Some Background

1
Some Background

• Im in the wind business ---
• My thesis dealt with the mathematical solution
  for PBL winds
• Ive written two texts on flow equations in the
  PBL and entire atmosphere.
• At one time I was PI or co-PI on 5 EOS grants
  LAWS, Seawinds, SSMI (Wetnet) and 2
  interdisciplinaries
• We have programs to use winds in weather
  climate analyses
• I want winds from ANY source

2
Winds are not --- have never been --- on NASA/s
menu. Why?

• I surveyed EOS investigators It is
  assumed that the winds will be provided by GCMs
• Scatterometer data showed this is not true
• Missing storms, details
• PBL Winds unphysical, often too low
• Mainly a resolution problem, but also because
  GCMs cannot handle Turbulence in many cases (PBL,
  Conv. Towers, tropopause, jets.) or sub-grid
  organized flow (OLE).

3
The Need for Winds
4
Applications
Better GCM Progs
Better Storms Definition
Higher Winds (heat fluxes)
Better Climate Models
Little Science things like Proof of ubiquity of
Rolls (OLE)
RABrown 2001
5
A Winds Motivation

• High Marine Surface Winds do not appear in
• Buoy data
• Climate records
• General Circulation Models
• Satellite sensor algorithms
• High Marine Surface Winds do appear in
• Ocean Meteorology Ship reports
• Dedicated Airplane PBL Flights
• A PBL model that includes OLE
• Higher winds imply higher heat fluxes in
  climatology revised ocean mixed layer models.

R.A. Brown, 1997, 2000 01
6
There exists an opportunity for satellite
data

• Measurements from sondes, ships buoys incur
  large errors due to turbulence OLE
• There are few measurements of winds in the PBL
  in situ
• There are no satellite determined winds IN the
  PBL
• The fluxes (air-surface) require boundary layer
  winds
• Climate Analyses have been made on extremely
  poor climatology data

R. A. Brown 1/2001
7
The Available Winds (1990-2005)
8
Sources of Surface Wind Fields for Climate Studies

• From Surface Measurements
• Ships Buoys
• Radiosondes
• From Models
• GCM (with K-theory PBLs)
• UW Similarity Model (with OLE)

R.A. Brown, 1997, 2001
9
Satellite Wind Sensors

• Scatterometers
• ERS (ESA) Quikscat (USA) (2001 - )
• SeaWinds on Adeos (USA,Japan) (2002)
• AScat (ESA) (2004)
• SARs
• ERS (ESA) Radarsat (Canada) Envisat (ESA)
• Passive Radiometers
• Windsat (USA) (2002)
• Lidars
• ESA (2008)

10
Scatterometer wind fields here Pressure field SAR
Wind field
11
Theory
A conversation in 1977 Businger to Brown
Youre a fluiddynamacist, wed like the solution
to the relation between the surface wind and the
wave generation Brown to Businger OK (I
know its impossible, but its a living)
Bottom line (20 years later) There is no proven
theory for wind generation of waves. However, in
the best tradition of Atmospheric Science ---
there is a curve fit
Epilogue Satellite Data Prove PBL Winds Theory
12
Appraisal of Basics Theory for Scatterometer,
SAR, radiometer
? Data cm-scale, average density of capillaries
and short gravity waves in a footprint.
50km ? 25km ? 7km ? 100m (SAR)

• ? Theory State 1-10, poor to excellent
• ? Wind generation of water waves 1
• ? energy into short/long waves 2
• Wave-wave interaction 3
• Surface layer wind 8
• PBL wind (without OLE) 4
• (with OLE) 8

R.A. Brown 2001
13
Appraisal of Basics Microwave Data from
Scatterometry, SAR, Radiometers
? Data cm-scale, average density of capillaries
and short gravity waves in a footprint.
50km ? 25km ? 7km ? 100m (SAR) And surface
truth wind.
? Parameterizations State 1-10, poor to
excellent ? U10 (u) land
8 ? U10 (u) ocean
5 ? PBL U(z)
(similarity) 7 ?
Scatterometer Model Function ? u (?o)
4 ? U10 (?o) 8 ? ?P
(?o) 7
R.A. Brown 2001
14
Practical Aspects of Wind Measurements (Surface
Truth Limits)
Ship winds Sparse and inaccurate (except Met.
Ships). Buoy winds Sparse a point. Tilt
variable height - miss high winds and low wind
directions. GCM winds Bad physics in PBL Models
Too low high winds, too high low winds.
Resolution coarse (getting better). Satellite
winds Lack good calibration data. Resolution
().
11-99, 5/00, 7/01 RAB
15
Height meters
The Surface Layer the log layer
the law of the wall
200
U10/VG ? 0.7
100
V
16

• Practical Aspects of a Geostrophic Wind Model
  Function (Pressures)
• Surface Truth Limits
• Radiosondes (winds)
• Sparse NG in PBL
• Buoy and ship pressures Accurate in low and
  high wind regimes sparse
• GCM (winds pressures)
• Poor winds. Good pressure verification,
  compatible

11-99, 7/01 RAB
17
Geostrophic Flow
1-3 km
VG(u) effects
Ekman Layer with OLE
Thermal Wind
Nonlinear OLE
Gradient Wind
Advection,centrifugal terms
Non steady-state
0 100 m
U10(u) effects
Stratification
U10
Surface Layer
Surface Stress, u
Variable Surface Roughness
Ocean surface
R.A. Brown PORSEC 2000
18
CONCLUSIONS

• The surface layer relation, hence U10 u(?o )
  works well 0 lt z lt 100 meters
• There is almost no surface truth --- buoy or GCM
  surface winds with U10 gt 25 m/s
• The U10 model function can be extrapolated to
  about 35 m/s
• There are indications that ?o responds to the
  sea state for U10gt40 m/s. (H-pol gt 60 m/s?)
• There is a Model function yielding winds possibly
  to 60 m/s (2000)
• The PBL model yields U(z), 0 lt Z lt 1 km
  (gradient)
• Requires U10.
• Requires Stratification Information

RABrown, 99 01
19
The Struggle to get Satellite Wind Sensors
20
A Brief History of Scatterometers
1970 1980 1990 2000 2010
Conception
SeaSat Built --- with Scat, SAR, SMMR, Alt
SeaSat Launch --- Lasts 99 days
NSCAT conceived and built
Dark Ages launch to gulf carribean
wars, refurbish battleships, 200 ship fleet,
Star Wars
ERS-1 Launch (turned off)
NSCAT launched on ADEOS --- 9 mos. ERS-2
Launch Quikscat Launch
Dark Ages 11 in USAI Star
Wars 11
SeaWinds on ADEOS - II
ESA A-SCAT
R. A. Brown 1/2001
21
Programs and Fields available onhttp//pbl.atmos.
washington.edu Questions to rabrown, neal
or jerome_at_atmos.washington.edu

• Direct PBL model PBL_LIB. (75 -01) 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 (VG) ?P
  (U10 , ?To , ?Ta , ?) (1986 - 2001)
• Pressure fields directly from the PMF ?P (?o)
  along all swaths (exclude 0 - ? 5 lat) (2001 in
  progress)
• Surface stress fields from PBL_LIB corrected for
  stratification effects along all swaths (2001 in
  progress)

R.A. Brown 2000, 01