Nimbus buv and toms data Substantiate the Atmospheric Ozone Depletion Concerns Arlin Krueger


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Nimbus BUV and TOMS Data Substantiate the Atmospheric Ozone Depletion Concerns

  • Arlin Krueger

  • Joint Center for Earth Systems Technology

  • University of Maryland, Baltimore County


Nimbus BUV and TOMS Data Substantiate the Atmospheric Ozone Depletion Concerns

  • By

  • S Ahmad, Z Ahmad, P Anderson, E Beach, D. Becker, A Belmont, PK Bhartia, L Bowlin, R Browning, D. Burchfield, W. Byerly, E Canevari, B Cano, S Carn, R Casey, G Chalef, S Chandra, P Collins, M Comberiate, C Cote, S Cox, D Cunold, JV Dave, C Davis, M Deland, S Doiron, J. Dowser, J Elliot, R Farquhar, A.J. Fleig, D. Flittner, L Flynn, M Foreman, J Frederick, J Gatlin, P Ginoux, J Gleason, C Gordon, D Gordon, A.E. Green, X Gu, B Guenther, S. Guenther, R. Hering, D Harrison, U Hartmann, DF Heath, BD Henderson, B Herman, J Herman, R. Hertel, C Hestor, M Hinman, R Hudson, J Hurley, R Ignasiak, W.L. Imhof, G Jaross, T Jennings, A Kaveeshwar, K Klenk, R. Kobiachi, G. Kobiachi, M. Kobiachi, N Koep-Baker, N Krotkov, *A Krueger, G Labow, D Larko, K Lee, J Leithch, J Leithch, J Lienesch, B Lowry, CL Mateer, C McKenzie, R McPeters, D. Merrill, T Miles, A J Miller, P. Mitzen, B Monosmith, G. Montwell, R Nagatoni, P Newman, W Nickum, A Oakes, R Ormsby, N Oslik, B Palmer, H Park, V Pavanasaisam, S Plageman, N. Preketes, H Press, J Purcell, B Raines, S Ray, H Reed, S Reed, H Reid, HB Roeder, M. Ruecker, E Rutkowski, R Salikov, S Schaefer, B Schlesinger, J Schneider, C Schnetzler, M Schoeberl, D Schuster, C Seftor, M Shapiro, R Shapiro, R Sipes, J Sisala, P Smith, I Sprod, R Stevenson, J Stokes, R Stolarski, T Swissler, S Taylor, O Torres, S Truong, K Venkatakrishna, L Walters, S Weiland, R White, C Wong, J Ziemke

  • * speaker



What did we know about ozone before Nimbus BUV and TOMS?

  • Theory: Chapman proposed photochemistry of oxygen could explain ozone.

  • Observations:

    • Total ozone - Dobson measured latitude and seasonal variations; suspected meteorology produced variability.
    • Vertical ozone distribution - balloons showed effects of weather; rockets supported photochemical model.
  • Laboratory: Chemists said nitrogen radicals could destroy ozone in catalytic cycle.

    • Chemical rate coefficients too poorly known to decide if nitrogen cycle worked in the atmosphere.
    • Halogens were even better catalysts than nitrogen or hydrogen.


Backscatter UV Origins 1970: The Nimbus-4 BUV

  • Ozone profile

    • First satellite experiments had measured ozone profile
    • Instrument calibration established from coincident rocket soundings
  • Total ozone

    • Sparse Dobson spectrophotometer network
    • Inter-instrument calibration errors large
    • CP Cuddapah used Nimbus 3 IRIS data for first total ozone from space
  • BUV Instrument

    • NCAR proposal (1965) Dave and Mateer
    • Instrument:
      • Goddard Space Flight Center:
      • Heath (Tech. Officer - Krueger)
      • Beckman Instruments Henderson, Roeder, Meloy, Reid
    • Solar diffuser plate for calibration
    • Optimized wavelengths
    • Total ozone sounding method


BUV data confirmed catalytic cycle in ozone chemistry

  • August 1972 solar proton event.

