Transcript NASA LASE (Browell)

LASE Measurements of Water Vapor
During IHOP
Edward V. Browell,1 Syed Ismail,1 Richard A. Ferrare,1
Susan A Kooi,1 and Vince G. Brackett,1
1NASA Langley
Research Center, Hampton, Virginia
2Space Science & Engineering Center, University of Wisconsin, Madison, WI
Funding provided by Dr. Jim Dodge, NASA Headquarters
IHOP Water Vapor Intercomparison Meeting, NCAR, 2-3 October 2003
Lidar Atmospheric Sensing Experiment (LASE)
• Airborne Water Vapor DIAL
• Laser
- 5 Hz doubled-pulsed Ti:sapphire
- 100 mj at lon and loff
• Wavelengths
- 815 nm (lon- loff = 40-70 pm)
- Two separate line pairs
• NASA ER-2, P-3, DC-8 aircraft
• Simultaneous nadir, zenith operations
• Real-time data analysis and display
LASE Water Vapor, Aerosol, & Cloud Profiling on NASA DC-8
9 June 2002 (Flt. 9) Morning Low Level Jet and Convective Initiation #3
• Water vapor profiles
- daytime and nighttime
- 0.2 km to upper trop.
- 0.01 to 25 g/kg
- accuracy: 6% or 0.01 g/kg
- resolution (variable)
vertical: 330 m
horizontal: 14 km (1 min)
• Aerosol/cloud profiles
- daytime and nighttime
- 0.03 to 25 km
-resolution (variable)
vertical: 30 m
horizontal: 200 m
LASE Water Vapor & Relative Humidity Profiling on NASA DC-8
9 June 2002 (Flt. 9) Morning Low Level Jet and Convective Initiation #3
• Water vapor profiles
- daytime and nighttime
- surface to upper trop.
- 0.01 to 25 g/kg
- accuracy: 6% or 0.01 g/kg
- resolution (variable)
vertical: 330 m
horizontal: 14 km (1 min)
LASE Water Vapor & Relative Humidity Profiling on NASA DC-8
9 June 2002 (Flt. 9) Morning Low Level Jet and Convective Initiation #3
• Water vapor profiles
- daytime and nighttime
- surface to upper trop.
- 0.01 to 25 g/kg
- accuracy: 6% or 0.01 g/kg
- resolution (variable)
vertical: 330 m
horizontal: 14 km (1 min)
• Relative humidity profiles
- derived Scanning-HIS or
radiosonde temperature
distributions
LASE Measurements during IHOP
• Participated in 8 IHOP science flights from May 23-June 14, 2002
LASE Water Vapor Comparisons
Nighttime
Daytime
LASE/IHOP 2002 ALL COMPARISONS
(delta time < 75 min, delta location < 75 km)
Flight
Date
RS90
BF
CF
5
5/24
6
5/30
7
6/02
4
8
6/03
1
9
6/09
10
6/11
11
6/14
TOTAL
2
RD93
RS80
Lear Falcon HS MG
8
DC
5
2
1
8
1
3
BF - Boundary Facility sonde
CF - Central Facility sonde
Lear - Dropsonde
Falcon - Dropsonde
2
1
3
7
1
7
15
8
2
3
4
4
1
4
3
9
2
8
11
28
5
22
39
15
1
3
7
9
SRL Total
2
1
1
AERI CARL DLR
HS - Homestead sonde
MG - MGLASS mobile sonde
DC - Dodge City sonde (VIZ)
AERI- at Homestead
3
2
9
11
3
3
17
1
3
30
3
38
23
7
3
9
31
18
158
CARL - Raman Lidar at CF
DLR - Lidar on Falcon
SRL- Scanning Raman Lidar
at Homestead
LASE/IHOP 2002 CLOSEST COMPARISONS
(delta time < 20 min, delta location < 20 km)
Flight Date
RS90
BF
CF
RD93
RS80
Lear Falcon HS MG
5
5/24
6
5/30
7
6/02
8
6/03
1
9
6/09
4
10
6/11
2
11
6/14
TOTAL
BF - Boundary Facility sonde
CF - Central Facility sonde
*Lear - Dropsonde
Falcon - Dropsonde
* = “ BEST”
DC
AERI CARL DLR
1
7
2
3
2
1
1
3
4
1
3
1
2
1
3
2
5
SRL Total
2
3
3
5
1
3
12
3
17
4
2
4
1
8
8
6
1
22
*HS - Homestead sonde
*MG - MGLASS mobile sonde
DC - Dodge City sonde (VIZ)
AERI- at Homestead
8
8
7
3
9
24
18
77
CARL - Raman Lidar at CF
DLR - Lidar on Falcon
*SRL- Scanning Raman Lidar
at Homestead
LASE-Raman Lidar (RL) Comparisons (<20 km & <20 min)
Current Comparison
CART CF-RL
+
Homestead (HS)-SRL
Previous Comparison
LASE-Dropsonde Comparisons (<75 km & <75 min)
+
LASE-Balloonsonde Comparisons (<75 km & <75 min)
+
+
+
+
LASE-AERI Comparisons (<20 km & <20 min)
Previous Comparison
Latest Comparison
LASE-DLR DIAL Comparisons (<20 km & <20 min)
LASE-All Instruments Comparisons (<75 km & <75 min)
LASE-All Instruments Comparisons (<20 km & <20 min)
LASE-All Instrument Comparisons by Flight (<20 km & <20 min)
(“Best”: L-DS; H-RL; H-BS; MG-BS)
Summary
• Comparisons were possible on only 7 of 8 flights and Flight #5 (5/24) only
had 3 close comparisons.
• Most comparisons were within 50 min and 50 km although a few went to 75
min and 75 km. In all there were 158 comparison opportunities with less
than half of them (77) within 20 min and 20 km.
• Raman lidar (CARL & H-RL) comparisons were excellent (generally <5%).
• Lear dropsondes were in good agreement overall (<5%), but Falcon
dropsondes were consistently drier by ~8%.
• Reasonable overall agreement (<10%) with balloons, but large scatter on
individual comparisons.
• Excellent comparisons (<5%) with AERI.
• Average agreement with DLR (~10%) but few comparisons available.
• Comparisons with all instruments shows no systematic difference greater
than the 5% level.
• Some localized large differences in mid trop due to presence of very dry
layers that are difficult to measure with sondes.
• LASE water vapor data appear to be within <6% absolute accuracy.