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Discussion of the Namibian Stratocumulus Regime:

Discussion of the Namibian Stratocumulus Regime: Questions of Anthropogenic and Natural Cloud-Aerosol Interactions. S. Platnick 1 , R. J. Swap 2 1 NASA Goddard Space Center, Greenbelt MD, USA 2 University of Virginia, Charlottesville VA, USA. RSP Discussion 15 October 2003. NAMIBIA.

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Discussion of the Namibian Stratocumulus Regime:

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  1. Discussion of the Namibian Stratocumulus Regime: Questions of Anthropogenic and Natural Cloud-Aerosol Interactions S. Platnick 1, R. J. Swap 2 1 NASA Goddard Space Center, Greenbelt MD, USA 2 University of Virginia, Charlottesville VA, USA RSP Discussion 15 October 2003

  2. NAMIBIA Discussion items: • The Namibian (Angolan) marine stratocumulus regime • Overview & “eye candy” • Science questions • Summary of RSP Dec. 2002 proposal • Discussion of potential reduced-cost/science single campaign effort • Leverage off of Terra/Aqua data analysis NRA

  3. A personal perspective —Indirect effect difficult because: • Issues span traditional scientific disciplines (e.g., ocean biogeochemistry, physics, meteorology, agricultural/human activity) • Separation of microphysics and dynamic components (esp. problematic for global satellite observations) • Cloud properties are inherently variable, need to be careful when correlating with aerosol burden/characteristics a statistical problem • Indirect effect can’t be inferred unless natural CCN sources are quantified (have to establish a reference base line - often overlooked) need for in situ data when both sources present likely “easier” to get a handle on these issue with regional studies Platnick, RSP, 10/03

  4. Regional studies of indirect effect wish list • Both anthropogenic and potential natural aerosol sources present in a relatively small region • Anthropogenic and natural sources often spatially separated (vertically, horizontally) • Meteorological conditions relatively stable Namibia/Angola Sc regime good candidate Platnick, RSP, 10/03

  5. Marine Stratocumulus (Sc) • Extensive, semi-permanent, boundary-layer cloud decks off west coast of continents (N.A.-California, S.A.-Peru, southern Africa-Namibia, Angola), Arctic ocean • associated with sub-tropical anticyclonic subsidence, cool SST’s; relatively uniform, low cloud top heights (~1 km), capped by strong temperature inversion • Climatically important cloud type (cooling) • Namibian Sc has received very little attention • “indirect effect” (interplay between DMS production, CCN, and cloud properties; effect of continental pollution; etc.) • impact on marine environment & Namib desert ecosystems • plane-parallel-like geometry ideal for satellite/aircraft remote sensing studies (e.g., MODIS) Platnick, RSP, 10/03

  6. Major sub-tropical Sc regimes Example MODIS Monthly Water Cloud Frequency - August 2003 Platnick, RSP, 10/03

  7. Overview of Namibiancoastal region and Sc Platnick, RSP, 10/03

  8. Sc view from above - MODIS Terra, 15 Sept. 2003 Platnick, RSP, 10/03

  9. Sc view from the groundHenties Bay, Namibia, 30 Sept. 2003 - mouth of Omaruru River Platnick, RSP, 10/03

  10. MODIS 6-27-2003 Cape Cross Gobabeb Res. Centre desert dust Kuiseb River sand dunes (Namib-Naukluft Park) Maps & Coastal Features Platnick, RSP, 10/03

  11. Kuiseb River MODIS Airborne Simulator (MAS)11 Sept. 2000 N Platnick, RSP, 10/03

  12. Kuiseb River Landsat “fly-by” Platnick, RSP, 10/03

  13. Dunes from the groundGobabeb, Namibia, 27 Sept. 2003 - south of research center Platnick, RSP, 10/03

  14. Platnick, RSP, 10/03

  15. Platnick, RSP, 10/03

  16. Annual rainfall(50 mm increments) Fog days/year Platnick, RSP, 10/03

  17. Anthropogenic Sources:advection of biomass burning over the Sc Platnick, RSP, 10/03

  18. TOMS aerosol + AVHRR fires (9-25-00) Platnick, RSP, 10/03

  19. MODIS Aerosol Product 2001 time series Platnick, RSP, 10/03

  20. Elevation of Aerosol LayersSouthern African dry season meteorology (R. Swap) Recirculating Gyre Capping Stable Layers Platnick, RSP, 10/03

