TOMS 3 –F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

1. TOMS3–F:Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks Steven Lloyd The Johns Hopkins University Applied Physics Laboratory January 19, 2001

2. Total Ozone Offsets Earth Probe TOMS total ozone values are consistently higher than ozonesondes and ground–based spectrometers (Dobson,Brewer and MkIV). TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

3. Total Ozone Offsets The Earth Probe TOMS offset for Fairbanks is 1–5%. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

4. Total Ozone Offsets TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

5. Total Ozone Offsets In general, the offset increases with latitude. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

6. Total Ozone Offsets Offset between Earth Probe TOMS and 13 Northern Hemisphere Brewer and Dobson ground stations as a function of latitude. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

7. Total Ozone Offsets Apparent offset of Nimbus 7 and Earth Probe TOMS relative to 30 Northern Hemisphere ground stations (Dobson and Brewer spectrometers) over the period 1978-1999 (pluses), and also relative to 18 Southern Hemisphere ground stations (blue stars). Plot courtesy of Gordon Labow, Raytheon ITSS. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

8. Total Ozone Offsets Does the offset vary with season? TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

9. Total Ozone Offsets No seasonality to offset in Churchill dataset. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

10. Total Ozone Offsets No solar zenith angle dependence to offset in Churchill dataset. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

11. Total Ozone Offsets Issue of raw vs. filtered data in Churchill dataset TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

12. Total Ozone Offsets Although average North-South gradient in ozone is small, instantaneous gradient may be substantial. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

13. TOMS3–F Campaign Planning TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

14. TOMS3–F Campaign Planning Key Science Issues: Goal 1. To understand how well total ozone measured by Dobson and Brewer instruments agree over a broad range of total ozone and solar zenith angles, and to understand when, where, and why they disagree. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

15. TOMS3–F Campaign Planning Key Science Issues: Goal 1. Justification: Previous instrument intercomparisons have been done under more benign conditions, with total ozone close to 325 DU. Certain types of instrumental errors can be detected only by taking measurements over a broad range of total ozone amounts. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

16. TOMS3–F Campaign Planning Key Science Issues: Goal 1. Implementation: 2 Dobsons and 3 Brewers making multiple daily observations over 2 months, covering 50-90° SZA and 350-500 DU total ozone, will provide statistically meaningful samples. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

17. TOMS3–F Campaign Planning Key Science Issues: Goal 2. To compare TOMS with ground-based total ozone observations over a broad range of total ozone amounts and observing conditions, with the aim of understanding the cause(s) of their difference. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

18. TOMS3–F Campaign Planning Key Science Issues: Goal 2. Justification: Comparison of total ozone from the global Dobson network with TOMS shows significant biases that vary with latitude, season and total ozone amounts. Their cause is not understood. This campaign is designed to look at few possible sources of difference, including instrument and algorithm errors in both ground and satellite retrievals. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

19. TOMS3–F Campaign Planning Key Science Issues: Goal 2. • Specific questions: • How well does TOMS agree with the median of Dobson/Brewer total O3 amounts? • How much of the difference can be attributed to O3 variability near Fairbanks? • Is there scan angle or mu–dependence of the difference? TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

20. TOMS3–F Campaign Planning Key Science Issues: Goal 3. To investigate the impact of replacing climatological temperature and O3 profiles assumed by Dobson, Brewer and TOMS algorithms with profiles measured by ground-based/satellite instruments near Fairbanks? (for TOMS algorithm correction, need accurate ozone values near 30 km from ozonesondes, Umkehr, mm-wave radiometer, FTIR) TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

21. TOMS3–F Campaign Planning Key Science Issues: Goal 4. • To determine if the relationship between zenith sky radiances and total ozone agrees with radiative transfer theory. • How well does the slope of the Dobson C-pair zenith-sky N-value for total O3 agree with radiative transfer calculations at SZA<75˚? TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

22. TOMS3–F Campaign Planning Zenith Sky N-value vs. Total Ozone TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

23. TOMS3–F Campaign Planning Key Science Issues: Goal 4. Justification: Slope of Dobson C-pair N-values against total ozone computed from the Arosa station data shows 14% difference from theory (see attached figures). Other stations (Tateno and Boulder) show 10% difference. Resolution of this difference may also shed light on satellite and ground biases since (satellite-measured) nadir and (ground-measured) zenith-sky UV radiances are intimately related through the radiative transfer theory. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

