In:
Atmospheric Measurement Techniques, Copernicus GmbH, Vol. 14, No. 3 ( 2021-03-23), p. 2261-2283
Abstract:
Abstract. The Brewer ozone spectrophotometer (the Brewer) was designed at
Environment and Climate Change Canada (ECCC) in the 1970s to make accurate
automated total ozone column measurements. Since the 1980s, the Brewer instrument has
become a World Meteorological Organization (WMO) Global Atmosphere Watch
(GAW) standard ozone monitoring instrument. Now, more than 230 Brewers have
been produced. To assure the quality of the Brewer measurements, a
calibration chain is maintained, i.e., first, the reference instruments are
independently absolutely calibrated, and then the calibration is transferred
from the reference instrument to the travelling standard, and subsequently
from the travelling standard to field instruments. ECCC has maintained the
world Brewer reference instruments since the 1980s to provide transferable
calibration to field instruments at monitoring sites. Three
single-monochromator (Mark II) type instruments (serial numbers 008,
014, and 015) formed this world Brewer reference triad (BrT) and
started their service in Toronto, Canada, in 1984. In the 1990s, the Mark III
type Brewer (known as the double Brewer) was developed, which has two
monochromators to reduce the internal instrumental stray light. The double-Brewer world reference triad (BrT-D) was formed in 2013 (serial numbers
145, 187 and 191), co-located with the BrT. The first assessment
of the BrT's performance was made in 2005, covering the period between 1984
and 2004 (Fioletov et al., 2005). The current work
provides an updated assessment of the BrT's performance (from 1999 to 2019)
and the first comprehensive assessment of the BrT-D. The random
uncertainties of individual reference instruments are within the WMO/GAW
requirement of 1 % (WMO, 2001): 0.49 % and 0.42 % for
BrT and BrT-D, respectively, as estimated in this study. The long-term
stability of the reference instruments is also evaluated in terms of
uncertainties of the key instrument characteristics: the extraterrestrial
calibration constant (ETC) and effective ozone absorption coefficients (both
having an effect of less than 2 % on total column ozone). Measurements
from a ground-based instrument (Pandora spectrometer), satellites (11
datasets, including the most recent high-resolution satellite, TROPOspheric
Monitoring Instrument), and reanalysis model (the second Modern-Era
Retrospective analysis for Research and Applications, MERRA-2) are used to
further assess the performance of world Brewer reference instruments and to
provide a context for the requirements of stratospheric ozone observations
during the last two decades.
Type of Medium:
Online Resource
ISSN:
1867-8548
DOI:
10.5194/amt-14-2261-2021
DOI:
10.5194/amt-14-2261-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2505596-3
Permalink
