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DLR-DIAL Observations

DLR-DIAL Observations. Instrument PI: Gerhard Ehret Instrument operation: Gorazd Poberaj, Andreas Fix, Martin Wirth Data processing: Christoph Kiemle and Harald Flentje Dropsonde operation: Reinhold Busen

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DLR-DIAL Observations

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  1. DLR-DIAL Observations Instrument PI: Gerhard Ehret Instrument operation:Gorazd Poberaj, Andreas Fix, Martin Wirth Data processing:Christoph Kiemle and Harald Flentje Dropsonde operation:Reinhold Busen Institute for Atmospheric Physics, DLR Oberpfaffenhofen,Germany Falcon operation PI:Heinz Finkenzeller Falcon in-situ data:Andreas Giez, Martin Zöger Flight facility, DLR Oberpfaffenhofen,Germany Co-operation: Mike Hardesty, NOAA ETL, Ken Davis, PSU, V. Wulfmeyer, Uni Hohenheim

  2. Topics • Research objectives • Falcon instrumentation • DLR H2O-DIAL • DIAL data from BL and CI missions • Preliminary statistical analysis of BL data • Data overview • Conclusion and next steps

  3. Research Objectives • detailed structure of BL water vapour budgets • and depth as well as its evolution • moisture pooling (moist plume structures) along • mesoscale boundaries and convective initiation • answer the question: • can remote sensing instrumentation on aircraft • platforms provide flux divergence?

  4. Falcon Instrumentation wind,TAS T,p,q DIAL Dropsondes HRDL Novelty: Co-located Doppler wind Lidar and H2O-DIAL on the Falcon • DLR H2O-DIAL • - 2-d H2O cross section • - 2-d aerosol cross section • - 2-d depolarisation • NOAAHRDL • - 2-d vertical wind • - horizontal wind information • - 2-d aerosol cross section • Dropsondes • - p,T,q, wind • In-situ • - p,T,q, wind Falcon flight performance

  5. Measurementquantity • Wavelength (nm) • Repetition (Hz) • Energy (mJ) • Availability • H2O mixing ratio • 925(on/off-line) • 50 (on/off) • 18 • yes • Aerosol backscatter • 925 (off-line) • 1064* • 532* • 50 • 100 • 100 • 18 • 50 • 40 • yes • yes • no DLR's H2O-DIAL on the Falcon Selected parameter for IHOP * detection of s- and p-polarized backscatter DLR H2O-DIAL with nadir viewing telescope aboard the Falcon Performance (H2O) boundary layer: z = 250m, x = 250m, range: full depth of PBL, rms ~ 5% free troposphere: z = 300m, x = 300m, range: 5 km, rms ~ 5% bias ~ 5%

  6. ppmv H2O mixing ratio [ppmv] 6 10 9 Altitude [km] 8 60 Dropsonde release 7 6 600 5 0 50 100 150 200 250 300 200 Distance [km] 11 Dropsonde 11 Dropsonde 10 10 DIAL DIAL 9 9 Altitude [km] 8 8 7 7 6 6 5 5 0 20 40 60 80 100 0 100 200 300 H2O mixing ratio [ppmv] H2O-DIAL Validation in Troposphere H2O_DIAL validation during MAP 1999 Poberaj G., Fix A., Assion A., Wirth M., Kiemle C., and Ehret G.: All-Solid-State Airborne DIAL for Water Vapour Measurements in the Tropopause Region: System Description and Assessment of Accuracy Appl. Phys. B 75, 165-172, 2002

  7. H2O DIAL Validation in the low troposphere during IHOP

  8. BLH, 17 May (39.5,100.3°) Homestead (36.5°,100.6°) (39.5,100.3°) OKC Homestead north-south direction from (39.5°,100.3°) to homestead: homogeneous moisture distribution, thermals clearly visible in moisture and aerosol cross sections west-east direction from homestead to OKC: strongly decreasing PBL depth while increasing moisture content Homestead OKC

  9. BLH, 21 May (37.4°,97.5°) homestead (36.8°,97.5°) (35.4°,99.7°) homestead South west area (35.4°,99.7°)-homestead: strongly structured BL top, thermals clearly visible in WV cross section, near homestead moist layer above BL top North east area (37.4°,97.5°) - (36.8°,97.5°): smooth PBL top, no turbulence elements visible, very thin and dry layer close above PBL top

  10. Spatial resolution example (BLH, 06 June) (37°,102°) (37°,101°) Data smoothing:  x = 70m (0.5s)  z = 100m - 300m rms (H2O) = 7% BL turbulence structure very well resolved in both cross sections

  11. 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Preliminary Spectral Analysis Autocovariance of H2O time series ~5/3 H2O spectrum at 2.5 km H2O spectrum at 1.8 km Instrumental noise H2O-Variance profile km asl. 3.0 2.5 2.0 2 water vapor variance profile (g/kg) uncorr. stat. err. variance (dashed)

  12. CI-Mission, 24 Mai 2002 WV cross section along broken cloud field Sharp horizontal and vertical WV gradient across dry line

  13. CI-Mission, 15 June Moist plume Lifting BL, convection initiation

  14. Water Vapor DIAL Data Overview • From a total of 21 flights (75h), 52 hours of lidar data were collected: • BL heterogeneity: 11 flights for a total of 26 h 4 min. • BL evolution: 2 flights for a total of 3 h 29 min. • Convective Initiation: 4 flights for a total of 12 h 31 min. • Low-level-jet: 4 flights for a total of 7 h 39 min. • Quality of H2O-Data • 9 flights are of high quality and 4 flights of moderate quality: • BL heterogeneity: 17, 21, 28 and 29 May20 and 25 May • BL evolution: 14 June14 June (2nd flight) • Convective Initiation: 24 May, 2 and 15 June • Low-level-jet: 9 June3 June (1st flight) All lidar data are of high quality with respect to aerosol backscatter

  15. Conclusion • large set of water vapor and aerosol data acquired during IHOP • the measured data contains detailed information on BL water • vapor budget, depth, heterogeneity, evolution as well as • convective initiation • the very high temporal resolution (0.5-2s) of the H2O-cross • section is one of the most remarkable characteristics of the • DIAL measurements • H2O-DIAL fulfils the measurement requirements • for flux divergence determination from airborne platform • DIAL profiles show very good agreement to dropsonde data

  16. Next steps • completion of data processing • data intercomparison to other sensors in the field • determination of entrainment flux as well as flux divergence • Current collaborations: • Flux divergence, M. Hardesty, NOAA, ETL • Sensor intercomparison V. Wulfmeyer, University of Hohenheim • ABL statistics, Ken Davis, Penn State • Bore analysis LLJ, Steve Koch, NOAA, FSL

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