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Animation of the Antarctic Ozone Loss

Monitoring or Near-Real Time Ozone System

Instrument Changes Revealed by GMAO Monitoring

Several jumps can be seen in the timeseries of the NOAA-16 SBUV/2 O-F statistics in year 2001, especially for the mean of the layer 7.

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LEGEND: black = global, red = tropics, blue = northern midlatitudes, green = southern midlatitudes

• In May: Photomultiplier tube temperature correction was changed in the retrieval algorithm.
• On October 9: Calibration was changed to use automatic inter-range ratio update using on-orbit data instead of extrapolated time dependent table.
• On October 13: Automatic process of getting NOAA-16 SBUV/2 data failed. The data file was obtained manually, and it erroneously contained NOAA-14 data. Assimilation of NOAA-14 data produced a jump in the O-F statistics because of the offset (bias) between NOAA-16 and NOAA-14 SBUV/2 data.
• On December 4: Calibration started using new time dependent albedo correction factors. The retrieval algorithm for pressure mixing of ozone estimates for different wavelength pairs was modified.

Notes: The Terra ozone assimilation is now using NOAA-16 SBUV/2 data only. The NOAA-14 SBUV/2 profile data were assimilated by the Terra first look system from January 1, 2000 to April 11, 2001 and by the Terra late look system from January 1, 2000 to March 30, 2001. The Earth Probe TOMS total ozone column data were assimilated by the Terra first look system from January 1, 2000 to May 09, 2001 and by the Terra late look system from January 1, 2000 to April 25, 2001.

LEGEND: black = global, red = tropics, blue = northern midlatitudes, green = southern midlatitudes

Monitoring of the Operational System for the Current Year

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Note that the Jumps in O-F Residuals in Upper Layers in mid July 2004 that are Visible in the Figures above are due to a Change in the Parameterized Chemistry Model

Beginning data date 7/14/04, the Ozone Assimilation System for GEOS-4 was modified. The chemistry model was modified to include changes in the ozone production rates in the upper-stratosphere. Ozone chemical equilibrium (the quotient between production and loss rates) now agrees with the extended UARS ozone climatology. In the previous system the chemical equilibrium agreed with the climatology by Langematz (Geophys. Res. Lett., 27, 2077-2080, 2000). The new rates will have a direct impact on ozone in the upper stratosphere. The change was made because ozone in the previous system near 2 hPa in the winter high latitudes was excessive in comparison with independent POAM profiles.