    • High energy protons produce nitric oxide in upper stratosphere.
    • Paul Crutzen predicted decrease of ozone.
    • BUV data show 20% decrease.
  • Ozone depletion in auroral oval proved catalytic cycle was controlling ozone.

    • Opened the possibility of catalytic loss of ozone by halogens.


Total ozone from space: Dave and Mateer



Total ozone mapping origins 1978: The Nimbus-7 TOMS

  • Coverage:

    • Daily global survey
    • Avoid missed event issues by observing:
      • every location
      • every day
  • Ground resolution:

    • Limited by 1970’s data rate, data storage
    • Resolve jet streams
    • Identify local ozone perturbations


TOMS & BUV Global Coverage Survey vs. Sample



Global total ozone maps



Formation of a Kona Low



Polar ozone depletion

  • Environmental concerns overwhelmed meteorological research.

  • British Antarctic Survey (Farman, et al.,1985) pointed out steep decline in 25-year ozone record over Halley Bay Dobson station; attributed it to chlorine from CFC’s.

  • TOMS found large ozone loss in Antarctic-size hole (Bhartia et al, 1986; Stolarski, et al., 1986). Dynamic vs chemical cause disputed.

  • In-situ data from NASA DC-8 and ER2 aircraft found enhanced ClO from heterogeneous reactions of ClONO2 and HCl on polar stratospheric clouds.

  • Similar ozone losses found in Arctic.



The Antarctic Ozone Hole



Polar ozone depletion Antarctic ozone hole and the Montreal Protocol

  • Images of rapid springtime ozone loss over Antarctica each year lent credibility to environmental concerns

  • Progressive annual deepening produced urgency



Antarctic Ozone Hole



Global Ozone Trends Ozone depletion and the SBUV/TOMS calibrations

  • Nimbus-7 TOMS shared SBUV diffuser plate

  • Diffuser reflectance and BRDF change with solar exposure

  • Model-based relative calibrations developed (Pair justification, spectral discrimination)

  • New TOMS instruments used triple diffuser carousel with different exposure times to infer degradation



Impact of BUV & TOMS

  • Catalytic ozone destruction accepted by scientific community (1977).

  • Ozone hole images and ozone trends convince public of danger of CFC’s (1986).

  • Montreal Protocol on Substances that Deplete the Ozone Layer signed (1987).

  • Nobel Prize in chemistry awarded to Crutzen, Rowland, and Molina (1995).

  • CFC production phased out.



Beyond total ozone…..

  • TOMS data products

    • Total ozone
    • Ground/cloud reflectivity
    • Total sulfur dioxide
    • Aerosols
      • optical depth
      • effective radius or single scattering albedo
    • Tropospheric ozone
    • UVB fluxes


Tracking volcanic sulfur dioxide clouds



25 years of SO2 mass from volcanic eruptions



Absorbing aerosols Smoke, mineral dust, and volcanic ash

  • Aerosols change the wavelength dependence of scattered light

  • Compare observed and model Rayleigh spectra to get aerosol signal

  • Low UV reflectivity of soil and water makes detection easy over land and ocean



Tropospheric column ozone

  • Residual between TOMS total ozone and MLS stratospheric column

  • High Atlantic values due to biomass burning, lightning, and Walker circulation



The success of TOMS led in unexpected directions.



Conclusions

  • BUV and TOMS surpassed all expectations

    • Long life missions due to excellent engineering by Beckman Instruments and dedication of GSFC satellite operations teams
    • Algorithm development, instrument calibration, and data processing successful due to GSFC Ozone Processing Team
    • Broad use of data due to high quality daily global census, yet compact datasets
  • Impacts on geosciences and environmental controls are far reaching



Ozone Theory

  • Sydney Chapman proposed oxygen photochemistry driven by solar UV.

    • O2 + h --> O + O (1)
    • O + O2 + M --> O3 + M (2)
    • O3 + h --> O + O2 (3)
    • O3 + O --> 2 O2 (4)
  • Chemists knew that nitrogen and hydrogen radicals could catalytically destroy ozone in the lab. For example, NO can destroy ozone:

    • NO + O3 --> NO2 + O2
    • NO2 + O --> NO + O2
  • Other radicals are H, OH, Cl, or Br.




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