1. SPARC WAVAS-2 activity chairs: Cornelius Schiller, Thomas Peter, Karen Rosenlof SPARC Newsletter January 2008 https://sparch2o.icg.kfa-juelich.de/SPARCH2O/

2. Timing Kick-off Bologna Sep 2008 Informal meeting Hawaii Oct 2008 Author meetingTorontoMar 2009 Planning meetingCorsicaSep 2009 Next steps: Open SPARC data baseend of 2009 Writing of chapters & papers Chapter meetingsspring/summer 2010 Reviewend of 2010 Report completedmid 2011

3. Chapter Outline 1.Introduction 2.Data Quality 3.Supersaturation 4.UTS climatology and trends 5.Synthesis

4. 2. Data quality (Schiller, Read) 2.1Introduction 2.2Listing and description of instruments, including list of missions 2.2.1UTLS in-situ instruments (Schiller) 2.2.2UTH instruments (NN) 2.2.3Satellites (Read) 2.2.4Remotes sensing ground-based (Schiller) 2.3Field intercomparions (Pfister, Schiller, Vömel, Weinstock, Herman, Khaykin) 2.4AquaVIT (Fahey, Gao, Möhler) Whitepaper/peer reviewed paper 2.5Validation and comparison of remote sensing data sets (Read) 2.6Derived quantities (2CH4+H2O, RHi, amplitudes …) 2.7Summary/Assessment (Schiller, Read, NN, Fahey, Möhler, Pfister)

5. Data selection Criterion contribution to trends, supersaturation, or major validation instrument need to deliver data to data base Supersaturation CFH, HW, JLH, FISH, FLASH, APICT (AquaVIT) satellite/MOZAIC PDFs Trends stratosphere: HALOE + MLS (UARS/AURA), LIMS, SAGE-2, MIPAS-E, SCIAMACHY, ODIN, ACE, NOAA frostpoints, WVMS, MIPAS-B, MK-IV UTH: HIRS, SAGE-2, MLS, IASI, AIRS, LIDAR, MOZAIC, radio sondes, DLH SPARC WAVAS 2000

6. Courtesy of Holger Vömel Atmospheric Water Vapor Intercomparison HW - CFH 6 TC-4: tropics in Aug. 2007 1993-2007

7. AquaVIT2007: Core Instrument Accuracy 7 AquaVIT whitepaper, published https://aquavit.icg.kfa-juelich.de/AquaVit/

8. AquaVIT results and recommendations AquaVIT Findings For 1-10 ppm, average deviations from reference within about ±10% Absolute standard for multi-instrument calibration not yet developed, but APicT promising candidate Differences between CFH and HWV are smaller than in field observations SPARC Create a master intercomparison dataset of co-located insitu observations: aircraft, balloon, satellite Document AquaVIT results in the SPARC assessment report Community Conduct further coordinated intercomparisons of insitu measurements (< 20 ppm) on respective platforms Develop in-flight performance criteria for insitu instruments regarding precision and accuracy limits and stability by Dave Fahey, Rushan Gao, Ottmar Möhler

9. 3.1Introduction (Peter, Koop, Gierens) 3.2Basic concepts of microphysics (Baker, Peter, Krämer) 3.3Cloud-scale coupled dynamics/microphysics (Spichtinger, Gierens, Jensen/Pfister, Murphy, Peter) 3.4Laboratory studies of ice nucleation and growth (Murray, Möhler, Koop, Ebert, Saathoff) 3.5Summary of field observations of relative humidity (Smith/Weinstock, Krämer/ Schiller, Troy/Herman, Khaykin, Vömel, Moyer, Fahey/Gao, Spichtinger/Gierens) 3.6Critical discussion of mechanisms leading to supersaturation (all) 3.7Implications of supersaturation (Kärcher, Forster, Gierens) 3.8Conclusions (all) 3.9Open issues: Recommendations for future work (all) review paper 3. Supersaturation (Peter, Koop)

10. Super- saturation puzzle – where we started 3 years ago SPARC workshop Karlsruhe 2007

11. Reanalysed data: How much evidence for unexplained data remains? clear sky inside clouds Krämer et al., 2009 FISH/FLASH revisited CFH revisited Re-analysis of JLH data in progress HU has no evidence for changes so far – remains the only striking data set?

12. Microphysics Low numbers of ice crystals - observed Low surface areas and therefore slow uptake of water Possible explanation for in cloud high humidity Why are there low numbers? Lab measurements: strong differences in behaviour below 200 K: Cubic ice forms and persists Accommodation coefficient changes Glass forms (inorganic particles) Vapour pressure measurements show abrupt scatter Dynamics on cloud scale Might be selective to favour only few particles to grow E.g. large-scale updraught with high-frequency short waves

13. 4.UTS climatology and trends (Rosenlof, Oltmans, NN) 4.1Introduction 4.2Upper tropospheric water (Oltmans, PIs of instruments involved) 4.2.1Initial description of data used in this chapter 4.2.2Distribution (2 and 3D, and also PDFs... relation to clouds) 4.2.3Periodic cycles (annual, ENSO, maybe QBO) 4.2.4Trend capabilities 4.2.5Discussion of measurement needs 4.3Stratospheric water (Rosenlof, Oltmans, PIs of instruments involved) 4.3.1Discussion on how to best construct climatology combining multiple data sets, or whether data quality assessments (chapter 2) indicate that it shouldn't be done at all 4.3.2Distribution 4.3.2Periodic cycles 4.3.3Trends (and trend capabilities with a combined data set) 4.3.4Discussion of measurement needs (maybe) 4.4Summary and recommendations review paper

14. Trends before and after 2000

15. Water vapour / 30°S to 30°N / 25-35 km SAGE Odin/SMR HALOE Aura/MLS H2O anomaly [%] Ashley Jones - Chalmers [ACPD-2009] 1984-2008 - deseasonalized and combined data sets

16. (In)consistencies between data sets What is the optimum time to publish WAVAS-2? - New retrievals (e.g. MLS/AURA, HALOE) and new data (e.g. ACE, SCIAMACHY) - Extension of data records (new satellites, after 2000 break)

17. 68 mb Update of WAVAS 2000 figures?

18. UTH < 100 ppmv Problems: Large variability Large gradient Instrument accuracy

19. 5. Synthesis (tbd) 5.1Processes (Fueglistaler) 5.2Radiation impact of changing H 2 O (Harries, Fu) 5.3Projections and link to CCMVal (Gettelman)

20. Timing Kick-off Bologna Sep 2008 Informal meeting Hawaii Oct 2008 Author meetingTorontoMar 2009 Planning meetingCorsicaSep 2009 Next steps: Open SPARC data baseend of 2009 Writing of chapters & papers Chapter meetingsspring/summer 2010 Reviewend of 2010 Report completedmid 2011