  21. Topographic Influence Note: darker brown colors are elevations ~2 km + Platnick, RSP, 10/03

  22. ER-2 S2k CPL 532 nm extinction (M. McGill, D. Hlavka)off Namibian coast 11-Sept-00 13-Sept-00 Platnick, RSP, 10/03

  23. NASA Ames AATS-14, 13Sep 2000 (Schmid, Redemann, Russell, et al.) column water vapor Platnick, RSP, 10/03

  24. S2k CPL 532 nm extinction (M. McGill, D. Hlavka)off Angolan coast Diurnal influences? Typical? western track:14-Sept-00 eastern track: 14-Sept-00 Platnick, RSP, 10/03

  25. NSS: DMSP —> DMS —> ocean flux —> atmospheric MSA and/or sulfate DMS vs. phytoplankton concentration nonlinear, species-dependent (coccolithophores, dinoflagellates), hypothesized to be inv. prop. to mixed-layer depth (?), … note: Gypsum (CaSO4) in Etosha pan et al. in central Namibia derived mainly from coastal DMS [Eckhardt and Spiro, Sedim. Geology, 1999] SeaWIFS (11-3-98) Natural coastal sulfur sources, DMS Platnick, RSP, 10/03

  26. Natural coastal sulfur sources: H2S from B. Curie, Ministry of Fisheries and Marine Resources, Swakopmund, Namibia Platnick, RSP, 10/03

  27. 18 March 29 March 3 April oxidized sulfur granules Space shuttle 1985 Natural coastal sulfur sources: H2S, cont. S. Weeks, et al., Nature, 415, 2002. Platnick, RSP, 10/03

  28. Natural coastal sulfur sources: H2S, cont. Lobster “walk out” Platnick, RSP, 10/03

  29. Coastal dust sources determined to be from pan deflation, not dunes (Eckhardt) SeaWIFS: 9-19-00 Platnick, RSP, 10/03

  30. MODIS calcite retrieval (left image, B. Balch) & Chl (rt.) Platnick, RSP, 10/03

  31. 21-28 August 2003 MODIS Chl MODIS calcite Platnick, RSP, 10/03

  32. Some obvious science ?’s • To what extent are Sc off Namibia/Angola affected by anthropogenic (continental biomass, industrial) and/or natural ocean sulfur & sea salt sources? • What are the sources of coastal BL sulfur (i.e., as determined from chemical analyses such as stable isotope, etc.)? • What are the atmospheric processes and/or dynamics associated with growth/decay of boundary layer (BL) and vertical mixing of aerosols aloft? • To what extent can satellites that provide cloud, aerosol, and ocean color information capture these dependencies? • To what extent can modeling studies help in assessing the above questions? Platnick, RSP, 10/03

  33. Potential linkages between Sc and local/regional effects Benguela upwelling droplet size CCN DMS phytoplankton meteorology marine ecosystem Boundary-layer Sc properties continental burning, pollution Platnick, RSP, 10/03

  34. Summary of RSP proposal Dec. 2002 RAMS modeling w/sources: Freitas, Longo, Brazil Sc LES modeling: A. Ackerman, ARC MPL: J. Welton, GSFC (BL height, smoke layers) Acoustic sounder: D. Fitzjaarald, SUNY Albany (BL characterization) meteorology Benguela upwelling marine ecosystem Boundary-layer Sc properties droplet size CCN DMS phytoplankton continental burning, pollution MODIS cloud products: GSFC MODIS ocean products: P. Matrai, Bigelow In situ a/c: S. Piketh (aerosol, clouds, chem.), U. Wits, Johannesburg, R. Bruintjes (CCN), NCAR In situ gnd-based: Chemistry: DMS vs. Smoke isotopic and filter analysis, S. Macko, R. Swap UVa; impactor sampling, Wits; etc., Meteor: radiosonde, balloon, UVa, Wits, … Platnick, RSP, 10/03

  35. Summary of RSP proposal Dec. 2002, cont. Other: J. Henschel, Gobabeb Research and Training Centre, Namibia D. Terblanche, South African Weather Service (SAWS) Collaborators: R. Chatfield, ARC Platnick, RSP, 10/03

