Actinic flux and O&amp;lt;sup&amp;gt;1&amp;lt;/sup&amp;gt;D photolysis frequencies retrieved from spectral measurements of irradiance at Thessaloniki, Greece

Kazadzis, Stelios; Topaloglou, C.; Bais, A. F.; Blumthaler, M.; Balis, Dimitris; Kazantzidis, Andreas; Schallhart, B.

doi:10.5194/acp-4-2215-2004

Cited by 19 publications

(25 citation statements)

References 34 publications

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“…(6) and no knowledge of the direct to global irradiance ratio (Kylling et al, 2003;Webb et al, 2002). Using global irradiance measurements combined with direct irradiance every 10 nm, Kazadzis et al (2004) estimate an overall uncertainty in F of around 10 % (1σ ).…”

Section: Estimating Actinic Flux Density From Irradiance Measurementsmentioning

confidence: 99%

“…Both omissions have been made for clarity. Most quantitative UV observations measure global irradiance (E) (the radiative power striking a horizontal plane), and so there have been a number of attempts to convert global irradiance into actinic flux (Kazadzis et al, 2004;Kylling et al, 2003;McKenzie et al, 2002;Schallhart et al, 2004;Webb et al, 2002).…”

Section: Estimating Actinic Flux Density From Irradiance Measurementsmentioning

confidence: 99%

“…If the diffuse irradiance is not measured, this can be rearranged into the following relationship suggested by Kazadzis et al (2004).…”

Section: Estimating Actinic Flux Density From Irradiance Measurementsmentioning

confidence: 99%

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Characterisation of J(O1D) at Cape Grim 2000–2005

Wilson

2015

Atmos. Chem. Phys.

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Abstract.Estimates of the rate of production of excited oxygen atoms due to the photolysis of ozone (J (O 1 D)) have been derived from radiation measurements carried out at Cape Grim, Tasmania (40.6 • S, 144.7 • E). The individual measurements have a total uncertainty of 16 % (1σ ). These estimates agree well with model estimates of clear-sky photolysis rates. Observations spanning 2000-2005 have been used to quantify the impact of season, clouds and ozone column amount. The annual cycle of J (O 1 D) has been investigated via monthly means. These means show an interannual variation (monthly standard deviation) of 9 %, but in midsummer and midwinter this reduces to 3-5 %. Variations in solar zenith angle and total column ozone explain 86 % of the observed variability in the measured photolysis rates. The impact of total column ozone, expressed as a radiation amplification factor (RAF), is found to be ∼ 1.53, in agreement with model estimates. This ozone dependence explains 20 % of the variation observed at medium solar zenith angles (30-50 • ). The impact of clouds results in a median reduction of 30 % in J (O 1 D) for the same solar zenith angle range. Including estimates of cloudiness derived from long-wave radiation measurements resulted in a statistically significant fit to observations, but the quality of the fit did not increase significantly as measured by the adjusted R 2 .

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Section: Estimating Actinic Flux Density From Irradiance Measurementsmentioning

confidence: 99%

Section: Estimating Actinic Flux Density From Irradiance Measurementsmentioning

confidence: 99%

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Characterisation of J(O1D) at Cape Grim 2000–2005

Wilson

2015

Atmos. Chem. Phys.

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“…Methods have now been developed for converting irradiance to actinic flux. [27][28][29][30][31][32] The uncertainty in irradiance-derived actinic flux for J(O 1 D) is greater than for directly measured values. The uncertainty in the conversion of irradiance into actinic flux depends on the solar zenith angle, wavelength, and ambient conditions, but can be as low as 7% (95% confidence).…”

