Stratospheric ozone measurements at Arosa (Switzerland):  history and scientific relevance

Staehelin, J.; Viatte, P.; Stübi, René; Tummon, Fiona; Peter, Thomas

doi:10.5194/acp-18-6567-2018

Cited by 14 publications

(14 citation statements)

References 63 publications

(74 reference statements)

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“…Bowen and Regener (1951) present ozone data from Capillo Peak Observatory in New Mexico (approximately 2800 m asl). Four years of ozone data were obtained at the Arosa Light Observatory (located on the northern edge of the town of Arosa in a Swiss valley, 1810 m (Staehelin et al, 2018)) using the Ehmert technique (Perl, 1965). In August 1953 and June/July and September 1954 ozone observations were made utilizing an 80 m tower using the Cauer method (Section 2.1.4) at Lindenberg (98 m) in northeastern Germany (Teichert 1955).…”

Section: -1970smentioning

confidence: 99%

Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties

Tarasick

Galbally

Cooper

et al. 2019

Elementa: Science of the Anthropocene

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158

168

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From the earliest observations of ozone in the lower atmosphere in the 19th century, both measurement methods and the portion of the globe observed have evolved and changed. These methods have different uncertainties and biases, and the data records differ with respect to coverage (space and time), information content, and representativeness. In this study, various ozone measurement methods and ozone datasets are reviewed and selected for inclusion in the historical record of background ozone levels, based on relationship of the measurement technique to the modern UV absorption standard, absence of interfering pollutants, representativeness of the well-mixed boundary layer and expert judgement of their credibility. There are significant uncertainties with the 19th and early 20th-century measurements related to interference of other gases. Spectroscopic methods applied before 1960 have likely underestimated ozone by as much as 11% at the surface and by about 24% in the free troposphere, due to the use of differing ozone absorption coefficients.There is no unambiguous evidence in the measurement record back to 1896 that typical mid-latitude background surface ozone values were below about 20 nmol mol -1 , but there is robust evidence for increases in the temperate and polar regions of the northern hemisphere of 30-70%, with large uncertainty, between the period of historic observations, 1896-1975, and the modern period (1990-2014). Independent historical observations from balloons and aircraft indicate similar changes in the free troposphere. Changes in the southern hemisphere are much less. Regional representativeness of the available observations remains a potential source of large errors, which are difficult to quantify.The great majority of validation and intercomparison studies of free tropospheric ozone measurement methods use ECC ozonesondes as reference. Compared to UV-absorption measurements they show a modest (~1-5% ±5%) high bias in the troposphere, but no evidence of a change with time. Umkehr, lidar, and FTIR methods all show modest low biases relative to ECCs, and so, using ECC sondes as a transfer standard, all appear to agree to within one standard deviation with the modern UV-absorption standard. Other sonde types show an increase of 5-20% in sensitivity to tropospheric ozone from 1970-1995. Biases and standard deviations of satellite retrieval comparisons are often 2-3 times larger than those of other free tropospheric measurements. The lack of information on temporal changes of bias for satellite measurements of tropospheric ozone is an area of concern for long-term trend studies.

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Section: -1970smentioning

confidence: 99%

Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties

Tarasick

Galbally

Cooper

et al. 2019

Elementa: Science of the Anthropocene

Self Cite

158

168

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“…In Stübi et al (2017a), an analysis of the daily Brewer data to discern the mid-to-long-term variations of the differences and the short-term random fluctuations of coincident measurements was introduced. This was an alternative method to the one introduced by Fioletov et al (2005) to study the stability of the Toronto Brewer reference triad.…”

Section: Resultsmentioning

confidence: 99%

Quality assessment of Dobson spectrophotometers for ozone column measurements before and after automation at Arosa and Davos

et al. 2021

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Abstract. The longest ozone column measurement series are based on the Dobson sun spectrophotometers developed in the 1920s by Gordon B. W. Dobson. These instruments still constitute an important part of the World Meteorological Organization's global network due to their optical qualities and ruggedness. The primary drawback of this instrument is the effort needed for its manual operation. In industrialized and some less developed countries, most stations have made the choice to replace the Dobson by the automated Brewer sun spectrophotometers, but some are still relying on the Dobson instrument. One of them is the Arosa station where both instrument types are run in parallel. Here, an automated version of the Dobson instrument was developed and implemented recently. In the present paper, the results of the analysis of simultaneous measurements from pairs of Dobson instruments that were either collocated at Arosa or Davos or operated one at each location are presented for four distinct time periods: 1992–2012 – manual vs. manual operation of collocated Dobson instruments (MMC); 2012–2013 – manual vs. automated operation of collocated Dobson instruments (MAC); 2012–2019 – automated vs. automated operation of collocated Dobson instruments (AAC); 2016–2019 – automated vs. automated operation of distant Dobson instruments (AAD). The direct comparison of two instruments using the standard operation procedure during the MMC period gives a metric necessary to validate the automated version of Dobson instruments. The direct comparison of two collocated instruments using the standard manual operation procedure reveals random differences of coincident observations with a standard deviation of ∼ 0.45 % and monthly mean differences between −1.0 % and +0.8 %. In most cases the observed biases are not statistically significant. The same analysis of two automated Dobson instruments yields significantly smaller standard deviation of ∼ 0.25 % and biases of between −0.7 % and 0.8 %. This demonstrates that the repeatability has improved with the automation, while the systematic differences are only marginally smaller. The analysis of the AAD period of coincident measurements from the distant sites Arosa and Davos reveals a small positive bias (not significant) compatible with the 250 m altitude difference. The description of the automated data acquisition and control of the Dobson instrument is presented in a separate paper (Stübi et al., 2020).