24. TOMS3–F Campaign Planning Key Science Issues: Goal 4. • calculation requires aerosol optical depth and temperature profile, but absolute calibration of ZS N-value not required. • ZS C-pair N-values should be proportional to total O3 amount at SZA<75˚, with virtually no O3 profile sensitivity. • noise in the Arosa data are largely due to tropospheric aerosols, which have a significant effect on C-pair N-values. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

25. TOMS3–F Campaign Planning Verification of calibration: The “Dream Teams” TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

26. TOMS3–F Campaign Planning Why Fairbanks? Facilities and Instrumentation • Fairbanks: • Dobson 63– in continuous operation 1965–73 and 1984–present, moved from Poker Flats to the Geophysical Institute (GI) at the University of Alaska at Fairbanks (UAF) in 1992 • Sondes– staff at the GI have the experience and equipment to launch sondes, have worked with NOAA/CMDL (Oltmans and Johnson) to launch sondes for ADEOS validation and POLARIS campaign TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

27. TOMS3–F Campaign Planning Why Fairbanks? Facilities and Instrumentation • Poker Flat Research Range (PFRR): • sondes– inflation and launch facility • aerosol lidar– Richard Collins • Bruker FTIR– Frank Murcray and Pierre Fogal for CRL • mm–wave radiometer– Satoshi Ochiai • USDA UV– and vis–MFRSR– Jim Slusser • all–sky imaging cameras TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

28. Satellite Instruments TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

29. Satellite Instruments POAM III Orbit Predictions 4 Sunsets: March 31 April 5 April 9 April 14 Overpass within 2 degrees longitude TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

30. Satellite Instruments HALOE Orbit Predictions Only near-coincidence on April 23 at Latitude 62.86°N Longitude 145.23°W (Fairbanks is at Latitude 64.82°N Longitude 147.87°W) TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

31. Sondes and Spectrometers Primary Instrumentation: 2 Dobson Spectrometers, 3 Brewer Spectroradiometers and 30 ECC Ozonesondes Launched from Fairbanks and Poker Flat Research Range (PFRR), Alaska TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

32. Sondes and Spectrometers Secondary Instrumentation TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

33. Sondes and Spectrometers Secondary Instrumentation Locations Barrow Poker Flat Barrow Denali TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

34. TOMS3–F Campaign Planning First Priority: Maximum Total Ozone Plot courtesy of NOAA CMDL. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

35. TOMS3–F Campaign Planning First Priority: Maximum Total Ozone TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

36. TOMS3–F Campaign Planning First Priority: Maximum Total Ozone TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

37. TOMS3–F Campaign Planning Secondary Priority: Large Solar Zenith Angles Plot courtesy of Bill Swartz, JHU/APL. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

38. TOMS3–F Campaign Planning Secondary Priority: Large Solar Zenith Angles TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

39. TOMS3–F Campaign Planning Time of Earth Probe TOMS Overpasses TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

40. TOMS3–F Campaign Planning Maximum Clear Sky Viewing Conditions Plot courtesy of Bill Swartz, JHU/APL. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

41. TOMS3–F Campaign Planning TOMS 360 nm Surface Reflectivity TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

42. TOMS3–F: Facilities Geophysical Institute (GI) and International Arctic Research Center (IARC) at the University of Alaska at Fairbanks (UAF) TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

43. TOMS3–F: Facilities View of International Arctic Research Center (IARC) from Roof of Geophysical Institute (GI) TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

44. TOMS3–F: Facilities Brewer Spectroradiometer Environment Canada Meteorological Service of Canada TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

45. TOMS3–F: Facilities Campaign Headquarters with a View TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

46. TOMS3–F: Facilities Campaign Headquarters and Sushi Bar TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

47. TOMS3–F: Facilities Prof. Bill Simpson and the Fairbanks Dobson spectrometer on top of the Geophysical Institute Building at UAF TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

48. TOMS3–F: Facilities Fairbanks Dobson spectrometer (instrument no. 63) inside observatory dome TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

49. TOMS3–F: Facilities Fairbanks Dobson spectrometer (instrument no. 63) long–term dataset Plot courtesy of NOAA CMDL. TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks

50. TOMS3–F: Facilities Fairbanks Dobson spectrometer (instrument no. 63) long–term dataset 1965–1997 Trend 1965–2001 Trend TOMS3–F: Total Ozone Measurements by Satellites, Sondes and Spectrometers at Fairbanks