The contribution of remote sensing to the implementation of the Montreal Protocol and the monitoring of its success

Cracknell, A. P.; Varotsos, C.

doi:10.1080/01431160902821999

Cited by 8 publications

(4 citation statements)

References 66 publications

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“…There are three CFC-11 −0.40 ± 0.07 −0.39 ± 0.08 CFC-12 −0.49 ± 0.05 −0.46 ± 0.05 HCFC-22 2.12 ± 0.13 2.22 ± 0.14 sources of data for the concentration of halocarbons in the atmosphere. First, the in situ measurements at the surface (carried out exactly by the in situ and flask methods) are available from the AGAGE (Dunse et al, 2005) and HATS (Montzka et al, 1993) 6; columns 2 and 4) for the GVMR data are −0.53, −0.59, and 2.0 % yr −1 ; for the FTIR data, they are −0.38, −0.48, and 2.0 % yr −1 for CFC-11, CFC-12, and HCFC-22, respectively. Taking into account the spatial discrepancy, the different nature of the measured quantities and the different measurement conditions (background conditions on the Atlantic coast and measurements near the large agglomeration of St. Petersburg), the agreement between the mean values and the trends can be considered satisfactory.…”

Section: Comparison With Independent Datamentioning

confidence: 99%

Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

et al. 2021

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Abstract. Monitoring atmospheric anthropogenic halocarbons plays an important role in tracking their atmospheric concentrations in accordance with international agreements on emissions of ozone-depleting substances and, thus, in estimating the ozone layer recovery. Within the Network for the Detection of Atmospheric Composition Change (NDACC), regular Fourier transform infrared (FTIR) measurements can provide information on the abundancies of halocarbons on a global scale. We improved retrieval strategies for deriving the CFC-11 (CCl3F), CFC-12 (CCl2F2), and HCFC-22 (CHClF2) atmospheric columns from IR solar radiation spectra measured by the Bruker IFS125HR spectrometer at the St. Petersburg site (Russia). We used the Tikhonov–Phillips regularization approach for solving the inverse problem with optimized values of regularization parameters. We tested the strategies developed by comparison of the FTIR measurements with independent data. The analysis of the time series of column-averaged dry air mole fractions (Xgas) measured in 2009–2019 gives mean values of 225 pptv (parts per trillion by volume; CFC-11), 493 pptv (CFC-12), and 238 pptv (HCFC-22). Trend values total −0.40 % yr−1 (CFC-11), −0.49 % yr−1 (CFC-12), and 2.12 % yr−1 (HCFC-22). We compared the means, trends, and seasonal variability in XCFC-11, XCFC-12, and XHCFC-22 to that of (1) near-ground volume mixing ratios (VMRs), measured at the observational site Mace Head, Ireland (GVMR), (2) the mean in the 8–12 km layer VMRs, measured by ACE-FTS and averaged over 55–65∘ N latitudes (SVMR), and (3) Xgas values of the Whole Atmosphere Community Climate Model (WACCM) for the St. Petersburg site (WXgas). In general, the comparison of Xgas with the independent data showed a good agreement of their means within the systematic errors of the measurements considered. The trends observed over the St. Petersburg site demonstrate the smaller decrease rates for XCFC-11 and XCFC-12 than that of the independent data and the same increase rate for XHCFC-22. As a whole, Xgas, SVMR, and WXgas showed qualitatively similar seasonal variations, while the GVMR variability is significantly less, and only the WXHCFC-22 variations are essentially smaller than that of XHCFC-22 and SVMRHCFC-22.

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Section: Comparison With Independent Datamentioning

confidence: 99%

Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

et al. 2021

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“…The fact that the earliest studies and the preliminary data records of TOC were made using the Dobson spectrophotometer it makes this instrument a reference device for TOC data obtained by other ground-based and satellite borne instrumentation. As a result, any new device, on board a satellite or ground-based, that is constructed for TOC measurements is validated against Dobson which is considered as a standard instrument (Bernhard et al, 2003;McPeters et al, 2008;Cracknell and Varotsos, 2009, 2012Tzanis, 2005Tzanis, , 2009. So, it is important to understand and study all sources of errors in Dobson instrument operations that could lead to a false measurement or miscalculation of TOC.…”

Section: Introductionmentioning

confidence: 99%

An assessment of the stray-light in 25 years Dobson total ozone data at Athens, Greece

Christodoulakis¹,

Varotsos²,

Cracknell³

et al. 2015

Preprint

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Abstract. In this study, we investigated the susceptibility of the Dobson spectrophotometer No. 118 to stray-light interference. In this regard, a series of total ozone content measurements were carried out in Athens, Greece for airmass values (μ) extending up to μ = 5. The monochromatic-heterochromatic stray-light derived by Basher's model was used in order to evaluate the specific instrumental parameters which determine if this instrument suffers from this problem or not. The results obtained indicate that the Athens Dobson instrument appears to have an insignificant stray-light error. The comparison of the values of the same parameters measured 15 years ago with the present ones indicates the good maintenance of the Dobson spectrophotometer No. 118. This fact is of crucial importance because the variability of the daily total ozone observations collected by the Athens Dobson Station since 1989 has proved to be representative to the variability of the mean total ozone observed over the whole mid-latitude zone of the Northern Hemisphere. This stresses the point that the Athens total ozone station, being the unique Dobson station in south eastern Europe, may be assumed as a ground-truth station for the reliable conversion of the satellite radiance observations to total ozone measurements.

