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1970-2020 Profile and Total Column Ozone from the SBUV Instrument Series


The Solar Backscatter Ultraviolet (SBUV) observing system consists of a series of instruments that measure the ozone profile from the ground to the top of the atmosphere. All data have been retrieved using the Version 8.7 algorithm (released Fall 2021). Measurements are reported as partial column ozone amounts in defined pressure layers. The total column ozone is the sum of the partial column amounts. Three versions of the SBUV instrument are used in the series, but the fundamental measurement technique is the same over the evolution of the instrument from BUV to SBUV/2. A next generation instrument, the Ozone Mapping Profiler Suite (OMPS) Nadir Profiler, continues the SBUV series.

We use the following rules to construct v2 Release 1 of the Merged Ozone Data Set (New Rules Highlighted)

  • Include only measurements taken when the Local Equator Crossing Time (LECT) of the orbit is between 8am and 4pm, with the exception of N11 pre-terminator data to avoid gaps in the record. Additionally, N14 and N16 data taken after the orbit passed through the terminator are not included in this version.
  • To remove diurnal differences due to different satellite measurement times, measurements from each instrument (except OMPS NP) are adjusted post-retrieval to an equivalent measurement time of 1:30pm using a model-based diurnal ozone climatology.
  • Do not include N9 data, except to fill gaps in the TOTAL OZONE in 1994-1995 as N11 progressed towards the terminator and lost latitudinal coverage.
  • Filter Profile MOD after the eruptions of the El Chichon and Mt. Pinatubo volcanoes.
  • Use a simple average to combine data when multiple instruments are operating to construct a single consistent data set. No additional offsets are applied to indivdiual data sets.

Table of Measurements used in v2 Release 1 MOD

Instrument Data Links* Data Start Data End Data Usage/Comments
Nimbus 4 BUV 5° MZM (Text)

5° MZM (HDF)
May, 1970 April, 1976 In mid-1972 partial failure of the N4 solar power array forced limitations on instrument operating time, resulting in intermittent data coverage, which became increasingly sparse with time. Zonal mean data are limited after mid-1972 but zones with sufficient coverage are included in the data set.
All N4 BUV data are included for historical reference, but these data should not be used for trend analysis.
Nimbus 7 SBUV 5° MZM (Text)

5° MZM (HDF)
November, 1978 May, 1990 N7 SBUV data after February 1987 are affected by chopper wheel synchronization errors. This caused an increase in measurement noise, but monthly zonal mean values are minimally effected.
All N7 SBUV data are used.
NOAA 9 SBUV/2 5° MZM (Text)

5° MZM (HDF)
February, 1985 January, 1998 N9 SBUV/2 profile data are of poorer quality, though the total column ozone compare well with other instruments. Therefore N9 total ozone are used, but only to fill gaps in the MOD total ozone data set caused by decreased N11 latitude coverage in 1994-1995. Power problems after June 1997 seriously degraded the N9 longitudinal coverage. The N9 orbit drifted throughout its operation.
No N9 SBUV/2 profile data are used.
N9 SBUV/2 total column data are used only to fill gaps in 1994-1995.
NOAA 11 SBUV/2 5° MZM (Text)

5° MZM (HDF)
January, 1989 March, 2001 N11 SBUV/2 suffered problems with the instrument grating drive beginning in late 1993. These errors increased in the late 1990s, but soft-calibration techniques are used to correct the data. The N11 orbit drifted in time, such that the satellite was in a terminator orbit from April 1995 - July 1997. We use all data before the orbit reached terminator, and data after the LECT passed 8am.
Apr 1995 - Sep 1997 N11 SBUV/2 data are not used.
NOAA 14 SBUV/2 5° MZM (Text)

5° MZM (HDF)
March, 1995 September, 2006
N14 SBUV/2 developed grating drive errors several months after launch, and the errors became progressively worse with time. In addition, the cloud cover radiometer failed directly after launch. The grating drive control was reprogrammed in June 1998 to compensate for grating drive issues as well as for the CCR failure. The N14 satellite was in a terminator orbit from May 2002 - August 2003 and outside the 8am-4pm LECT range from May 2000 - June 2004.
N14 SBUV/2 Data after May 2000 are not used.
NOAA 16 SBUV/2 5° MZM (Text)

5° MZM (HDF)
October, 2000 May, 2014 N16 SBUV/2 periodically experiences electronic interference in measurements that are used in the derivation of total ozone. However, total ozone calculated as the sum of the profile total, as is done in the V8.7 SBUV MOD, is not sensitive to this error. The N16 satellite began drifting in early 2004, was in a terminator orbit from May 2009 - March 2010, and was outside the 8am-4pm LECT range from July 2007 - November 2011. The N16 instrument failed in early June, 2014.
N16 SBUV/2 Data after July 2007 are not used .
NOAA 17 SBUV/2 5° MZM (Text)

5° MZM (HDF)
August, 2002 March, 2013 The N17 satellite was launched into a morning local solar time orbit, and began drifting toward the terminator (earlier in time) in late 2007. In October 2011 N17 passed the 8am LECT orbit threshold, and entered into a terminator orbit in February 2013. N17 was decommisioned in April, 2013.
No N17 SBUV/2 data are used after September 2011.
NOAA 18 SBUV/2 5° MZM (Text)

5° MZM (HDF)
July, 2005 November, 2012 The N18 instrument chopper wheel ceased operating in December 2012.
All N18 SBUV/2 data are used.
NOAA 19 SBUV/2 5° MZM (Text)

5° MZM (HDF)
March, 2009 Operational NOAA-19 was launched in March 2009, but has now drifted beyond the 4pm LECT threshold.
No N19 SBUV/2 data are used after March 2018.
Suomi NPP OMPS 5° MZM (Text)

5° MZM (HDF)
December, 2011 Operational OMPS is the next generation nadir-viewing BUV instrument used to continue the MOD time series. OMPS Nadir Profiler V2.8 data are now included in MOD. The V2.8 data have been inter-calibrated to the SBUV series based on overlap comparisons with N19.
All OMPS NP Data after April 2012 are used.
SBUV Satellite Data Coverage shows the time period during which each instrument was collecting reliable profile ozone measurements (blue line segments in figure). When data from all the instruments are included, the coverage is nearly continuous from late 1978 to the present.

*The 5° MZM files for each instrument are the base data sets for the Merged Data Set. The MZM files are available in a simple text format and in HDF format. HDF files contain ancillary data including Smoothing Error, Averaging Kernels, Averaging Statistics, A Priori, Standard Deviations and more.

Additional V8.7 SBUV Data Links

Several data products are available based on the Version 8.7 SBUV data. Users may follow these links to access SBUV data for specific purposes.