A comparison of the stratospheric aerosol background periods of 1979 and 1989–1991

Thomason, L. W.; Kent, G. S.; Trepte, Charles R.; Poole, L. R.

doi:10.1029/96jd02960

Cited by 85 publications

(54 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similar time series have been shown and related to volcanoes by Yue et al [1991], who presented SAGE optical depth time series; by McCormick and Trepte [1987], who presented SAM optical depth data; and by both Hitchman et al [1994] and Thomason et al [1997aThomason et al [ , 1997b, who combined SAGE I, SAM II, and SAGE II. Hofmann [1987] presented satellite data but also discussed lidar and balloon-borne aerosol measurements in time series beginning in 1971.…”

Section: Background Reference Aerosol Extinction Climatologymentioning

confidence: 84%

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

2003

View full text Add to dashboard Cite

A 22 year, high‐latitude, stratospheric aerosol and cloud database has been formed in a “unified” manner by combining the Stratospheric Aerosol Measurement (SAM) II, Stratospheric Aerosol and Gas Measurement (SAGE) II, Polar Ozone and Aerosol Measurement (POAM) II, and POAM III 1 μm aerosol extinction profiles. The database is “unified” in that it embodies similar aerosol extinction measurements, uses a single meteorological data set, and employs a single algorithm for calculating background extinction and cloud detection thresholds. Latitude is constrained to poleward of 45° in each hemisphere. The Unified cloud detection algorithm and database are designed for the straightforward addition of new data when other compatible data sets (e.g., SAGE III) become available. “Unified” cloud detection is similar to, but a refinement of, earlier attempts to identify polar stratospheric clouds (PSCs) with SAM II and POAM II data. The Unified algorithm is instrument‐independent and circumvents fundamental cloud detection pitfalls. The database contains over 73,000 (36,000) polar vortex‐region profiles in the Antarctic (Arctic) and over 21,000 (2000) PSC observations. An introductory climatology of Unified “background” extinction is presented. It is seen that volcanic effects dominate the evolution of outside‐vortex background extinctions, but perturbations apparently not related to volcanoes are seen as well. Interannual variations of background extinction inside the austral vortex are seen to be nearly decoupled from volcanic effects, while in the Arctic, inside‐vortex extinctions show a considerable volcanic influence. An analysis of long‐term PSC sighting is presented. Midwinter (July and January) PSC and clear‐sky measurements at 20 km, in a fixed temperature range, are used for computing PSC probability. The grand average PSC probability calculated this way is nearly identical between hemispheres. In the Antarctic the interannual PSC probability pattern is distinctly cyclic but is convoluted by volcanic perturbations in background aerosol. In the Arctic the PSC probability has much less temporal coherence than in the Antarctic but is similarly impacted by volcanic background increases. An explanation for the variation in PSC probabilities, in terms of interannual differences in denitrification, is discussed. Finally, a statistical analysis of tropopause height in relation to PSC formation is also presented. PSC observations are seen to be strongly associated with elevated tropopause heights, indicating that tropospheric, synoptic‐scale flow perturbations are the primary forcing mechanism for Arctic PSC formation, as evidenced in this long‐term satellite record.

show abstract

Section: Background Reference Aerosol Extinction Climatologymentioning

confidence: 84%

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

2003

View full text Add to dashboard Cite

show abstract

“…This view has been under scrutiny following reports of a gradual increase in background stratospheric aerosol loading [Hoffman, 1990] with no corresponding increase in atmospheric OCS levels [Chin and Davis, 1995]. However, more recent analysis of satellite data suggests that the background aerosol loading did not increase significantly from 1979 to 1990 [Thomason et al, 1997]. The importance of the stratospheric aerosol layer has recently taken on special significance because of the recognition of its potential for causing catalytic ozone loss on a global scale [Rodriguez et There has been no measurable increase in average atmospheric OCS concentrations to match the apparent sourcesink imbalance.…”

Section: Introductionmentioning

confidence: 99%

Interhemispheric ratio and annual cycle of carbonyl sulfide (OCS) total column from ground‐based solar FTIR spectra

