refractivity during ihop_2002
DESCRIPTION
Refractivity During IHOP_2002. Tammy M. Weckwerth (NCAR/ATD), Crystalyne R. Pettet (NCAR/ATD), Frédéric Fabry (McGill University), ShinJu Park (McGill University) and James W. Wilson (NCAR/ATD). Intercomparisons. Fixed and mobile surface stations AERIBAGO SRL Aircraft. Intercomparisons. - PowerPoint PPT PresentationTRANSCRIPT
Water Vapor Intercomparison Workshop, Boulder, 2-3 October 2003
Refractivity During IHOP_2002
Tammy M. Weckwerth (NCAR/ATD), Crystalyne R. Pettet (NCAR/ATD), Frédéric Fabry (McGill University),
ShinJu Park (McGill University) and James W. Wilson (NCAR/ATD)
Intercomparisons
Fixed and mobile surface stationsFixed and mobile surface stations
AERIBAGOAERIBAGO
SRLSRL
AircraftAircraft
Intercomparisons
Bias is not related to propagation effects since it’s not diurnally dependentBias is worse at higher humidities
Surface Station Intercomparisons
Surface StationIntercomparisons
22 May 2002
1600 1800 2000 2200 0000
Time (UTC)
240
260
280
300
320
Refr
act
ivity
0200 0400
ISFF1
S-Pol
r = 0.77
N = 283.51N = 288.09
1600 1800 2000 2200 0000Time (UTC)
240
260
280
300
320
Refr
act
ivity
0200 0400
ISFF2
S-Pol
r = 0.85
N = 280.15N = 282.08
1600 1800 2000 2200 0000
Time (UTC)
240
260
280
300
320
Refr
act
ivity
0200 0400
S-Pol
ISFF3
r = 0.86
N = 273.13N = 278.47
1600 1800 2000 2200 0000Time (UTC)
240
260
280
300
320
Refr
act
ivity
S-Pol
Verle
0200 0400
r = 0.99
N = 258.88N = 264.01
1600 1800 2000 2200Time (UTC)
240
260
280
300
320
Refr
act
ivity
0000 0200 0400
Playhouse
S-Pol
r = 0.98
N = 269.88N = 271.14
1600 1800 2000 2200 0000Time (UTC)
240
260
280
300
320
Refr
act
ivity
0200 0400
S-Pol
Homestead
r = 0.92
N = 282.18N = 285.59
1600 1800 2000 2200 0000Time (UTC)
240
260
280
300
320
Refr
act
ivity
0200 0400
Lincoln
S-Pol
r = 0.96
N = 269.74
• Excellent correlations• Radar has negative bias
-100.70 -100.66 -100.62Longitude
250
260
270
280
290
Refr
acti
vit
y
0 2 4 6 8Distance (km)
Refractivity at 000509 UTCMM1 center at 000651 UTC
S-Pol
Probe 1
Mobile Mesonet comparisons
Correlation = 0.81
-100.75 -100.70 -100.65 -100.60Longitude
250
260
270
280
290
Refr
acti
vit
y0 2 4 6 8 10 12 14
Distance (km)
Refractivity at 224830 UTCMM8 center at 224859 UTC
Probe 8
S-Pol
Correlation = 0.88
1600 1800 2000 2200 0000
Time (UTC)
250
260
270
280
290
300
0200 0400
Refr
act
ivit
y
AERI 175 mS-Pol
AERI 310 mAERI 670 m
AERIBAGO comparisons
Correlation=0.42Correlation=0.75Correlation=0.89
SRL comparisons22 May 2002 Scanning Raman Lidar
20 22 24 26 28Time (UTC)
0
500
1000
1500
2000
2500
3000
He
ight
(m A
GL)
250
260
270
280
290
300
S-P
ol R
efr
act
ivity
5
6
7
8
9
10
11
12
5.0 6.3 7.6 8.9 10.2 12.0H20 mixing ratio (g kg-1)
H20
mix
ing
ra
tio
(g
kg
-1)
S-Pol N
UWKA comparisons
-100.65-100.60-100.55-100.50-100.45250
260
270
280
290
3000 5 10 15 20 25
Distance (km)
Refractivity at 224230 UTCUWKA Zavg = 163 m AGLUWKA at 224330 UTC
S-Pol
UWKA
Refr
acti
vit
y
Correlation=0.93
Correlation drop occurs between 358 m leg (0.96) and 673 m leg (0.74)
-100.70 -100.60 -100.50 -100.40250
260
270
280
290
3000 10 20 30
Distance (km)
Refractivity at 234830 UTC
UWKA center at 234753 UTCUWKA Zavg = 167 m AGL
Longitude
Refr
act
ivit
y
S-Pol
UWKA
Correlation=0.88
Summary
Radar Refractivity may be a proxy for water Radar Refractivity may be a proxy for water vapor during the warm season.vapor during the warm season.