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“…Emissions of these human-manufactured, chlorine-bearing gases began increasing by 1965 as shown by the green line for total tropospheric chlorine [61]. By 1970, total column ozone measured at Arosa Switzerland [62] began decreasing as shown by the black line smoothed with a five-point, centered, running mean (y-axis inverted).…”

Section: Ozone Depletion Caused By Humans Appears To Have Warmed the mentioning

confidence: 99%

“…The first routine measurements of total column ozone looking up vertically from Earth began in Arosa Switzerland in 1927 [62]. Ozone concentrations vary substantially by the second, the minute, the hour, the day, and the month.…”

Section: How Annual Mean Total Column Ozone and Temperatures Have Chamentioning

confidence: 99%

The Photochemistry of Gas Molecules in Earth’s Atmosphere Determines the Structure of the Atmosphere and the Average Temperature at Earth’s Surface

Ward¹

2020

AJPC

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A molecule of oxygen absorbing solar ultraviolet-C radiation is photo-dissociated into two atoms of oxygen that fly apart at high velocity, converting kinetic energy of oscillation of the molecular bond directly and completely into kinetic energy of linear motion of the oxygen atoms. This increases air temperature. Two oxygen atoms can then collide forming a new oxygen molecule that can then be dissociated again as long as sufficient ultraviolet-C radiation exists. This continual dissociation of oxygen molecules is the primary reason for the stratopause being 30-40 degrees warmer than the tropopause and for all ultraviolet-C radiation being absorbed before reaching the lower stratosphere. Furthermore, an oxygen molecule and an oxygen atom can collide to form a molecule of ozone, which is photo-dissociated by solar ultraviolet-B radiation. Normally, 97-99 percent of ultraviolet-B radiation is absorbed in the ozone layer, warming the lower stratosphere. By 1970, however, humans manufacturing chlorofluorocarbon gases caused up to 70% depletion of ozone, cooling the ozone layer and allowing more ultraviolet-B to reach Earth where it photo-dissociates ground-level ozone pollution, raising air temperatures, especially in the most polluted areas. Ultraviolet-B also penetrates oceans tens of meters, efficiently raising ocean heat content. Earth's surface warmed 0.6°C from 1970 to 1998 with warming twice as great in the northern hemisphere containing 90% of global population. In 2014, Bárðarbunga volcano in central Iceland extruded 85 km 2 of basaltic lavas in six months, depleting the ozone layer and warming Earth another 0.3°C by 2016. Throughout Earth history, basaltic lava flows covering areas of up to millions of square kilometers are contemporaneous with sudden global warming-the larger the lava flow, the greater the warming. Large explosive volcanic eruptions, on the other hand, typically form aerosols in the lower stratosphere that spread throughout the world, reflecting and scattering sunlight, cooling Earth approximately 0.5°C for two to four years. Computer modelling shows the effects of this global cooling can still be observed in ocean temperatures a century later. Several large explosive volcanic eruptions per century, continuing for millennia, cool oceans incrementally down into ice-age conditions. Detailed measurements of air temperatures in ice cores at Summit Greenland over the past 122,000 years show that the footprints of climate change are sudden warming within years, followed by slow, incremental cooling over millennia, in highly erratic sequences averaging only a few thousand years in length. Ozone depletion and aerosols are particularly effective because they occur worldwide.

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Stratospheric ozone measurements at Arosa (Switzerland): history and scientific relevance

Cited by 14 publications

References 63 publications

Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties

Tropospheric Ozone Assessment Report: Tropospheric ozone from 1877 to 2016, observed levels, trends and uncertainties

Quality assessment of Dobson spectrophotometers for ozone column measurements before and after automation at Arosa and Davos

The Photochemistry of Gas Molecules in Earth’s Atmosphere Determines the Structure of the Atmosphere and the Average Temperature at Earth’s Surface

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