Bojan R. Bojkov et al. NASA GSFC/SSAI. Atmospheric Science Conference 8-12 May, ESA ESRIN Frascati

Transcription

1 Bojan R. Bojkov et al. NASA GSFC/SSAI

2 Outline Background of SAUNA total ozone intercomparison Campaign overview» Host facilities» Participants» Instrumentation» March/April 2006 Preliminary results» Groundbased data» Satellite TOZ comparison

3 Background Most groundbased total ozone intercomparisons are performed at mid-latitude and column amounts of ~300DU» Agreement is usually of the order of about 3% Instrument-instrument performance show significant differences under conditions of low-sun and high ozone column amounts» ~5% differences, up to 10% in winter Satellite-groundbased differences 5-10% under these conditions» Satellite performance thought to be good to SZA ~80 o Satellite-satellite differences of the order of 5-10% persist

4 Groundbased differences Comparison of extremely well calibrated instruments, such as the 22 year Dobson-Brewer record at Hohenpeissenberg Diff. within 3% After effective height and T corrections, diff. <2% Delta rel D104-BR10 in % DeltaD104-BR010ori DeltaTeffCorr_new DeltaTeff_newMueCorr Linear (DeltaD104-BR10ori) Linear (DeltaTeff_newMueCorr) Year Courtesy: U. Koehler (DWD)

5 Satellite differences GOME GDOAS vs. EP-TOMS V8 for 1997 Differences of +/- 3% for mid latitudes, particularly during late-fall and Winter 5-8% differences at high lat., for high SZA and high TOZ Different crossing times:» ERS-2 ~10:00 desc.» EP ~ 12:00 asc. ESA, 2002

6 Driving issue: Why do total column ozone measurements from groundbased and satellite instruments and their respective retrieval algorithms continue to differ at mid and high latitudes, and where large solar zenith angles and high total ozone amounts are typical?

7 SAUNA campaign Organized by NASA, FMI and ESA» Follow on to the 2001 TOMS3F campaign in Alaska Hosted by the Finnish Meteorological Institute Arctic Research Center at Sodankyla, Finland FMI-ARC is a fully operational long-term site» 20 year grounbased and balloons ozone records» Ancillary data collections» Satellite receiving station (Aura OMI VFD) ~120km north of Arctic circle (67.37N, 26.63E) Boreal climate, Arctic atmosphere

8 Campaign participants 30+ Scientists from 10 Institutions and 9 Countries: NASA-GSFC (USA), FMI-ARC (Finland), ESA-ESRIN (Italy), BIRA-IASB (Belgium), CNRS-SA (France), DWD-MOHp (Germany), INM-Izana (Spain), KNMI (Netherlands), MSC (Canada), NOAA-ERL-GMD (USA) Funding/Sponsors:» NASA-HQ, FMI, and ESA» EOS-Aura Project Science Office» National contributions from Canada, France and Spain

9 Campaign instruments Instrument Principal Investigator Affiliation Brewer (single monochromator at FMI-ARC) E. Kyrö FMI-ARC (Finland) Brewer: 1 single (World standard), 1 double Brewer: double Brewer: 1 double (European Standard) Dobson (Traveling standard) Dobson (European standard) DOASs: 1 UV, 1 vis, 1 minidoas minidoas SAOZ (permanently located at FMI-ARC) STROZ-Lite LIDAR (NDSC standard) Ozonesondes T. McElroy A. Cede/R. McPeters A. Redondas/E. Cuevas R. Evans U. Koehler M. van Roozendael E. Brinksma F. Goutail T. McGee R. Kivi B.R. Bojkov E. Brinksma MSC (Canada) NASA GSFC (USA) INM-Izana (Spain) NOAA-ERL/GMD (USA) DWD-MOHp (Germany) BIRA-IASB (Belgium) KNMI (Netherlands) CNRS-SA (France) NASA-GSFC (USA) FMI-ARC (Finland) NASA-GSFC (USA) KNMI (Netherlands)

10 FMI-ARC facilities during SAUNA Campaign instruments NASA LIDAR Sounding station Dobsons Tower with minidoass

11 March 26-April 13, 2006 OMI ozone March 26, 2006 X March/April did provide:» Total ozone columns in the range 400DU to ~520DU» High variability/strong gradients» hour measurement days» Minimum solar zenith angle of 65 degrees» 75% clear sky (12 of 18 good days!) Up to 3 overpasses for swath instruments