  36. Cost summary of RSP proposal Dec. 2002. Platnick, RSP, 10/03

  37. Monitor BL Key science ?’s compatible with a single field campaign Some obvious science ?’s • To what extent are Sc off Namibia/Angola affected by anthropogenic (continental biomass, industrial) and/or natural ocean sulfur & sea salt sources? • What are the sources of coastal BL sulfur (i.e., as determined from chemical analyses such as stable isotope, etc.)? • What are the atmospheric processes and/or dynamics associated with growth/decay of boundary layer (BL) and vertical mixing of aerosols aloft? • To what extent can satellites that provide cloud, aerosol, and ocean color information capture these dependencies? • To what extent can modeling studies help in assessing the above questions? No modeling effort, no ocean r.s. effort, reduced ground-based scope, at whim of met. for single effort Platnick, RSP, 10/03

  38. Site survey at the University of NamibiaHenties Bay Marine and Coastal Resources Research Centre Platnick, RSP, 10/03

  39. Henties Bay Marine and Coastal Resources Research Centre - power, internet connections, office space- director and staff are interested in resident research activities- plan (vision) for resident housing on site

  40. Henties Bay Marine and Coastal Resources Research Centre

  41. Henties Bay Marine and Coastal Resources Research Centre- site layout Platnick, RSP, 10/03

  42. Other potential sites …Cape Cross (friendly but vocal local population) Platnick, RSP, 10/03

  43. Likely monies needed ~ 4 week campaign in September 2004, per person costs for $2,500 rt air, $3,500 per diem at Swakop or Henties Bay (30 days at $115/day), rental car of $2000 inc. insurance (~$60/day) • UVa (Swap - 2 mos., Macko - 1 mos., student - 1 yr.): • Science: sources of coastal BL sulfur determined from chemical analyses of stable isotopes (bulk C, N, S ), possibly size segregated; explore ion chromotography (ion, cation concentrations to help identify air mass); pixie analysis (elemental) from UVa streaker samplers already in region • Equipment: two ground based streaker samplers (4 hr samples at 2 different size fraction for elemental analyses); 2 hi-vol samplers, radiosondes for vertical profiles • $100K ($37K less than original proposal) • GSFC (Platnick, Welton, et al.): programmer support for ~3 mos. x2, shipping, ~ $80K w/overhead (?), same as original proposal • Wits (Piketh, et al.): Wits group will provide 25 flt hours out of current funding + personnel and data anlaysis expenses for up to 6 weeks. Asking for additional 25 flt hours ($1225/hr + UVa subcontract overhead) + NCAR CCN counter • $45K (inc. overhead) through UVa sub-contract (services only) • Now has multiple radio-controlled A/C (1-2 m wingspan) capable of flying particle probes and canisters Platnick, RSP, 10/03

  44. Other interested parties Science interest expressed from: • Other original proposers/collaborators • S. C. Tsay, GSFC Other agencies: • NSF being explored Platnick, RSP, 10/03

  45. Summary of Wits capability (Stuart Piketh) Long-term commitment • Planning installation of automatic weather station in Dec. 2003 (T, RH, u, v, w, p), solar radiation, precipitation; continuous particle sampler Campaign • Ground-based: • Research Caravan - SO2, H2S, CO, CO2, O3, NO, NOx, NH3 - plus 2 GC's to analyze ground and airborne VOC flasks • CIMEL Sun Photometer • Aircraft (AeroCommander 690A): • TG (SO2, H2S, CO, CO2, O3, NO and NOx + TG flask) • aerosol - CN counter with attachment to count aerosol size • distributions from 0.01 (micron), PCASP, Airborne Streaker Sampler • Cloud droplet (FSSP, 2DP, 2DC probes) • State parameters (dry bulb, dew point, press, RH, LWC, true air speed) • Can/may be able to source out NCAR CCN counter (R. Bruintjes) • Remote controlled aircraft: • up to 15K ft (w/15kg payload), /self navigation, capabilities for met, some aerosol (PMS HANDILAZ 300 - four aerosol size fractions), some TG obs (O3 and small TG VOC flasks) Platnick, RSP, 10/03

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