a long term data record of the ozone vertical distribution in43b-1150 by richard mcpeters 1, stacey...
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A Long Term Data Recordof the Ozone Vertical Distribution
IN43B-1150by
Richard McPeters1, Stacey Frith2, and Val Soika3
1) NASA GSFC [email protected], 2) SSAI [email protected], and 3) Adnet Systems Inc [email protected]
Abstract. The Ozone Processing Team (OPT) at Goddard Space Flight Center was one of the first groups to create a long term record of total column ozone. A merged ozone data record (MOD) was created by combining total column ozone data from TOMS, OMI, and SBUV instruments. An initial record of ozone vertical profile ozone has been produced using data from a series of SBUV and SBUV/2 instruments, but instrument drift and calibration offsets limit the accuracy of the time series. Intra-instrument comparisons as well as SAGE II and UARS MLS data have been used to evaluate the consistency of the record and make calibration adjustments as needed. Under the MEaSUREs program we are now deriving the radiance corrections needed for each instrument and re-processing the complete data record to produce a coherent profile data record. Ozone profiles derived from the Aura OMI instrument are being evaluated for inclusion in the series, and data from the NPOESS OMPS instrument will extend this data record after the launch of NPP. The ultimate goal is an ozone Earth Science Data Record (ESDR) - a consistent, calibrated ozone time series that can used for trend analyses and other studies.
Data reprocessing under MEaSUREs
Total Column Ozone
Ozone Data Sets used for Trend Analysis(ESDR – Earth Science data record)
Problems addressed by instrument team:1) dark current errors 3) near terminator orbit 5) stepper motor errors2) chopper synch errors 4) diffuser stuck 6) calibration errors
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Orbit drift of NOAA satellites is a problem because a calibration error can produce a spurious trend. Similarly, a drifting orbit sampling real diurnal variation in the upper stratosphere can produce an apparent trend.
A major issue is establishing relative calibration when there is no overlap of instruments in good parts of drifting orbits, as in 1997 with NOAA 9 and NOAA 11.
SAGE ozone data can be used as a transfer standard to compensate for data gaps and show the effect of orbit drift.
Problems in Ozone Trend Analysis
Merged Ozone Data (MOD) from a series of SBUV(/2), SAGE, and MLS instruments. Two broad altitude layers: 28 – 48 km (1-16 hPa) and 19 – 28 km (16-64 hPa)Three latitude zones: 60º - 65º S (left), the equator (center), and 40º - 45º N (right) Layer ozone and % deviations from the 1979/1980 monthly averages
In each case ozone has been adjusted instrument to instrument for long term consistency. for details or data see http://hyperion.gsfc.nasa.gov/Data_services/merged/index.html
MEaSUREsMaking Earth Science Data Recordsfor Use in Research Environments
1960 1970 1980 1990 2000 2010
Figure from V. Fioletov et al. at the 2008 Quadrennial Ozone Symposium in Tromso Norway showing deseasonalized global mean ozone time series from SBUV(/2) and other sources.
Total column ozone from the MOD (merged ozone data) time series agrees well with a simple TOMS/OMI series and is very similar to plot of ground based ozone and a NIWA analysis of long term ozone (plot below). Note the increase in OMI ozone since the 1990’s. The question is whether this is evidence for an ozone recovery. (Percent deviations from the 1979-1980 monthly averages are plotted.)
• Archive the current MOD total column ozone data set as a MEaSUREs data set• Use v8 profile algorithm to process OMI data• Reprocess all TOMS data using OMI cloud height climatology
• Use new ozone cross sections (Brion, Daumont, Malicet)• Reprocess all profile data using v9 algorithm
• Designed to be applicable to hyperspectral instruments as well as to traditional SBUVs
• On-the-fly radiative transfer using LIDORT• Off axis FOV, 0-65 km model in 24 layers, arbitrary slit
functions• reprocess all SBUV, NOAA 9,11,16,17,18 data
Nimbus-4 BUV (1970-1975) Nimbus-7 TOMS (1978-1993)Nimbus-7 SBUV (1978-1990)SAGE II (1984-2005)NOAA-9 SBUV/2 (1985-1989, 1992-1998)NOAA-11 SBUV/2 (1988-2001)UARS MLS (1991-1994)Earth Probe TOMS (1996-2006)NOAA-16 SBUV/2 (2000-present)NOAA-17 SBUV/2 (2002-present)Aura OMI (2004-present)Aura MLS (2004-present)NOAA-18 SBUV/2 (2005-2008)MetOp GOME 2 (2007-present)NPP OMPS (2010?)
The Aura Ozone Monitoring Instrument (OMI) is a hyperspectral imaging spectrometer that measures backscattered sunlight in three spectral ranges: UV1 (270-314 nm), UV2 (306-380 nm), and VIS (350-500 nm). UV2 data from OMI have been used to continue the TOMS record of total column ozone. Here, data from UV1 are being used to retrieve the ozone vertical distribution using the version 8 SBUV ozone profiling algorithm.
Profiles from OMI
Ozone Profile Data