SPARC WAVAS-2 activity

chairs: Cornelius Schiller, Thomas Peter, Karen Rosenlof

SPARC Newsletter January 2008

https://sparch2o.icg.kfa-juelich.de/SPARCH2O/

Timing

Kick-off Bologna Sep 2008Informal meeting Hawaii Oct 2008Author meeting Toronto Mar 2009Planning meeting Corsica Sep 2009

Next steps:Open SPARC data base end of 2009Writing of chapters & papersChapter meetings spring/summer

2010Review end of 2010Report completed mid 2011

Chapter Outline

1. Introduction

2. Data Quality

3. Supersaturation

4. UTS climatology and trends

5. Synthesis

2. Data quality (Schiller, Read)

2.1 Introduction

2.2 Listing and description of instruments, including list of missions2.2.1 UTLS in-situ instruments (Schiller)2.2.2 UTH instruments (NN)2.2.3 Satellites (Read)2.2.4 Remotes sensing ground-based (Schiller)

2.3 Field intercomparions (Pfister, Schiller, Vömel, Weinstock, Herman, Khaykin)

2.4 AquaVIT (Fahey, Gao, Möhler)Whitepaper/peer reviewed paper

2.5 Validation and comparison of remote sensing data sets (Read)

2.6 Derived quantities (2CH4+H2O, RHi, amplitudes …)

2.7 Summary/Assessment (Schiller, Read, NN, Fahey, Möhler, Pfister)

Data selection

Criterioncontribution to trends, supersaturation, or major validation instrumentneed to deliver data to data base

SupersaturationCFH, HW, JLH, FISH, FLASH, APICT (AquaVIT)satellite/MOZAIC PDFs

Trendsstratosphere: HALOE + MLS (UARS/AURA), LIMS, SAGE-2, MIPAS-E, SCIAMACHY, ODIN, ACE, NOAA frostpoints, WVMS, MIPAS-B, MK-IVUTH: HIRS, SAGE-2, MLS, IASI, AIRS, LIDAR, MOZAIC, radio sondes, DLH

SPARC WAVAS 2000

Courtesy of Holger Vömel

Atmospheric Water Vapor Intercomparison

HW - CFH

6

TC-4: tropics in Aug. 2007

1993-2007

AquaVIT2007: Core Instrument Accuracy

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

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

3.1 Introduction (Peter, Koop, Gierens)3.2 Basic concepts of microphysics (Baker, Peter, Krämer)3.3 Cloud-scale coupled dynamics/microphysics (Spichtinger,

Gierens, Jensen/Pfister, Murphy, Peter)3.4 Laboratory studies of ice nucleation and growth (Murray, Möhler,

Koop, Ebert, Saathoff)3.5 Summary of field observations of relative humidity

(Smith/Weinstock, Krämer/ Schiller, Troy/Herman, Khaykin, Vömel, Moyer, Fahey/Gao, Spichtinger/Gierens)

3.6 Critical discussion of mechanisms leading to supersaturation (all)3.7 Implications of supersaturation (Kärcher, Forster, Gierens)3.8 Conclusions (all)3.9 Open issues: Recommendations for future work (all)

review paper

3. Supersaturation (Peter, Koop)

Super-saturation puzzle – where we started 3 years ago

SPARC workshop Karlsruhe 2007

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?

Microphysics

• Low numbers of ice crystals - observedLow surface areas and therefore slow uptake of waterPossible explanation for in cloud high humidityWhy are there low numbers?

• Lab measurements: strong differences in behaviour below 200 K:Cubic ice forms and persistsAccommodation coefficient changesGlass forms (inorganic particles)Vapour pressure measurements show abrupt scatter

• Dynamics on cloud scaleMight be selective to favour only few particles to growE.g. large-scale updraught with high-frequency short waves

4. UTS climatology and trends (Rosenlof, Oltmans, NN)

4.1 Introduction

4.2 Upper tropospheric water (Oltmans, PIs of instruments involved)4.2.1 Initial description of data used in this chapter4.2.2 Distribution (2 and 3D, and also PDFs ... relation to clouds)4.2.3 Periodic cycles (annual, ENSO, maybe QBO) 4.2.4 Trend capabilities4.2.5 Discussion of measurement needs 4.3 Stratospheric water (Rosenlof, Oltmans, PIs of instruments involved)4.3.1 Discussion 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

4.3.2 Distribution4.3.2 Periodic cycles4.3.3 Trends (and trend capabilities with a combined data set)4.3.4 Discussion of measurement needs (maybe)

4.4 Summary and recommendations

review paper

Trends before and after 2000

Water vapour / 30°S to 30°N / 25-35 km

SAGE

Odin/SMR

HALOE

Aura/MLS

H2

O a

no

ma

ly

[%]

Ashley Jones - Chalmers [ACPD-2009]

1984-2008 - deseasonalized and combined data sets

(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)

68 mb

Update of WAVAS 2000 figures?

UTH < 100 ppmvProblems:Large variabilityLarge gradientInstrument accuracy

5. Synthesis (tbd)

5.1 Processes (Fueglistaler)

5.2 Radiation impact of changing H2O (Harries, Fu)

5.3 Projections and link to CCMVal (Gettelman)

Timing

Kick-off Bologna Sep 2008Informal meeting Hawaii Oct 2008Author meeting Toronto Mar 2009Planning meeting Corsica Sep 2009

Next steps:Open SPARC data base end of 2009Writing of chapters & papersChapter meetings spring/summer

2010Review end of 2010Report completed mid 2011