Radar Refractivity shows excellent correlation Radar Refractivity shows excellent correlation with surface station and aircraft refractivity.with surface station and aircraft refractivity.
Radar Refractivity has a low bias vs fixed Radar Refractivity has a low bias vs fixed surface stationssurface stations
Vertical depth represented appears to be Vertical depth represented appears to be lower levels of the ABL (<~300 m?).lower levels of the ABL (<~300 m?).
Horizontal resolution is approximately 4 km Horizontal resolution is approximately 4 km (although it sometimes appears better).(although it sometimes appears better).
Ongoing Work Evaluate accuracy of low-level refractivity retrievalEvaluate accuracy of low-level refractivity retrieval
Fixed and mobile mesonetsFixed and mobile mesonets Plan to: Add GPS intercomparisonsPlan to: Add GPS intercomparisons Plan to: Add DRI MMR intercomparisonsPlan to: Add DRI MMR intercomparisons
Evaluate layer over which refractivity retrieval is Evaluate layer over which refractivity retrieval is representativerepresentative Aircraft in situ measurementsAircraft in situ measurements SRL intercomparisonsSRL intercomparisons AERI intercomparisonsAERI intercomparisons Plan to: Add Sounding & Dropsonde comparisonsPlan to: Add Sounding & Dropsonde comparisons Plan to: Add horizontal and vertical pointing airborne Plan to: Add horizontal and vertical pointing airborne
DIALDIAL Plan to: Add TAOS intercomparisonsPlan to: Add TAOS intercomparisons Possibly add: MIPS profiling radiometer Possibly add: MIPS profiling radiometer
intercomparisonsintercomparisons Plan to: Evaluate two more days in detailPlan to: Evaluate two more days in detail
-100.70 -100.60 -100.50 -100.40250
260
270
280
290
3000 10 20 30
Distance (km)
Refractivity at 234830 UTC
UWKA center at 234753 UTCUWKA Zavg = 167 m AGL
Longitude
Refr
act
ivit
y
S-Pol
UWKA
Correlation=0.882 km 11 km
dryline
S-Pol Refractivity Retrieval
dryline
cool/moist
• Variations in q, T and p• Boundary detection• Advection• Pettet et al., next; Fabry and Park, 1700
warm/dry
Refractivity: One Day After Heavy Rainfall Aircraft in-situ data
Northern edge of aircraft track Ts=45 deg C,Theta60=307 K, q60 = 8.5 g/kg
Southern edge of aircraft track Ts=32 deg C,Theta60=306.2 K, q60 = 11 g/kg
warm/dry
cool/moist
1600 1800 2000 2200 0000Time (UTC)
240
260
280
300
320
Refra
ctivity
S-Pol
Verle
0200 0400
Surface station comparisons
Correlation = 0.99
1600 1800 2000 2200 0000Time (UTC)
240
260
280
300
320
Refra
ctivity
0200 0400
S-Pol
Homestead
Correlation = 0.92
1600 1800 2000 2200Time (UTC)
240
260
280
300
320
Refra
ctivity
0000 0200 0400
Playhouse
S-Pol
Correlation = 0.98
-100.68 -100.64 -100.60 -100.56Longitude
250
260
270
280
290
Refr
act
ivit
y2 4 6 8 10 12
Distance (km)
Refractivity at 220029 UTCMM6 center at 215751 UTC
0
Probe 6
S-Pol
Correlation = 0.14