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United States of America National Report on Surface-Based Ozone Research

United States of America National Report on Surface-Based Ozone Research. Seventh WMO/UNEP Ozone Research Managers Meeting Geneva, Switzerland 18-21 May, 2008. US AGENCIES CONTRIBUTING. National Aeronautics & Space Administration (NASA) National Oceanic & Atmospheric Administration (NOAA)

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United States of America National Report on Surface-Based Ozone Research

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  1. United States of America National Report on Surface-Based Ozone Research Seventh WMO/UNEP Ozone Research Managers Meeting Geneva, Switzerland 18-21 May, 2008

  2. US AGENCIES CONTRIBUTING • National Aeronautics & Space Administration (NASA) • National Oceanic & Atmospheric Administration (NOAA) • National Science Foundation (NSF) • Department of Agriculture (USDA) • Environmental Protection Agency (EPA) SURFACE-BASED NETWORKS • Dobson Ozone Spectrophotometer Network • Ozonesonde Networks (including SHADOZ) • Network for the Detection of Atmospheric Composition Change (NDACC) • Advanced Global Atmospheric Gases Experiment (AGAGE) Network • ESRL Global Monitoring Division Ozone-Depleting Gas Network • Ultraviolet Radiation Networks

  3. OBSERVATIONAL ACTIVITIES OZONE • Dobson Ozone Spectrophotometers (column and umkehr profiles - Part of GAW) – 16 global instruments plus the WMO World Standard instrument • UV-Multi Filter Shadowband Radiometer (column) – 32 US, 2 Canadian, 1 New Zealand • Brewer Spectrometer Network – 6 US Instruments • Ozonesondes (profile) – 10 global sites plus additional near-annual balloon campaigns • Miscellaneous Remote Profile Sensors - LIDAR, Microwave Radiometer, FTIR

  4. OBSERVATIONAL ACTIVITIESOzone-Relevant Gases and Variables • Aircraft and Balloon-borne – H2O, CFC’s, HCFC’s, HFC’s, CH3CCl3, CH3Br, CH3Cl • Surface – Global measurements of 25 ozone-depleting gases for determination of equivalent effective chlorine (EECl) • UV Visible spectrometers – NO2, BrO, OClO • FTIR spectrometers – HCl, HF, HNO3, ClONO2, NO

  5. OBSERVATIONAL ACTIVITIESUV BROADBAND & FILTER INSTRUMENTS: • SURFRAD Network – 7 sites • ESRL Network – Boulder and Mauna Loa (in conjunction with spectroradiometers) • USDA UVB Monitoring Program – 34 sites SPECTRORADIOMETERS: • SURFRAD UV spectroradiometers at Table Mountain • NDACC spectroradiometers at Mauna Loa and Boulder (in collaboration with NIWA-New Zealand) • NSF UV Monitoring Network - spectroradiometers at 7 sites, mainly in the polar regions • ESRL/EPA Brewer Mark IV spectrometers at 6 US sites

  6. SIGNIFICANT RESULTS CONTRIBUTIONS TO OZONE ASSESSMENTS OZONE LOSS LINKED TO ANTARCTIC CLIMATE CHANGE OZONE-DEPLETING GAS OBSERVATIONS DOBSON TOTAL OZONE TRENDS OZONE HOLE TRENDS AT SOUTH POLE RECENT INCREASES IN HCFCs CLIMATE BENEFITS OF THE MONTREAL PROTOCOL RECENT AIRBORNE MEASUREMENTS OF TROPICAL BROMINE GASES EVALUATING ODSs IN THE LABORATORY UV RADIATION TRENDS

  7. Tropospheric Organic Chlorine

  8. Long-Lived Halocarbons Contributing to Equivalent Effective Cl ESRL

  9. Equivalent Effective Stratospheric Chlorine - Antarctica The Ozone Depleting Gas Index (ODGI) ODGIMAX = 100 (1994) EESC Observations ODGI2007 = 86 HCFCs go away? Projection WMO 2006 1980 level ODGIRecovery = 0 ESRL

  10. Dobson Ozone Trends Dobson Ozone Trends – A New Look Smooth trend curves of monthly ozone values from selected Dobson stations (South Pole, continental US, and the tropics) are shown. Changes represented by the growth rate determined from differentiating these trend curves is an instantaneous measure of the rate of change of stratospheric ozone and thus represents various aspects of ozone layer recovery. No attempt to remove possible Pinatubo effects has been made Harris, J.M., S.J. Oltmans, P.P. Tans, R.D. Evans, and D.L. Quincy, Geophys. Res. Lett. 28, 4535, 2001 (updated) ESRL

  11. Continental U.S. Total Column Ozone Growth Rate Instantaneous growth rate curve (± 2 SD) found from differentiating the trend curve Average growth rate 1968-1995: -2.16 %/decade Average growth rate 1996-2007: +1.73 %/decade

  12. South Pole Total Column Ozone Growth Rate Instantaneous growth rate curve (± 2 SD) found from differentiating the trend curve Average growth rate 1968-1995: -11.1 %/decade Average growth rate 1996-2007: -1.38 %/decade

  13. 2006 Antarctic Ozone Hole 14 – 21 km total depletion region South Pole Balloon-borne Measurements October 9, 2006 OMI Satellite Measurements – Sept. 24, 2006

  14. South Pole 14-21 km Column Ozone From Balloon Ozonesondes ~1500 Balloon Flights Beginning of recovery? Probably Not ESRL

  15. Recent Changes in HCFCs ESRL

  16. Ozone-Depleting Gases also Affect Climate CH4 CH4 N2O N2O CCl4, CH3CCl3 CFCs CFCs

  17. Recent Airborne measurements define composition and distribution of organic bromine source gases in the tropical atmosphere 0 -1 km 4 - 8 km MeBr=31% Halons=34% S.Lived=35% MeBr=38% Halons=41% S.Lived=20% ~ 17 km MeBr=47% Halons=46% S.Lived=7.5%

  18. Evaluating Proposed Substitutes for ODSs Montreal Protocol Kyoto Protocol Taken from IPCC Special Report (2005) • What is a Good Substitute ? • Zero ODP • Short Atm. Lifetime • Low GWP • Minimal Impact of Degradation Products Evaluation of the environmental impact of a compound from production to end-of-life. Laboratory studies are used to evaluate and quantify atmospheric removal, climate impact, and degradation products. Degradation Deposition ESRL

  19. USDA UV-B Monitoring and Research Program Preliminary analysis at eight sites shows changes in annual UV-B irradiance ranged from +6% to +14% over most of the US (orange bars) for the 10 year period 1994 to 2004. Purple bars show monthly variability.

  20. UV Monitoring Local noon erythemal radiation calculated from UV spectroradiometers (1 nm resolution) at Mauna Loa, Hawaii and Boulder, Colorado Mauna Loa Observatory, Hawaii Boulder, Colorado ESRL and NIWA

  21. SUMMARY • Measurements of ozone-depleting gases show a decline in total ozone-depleting potential (EESC) heralding the potential beginning of ozone layer recovery (14% and 27% of the way to 1980 levels for Antarctica and mid-latitudes, respectively). • To date, no clear indication of the beginning of ozone hole recovery has been observed at the South Pole. At mid-latitudes, ozone depletion has ceased increasing and may be in the first stages of recovery. • The job is not completed. The ozone hole will last through most of the 21st century. Continued support for long-term measurements of ozone and ozone-depleting substances is necessary. As we look to satellite measurements in the future, we must be vigilant that they are accompanied by accurate surface measurements. We are trying to observe a change of ~1% over a time period of ~10 years!

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