Griffith¹,

Jones²,

Matthews³

1998

J. Geophys. Res.

View full text Add to dashboard Cite

Abstract. We have made extensive measurements of total column OCS by ground-based highresolution solar Fourier transform infrared absorption spectroscopy from two southern hemisphere sites to complement earlier measurements in the northern hemisphere and to investigate the interhemispheric ratio, variability, and seasonal cycles of OCS in the atmosphere. The measurements were made at Lauder, New Zealand (45.0øS, 169.7øE, 370 rn asl, 547 spectra March 1993 through April 1997), and Wollongong, Australia (34.45øS, 150.88øE, 30 rn asl, 358 spectra May 1996 through April 1997). The annual mean column amounts are 9.15 x 10 •5 molecules cm -2 above Lauder and 9.84 x 10 •5 molecules cm -2 above Wollongong, corresponding to tropospheric mixing ratios of 480 and 490 parts per trillion by volume, respectively, with the assumed mixing ratio vertical profiles. The secular trend in total column OCS is less than 1% per year. Variability of all measurements about the means implies an atmospheric lifetime for OCS of at least 2.8 years. Comparison with earlier measurements in the northern hemisphere yields a north/south interhemispheric ratio in the range 1.1-1.2. There are peak-to-peak apparent annual cycles in total column OCS of 6% at Lauder and 18% at Wollongong with a late summer maximum. Seasonal tropopause height variation accounts for a 5-6% amplitude, and the remainder of the amplitude in Wollongong is assumed to be due to changes in the tropospheric mixing ratio.

show abstract

“…We did not use the SAGE 450-nm measurements in 25 this analysis since they are poor quality and not usable at all below 20 km (Thomason et al, 1997a). The SAGE data are supplemented by 1000-nm extinction measurements by the Stratospheric Aerosol Measurement (SAM II;1978to 1993 which provides data only at high latitudes (>60 degrees).…”

Section: Pre Sage II Period (January 1979 To September 1984)mentioning

confidence: 99%

“…Any OSIRIS or CALIPSO data above 30 km at 525 and 1020 nm is replaced with the the climatology and flagged. 35 ( Thomason et al, 1997a) and using 2000 as the background year in a repeating series has discontinuities as large as a factor of two every January. The five-year average, while generally slightly larger than 2000 levels effectively removes most if not all QBO-related discontinuities.…”

Section: High Altitude Climatology For Osiris/calipso Periodmentioning

confidence: 99%

A global, space-based stratospheric aerosol climatology: 1979 to 2016

Thomason¹,

Vernier²,

Bourassa³

et al. 2017

Preprint

View full text Add to dashboard Cite

We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the 15 construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (1979 to 2014) and we have extended it through 2016 following an identical process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment (SAGE) series of instruments through mid-2005 and on the Optical Spectrograph and InfraRed Imager System (OSIRIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data thereafter. We also use data from other space 20 instruments and from ground-based, air and balloon borne instruments to fill in key gaps in the data set. The end result is a global and gap-free data set focused on aerosol extinction coefficient at 525 and 1020 nm and other parameters on an 'as available' basis. For the primary data sets, we developed a new method for filling the post-Pinatubo eruption data gap for 1991 to 1993 based on data from the Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new method for populating wintertime high 25 latitudes during the SAGE period employing a latitude-equivalent latitude conversion process that greatly improves the depiction of aerosol at high latitudes compared to earlier similar efforts. We report data in the troposphere only when and where it is available. This is primarily during the SAGE II period except the most enhanced part of the Pinatubo period. It is likely that the upper troposphere during Pinatubo was greatly enhanced over non-volcanic periods and that domain remains substantially under characterized. 30We note that aerosol levels during the OSIRIS/CALIPSO period in the lower stratosphere at mid and high latitudes is routinely higher than what we observed during the SAGE II period. While this period had nearly continuous low-level volcanic activity, it is possible that the enhancement in part reflects deficiencies in the data set. We also expended substantial effort to quality assess the data set and the product is by far the best we have produced. GloSSAC version 1.0 is available in netCDF format at the NASA Atmospheric 35 Data Center at https://eosweb.larc.nasa.gov/. GloSSAC users should cite this paper and the data set DOI

show abstract

A comparison of the stratospheric aerosol background periods of 1979 and 1989–1991

Cited by 85 publications

References 26 publications

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

A unified, long‐term, high‐latitude stratospheric aerosol and cloud database using SAM II, SAGE II, and POAM II/III data: Algorithm description, database definition, and climatology

Interhemispheric ratio and annual cycle of carbonyl sulfide (OCS) total column from ground‐based solar FTIR spectra

A global, space-based stratospheric aerosol climatology: 1979 to 2016

Contact Info

Product

Resources

About