Section: Atmospheric Photolysismentioning

confidence: 99%

Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change

Wilson

Solomon

Tang

2007

Photochem Photobiol Sci

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X. (2007). Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change. Photochemical and Photobiological Sciences, 6 (3), 301-310. Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change AbstractIt is well-understood that reductions in air quality play a significant role in both environmental and human health. Interactions between ozone depletion and global climate change will significantly alter atmospheric chemistry which, in turn, will cause changes in concentrations of natural and human-made gasses and aerosols. Models predict that tropospheric ozone near the surface will increase globally by up to 10 to 30 ppbv (33 to 100% increase) during the period 2000 to 2100. With the increase in the amount of the stratospheric ozone, increased transport from the stratosphere to the troposphere will result in different responses in polluted and unpolluted areas. In contrast, global changes in tropospheric hydroxyl radical (OH) are not predicted to be large, except where influenced by the presence of oxidizable organic matter, such as from largescale forest fires. Recent measurements in a relatively clean location over 5 years showed that OH concentrations can be predicted by the intensity of solar ultraviolet radiation. If this relationship is confirmed by further observations, this approach could be used to simplify assessments of air quality. Analysis of surfacelevel ozone observations in Antarctica suggests that there has been a significant change in the chemistry of the boundary layer of the atmosphere in this region as a result of stratospheric ozone depletion. The oxidation potential of the Antarctic boundary layer is estimated to be greater now than before the development of the ozone hole.Recent modeling studies have suggested that iodine and iodine-containing substances from natural sources, such as the ocean, may increase stratospheric ozone depletion significantly in polar regions during spring. Given the uncertainty of the fate of iodine in the stratosphere, the results may also be relevant for stratospheric ozone depletion and measurements of the influence of these substances on ozone depletion should be considered in the future.In agreement with known usage and atmospheric loss processes, tropospheric concentrations of HFC-134a, the main human-made source of trifluoroacetic acid (TFA), is increasing rapidly. As HFC-134a is a potent greenhouse gas; this increasing concentration has implications for climate change. However, the risks to humans and the environment from substances, such as TFA, produced by atmospheric degradation of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are considered minimal. Perfluoropolyethers, commonly used as industrial heat transfer fluids and proposed as chlorohydrofluorocarbon (CHFC) substitutes, show great stability to chemical degradation in the atmosphere. These substances have been suggested as substitutes for CHFCs but, as they are very persistent in t...

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“…Several methods include conversion of ground-based (GB) measurements of irradiance to actinic flux, which is then used for the photolysis frequency calculation (Van Weele at al., 1995;Cotté et al, 1997;Kazadzis et al, 2000;Webb et al, 2002b;Kylling et al, 2003;Schallhart et al, 2004) while more recent work introduces the direct calculation of photolysis frequencies from irradiance from empirical relationships (McKenzie et al, 2002;Seroji et al, 2004;Kazadzis et al, 2004;Topaloglou et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Estimation of photolysis frequencies from TOMS satellite measurements and routine meteorological observations

et al. 2008

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Abstract.A study on the estimation of J(O 1 D) and J(NO 2 ) photolysis frequencies when limited ground based measurements (or even no measurements at all), are available is presented in this work. Photolysis frequencies can be directly measured by chemical actinometry and filter radiometry or can be calculated from actinic flux measurements. In several meteorological stations, none of the methods above are applicable due to the absence of sophisticated instruments such as actinometers, radiometers or spectroradiometers. In this case, it is possible to calculate photolysis frequencies with reasonable uncertainty using either a) standard meteorological observations, such as ozone, cloud coverage and horizontal visibility, available in various ground based stations, as input for a radiative transfer model or b) satellite observations of solar global irradiance available worldwide, in combination with an empirical method for the conversion of irradiance in photolysis frequencies. Both methods can provide photolysis frequencies with a standard deviation between 20% and 30%. The absolute level of agreement of the retrieved frequencies to those calculated from actual actinic flux measurements, for data from all meteorological conditions, is within ±5% for J(O 1 D) and less than 1% for J(NO 2 ) for the first method, while for the second method it rises up to 25% for the case of J(O 1 D) and 12% for J(NO 2 ), reflecting the overestimation of TOMS satellite irradiance when compared to ground based measurements of irradiance for the respective spectral regions. Due to the universality of the methods they can be practically applied to almost any station, thus overcoming problems concerning the availability of instruments measuring photolysis frequencies.

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Actinic flux and O<sup>1</sup>D photolysis frequencies retrieved from spectral measurements of irradiance at Thessaloniki, Greece

Cited by 19 publications

References 34 publications

Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005

Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005

Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change

Estimation of photolysis frequencies from TOMS satellite measurements and routine meteorological observations

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Actinic flux and O&lt;sup&gt;1&lt;/sup&gt;D photolysis frequencies retrieved from spectral measurements of irradiance at Thessaloniki, Greece

Cited by 19 publications

References 34 publications

Characterisation of &lt;i&gt;J&lt;/i&gt;(O&lt;sup&gt;1&lt;/sup&gt;D) at Cape Grim 2000–2005

Characterisation of &lt;i&gt;J&lt;/i&gt;(O&lt;sup&gt;1&lt;/sup&gt;D) at Cape Grim 2000–2005

Changes in tropospheric composition and air quality due to stratospheric ozone depletion and climate change

Estimation of photolysis frequencies from TOMS satellite measurements and routine meteorological observations

Contact Info

Product

Resources

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Actinic flux and O<sup>1</sup>D photolysis frequencies retrieved from spectral measurements of irradiance at Thessaloniki, Greece

Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005

Characterisation of <i>J</i>(O<sup>1</sup>D) at Cape Grim 2000–2005