Outline for Today26-8-2010

MotivationMotivationTheoryTheory for Winds for WindsThe Satellite Instruments The Satellite Instruments

TheThe scatterometer, scatterometer, lidar,lidar, SARSARThe The ResultsResults of Winds from Space of Winds from SpaceThe The Consequences Consequences for surface wind analysisfor surface wind analysis

The long, slow, tedious road to winds for PBL study

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)

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.

The & of measuring from Space

Science Politics

How do you measure the wind vector (speed & direction) in the atmosphere from hundreds of miles away in space ?The Evolution of a Conspiracy theory over 20-years

Winds

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…..

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.)

Revelations from scatterometers

* 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)

• Ship or Buoy winds are not good surface truth in general. Hence the climate record is incorrect.

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

R. A. Brown 03

The buoys in high winds, high seas

Buoy~ 3 m

Sheltering: The high waves place the buoy in shelter and/or turbulent wake of the waves yielding low windsDisplacement height: When surrounding topography is rough, the sensor is ‘displaced’ downward to reflect its lower position in a more turbulent boundary layer =lower winds

Wave height~ 10 m

10-m wind

R. A. Brown 2003 U. ConcepciÓn

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

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

Station B

2 - 5 km

Taking measurements in the Rolls

with Tower & Sondes

Station A

1-km

R. A. Brown U. ConcepciÓn

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

Revelations from scatterometers

* 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)

• 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.

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

Revelations from scatterometers

* 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)

• 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.

The Newest satellites:6-20-2014

New scatterometers; One K-band and one C-band dedicated to hurricane

analyses. A scatterometer tamden with a SAR (100-meter

resolution) for global surface winds.

In the meantime……

PBL turbulence spectrum

Roll details Aerosol statistics

PBL (Inversion) height

Surface characteristics R. A. Brown 2010

Initialization for Weather & Climate Models

18° (neutral stratification)Surface wind

Geostrophic Wind direction

Geostrophic Wind or the

scatterometer 1-km wind

Mid- PBL

VG = P / ( f )

V = P / ( f) - Fviscous

25° (Stable strat.)

5° (Unstable strat.)

-10° to 40° (Thermal Wind Effect)

Lidar average wind in PBL

R. A. Brown U. ConcepciÓn

1-3 KM

30-meters

5/10 RAB

Practical Aspects of Wind Measurements available for parameterization:Surface ‘Truth’ Limits

Buoy winds: Sparse; a point. They tilt; have variable height - miss high winds and low wind directions.

GCM winds: Inaccurate physics in PBL Models; Too low high winds, too high low winds. Resolution coarse (getting better).

Ship winds: Sparse and inaccurate (except some Met. Ships).

11-99, ’08 RAB

Buoy and ship pressures: Sparce but accurate in low and high wind regimes.GCM: Good verification; compatible scale

Revelations from scatterometers

* 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)

• * 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

CROSS-VALIDATION OF SCATTEROMETER WINDS VIA CROSS-VALIDATION OF SCATTEROMETER WINDS VIA

SEA-LEVEL PRESSURE RETRIEVALSEA-LEVEL PRESSURE RETRIEVAL

JJéérrôôme Patouxme PatouxRalph C. FosterRalph C. FosterRobert A. BrownRobert A. Brown

May 19, 2010May 19, 2010

Original winds

Derive a new set of winds from the

SLP field

New winds

(SLP_u10)

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

Comparison of QS- and ASCAT-derived SLP fields

ECMWF analysis

QuikScat analysis

Surface Pressures

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.

Programs and Fields available onhttp://pbl.atmos.washington.edu

Questions to 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)

R.A. Brown 2010

http://blog.seattlepi.com/robertbrown/