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“…Since Molina and Rowland (1974) have reported that CFCs accumulated in the Earth's atmosphere lead to an increased rate of ozone depletion, the attention of both scientists and policymakers to the ozone hole problem has been increasing. Detecting and monitoring the ozone and other stratospheric gases as well as the ozone depleting substances including CFCs are crucial for testing the theories of the ozone hole formation mechanism (Cracknell and Varotsos, 2009).…”

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confidence: 99%

Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

Polyakov¹,

Poberovsky²,

Makarova³

et al. 2020

Preprint

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Abstract. The retrieval strategies for deriving the atmospheric total columns (TCs) of CFC-11 (CCl3F), CFC-12 (CCl2F2), and HCFC-22 (CHClF2) from ground–based measurements of IR solar radiation have been improved. We demonstrate the advantage of using the Tikhonov-Phillips regularization approach for solving the inverse problem of the retrieval of these gases and give the optimized values of regularization parameters. The estimates of relative systematic and random errors amount to 7.61 % and 3.08 %, 2.24 % and 2.40 %, 5.75 % and 3.70 %, for CFC-11, CFC-12, and HCFC-22, respectively. We analyze the time series of the TCs and mean molar fractions (MMFs) of CFC-11, CFC-12, and HCFC-22 measured at the NDACC site St. Petersburg located near Saint Petersburg, Russia for the period of 2009–2019. Mean values of the MMFs for CFC-11, CFC-12, and HCFC-22 total 225, 493, and 238 pptv, respectively. Estimates of the MMFs trends for CFC-11, CFC-12, and HCFC-22 account for −0.40 ± 0.07 %/yr, -0.49 ±0.05 %/yr, and 2.12±0.13 %/yr, respectively. We have compared the mean values, trends and seasonal variability of CFC-11, CFC-12, and HCFC-22 MMFs measured at the St. Petersburg site in 2009–2019 to that of 1) near–ground volume mixing ratios (VMRs) measured at the observational site Mace Head, Ireland (GVMR); 2) the mean in the 8–12 km layer VMRs measured by ACE–FTS and averaged over 55–65° N latitudes (SVMR); and the MMFs of the Whole Atmosphere Community Climate Model for the St. Petersburg site (WMMF). The means of the MMFs are less than that of the GVMR for CFC-11 by 9 pptv (3.8 %), for CFC-12 by 24 pptv (4.6 %); for HCFC-22, the mean MMFs does not differ significantly from the mean GVMR. The absolute value of the trend estimates of the MMFs is less than that of the GVMR for CFC-11 (−0.40 vs −0.53 %/yr) and CFC-12 (−0.49 vs −0.59 %yr); the trend estimate of the HCFC-22 MMFs does not differ significantly from that of the GVMR. The seasonal variability of the GVMR for all three gases is much lower than the MMFs variability. The means of the MMFs are less than that of the SVMR for CFC-11 by 10 pptv (4.3 %), for CFC-12 by 33 pptv (6.3 %), and for HCFC-22 by 2 pptv (0.8 %). The absolute value of the trend estimates of the MMFs is less than that of the SVMR for CFC-11 (−0.40 vs −0.63 %/yr) and CFC-12 (−0.49 vs −0.58 %/yr); the trend estimate of the HCFC-22 MMFs does not differ significantly from that of the SVMR. The MMF and SVMR values show nearly the same qualitative and quantitative seasonal variability for all three gases. The means of the MMFs are greater than that of the WMMF for CFC-11 by 22 pptv (10 %), for CFC-12 by 15 pptv (3.1 %), and for HCFC-22 by 23 pptv (10 %). The absolute value of the trend estimates of the MMFs is less than that of the WMMF for CFC-11 (−0.40 vs −1.68 %/yr), CFC-12 (−0.49 vs −0.84 %/yr), and HCFC-22 (2.12 %/yr vs 3.40 %/yr). The MMFs and WMMF values show nearly the same qualitative and quantitative seasonal variability for CFC-11 and CFC-12, whereas the seasonal variability of the WMMF for HCFC-22 is essentially less than that of the MMFs. In general, the comparison of the MMFs with the independent data shows a good agreement of their means within the systematic error of considered measurements. The observed trends over the St. Petersburg site demonstrate the smaller decrease rates for CFC-11 and CFC-12 TCs than that of the independent data, and the same decrease rate for HCFC-22. The suggested retrieval strategies can be used for analysis of the IR solar spectra measurements using Bruker FS125HR spectrometers, e.g. at other IRWG sites of the NDACC observational network.

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The contribution of remote sensing to the implementation of the Montreal Protocol and the monitoring of its success

Cited by 8 publications

References 66 publications

Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

An assessment of the stray-light in 25 years Dobson total ozone data at Athens, Greece

Measurements of CFC-11, CFC-12, and HCFC-22 total columns in the atmosphere at the St. Petersburg site in 2009–2019

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