Automated Quality Control and Analysis of NOAA WP-3D Airborne Doppler Data and its Use during the 2005 Hurricane Season

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Automated Quality Control and Analysis of NOAA
WP-3D Airborne Doppler Data and its Use during
the 2005 Hurricane Season

• John Gamache
• NOAA/AOML/Hurricane Research Division

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WP-3D Aircraft and their Radars
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Vertically scanning X-band Doppler radar aboard
the NOAA P-3 Aircraft NOAA Antenna
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(No Transcript)
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Radar Characteristics

• 3.22 cm wavelength--X band
• Beam width normal to scanning is 1.35 deg--1 km
  resolution at 40 km--long range horizontal
  resolution
• Beam width along scan is 1.9 degrees--translates
  to 1 km at 30 km range or 2 km at 60 km
  range--long-range vertical resolution
• Radial (along beam) resolution is 150 m. This is
  the resolution directly above and below the
  aircraft.

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JHT Project Real-Time Dissemination of
Hurricane Wind Fields Determined from Airborne
Doppler Radar DataProject officially ended June
30 2005

• Goals
• To demonstrate capability to automatically
  quality control airborne Doppler data well enough
  that they may be assimilated in real-time, and
  also used to produce analyses of the hurricane
  core winds--demonstrated in 2004
• To demonstrate capability to produce
  three-dimensional wind analyses in real time on
  the aircraft--demonstrated in 2004
• To demonstrate capability to transmit the
  analyses to the NHC/TPC--demonstrated in 2005
• To demonstrate transmission of the
  quality-controlled Doppler radial-velocity data
  to EMC for assimilation into HWRF--real time
  quality control has been done but transmission
  presently severely limited by bandwidth

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HRD Software Prior to JHT

• Three-dimensional variational analysis of winds
  from airborne Doppler radar data
• Higher resolution radius height cross-section of
  wind along the inbound and outbound legs

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Development Required for JHT Project

• Automated Quality Control of Raw Doppler Data
  (completed)
• Software to generate batch job files (completed,
  although present implementation may still require
  too much operator input--improved in last 2
  months)
• Software to generate output files that can be
  transmitted off the aircraft by SATCOM to TPC
  (completed) and EMC (completed but not yet
  transmitted)
• Path to TPC (completed, but will be revised to
  make more operational) and EMC (not yet completed)

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Variational Analysis--Minimize the following
simultaneously

• The difference between the projection of wind
  analysis on the Doppler radials and the original
  Doppler radial velocities.
• The three-dimensional mass divergence (analestic
  approximation).
• Second derivative in all three directions, as
  well as cross derivatives. This is a smoother
  and should be given a light weight.
• Difference between vertical wind at vertical
  boundaries, and wind-analysis vertical wind.

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Doppler projection equations
Anelastic mass-continuity equation
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Filtering
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Bottom boundary condition
Top boundary condition
where ?ijk 0 if ijk does not represent a top
boundary, ?ijk 1 if ijk does represent a top
boundary.
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The total cost function F is then given by
For every point ijk there are three equations
and
If there are Np points then the system to be
solved will have 3Np equations. After solution
points not constrained by data are flagged.
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Bousquet and Chong (1998)
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Doppler de-aliasing/unfolding

• Doppler velocity comes from phase shift (maximum
  unambiguous phase shift is - ? to ?).
• ? usually represents 20 m/s or Nyquist velocity
  (VN). 21 m/s away from the Doppler radar will be
  interpreted as 19 m/s (-19 m/s) toward the radar.
  
• Thus VRobs VDop 2n (VN). De-aliasing or
  unfolding means determining n at each radar bin.
• Bargen-Brown de-aliasing consists of using the
  average of several radar bins inward from the
  present bin to determine the most likely value of
  n at the present bin. First bin determined from
  wind measured at radar.
• This will even operate with a gap in data,
  although the process then becomes more
  unreliable.

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Automatic quality control

• Remove data with high velocity spectral width
• Remove reflection of main- and side-lobe by sea
  surface
• Remove isolated speckles which can fool the
  automatic Doppler unfolding process
• Use single ray Bargen-Brown automatic unfolding
• Use a full sweep de-aliasing method developed at
  HRD
• Produce a wavenumber 0 and 1 analysis of wind
  velocity
• Use low-wavenumber analysis to improve
  Bargen-Brown and sweep dealiasing and further
  quality control
• Interpolate quality-controlled sweeps into
  three-dimensional cartesian analysis and
  higher-resolution radial-vertical cross-sections

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Doppler Radial Velocity
Hurricane Humberto 232855 UTC 23 Sep 2001
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First Pass--Wave No. 0 and 1 total wind
speed Hurricane Katrina 28 August 2005
North-south distance from center
East-west distance from center
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Second Pass--Fully 3D cartesian
analysis Hurricane Katrina 28 August 2005
North-south distance from center
East-west distance from center
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Radius-height cross-section of total wind
speed Hurricane Katrina 1725-1818 UTC 28 August
2005
18 km
0 m/s
90 m/s
60
30
175 kts
58
117
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Radius-height cross-section of radial wind
speed Hurricane Katrina 1725-1818 UTC 28 August
2005
18 km
-40
-20
0
20
40 m/s
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Doppler Wind Profile - 28 Aug 1725-1820 UTC
12 km
SW
NE
Flight Level
1 km
Doppler Wind Profile - 29 Aug 1000-1040 UTC
12 km
W
NE
Flight Level
1 km
Dramatic 12-h change in Katrina Wind Profile
CAT5-CAT3
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Products produced on aircraft

