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

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

• Seventh WMO/UNEP Ozone Research Managers Meeting
• Geneva, Switzerland
• 18-21 May, 2008

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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

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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

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OBSERVATIONAL ACTIVITIESOzone-Relevant Gases and
Variables

• Aircraft and Balloon-borne H2O, CFCs, HCFCs,
  HFCs, 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

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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

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SIGNIFICANT RESULTS

1. CONTRIBUTIONS TO OZONE ASSESSMENTS
2. OZONE LOSS LINKED TO ANTARCTIC CLIMATE CHANGE
3. OZONE-DEPLETING GAS OBSERVATIONS
4. DOBSON TOTAL OZONE TRENDS
5. OZONE HOLE TRENDS AT SOUTH POLE
6. RECENT INCREASES IN HCFCs
7. CLIMATE BENEFITS OF THE MONTREAL PROTOCOL
8. RECENT AIRBORNE MEASUREMENTS OF TROPICAL BROMINE
   GASES
9. EVALUATING ODSs IN THE LABORATORY
10. UV RADIATION TRENDS

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Tropospheric Organic Chlorine
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Long-Lived Halocarbons Contributing to
Equivalent Effective Cl
ESRL
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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
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Dobson Ozone Trends A New Look
Dobson Ozone Trends
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
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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
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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
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2006 Antarctic Ozone Hole
14 21 km total depletion region
South Pole Balloon-borne Measurements October 9,
2006
OMI Satellite Measurements Sept. 24, 2006
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South Pole 14-21 km Column Ozone From Balloon
Ozonesondes
1500 Balloon Flights
Beginning of recovery?
Probably Not
ESRL
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(No Transcript)
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Recent Changes in HCFCs
ESRL
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Ozone-Depleting Gases also Affect Climate
CH4
CH4
N2O
N2O
CCl4, CH3CCl3
CFCs
CFCs
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Recent Airborne measurements define composition
and distribution of organic bromine source gases
in the tropical atmosphere
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Evaluating Proposed Substitutes for ODSs
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
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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.
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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
and NIWA
ESRL
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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!