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North African Dust Production

North African Dust Production. Richard Washington Richard.washington@ouce.ox.ac.uk Climate Research Lab Oxford University Centre for the Environment Contributions from K.Schepanski, C.Bouet, G.Cautenet, S.Engelstaedter, E. Mackenzie. Main research Effort. Themes

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North African Dust Production

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  1. North African Dust Production Richard Washington Richard.washington@ouce.ox.ac.uk Climate Research Lab Oxford University Centre for the Environment Contributions from K.Schepanski, C.Bouet, G.Cautenet, S.Engelstaedter, E. Mackenzie

  2. Main research Effort Themes • Annual cycle of dust from surface and RS • Large scale atmospheric mechanisms responsible for dust emission and transport • Long term behaviour of dust sources Methods • Remote Sensing and surface products • Field Campaigns • Regional models & reanalysis

  3. Importance of North Africa dust

  4. Why is the Bodele such a prolific source of dust? • Is it a coincidence of co-location of strong winds and sediment? • What could happen to the Bodele over the forthcoming decades?

  5. right kind of wind focused on right kind of sediment 3 March 2003 The location of dry lakes in the Bodele Depression.

  6. Mean JFM Zonal Wind: Longitude-height along 18 N Washington and Todd 2005 GRL

  7. Tibesti Ennedi Gap Flow Bodele LLJ Palaeo Lake

  8. Bodele daily dust Vs 1000 hPa geopotentials and 950 vector winds (JFM) See key papers by Peter Knippertz on dynamics e.g. QJRMS 132-617 Washington and Todd 2005 GRL

  9. Contributed by K.Schepanski Washington et al in review PNAS

  10. Contributed by G.Cautenet and C.Bouet in Washington et al in review PNAS

  11. MM5 simulations JFM 2002-2007 Washington et al 2008

  12. Transport climatology from Bodele Washington et al in review PNAS

  13. 1991 – 2000 JFM near surface zonal wind Latitude-longitude plots MRI A2 forcing 2056 – 2065 2081 – 2090 2091 – 2100

  14. 1991 – 2000 JFM near surface zonal wind Latitude-height plots MRI A2 forcing 2046 - 2055 2091 - 2100

  15. JFM Vector wind difference, 2091-2100 minus 1999-2000, at 925hPa MRI Model A2 scenario

  16. Near surface zonal JFM wind pdf for 2 decades MRI A2 forcing

  17. North African Summer sources • Sources data set dependent • Mechanisms of emission unclear • Need for field data

  18. Schepanski et al 2007

  19. Are mechanisms of dust production in the summertime N African Sources bound up in moist convection or dry convection or both? TOMS suggests dry, other data sets suggest moist convective systems May be important. Heat Low Equator

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