12 Brewers ~100 coincident (<30s) clear day 5 instrument measurements» Measurement range: DU» Slant column range: DU» 0.5% accuracy and 0.3% precision (combined dataset) Result: stray light corrections for single Brewers» Single shows ~1% error at 1000DU slant column and ~5% error at 2000DU» Correction for measurements when slant column > 900DU» Useful for satellite validation 8-12 May, Photo: E. ESA Brinksma, ESRIN Frascati KNMI

13 Brewers: March differences attributed to stray light of single Brewers T. McElroy and V. Savastiouk, MSC

14 Dobsons results Measurements:» 3 very good days, 3 decent days and 6 partial days» More data than seen than at most Dobson intercomparisons Achieved all high-latitude measurements goals» Extended schedules» AD, CD, CDFI pairs, plus zenith sky Two Dobsons in good agreement throughout campaign» AD pair is ~2.9% below Brewers» CD pair ~2.5% below Brewers

15 R. Evans, NOAA

16 Ozonesondes 30 soundings (+ ~5 additional to early May):» Coincident with Aura and Envisat instrument overpasses» 27 single instrument soundings» 2 double sounding with agreement better than 2% in stratosphere» 1 ozonesonde + NOAA CFH sounding 34.3 km average burst height 426.7DU < TOZ < 500.8DU <2% groundbased column agreement

17 Ozone layer variability Ozone Partial Pressure [mpa] mid-lat. intrusion Trop. folding T. Turunen, FMI

18 SAOZ-DOAS(vis) Daily twilight measurements by both instruments types» Zenith-sky observations» All weather measurement capability Different optical path as Dobson/Brewer:» Due to measurement time differences» Measurement is at a different geolocation than instrument (up to 600km away)» Time/geolocation very for comparison, especially when large gradients present Retrievals and intercomparisons ongoing

19 LIDAR Measurements:» 4 full nights (3/28, 3/29, 3/30 and 4/7), 2 partial night (4/2, 4/10) Satellite coincidences (to be investigated)» 4 Aura overpasses including 2 TES SO (3/29, 3/31)» 5 HIRLDS coincidences (late evening) Ozonesonde coincidences» 2 single (3/29, 3/31) and 1 double sounding (4/7) Data is being evaluated» GSFC LIDAR team on deployment since January 28 06

20 Satellite comparisons Satellite products by FMI, BIRA-IASB, KNMI, NASA» Total column and profiles Initial comparisons of:» Groundbased vs. OMTO3, OMDOA3, SDOAS, TOSOMI» Investigations of clouds, reflectivity, SZA, TOZ effects Very preliminary!

21 Preliminary TOZ comparisons OMI TOMS, OMI DOAS and SDOAS Typical results during SAUNA Comparison for the Aura period (OMI DOAS and SDOAS are provisionally released data)

22 Satellite profile comparisons Comparison to be performed with LIDAR and sonde data 4 AURA instr.» Focus on TES and HIRDLS G. Osterman, JPL ENVISAT» GOMOS, MIPAS and Sciamachy NOAA SBUV/2s

23 Conclusions Exceptional efforts and organization by all SAUNA teams, and in particular the local hosts at FMI-ARC Very interesting preliminary results» Single Brewer stray-light correction» Spatial (optical path) considerations» Groundbased and satellite algorithm differences Continued investigations required prior to SAUNA workshop at Tenerife (October 2006)

24 Participants, Contributors and Co-authors NASA GSFC FMI ESA» B. Bojkov, R. McPeters, A. Cede, D. Haffner, J. Herman, T. McGee, D. Silbert, G. Sumnicht, M. Yan» E. Kyro, R. Kivi, O. Aulamo, P. Heikkinen, J. Kahru, T. Koskela» C. Zehner BIRA-IASB» M. van Roozendael, C. Fayt, C. Hermanns, J.-C. Lambert, G. Pinnardi CNRS-SA» F. Goutail, D. Ionov DWD-MOHp» U. Koehler, B. Hassler INM-Izana» A. Redondas, E. Cuevas, C. Guirado, C. Torres KNMI» E. Brinksma MSC» T. McElroy, V. Savastiouk, D. Tarasick NASA-JPL» G. Ostermann NOAA ERL GMD» R. Evans, B. Walsh Photo: F. Goutail