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Outline for Today 26-8-2010

Explore the motivation, theory, and satellite instruments used to measure wind vector in the atmosphere from space. Discover the consequences for surface wind analysis and the big questions defined by NASA.

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Outline for Today 26-8-2010

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  1. Outline for Today26-8-2010 The long, slow, tedious road to winds for PBL study • Motivation • Theory for Winds • The Satellite Instruments • The scatterometer,lidar,SAR • The Results of Winds from Space • The Consequences for surface wind analysis

  2. What are the “Big Questions” as defined by NASA (lidar related)RAB • Earth Questions:How is the global earth system changing? (climate modeling) • What are the primary forcings of the Earth system?(Solar heating of the Atmosphere, hence PBL dynamics; weather/climate modeling) • How does the earth system respond to natural and human-induced changes? (climate models) • What are the consequences of change in the earth system for human civilization? • How will the Earth system change in the future? (climate modeling)

  3. Within the possibilities of GW…… • No GW; just the Milankovich cycle into the next glacial (ice) age in 100-5000 years. MOS 10-50. • Moderate GW; wards off ice age, affects sea level + 5-10 feet by 2100; ocean acidification eliminates many species, corals; redistribution of agriculture; strong storms, droughts, etc. • Maximum possible GW; land ice melts, seas rise 200 feet, ocean life nearly eliminated, most land species eliminated, including homo sap.

  4. The & of measuring from Space Science Politics Winds How do you measure the wind vector (speed & direction) in the atmosphere from hundreds of miles away in space ? The Winds are the basic parameter in the equations of motion for weather and climate  the state of knowing : knowledge as distinguished from ignorance or misunderstanding Hence based on Observations. Using the Navier Stokes equations (F = ma for fluid parcel) under certain conditions, Newtonian fluid; calculus definition, eddy size….. The Evolution of a Conspiracy theory over 20-years

  5. Theory • * In the beginning (1905) there was the Ekman solution: • Linear, 2nd order, a 10-page paper • In 1970 there was the nonlinear, 4th order (1972; 6th order) (1990; 8th order), a 176 page book. • Modelers preferred the Ekman solution (Oceanographers and many Atmos. Science Boundary Layer modelers still do.)

  6. Revelations from scatterometers • Ship or Buoy winds are not good surface truth in general. Hence the climate record is incorrect. * Data on storms and fronts is revolutionary. (Patoux, J., G.J. Hakim and R.A. Brown, 2004: Diagnosis of frontal instabilities over the Southern Ocean, Monthly Weather Review)

  7. Sources of Surface Wind Fields for Climate Studies • Over land: limited, accuracy varies, No. Hemi. • Over the ocean from Surface measurements • Ships • Buoys R.A. Brown, 2010

  8. The buoys in high winds, high seas 10-m wind Wave height ~ 10 m Buoy ~ 3 m Sheltering: The high waves place the buoy in shelter and/or turbulent wake of the waves yielding low winds Displacement height: When surrounding topography is rough, the sensor is ‘displaced’ downward to reflect its lower position in a more turbulent boundary layer =lower winds R. A. Brown 2003 U. ConcepciÓn R. A. Brown 03

  9. Sources of Surface Wind Fields for Climate Studies • From Surface Measurements • Ships • Buoys • From Models • GCM (with K-theory PBLs) • UW Similarity Model (with OLE) R.A. Brown, 2010

  10. Coherent Structures in the PBL • Organization within an otherwise turbulent field • Nonlinear • Finite perturbation theory • Vortex solution; Contains same parcels • In the PBL, Organized Large Eddies (OLE) • Nomenclature problem with ‘Chaos’ (coherent structure solution in chaotic turbulence) R. A. Brown 2010

  11. Taking measurements in the Rolls with Tower & Sondes 1-km Station A 2 - 5 km Station B R. A. Brown U. ConcepciÓn

  12. K-Theory Vs Similarityor Why RAB loves satellite data • 1970: OLE is just a complicated theory for cloud streets • 1974 “Single parameter Similarity Model w/OLE is just a theory” [so is gravity, evolution…..] • 1977 “OK. They also occur in numerical models and a few experiments. And, if the theory is correct, diffusion models (used in all GCMs) have wrong physics. But, how often are OLE present globally? Need data not just theory” • 1978. Seasat SAR shows OLE surface imprints, often. • 1980: OLE do occur. Analytically, Numerically, and Observations --- and they all look similar. • 1998: SAR (RADARSAT) shows OLE produce signature on ocean surface stats ~ 80% of the time R. A. Brown 2010

  13. Revelations from scatterometers • Ship or Buoy winds are not good surface truth in general. Hence the climate record is incorrect. • * Weather & climate PBL models have the wrong physics. * Data on storms and fronts is revolutionary. (Patoux, J., G.J. Hakim and R.A. Brown, 2004: Diagnosis of frontal instabilities over the Southern Ocean, Monthly Weather Review)