• Three-dimensional wind field centered on storm
  center
• domain (44 x 44 x 37), resolution (3-5 km x
  3-5 km x .5 km)
• variables horizontal and vertical wind
  velocity, radar reflectivity
• Radial-vertical cross-sections of wind along the
  average azimuth flown outward from the storm
  center
• domain (59 x 121), resolution (1.5 km radial,
  150 m vertical)
• variables tangential, radial, vertical, and
  total wind speed
• Trimmed set of quality-controlled Doppler
  radial-velocity measurements

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Products transmitted from aircraft via SATCOM in
2005

• u- and v-components of wind at 0.5- and 1.0-km
  levels (1640 and 3280 ft) sent in knots as 4
  gzipped ASCII text files (4-5 km horizontal
  resolution
• Inbound and outbound vertical-radial profiles of
  total wind speed (1.5 km radial resolution, .15
  km vertical resolution, out to 88 km)

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Wind speed in m/s at 1-km altitude Hurricane Ivan
12 September 1115-1145 UTC (digital camera
picture of N43RF airborne workstation)
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40 Real-time analyses transmitted in 2005

• Hurricane Katrina--14 analyses
• 25 August (Florida Landfall)--5, 27 August--4,
  28 August--5
• Hurricane Ophelia--13 analyses
• 8 September--2, 9 September--3
• 11 September--6, 12 September--2
• (Extratropical Transition)16 September--1, 17
  September--1
• Hurricane Rita--6 analyses
• 20 September--1, 21 September--4, 22 September--1
• Hurricane Wilma--7 analyses
• 22 October--5, 23 October--2
• Higher resolution post-season analysis of all
  2005 cases except Gert can be found in the data
  section at http//www.aoml.noaa.gov/hrd

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Real-time 1600-ft analysis of Hurricane Katrina
Wind 1725 - 1818 UTC, 28 August 2005 wind in knots
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10,000 ft
Azimuth 045 from center
height
Hurricane Katrina 1725-1818 UTC 28 Aug 2005
169 kt
Real-time Radius-height Profile of total wind
speed
Azimuth 225 from center
0 nm
50 nm
Radial distance (nm)
168 kt
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Sonde - Doppler total-wind-speed
intercomparison Hurricane Katrina 28 August 2005
Sonde Doppler Wind Radar reflecitivity
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Comparison for all drops on 28 August 2005 by
NOAA 43 with real time airborne Doppler analysis
(0.5 - 1.0 km layer) note--nearly all drops are
eyewall (wind max) drops where wind variability
is high

• ?Radial wind mean difference (sonde Doppler)
  -6.7 m/s -13.0 kts
• ?Tangential wind mean difference (sonde
  Doppler) -1.5 m/s -2.9 kts
• ?Wind speed mean difference (sonde Doppler)
  -0.4 m/s -0.8 kts
• ?Radial wind RMS difference 13.6 m/s 26.4
  kts
• ?Tangential wind RMS difference 7.5 m/s
  14.6 kts
• ?Wind speed RMS difference 6.4 m/s 12.4
  kts

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Comparison of all NOAA drops in 2004 with
automatic quick-look airborne Doppler analyses
(from 0.5 km to flight level) note--nearly all
drops are eyewall (wind max) drops where wind
variability is high
Radial wind mean difference (sonde
Doppler) -1.4 m/s -2.7 kts Tangential wind
mean difference (sonde Doppler) 0.2 m/s
0.4 kts Wind speed mean difference (sonde
Doppler) 0.8 m/s 1.6 kts Radial wind RMS
difference 7.3 m/s 14.2 kts Tangential wind
RMS difference 6.0 m/s 11.7 kts Wind speed
RMS difference 6.2 m/s 12.1 kts
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Future work

• Automatically determine navigational coordinates
  for analysis
• (with some help from operator)
• Extend analysis beyond 100 km from storm
  center--make it work more effectively with no
  well defined center (disturbances and
  depressions)--mainly involves allowing larger
  radial gaps in data in weaker systems with much
  weaker velocity gradients
• With faster link in future--run analysis and
  quality software on the ground
• Assimilation testing in HWRF
• Determine errors in radial velocity better.

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Aircraft Aerosonde Plots/Ophelia 16 Aug, 2005
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Aerosonde/Doppler radar Ophelia 20050916
Doppler radar analysis at time of closest
approach of Aerosonde to wind center and just
after WP-3D SFMR penetration across the eye.
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Aerosonde/Doppler 20050916
NE
Nominal Aerosonde ht 2500 ft (.75 km)
Real-time Doppler winds and vertical profiles
SW
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Hurricane Wilma 1900-1945 UTC 23 October
2005 Total Wind Speed 0.5 km altitude
1.0 km altitude
96
96
-96
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Hurricane Wilma 2025-2110 UTC 23 October
2005 Total Wind Speed 0.5 km altitude
1.0 km altitude
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Hurricane Wilma 23 October 2005 Total Wind Speed
at 3.0 km altitude
1900-1945 UTC
2025-2110 UTC
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Hurricane Wilma 1920-1945 UTC Radius-height
cross-section along Azimuth 045 23 October
2005 Total Wind Speed
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Hurricane Wilma 2047-2110 UTC Radial-vertical
cross-section along azimuth 135 23 October 2005
Total Wind Speed