– Tropospheric sources of gravity waves (monsoon)– Filtering by background winds (Sudden Stratospheric
Warmings)• Evidence for gravity wave induced circulations (Titan)• Summary
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Radio-Occultation: FORMOSAT-3/COSMIC
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Radio-Occultation Observations: FORMOSAT-3/COSMIC
• A “constellation” of six satellites, used for GPS (US, Taiwan)
• orbital altitude 800 km
• Currently being used for data assimilation (Met Office, ECMWF)
• Europe: Galileo
Launch on April 14, 2006Vandenberg AFB, CA
Measures:Pressure, Temperature, HumidityRefractivityIonospheric Electron Density
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Radio Occultation Profile locations 1 January 2007
Wang & Alexander (2010)
CHAMP 151COSMIC 1936
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
A Typical GPS RO Profile
Wavenumbers 1-6 constitute ‘background’Wang & Alexander (2010)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Radio-Occultation: Wave-Momentum in the lower-stratosphere
Wang & Alexander (2010)
Vertical flux of horizontal momentum density
June-August 2007
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Limb Sounding Observations of Atmospheric Gravity Waves - HIRDLS
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Source: NASA
The NASA A-Train
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
HIRDLS
• The High Resolution Dynamics Limb Sounder (HIRDLS)
• Infrared limb sounder on the low-Earth orbiting Aura satellite
• Launched July 2004, data coverage from 01/2005 – 01/2008
• Data extend from ~tropopause to ~80km (version 6)
• ~1km vertical resolution, measurements ~80km apart
Temperature Perturbations
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Temperature Perturbations
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
The Stockwell Transform: T’ and the vertical wavelength
Temperature perturbation size
Vertical wavelength
In most cases, we select only the largest temperature perturbation at each height level for consideration( )
Stockwell et al (1996); Alexander et al (2006)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
The Stockwell Transform – Horizontal Wavelength
Horizontal wavelength
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Tropospheric Sources of Gravity Waves - Monsoon
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Monsoon and Gravity waves
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Precipitation, OLR and Gravity Waves
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Precipitation, OLR and Gravity Waves
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Background Wind Filtering of GW – Sudden Stratospheric Warmings
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
NH Winter Zonal Wind 2005 & 2006
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Sudden Stratospheric Warming 2006
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
HIRDLS zonal wind: 2006 60°N
Wright et al. (2010)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
HIRDLS GW MF: 2006 60°N
Wright et al. (2010)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Daily GW MF: 2005-2008
Wright et al. (2010)
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
>>Evidence for wind-based filtering of GWs during 2006 Sudden Stratospheric Warming
High GW activity near poles in 2005 and 2007
Significant reduction in 2006, corresponding to negative zonal winds
Gravity Wave Filtering
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Gravity Wave Filtering
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Evidence of a Gravity Wave Induced Circulation on Titan
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Brewer-Dobson Circulation on Earth
http://www.iau.uni-frankfurt.de/groups/PhysAtm/Research/Atmospheric_Transport1/index.html
Rossby Waves
Gravity Waves
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Evidence of GW induced circulations on Titan
Teanby et al, 2008
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Teanby et al, 2008
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Idealised meridional circulation on Titan
Teanby et al, 2008
9-10 November 2011 Atmospheric Waves Workshop, ESTEC
Summary
• Gravity waves are a ubiquitous dynamical feature of the Earths atmosphere.
• Significant regional sources of tropospheric gravity waves are seen during strong precipitation events (monsoon)
• Filtering by stratospheric winds is seen during extreme wintertime events in the stratosphere (SSW)
• Evidence of a gravity wave driven circulation is seen in the Earths mesosphere - lowest temperatures on earth being in the summer polar mesosphere.
• Tentative evidence of a similar circulation is seen in Titans polar mesosphere and via distributions of tracers.
• Radio-occultation and limb sounding observations provide useful quantitative measures of gravity waves.
