1 / 34

Monitoring Atmospheric Humidity from Commercial Aircraft by MOZAIC-IAGOS:

Monitoring Atmospheric Humidity from Commercial Aircraft by MOZAIC-IAGOS: In-sights from the Past and Present into the Future Herman G. J. Smit ( h.smit@fz-juelich.de ) Forschungszentrum Juelich (ICG-2). Past and Present: MOZAIC. Humidity Sampling. Quality Assurance & Synergy of Data.

terry
Télécharger la présentation

Monitoring Atmospheric Humidity from Commercial Aircraft by MOZAIC-IAGOS:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Monitoring Atmospheric Humidity from Commercial Aircraft by MOZAIC-IAGOS: In-sights from the Past and Present into the Future Herman G. J. Smit (h.smit@fz-juelich.de) Forschungszentrum Juelich (ICG-2) Past and Present: MOZAIC Humidity Sampling Quality Assurance & Synergy of Data Future: IAGOS H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  2. Why Monitoring Humidity in Upper Troposphere ?? Doubling CO2-concentration: 2-5oC Temperature increase 1/3-part: direct via CO2 2/3-part: via positive feedback of water vapor+clouds Upper troposphere most sensitive region in climate change H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  3. Routine Aircraft Measurements in the Global Observing System: The Link Between Surface and Space H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  4. MOZAIC: Humidity Sampling H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  5. MOZAIC: Humidity Sensor in Rosemount Air Inlet System SAT RHS TAT, RHD • In inlet speed reduction (Mach0.8 to 0) with adiabatic conversion: ► Heating (SAT to TAT) : in UT  30oC • ► Compression (PS to PD): in UT  Factor 1.6 • RH at detector (RHD) << RH sampled air (RHS) • ►At cruise altitude RHS 13 x RHD Rosemount Housing Total Temperature Model 102 BX H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  6. In: Helten et al., J.Geophys.Res., 1998 MOZAIC-Humidity Device: Pre-&Post Flight Calibration • Regular calibration (every 500 flight hours) • In environmental simulation chamber • Against Lyman()-fluorescence hygrometer • Under realistic flight conditions of humidity, temperature and pressure • Evaluation of two year record of pre- and post-flight calibrations • Results agree well with in-flight intercomparisons [Helten et al. Geophys.Res.1998, 1999] H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  7. MOZAIC Relative Humidity in Upper Troposphere (UT) over Atlantic % • MOZAIC provided the first • climatology of humidity in the UT • Large variability in time and • space • More than 30% of UTH-data • are Ice Super Saturated (ISS) • But less than 0.5-1% of data • are Saturated to Liquid • Long Term Changes ?? • Control of Humidity in UT?? H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  8. MOZAIC Critical aspects on inlet system • Separation solid / gas phase • Particle enhancement • Evaporation droplets & crystals • Wall memory effects • Well defined P & T (cq. SH & RH)-conditions Ice Super Saturation over North Atlantic: • More than 35% of UTH ice super saturated • But less than 1% of observations are saturated to liquid H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  9. Performance MOZAIC Humidity Device in Clouds Evaporation of Ice Crystals ??????? • Clouds are clearly detected as „RHI-burst“ to 200% by the Lyman ()-Total H2O • In clouds the MOZAIC-Humidity Device not exceeding 100% RHI H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  10. MOZAIC: Ice Super Saturation (ISS) in the UT Horizontal extent of ISS regions • 30% of the UT shows ice super saturation (ISS) • Global models do not reproduce ISS • ISS relates with sub-visible cirrus • Small scale phenomenon(X < 200 km, Z < 1-2 km) • Difficult to see by satellites • Importance: contrail & cirrus formation; • radiative balance; OH formation H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  11. AIRS MOZAIC 100 120 80 20 40 60 0 RH (liq.%) -100 50 -50 0 100 AIRS - MOZAIC RH (liq.