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Atmospheric Waves Workshop

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  1. Evidence of atmospheric gravity waves and their effects from satellite data Atmospheric Waves Workshop Scott Osprey1, Corwin Wright2 1AOPP, University of Oxford; 2Laboratoire de Physique des Oceans, Universite de Bretagne Occidental

  2. Gravity Waves Above the Indian Ocean source: MISR (NASA)

  3. Lenticular Clouds, Amsterdam Island MODIS, December 2005

  4. Sandwich Islands, South Atlantic, January 2004 Source MODIS on AQUA (NASA)

  5. 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

  6. Radio-Occultation: FORMOSAT-3/COSMIC

  7. Radio-Occultation Observations: FORMOSAT-3/COSMIC Launch on April 14, 2006 Vandenberg AFB, CA • 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 • Measures: • Pressure, Temperature, Humidity • Refractivity • Ionospheric Electron Density

  8. Radio Occultation Profile locations 1 January 2007 CHAMP 151 COSMIC 1936 Wang & Alexander (2010)

  9. A Typical GPS RO Profile Wavenumbers 1-6 constitute ‘background’ Wang & Alexander (2010)

  10. Radio-Occultation: Wave-Momentum in the lower-stratosphere Vertical flux of horizontal momentum density June-August 2007 Wang & Alexander (2010)

  11. Limb Sounding Observations of Atmospheric Gravity Waves - HIRDLS

  12. The NASA A-Train Source: NASA

  13. 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

  14. Temperature Perturbations

  15. Temperature Perturbations

  16. The Stockwell Transform: T’ and the vertical wavelength Stockwell et al (1996); Alexander et al (2006) Temperature perturbation size Vertical wavelength ( ) In most cases, we select only the largest temperature perturbation at each height level for consideration

  17. The Stockwell Transform – Horizontal Wavelength Horizontal wavelength

  18. Tropospheric Sources of Gravity Waves - Monsoon

  19. Monsoon and Gravity waves

  20. Precipitation, OLR and Gravity Waves

  21. Precipitation, OLR and Gravity Waves

  22. Background Wind Filtering of GW – Sudden Stratospheric Warmings

  23. NH Winter Zonal Wind 2005 & 2006

  24. Sudden Stratospheric Warming 2006

  25. HIRDLS zonal wind: 2006 60°N Wright et al. (2010)

  26. HIRDLS GW MF: 2006 60°N Wright et al. (2010)

  27. Daily GW MF: 2005-2008 Wright et al. (2010)

  28. Gravity Wave Filtering >>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

  29. Gravity Wave Filtering

  30. Evidence of a Gravity Wave Induced Circulation on Titan

  31. Brewer-Dobson Circulation on Earth Gravity Waves Rossby Waves http://www.iau.uni-frankfurt.de/groups/PhysAtm/Research/Atmospheric_Transport1/index.html

  32. Evidence of GW induced circulations on Titan Teanby et al, 2008

  33. Teanby et al, 2008

  34. Idealisedmeridional circulation on Titan Teanby et al, 2008

  35. 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.