Trend analysis of greenhouse gases over Europe measured by a network of ground-based remote FTIR instruments

Gardiner, Tom; Forbes, Alistair; Mazière, Martine De; Vigouroux, Corinne; Mahieu, Emmanuel; Demoulin, P.; Velazco, Voltaire A.; Notholt, Justus; Blumenstock, T.; Hase, Frank; Kramer, I.; Sussmann, Ralf; Stremme, Wolfgang; Mellqvist, J.; Strandberg, A.; Ellingsen, K.; Gauss, Michael

doi:10.5194/acp-8-6719-2008

Cited by 127 publications

(140 citation statements)

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“…The division into 3 time periods is in agreement with dedicated trend change points defined and used for methane in earlier work (Dlugokencky et al, 2003Angelbratt et al, 2011). Our trend analysis is based on the approach described in Gardiner et al (2008). See Table 2 for the resulting figures.…”

Section: Sounding Techniquementioning

confidence: 68%

Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

et al. 2012

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Section: Sounding Techniquementioning

confidence: 68%

Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

et al. 2012

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“…As p 1 p 2 represents the trend in molec/(cm 2 yr), the normalised (from now on called "relative") trend corresponds to the parameter p 2 , given in %/yr here. When calculating trends of stratospheric and tropospheric trace gases from measurements by FTIR instruments, Gardiner et al (2008) found that a third order Fourier series was the best balance between representing the time series and avoid over-fitting the data.…”

Section: Trend Analysis Methodsmentioning

confidence: 99%

Trends of HCl, ClONO<sub>2</sub>, and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden) in comparison with KASIMA model calculations

et al. 2011

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Abstract. Trends of hydrogen chloride (HCl), chlorine nitrate (ClONO 2 ), and hydrogen fluoride (HF) total column abundances above Kiruna (Northern Sweden, 67.84 • N, 20.41 • E) derived from nearly 14 years (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009) To calculate the long-term trends, a linear function combined with an annual cycle was fitted to the data using a least squares method. The precision of the resulting trends was estimated with the bootstrap resampling method.For HF, both model and measurements show a positive trend that seems to decrease in the last few years. This suggests a stabilisation of the HF total column abundance. Between 1996 and 2009, KASIMA simulates an increase of (+1.51±0.07) %/yr which exceeds the FTIR result of (+0.65±0.25) %/yr.The trends determined for HCl and ClONO 2 are significantly negative over the time period considered here. This is expected because the emission of their precursors (chlorofluorocarbons and hydrochlorofluorocarbons) has been restricted in the Montreal Protocol in 1987 and its amendments and adjustments. The trend for ClONO 2 from the FTIR measurements amounts to (−3.28±0.56)%/yr and the one for HCl to (−0.81±0.23)%/yr. KASIMA simulates a weaker Correspondence to: R. Kohlhepp (regina.kohlhepp@kit.edu) decrease: For ClONO 2 , the result is (−0.90±0.10) %/yr and for HCl (−0.17±0.06) %/yr. Part of the difference between measurement and model data can be explained by sampling and the stronger annual cycle indicated by the measurements. There is a factor of about four between the trends of HCl and ClONO 2 above Kiruna for both measurement and model data.

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“…The analysis is based on the approach described in Gardiner et al (2008). Briefly, the approach augments a basic linear trend model applied to the time series after substraction of a fitted intraannual function and uses least squares regression in conjunction with a bootstrap resampling of the residuals in order to determine confidence limits associated with the trend estimates.…”

Section: Iwv Trendsmentioning

confidence: 99%

Technical Note: Harmonized retrieval of column-integrated atmospheric water vapor from the FTIR network – first examples for long-term records and station trends

et al. 2009

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Abstract. We present a method for harmonized retrieval of integrated water vapor (IWV) from existing, long-term, measurement records at the ground-based mid-infrared solar FTIR spectrometry stations of the Network for the Detection of Atmospheric Composition Change (NDACC). Correlation of IWV from FTIR with radiosondes shows an ideal slope of 1.00(3). This optimum matching is achieved via tuning one FTIR retrieval parameter, i.e., the strength of a Tikhonov regularization constraining the derivative (with respect to height) of retrieved water profiles given in per cent difference relative to an a priori profile. All other FTIR-sonde correlation parameters (intercept=0.02(12) mm, bias=0.02(5) mm, standard deviation of coincident IWV differences (stdv)=0.27 mm, R=0.99) are comparable to or better than results for all other ground-based IWV sounding techniques given in the literature. An FTIR-FTIR side-byside intercomparison reveals a strong exponential increase in stdv as a function of increasing temporal mismatch starting at t≈1 min. This is due to atmospheric water vapor variability. Based on this result we derive an upper limit for the precision of the FTIR IWV retrieval for the smallest t (=3.75 min) still giving a statistically sufficient sample (32 coincidences), i.e., precision(IWV FTIR )<0.05 mm (or 2.2% of the mean IWV). The bias of the IWV retrievals from the two different FTIR instruments is nearly negligible (0.02(1) mm). The optimized FTIR IWV retrieval is set up in the standard NDACC algorithm SFIT 2 without changes Correspondence to: R. Sussmann (ralf.sussmann@kit.edu) to the code. A concept for harmonized transfer of the retrieval between different stations deals with all relevant control parameters; it includes correction for differing spectral point spacings (via regularization strength), and final quality selection of the retrievals (excluding the highest residuals (measurement minus model), 5% of the total).As [1996][1997][1998][1999][2000][2001][2002][2003][2004][2005][2006][2007][2008], whereas for the Jungfraujoch no significant trend is found. This confirms recent findings that strong variations of IWV trends do occur above land on the local to regional scale (≈250 km) in spite of homogeneous surface temperature trends. This paper provides a basis for future exploitation of more than a dozen existing, multi-decadal FTIR measurement records around the globe for climate studies.

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Trend analysis of greenhouse gases over Europe measured by a network of ground-based remote FTIR instruments

Cited by 127 publications

References 9 publications

Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

Trends of HCl, ClONO<sub>2</sub>, and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden) in comparison with KASIMA model calculations

Technical Note: Harmonized retrieval of column-integrated atmospheric water vapor from the FTIR network – first examples for long-term records and station trends

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Trend analysis of greenhouse gases over Europe measured by a network of ground-based remote FTIR instruments

Cited by 127 publications

References 9 publications

Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

Renewed methane increase for five years (2007–2011) observed by solar FTIR spectrometry

Trends of HCl, ClONO&lt;sub&gt;2&lt;/sub&gt;, and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden) in comparison with KASIMA model calculations

Technical Note: Harmonized retrieval of column-integrated atmospheric water vapor from the FTIR network – first examples for long-term records and station trends

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Trends of HCl, ClONO<sub>2</sub>, and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden) in comparison with KASIMA model calculations