%) MOZAIC- UTH: Comparison with AIRS-Satellite over 2003 (Work by Co PI: Andrew Gettelman, NCAR, Boulder, USA) • Development of proper „matching“ citeria of coincidence in space and time: • A priori estimation of contribution of natural variability • Direct comparison at (x,y,z,t) • Indirect by optimizing statistics of coincidence by using backward trajectories H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  12. Spec. Hum. Temp. Rel. Hum. Involvment Temperature Measurements Using TAT-Housings: Comparison Temperature Aircraft versus MOZAIC In addition, important aspect at low temperatures: Which H2O-saturation pressure Es(T)-table has been applied ??? H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  13. Development of Automatic In-flight Calibration (IFC) • Based on the technology and experience obtained • during 8 years of MOZAIC-operation. • Long-term zero drift of MOZAIC-device, particularly • at low temperatures, is the critical and accuracy • determining parameter • On-line determination of long term zero drift during • dry stratospheric episodes (5ppmv water vapor) as a • function of temperature. • On-Line correction of zero drift of RH-measurements H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  14. MOZAIC In-Flight Calibration (IFC): Validation In-flight comparison during SPURT with Ly()-Hygrometer (FISH) Comparison with MOZAIC IFC RH(IFC) – RH (MOZAIC) [%RH] H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  15. AMDAR Designed for automatic on-line sampling of humidity from aircraft for weather forecasting Diode laser (2f-detection) Compact ( 2.5 kg) Can new airborne WVSS-II measure humidity in UT and LS?: State of the Art • US-NWS has installed on 25 UPS aircraft since 2005 , now in evaluation phase but with plans to extend to large number • Poor documentation on evaluation of performance • FZJ has evaluated in the laboratory in 2005 • DWD has installed on three A320 of Lufthansa since 2007 • In the loop: plans to install on a MOZAIC/IAGOS A340 of Lufthansa ? Goal NWS: Reduce radiosounding network and replace by AMDAR H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  16. Compact Sensors for Measuring Humidity on In-Service Aircraft H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  17. AMDAR = Aircraft Meteorological DAta Relay Aboard Commercial Aircraft For Weather Forecasting Reports: • Aircraft Identification • Date • Time (UTC) • Position • Altitude (Pressure) • Temperature • Windspeed • Wind Direction • Planned: Water Vapor Mass Mixing Ratio H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  18. Can new airborne WVSS-II measure humidity in UT and LS???: Performance tests at Environmental Simulation Facility at Jülich, Germany AMDAR Designed for automatic on-line sampling of humidity from aircraft for weather forecasting Diode laser (2f-detection) Compact ( 2.5 kg) • WVSS at Frostpoint Temperatures: • Above ~290 K: No reliable signal • 225 K – 290 K: Good performance: • Accuracy ±(5-10)% • 215 K – 225 K: Rapid declining sensitivity, • Limited accuracy: <±(10-15)% • Below ~ 215 K: Below detection limit (80 ppmv) • Poor performance in UT/LS H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  19. MOZAIC/IAGOS: Summary QA-H2O/T Performance • Pre-and Post flight calibration every 500 flight hours) [Helten et al. 1998] • In-flight comparisons (In-service & Research) [Helten et al., 1999] • Evaluation in SPARC-water vapor assessment 2000 report • Development in-flight calibration (IFC) method [Smit et al., 2008] • Evaluation of detection of ice superation saturation [in-preparation] • Assessment of performance of 12 years of MOZAIC-flight operation [in preparation] • 12 year Climatology of MOZAIC-H2O/T data available in MOZAIC-data base at Toulouse • Participating in COST-action WaVaCS (Watewr Vapor in the Climate System) • Participating in new, second SPARC water vapor assessment • New instruments are under investigations. H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  20. H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  21. Extra Material H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  22. ECMWF Model Now With Ice Super-Saturation Tompkins, Gierens, Rädel, Quart.J.Roy.Met.Soc, 2007 H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  23. MOZAIC: Comparison Temperature Aircraft versus MOZAIC] • Both measured with Rosemount TAT • Assumption full adiabatic conversion: • Measurement of TAT (σ=±0.25K) • Determination M from TAP (σ=±0.25hPa) • & SAP (σ=±0.35hPa) • Determination SAT (σ=±0.50K) • Practice: • TAT-recovery only 99.5-99.7% • Correction tables based on wind duct • measurements (made in 1960/1970‘s) • Dependece on angle of attack • Dependence on location at aircraft skin • Remaining sources of uncertainties =0.2 TAT = Total Air Temperature SAT = Static Air Temperature TAP = Total Air Pressure SAT = Static Air Pressure H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  