1 / 23

Tropical UT/LS Hydration: In Situ Observations & Horizontal Transport

Study on tropical upper troposphere/lower stratosphere hydration, convective overshooting impact, water injection & horizontal transport. Balloon campaigns in Brazil.

crossi
Download Presentation

Tropical UT/LS Hydration: In Situ Observations & Horizontal Transport

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Dehydration, hydration and horizontal transport in the tropical UT/LS from high-resolution in situ observations Sergey M. Khaykin LATMOS-IPSL, CNRS/UVSQ J.-P. Pommereau, E. Riviere, N. Amarouche, M. Ghysel, A. Hauchecorne, J.-P. Vernier, F.G. Wienhold, H. Vömel, G. Held, S. Evan, T. Thornberry, A. Rollins, D. Fahey, K. Rosenlof,, M. Fujiwara. Strateole-2 workshop, Paris, March 18-19 2015

  2. Experimental setup TRO-Pico balloon campaigns, Brazil, 22°S, Feb-Mar 2012, Jan-Feb 2013 to study the impact of convective overshooting on stratospheric water budget • Zero-pressure plastic 500 and 1500 m3 balloons • 500, 800 and 1200 g Totex rubber balloons Plastic balloons Rubber balloons

  3. Hydration by convective overshooting TroPico-I balloon campaign, Brazil, 22°S, Feb-Mar 2012 Balloon sounding (FLASH hygrometer) Radar echo tops and trajectories ascent descent Balloon trajectory WV enhancements are associated with convective overshooting cells upwind (reaching 17 km) detected by the radar 6 hours before the sounding Injection of water into the stratosphere: hydration at local / mesoscale.

  4. Hydration by convective overshooting TroPico-I balloon campaign, Brazil, 22°S, Feb-Mar 2012 Balloon sounding (FLASH hygrometer) Radar echo tops and trajectories ascent descent WV enhancements are associated with convective overshooting cells upwind (reaching 17 km) detected by the radar 6 hours before the sounding Injection of water into the stratosphere: hydration at local / mesoscale.

  5. Hydration by convective overshooting: CRM modeling Tro-Pico-I balloon campaign, Brazil, 22°S, Feb-Mar 2012 BRAMS CRM simulation for 13 Mar 2012 Hydration by overshooting Courtesy of Emmanuel Riviere, GSMA CRM reproduces the injection of water into the stratosphere

  6. Horizontal transport (in-mixing) in the tropical LS sounding location Circles = trajectories initialized from the WV/BSR enhancement (18.5 km); Triangles = trajectories initialized at other levels.

  7. Horizontal transport (in-mixing) in the tropical LS CLaMS CTM simulation: H2O @ 420 K In situ, satellite and CTM H2O Horiz. transport Vertical transport Filament of humid air above Bauru captured by CTM In-mixing of extra-tropical air affects tropical LS composition

  8. Water vapour intercomparison TroPico-II balloon campaign, Brazil, 22°S, Jan-Feb 2013 Comparison between FLASH-B and Pico-SDLA hygrometers Excellent agreement between FLASH and PicoSDLA

  9. Anomalous cooling and dehydration in Jan 2013 Temperature anomaly at CPT level Exceptionally cold tropopause (- 4 K) in January 2013

  10. Dehydration 26 02 06 10 11 13 18 27 31 TroPico-II balloon campaign, Brazil, 22°S, Jan-Feb 2013 Dehydration Local scale Hydration Synoptic scale Significant dehydration of TTL (-2 ppmv) above S. America: regional or planetary scale event?

  11. SSW onset, Jan 6 SSW and TTL cooling/dehydration Change of 10 hPa temperature during SSW, 2012/13 winter Zonal mean H2O, H2O anomaly and T anomaly MLS and COSMIC, 2013-2014 Arctic Tropics Cold point T and Z CPZ CPT Khaykin et al., in prep. Evan et al., QJRMS, in review Enhanced tropical upwelling and convection during SSW resulted in TTL cooling and extreme dehydration

  12. 0.5 ppmv (!!!) SSW and TTL cooling/dehydration CFH and MLS H2O 10 Jan 2014, Biak, Indonesia CFH and MLS H2O 12 Jan 2014, Hanoi, Vietnam

  13. Clouds and dehydration Pre-dehydration phase: formation of subvisible cirrus clouds at CPT level with extreme supersaturation and low backscatter Tmin=187.8 K Cirrus with extreme supersaturation (165 %) and low backscatter Subsaturated cirrus with very high backscatter

  14. Light-weight instrumentation for water vapour and aerosol COBALD Compact Optical Backscatter AerosoLDetector FLASH-B Fluorescence Lyman-Alpha Stratospheric Hygrometer

  15. Unmanned aircraft (UAV) droppable from meteo balloon FLASH COBALD Courtesy of A. Lykov and D. Efremov (Roshydromet)

  16. Summary and proposal for Strateole-II In situ balloon soundings of H2O and aerosol show high potential for studying the mechanisms controlling tropical UT/LS composition (cross-tropopause overshooting, horizontal transport/in-mixing, dehydration, cloud formation etc.) Excellent agreement between FLASH-B and Pico-SDLA hygrometers Proposal for Strateole-II: validation flights with FLASH, COBALD and any other sensors => during or after the main phase of Strateole-II => equatorial site (same as Strateole ?) => small plastic or weather balloons => balloon-lifted UAV (cost-efficient soundings, indispensable for island sites) =>funding to be raised (ANR, CNES, … ?)

  17. No SSW Major SSW Major SSW Major SSW Major SSW Major SSW No SSW Major SSW No SSW Major SSW SSW and lower stratosphere composition Tape recorder signal in zonal mean H2O from Aura MLS Zonal wind @ 50-70 hPa H2O zonal mean latitude distribution @ 82 hPa Interannual variability of H2O is governed by the extra-tropical dynamics and QBO

  18. No SSW Major SSW Major SSW Major SSW Major SSW Major SSW No SSW Major SSW No SSW Major SSW SSW and lower stratosphere composition Tape recorder signal in zonal mean H2O from Aura MLS Zonal wind @ 50-70 hPa Zonal wind @ 50-70 hPa CO zonal mean latitude distribution @ 68 hPa Extratropical dynamics is an important driver of global LS composition

  19. SSW and lower stratosphere composition Tape recorder signal in zonal mean H2O from Aura MLS CMIP5 H2O Zonal wind @ 50-70 hPa AOGCM INM Institute of Numerical Mathematics, Russia Courtesy of P. Vargin and E. Volodin Jiang et al., 2012 Interannual variability of H2O is not correctly reproduced by CMIP5 models

  20. SSW and TTL cooling/dehydration SSW onset Increase of tropical upwelling and convection after SSW Enhanced transport of CO into the stratosphere above most convective region SH Africa Enhanced transport of H2O into the TTL and freezing at CPT Net effect = LS dehydration

  21. H2O zonal anomaly in SH tropics (25°S - 15°S) from Aura MLS Wet signal above continents during convective season Deep convection and LS water vapour Hydration of LS at synoptic scale seen by MLS. What is its contribution compared to dehydration?

  22. Temperature Water vapour Coincident cooling and drying above Brazil during Tropico-2013

More Related