  14. Sources of Surface Wind Fields for Climate Studies • From Surface Measurements • Ships • Buoys • From Models • GCM (with K-theory PBLs) • UW Similarity Model (with OLE) • From Satellites • Scatterometer (ESU ASCAT) • SARs, radiometers …. • (Lidar) R.A. Brown, 2010

  15. Revelations from scatterometers • Ship or Buoy winds are not good surface truth in general. Hence the climate record is incorrect. • * Weather & climate PBL models have the wrong physics. • * The winds are higher, the low pressures are lower & more frequent, heat fluxes are greater and stress much greater than climatology states. Climate modelers take note. * Data on storms and fronts is revolutionary. (Patoux, J., G.J. Hakim and R.A. Brown, 2004: Diagnosis of frontal instabilities over the Southern Ocean, Monthly Weather Review)

  16. The Newest satellites:6-20-2014 New scatterometers; One K-band and one C-band dedicated to hurricane analyses. A scatterometertamden with a SAR (100-meter resolution) for global surface winds. In the meantime……

  17. Lidar PBL possibilities Initialization for Weather & Climate Models Roll details Aerosol statistics PBL (Inversion) height PBL turbulence spectrum Surface characteristics R. A. Brown 2010

  18. Geostrophic Wind or the scatterometer 1-km wind VG=P / ( f ) 30-meters Mid- PBL V = P / ( f) - Fviscous Lidar average wind in PBL 1-3 KM Geostrophic Wind direction 25° (Stable strat.) 18° (neutral stratification) Surface wind 5° (Unstable strat.) -10° to 40° (Thermal Wind Effect) R. A. Brown U. ConcepciÓn

  19. Practical Aspects of Wind Measurements available for parameterization: Surface ‘Truth’ Limits Ship winds: Sparse and inaccurate (except some Met. Ships). Buoy winds: Sparse; a point. They tilt; have variable height - miss high winds and low wind directions. GCM winds: Inaccurate physics in PBL Models; Toolow high winds, too high low winds. Resolution coarse (getting better). 5/10 RAB

  20. Practical Aspects of a Geostrophic Wind Model Function ̶̶ (implied Surface Pressure fields) ------------------------------------- Surface ‘Truth’ Limits (pressure fields) Buoy and ship pressures: Sparce but accurate in low and high wind regimes. GCM: Good verification; compatible scale 11-99, ’08 RAB

  21. Revelations from scatterometers • * Ship or Buoy winds are not good surface truth in general. Hence the climate record is incorrect. • Weather & climate PBL models have the wrong physics. • Satellite PBL wind data can be used to improve weather forecasts and climate data * Data on storms and fronts is revolutionary. (Patoux, J., G.J. Hakim and R.A. Brown, 2004: Diagnosis of frontal instabilities over the Southern Ocean, Monthly Weather Review)

  22. CROSS-VALIDATION of scatterometer winds via sea-level pressure retrieval JérômePatoux Ralph C. Foster Robert A. Brown May 19, 2010

  23. Original winds New winds (SLP_u10) Derive a new set of winds from the SLP field

  24. The scatterometer-derived SLP fields compare well with NCEP and ECMWF SLP analyses.

  25. Comparison of QS- and ASCAT-derived SLP fields

  26. Surface Pressures QuikScat analysis ECMWF analysis

  27. Applications: Midlatitude cyclone intensification, tracking, and climatology of air-sea fluxes. Patoux J., X. Yuan and C. Li, 2009: Satellite-based midlatitude cyclone statistics over the Southern Ocean. Part I: Scatterometer-derived pressure fields and storm tracking, J. of Geophys. Res., D04105, doi:10.1029/2008JD010873 . Yuan X., J. Patoux and C. Li, 2009: Satellite-based midlatitude cyclone statistics over the Southern Ocean. Part II: Tracks and surface fluxes, J. of Geophys. Res., D04106, doi:10.1029/2008JD010874.

  28. Programs and Fields available onhttp://pbl.atmos.washington.eduQuestionsto rabrown, neal or jerome@atmos.washington.edu • Direct PBL model: PBL_LIB. (’75 -’00) An analytic solution for the PBL flow with rolls, U(z) = f( P, To , Ta , ) • The Inverse PBL model: Takes U10 field and calculates surface pressure field P (U10 , To , Ta , ) (1986 - 2000) • Pressure fields directly from the PMF: P (o) along all swaths (exclude 0 -  5° lat.?) (2001) • Surface stress fields from PBL_LIB corrected for stratification effects along all swaths (2001) http://blog.seattlepi.com/robertbrown/ R.A. Brown 2010

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