1. LASE Measurements of Water Vapor During IHOP
Edward V. Browell,1 Syed Ismail,1 Richard A. Ferrare, 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

2. 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 = pm)
- Two separate line pairs
NASA ER-2, P-3, DC-8 aircraft
Simultaneous nadir, zenith operations
Real-time data analysis and display

3. 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.
to 25 g/kg
- accuracy: 6% or 0.01 g/kg
- resolution (variable)
vertical: 330 m
horizontal: 14 km (1 min)
Aerosol/cloud profiles
to 25 km
resolution (variable)
vertical: 30 m
horizontal: 200 m

4. 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.
to 25 g/kg
- accuracy: 6% or 0.01 g/kg
- resolution (variable)
vertical: 330 m
horizontal: 14 km (1 min)

5. 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.
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

6. LASE Measurements during IHOP
Participated in 8 IHOP science flights from May 23-June 14, 2002

7. LASE Water Vapor Comparisons
Nighttime
Daytime

8. LASE/IHOP 2002 ALL COMPARISONS (delta time < 75 min, delta location < 75 km)
RS RD RS80
Flight Date BF CF Lear Falcon HS MG DC AERI CARL DLR SRL Total 5
5/24 2 8 17 6
5/30 1 3 9 7
6/02 4 11
6/03 30
6/09 15 38 10
6/11 23
6/14 31
TOTAL 39 28 22 18
158
BF - Boundary Facility sonde HS - Homestead sonde CARL - Raman Lidar at CF
CF - Central Facility sonde MG - MGLASS mobile sonde DLR - Lidar on Falcon
Lear - Dropsonde DC - Dodge City sonde (VIZ) SRL- Scanning Raman Lidar
Falcon - Dropsonde AERI- at Homestead at Homestead

9. Flight Date BF CF Lear Falcon HS MG DC AERI CARL DLR SRL Total
LASE/IHOP 2002 CLOSEST COMPARISONS (delta time < 20 min, delta location < 20 km)
RS RD RS80
Flight Date BF CF Lear Falcon HS MG DC AERI CARL DLR SRL Total 5
5/24 1 2 3 6
5/30 8 7
6/02
6/03 4 12 9
6/09 17 10
6/11 11
6/14 24
TOTAL 22 18 77
BF - Boundary Facility sonde *HS - Homestead sonde CARL - Raman Lidar at CF
CF - Central Facility sonde *MG - MGLASS mobile sonde DLR - Lidar on Falcon
*Lear - Dropsonde DC - Dodge City sonde (VIZ) *SRL- Scanning Raman Lidar
Falcon - Dropsonde AERI- at Homestead at Homestead
* = “ BEST”

10. LASE-Raman Lidar (RL) Comparisons (<20 km & <20 min)
Current Comparison
CART CF-RL +
Homestead (HS)-SRL
Previous Comparison

11. LASE-Dropsonde Comparisons (<75 km & <75 min)+

12. LASE-Balloonsonde Comparisons (<75 km & <75 min)+ + + +

13. LASE-AERI Comparisons (<20 km & <20 min)
Previous Comparison
Latest Comparison

14. LASE-DLR DIAL Comparisons (<20 km & <20 min)

15. LASE-All Instruments Comparisons (<75 km & <75 min)

16. LASE-All Instrument Comparisons by Flight (<20 km & <20 min)
(“Best”: L-DS; H-RL; H-BS; MG-BS)

17. 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.