24. Outstanding Issues UTH-ISS Observations • Rosemount-TAT inlet systems: • No indication of evaporation of ice crystals • Evaporation of liquid droplets • Large temperature sensitivity of H2O-saturation: • Review of water vapor saturation tables at low temperatures • Temperature measurement needs more attention: • Adiabatic recovery factor • Location at aircraft • Comparison with other in-situ temperature sensing technics • Scale analysis of spatial and temporal distribution of ISS • Climate impact of ISS H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  25. In: Helten et al., J.Geophys.Res., 1998 MOZAIC Humidity Device: Performance and Quality Assurance RHCAL (Ti) =a (Ti)+b (Ti) x RHUNCAL (Ti) • Calibration procedure: • Pre-flight calibration: a1(Ti) & b1(Ti) • - Installation in A340 • - 500 h of flight operation • - Exchange of MHD • 2. Post-flight calibration: a2(Ti) & b2(Ti) • - Cleaning RH- & T-sensor • Pre-flight calibration • - Etc. etc. • Uncertainty of RH is derived from: • Difference between pre-and post • flight calibration of RH • Uncertainty Temperature • Evaluation of two year record of pre- and post-flight calibrations • Results agree well with in-flight inter comparisons[Helten et al., J.Geophys.Res.1999] H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  26. MOZAIC-Humidity: In-Flight Comparison with Frost Point Hygrometer (Ovarlaz) on Falcon (DLR/Nov.1997) [Helten et al., J.Geophys.Res.1999] H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  27. 400 Slope = 0.98 (r=0.70) Offset= 3.6 ppmv 300 200 MOZAIC-UTH (ppmv) 100 0 100 300 400 200 POEM-UTH (ppmv) Coincidence criterion: 2.5º x 2.5º x 1 km x 6 h Total: 200 Coincidences April 1998-Feb.2000 MOZAIC-UTH: Comparison with POEM III Satellite • POEM III= Polar Ozone and Aerosol Measurement III satellite operational since April 1998 • Good agreement POEM with MOZAIC (Slope=0.98) • Large variations due to • Atmospheric variability & • Limited resolution of POEM (X=250 km) Source: Nedoluha et al., POAM III measurements of water vapor in the upper troposphere and lower most stratosphere, J. Geophys. Res., 2002 H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  28. MOZAIC-UTH: Comparison with MLS/UARS Satellite • MLS observe no ice super saturation (retrieval and/or limited horizontal resolution) • MLS lower than MOZAIC (Slope=0.64) • Large variations due to • Atmospheric variability & • Limited resolution of POEM (Z=4-5 km) Source: Read et al., UARS Microwave Limb Sounder upper tropospheric humidity measurement: Method and validation, J. Geophys. Res., 2001 Coincidence criterion: 1º x 1º x 1 km x 3 h Total: 384 Coincidences Aug.1994-Dec.1997 H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  29. MOZAIC: Distribution Relative Humidity in UT over Atlantic Z = 9-12 km, PV  2.0pvu, 10oW-70oW, Aug 1994 - June 2000 38% ISS 22% ISS 15% ISS 15% ISS H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  30. Performance MOZAIC Humidity Device & ISS: Artifacts due to Evaporation of Ice Crystals ??????? H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  31. MOZAIC-IFC: In-Flight Correction of Zero Drift of RH-measurements H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  32. Operational Aspects of MOZAIC-Humidity Device From Board Commercial Aircraft Every 6 months cleaning sensor at airport: rins with destilled water (1 min) rins with alcohol ( 1min) heat out (1 min @ ~90oC) Every 2 year overal check at service company: exchange humidity device and send to service company overall check of device (new sensors, calibration etc.). Outlook: automatic cleaning procedure at airport collaborations with companies for instrumental and QA support (e.g.Vaisala) H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  33. IAGOS-ERI: Time Table • 4/2008 IAGOS Design Study completed, - Prototypes available, - Partner airlines committed • 2008 First aircraft equipped and commissioned: O3, CO, H2O, Cloud Droplet Probe, NOy • 2009 Certification for CO2 and aerosol • 2016 20 aircraft equipped and commissioned • 2028 20 years of data available ~ 150 000 flights http://www.fz-juelich.de/icg/icg-ii/iagos Coordinator: Dr. Andreas Volz-Thomas E-mail: A.Volz-Thomas@fz-juelich.de H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

  34. WVSS-II Candidates for Automatic Monitoring Humidity by Commercial Aircraft H2O from MOZAIC-IAGOS // Herman Smit/FZJ ISSI-H2O Bern 11-14 Feb.2008

More Related