1. 1UNAVCO Science Workshop 2012 Junhong (June) Wang Earth Observing Laboratory National Center for Atmospheric Research, Boulder, CO Collaborators: Liangying (Liz) Zhang (NCAR/EOL), Aiguo Dai (NCAR/CGD), John Braun & Teresa Van Hove (UCAR/COSMIC), Steve Worley & Zaihua Ji (NCAR/CISL), Tong Ning & Gunnar Elgered (Chalmers University of Technology)

2. Gaffen et al. (1995) 2UNAVCO Science Workshop 2012

3. 3 GPSRadiosondeSatellite Availability all weatherDifficulty in thunderstorms IR: clear MW: ocean Temporal resolution High (5 min-2 hourly) 1-2/daily>12-hourly Temporal coverage ~17 years>50 years~30 years Spatial coverage ~1000 stations globe Accuracy High (< 3mm)Low, various, biasLow, depending on radiosonde Long-term stability StableSignificant temporal inhomogeneity Diurnal variation Climate extremes Diurnal variation Climate extremes Validations of other measurements Climate trends

4. 4UNAVCO Science Workshop 2012 Jan. 1995 to Dec. 2011 2 hourly (0100, 0300, …, 2300 UTC) 380 IGS, 169 SuomiNet, 1223 GEONET Accuracy: < 3 mm Ps, Tm, ZHD and ZWD also available http://dss.ucar.edu/datasets/ds721.1/ Wang et al. (2007)

5. 5UNAVCO Science Workshop 2012 The diurnal cycle is less than 5% of annual mean PW Larger magnitude in summer than in winter Peak around late afternoon to early evening An order of magnitude smaller than seasonal variation Globe S. H. N. H. Wang & Zhang (2009)

6. Europe30-70S N.H. MountainsDarwin region 6UNAVCO Science Workshop 2012

7. Vaisala RS92 Validating radiosonde data Before correction After correction Before correctionAfter correction GPS 7UNAVCO Science Workshop 2012

8. Diurnal Signal Feb vs Aug 2009 Braun et al. (2012 MWR) Lin et al. (2010)

9. 9UNAVCO Science Workshop 2012

10. 10UNAVCO Science Workshop 2012

11. Foster et al. 2003 Ka’ū storm, Big Island of HI, Nov. 1-2 2000; > 100mm/hr (~4”/hr) maximum hourly rain rate Most intense, widespread rain event in 20 years $70 M property damage Impacts on roads and other infrastructure for weeks afterward Using GPS PW data to predict rain rate and validate model results 11UNAVCO Science Workshop 2012

12. 12UNAVCO Science Workshop 2012 Mears et al. (2010) Mears et al. (2011)

13. 13UNAVCO Science Workshop 2012

14. 14UNAVCO Science Workshop 2012 El Nino La Nina Land Ocean Mears et al. (2012)

15. 15UNAVCO Science Workshop 2012 RegionsYearsTrendsComments Gradinarsky et al. (2002) Scandinavia (17) 1993-20000.1-0.2 mm/yrVariations with regions & seasons Jin et al. (2007) Globe (150)1994-2006~2 mm/d (15 mm/d. ZTD) Positive in N.H. Negative in S.H. Nilsson & Elgered (2008) Finland & Sweden 1996-2006-0.2 ~ 1 mm/dUncertainty in trend mainly due to PW natural vari.

16. 16UNAVCO Science Workshop 2012

17. 17UNAVCO Science Workshop 2012 ProductsPeriodAgenciesComments 2-hrly combined2/1997-11/2006GFZ 5-min PPP-IGS0010/2000 – 11/2006JPLrelative antenna phase model & IGS00 5-min PPP-IGS0511/2006 – 4/2011JPLAbsolute antenna phase model & IGS05 Reprocessed 5-min PPP 1/1995 – 4/2011JPLAbsolute antenna phase model & IGS05 USNO 5-min PPP4/2011 - presentUSNOIGS08 and other changes NCAR Data VersionPeriodZTD Products V1: non/before- reprocessed 2/1997-12/2010“2-hrly combined” “5-min PPP-IGS05” V2: Reprocessed1/1995 – 12/2011“Reprocessed 5-min PPP” “USNO 5-min PPP”

18. 18UNAVCO Science Workshop 2012

19. 19UNAVCO Science Workshop 2012

20. BRUS WSRT 20UNAVCO Science Workshop 2012

21. April 2011 21UNAVCO Science Workshop 2012

22. 2008 Annual PW at 252 stations 2008: 560 total; 308 not enough for annual mean Continuous data for 1997-2010: 70 22UNAVCO Science Workshop 2012

23. 23UNAVCO Science Workshop 2012  Provide long-term high-quality upper-air climate records  Constrain and calibrate data from more spatially-comprehensive global observing systems  Fully characterize the properties of the atmospheric column

24. 24UNAVCO Science Workshop 2012