ESRL Integrating Research and Technology Themes

Stratospheric Ozone Layer Recovery

    I. Goal and Scope

    The scientific goal is to determine and interpret trends in global stratospheric ozone, the Antarctic ozone hole, and global atmospheric ozone depleting substances; to investigate these trends for signs of recovery of the ozone layer and evaluate implications for climate change; and to study the efficacy of newly proposed substitutes for currently used ozone-depleting substances.

    The present scope includes accurately monitoring column ozone with Dobson spectrophotometers globally, monitoring the ozone profile at key sites, monitoring all relevant chlorine- and bromine-containing compounds globally, improving and developing new instrumentation, conducting laboratory studies of newly proposed chemicals, and using statistical models to test the observations for signs of ozone layer recovery.

    The observations will be interpreted with the aid of numerical models of the chemistry and dynamics of the stratosphere with new linkages across divisions. Temperature observations will also be studied and interpreted in a more integrated manner, in order to better understand the linkages of stratospheric ozone changes to surface climate.

    This activity also includes new interactions with NOAA NESDIS scientists regarding satellite observations of the Antarctic ozone layer, their comparison to ground-based and balloon-borne observations, and their interpretation with numerical modeling and analysis tools.

  1. Rationale and Payoff
  2. As a result of Montreal Protocol regulations, the net ozone-depleting capacity of atmospheric chlorine and bromine compounds is declining slowly; however, ozone depletion remains severe. Continued monitoring of ozone and ozone-depleting substances is essential for verification of ozone layer recovery as expected by about 2050, which hinges on the complete elimination of atmospheric ozone-depleting substances. Replacements for HCFCs, methyl bromide, and halons are still being sought, and studies of the new compounds must continue.

    NOAA scientists have a long history of scientific leadership in studies of Antarctic ozone, and NOAA satellite data will be important as new instrumentation (such as OMPS on NPOESS) becomes a cornerstone of the ozone monitoring system. NOAA scientists will systematically analyze ozone trend data and interpret findings at a level of integration and understanding never before achieved.

  3. Major Collaborators and Their Research Foci
    1. Earth System Research Laboratory
      • Global Monitoring Division: Provide surface Dobson spectrophotometer total ozone and umkehr profile measurements, balloon-borne ozone profile measurements, surface and airborne measurements of ozone-depleting substances. Conduct Dobson intercomparisons at numerous global locations to keep the World's Dobsons in calibration. Monitor spectral UV at Mauna Loa Observatory, Boulder, and at three stations in Alaska. Provide data and chapter authors for the WMO/UNEP Scientific Assessments of Ozone Depletion. Operate the Mauna Loa Observatory Network for the Detection of Stratospheric Change (NDSC) primary station. Operate stratospheric aerosol lidars at Mauna Loa Observatory, Boulder and the Samoa Observatory to detect changes in the surface area of aerosol in the stratosphere which would initiate enhanced ozone depletion and climate perturbations.
      • Chemical Sciences Division: Conduct chemistry investigations and modeling relevant to ozone depletion, test new ozone-depleting gas replacements, develop instruments, conduct process studies using aircraft instrumentation. Interpret global ozone measurements and their links to dynamical and radiative changes. Assist in the development of algorithms and in analysis of satellite measurements using the OMPS instrument. Provide leadership and chapter authors of the WMO/UNEP Scientific Assessments of Ozone Depletion and IPCC Assessments of the Physical Science Basis of Climate Change.
    2. Other NOAA
      • NESDIS/ORA: Satellite measurements and analysis of ozone. Caretakers of the NOAA Ozone Layer web page.
    3. Others
      • CIRES: Fully integrated contributions to all aspects of the program.
      • NASA: Satellite measurements and analysis of ozone.
      • Network for the Detection of Stratospheric Change: Universities and agencies involved in the Mauna Loa Observatory primary site.
      • WMO: GMD's ozone program is a major contribution to the WMO Global Atmosphere Watch Programme. GMD provides the World Standard Dobson instrument.
  4. Contributions to NOAA Goals
    • Public Law 95 - 95, Clean Air Act Amendments, 1990. NOAA (and NASA) is required to "... continue programs of research, technology, and monitoring of the phenomena of the stratosphere for the purpose of understanding the physics and chemistry of the stratosphere and for early detection of potentially harmful changes in the ozone in the stratosphere ..." Further, NOAA (and NASA) is required to report "... on the current average tropospheric concentration of chlorine and bromine and on the level of stratospheric ozone depletion."
    • NOAA Climate Goal (Program) CCSP Synthesis Assessment Product: Improve quantification of the forces bringing about changes in the Earth's climate and related systems. 2-4 year deliverable: Ozone layer recovery: observations and assessment
  5. Major Information Products, Customers, and Linkages
    • WMO/UNEP Scientific Assessment of Ozone Depletion (Quadrennial).
    • Montreal Protocol on Substances that Deplete the Ozone Layer (UN, 1987). NOAA is the Federal agency that is co-chair (since 1989) of the Protocol's Scientific Assessment Panel. The Panel's four-year scientific state-of-understanding deliverable is a key information product of the U.S. Climate Change Science Program.
    • United Nations Framework Convention on Climate Change (UNFCCC) and the Intergovernmental Panel on Climate Change. The current co-chair of IPCC WG1 is a NOAA scientist, and NOAA scientists have played leading roles in the reports since 1994. The Panel's six-year scientific state-of-understanding deliverable is a key information product that also relates to the CCSP.