Stability of OMTO3 total ozone data records for the 9-year period(Jan 2005-Jul 2013)

E.W. Chiou, P.K. Bhartia, and R.D. McPeters

A figure illustrating the stability of OMTO3 total ozone records

Extended studies to answer the following questions:(1) How stable is OMTO3 MZM data record beyond June 2011 (throughout 2005-2013)?(2) Is there any significant effect (in the long-term stability) due to the occurrence of Row Anomaly in 2008?(3) Could the stability of OMTO3 MZM data record be further improved using homogeneous row sampling throughout the 9-year period (2005-2013)?

Purpose: To investigate the long-term stability of

OMTO3 total ozone data records aiming to examine any noticeable effects due to row anomaly which began during mid 2008

* The stability of OMTO3 multi-year MZM data records could be affected by (i) Under-flagging or over-flagging for Row Anomaly implemented in OMTO3 Flagging scheme (ii) Sampling from different rows for Pre-Anomaly and Post-Anomaly periods.

Approach: Analysis of area-weighted monthly zonal means for (30S-30N), (30N-60N), and (50S-30S) covering 9-year period (2005-2013) using both (i) OMTO3 total ozone data records (ii) SBUV(v8.6) profile total ozone data records. Examine the stability of the Differences (OMTO3 minus SBUV) in MZM and MZM anomaly.

Assuming that the MZM data records of SBUV(v8.6) is stable throughout 2005-2013,

the results shown above indicate that : (1) Despite the occurrence of Row Anomaly OMTO3 MZM derived from all rows shows excellent stability at (30S-30N), and (30N-60N) (2) The stability of OMTO3 MZM (using all available non-flagged rows) is NOT as good for (50S-30S) compared to (30S-30N) and (30N-60N).

* Preliminary Summary OMTO3 MZM derived from homogeneous Row Sampling (restricted to Rows 1-24 only) demonstrates excellent stability for all 3 wide latitudinal zones: (30S-30N), (30N-60N), and (50S-30S).

How good is the stability for 10-degree latitudinal zones ??

Concluding Remarks:I. Despite the occurrence of Row Anomaly in mid 2008, OMTO3total ozone records remain very stable throughout the 9-yearperiod (2005-2013).II. For (30S-30N) and (30N-60N), results of the differences(OMTO3 minus SBUV) in MZM and MZM anomalydo NOT show noticeable trends for the 9-yr overlap period. [The trends are within the range of 0.01%/yr to 0.04%/yr ].III. For (50S-30S), The stability of OMTO3 data records indicatesslight influence due to Row Anomaly.However, the stability shows significant improvement using themonthly zonal means derived from homogeneous row sampling.IV. The major cause of slight effect in the stability of OMTO3 multi-year total ozone data records could be attributed to inhomogeneousrow sampling (when MZMs are derived from all non-flagged rows).