Ozone balloon soundings at Payerne (Switzerland): Reevaluation of the time series 1967–2002 and trend analysis

Jeannet, P.; Stübi, René; Levrat, G.; Viatte, P.; Staehelin, J.

doi:10.1029/2005jd006862

Cited by 34 publications

(36 citation statements)

References 46 publications

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“…The trends derived using all MOZAIC profiles (and not only morning profiles) show a negative summer trend of around −0.7 ppbv yr −1 . These results for surface ozone are in agreement with previous studies (Ordóñez et al, 2005;Zbinden et al, 2006;Jonson et al, 2006;Oltmans et al, 2006;Jeannet et al, 2007;Gilge et al, 2010). They most probably result from the decrease in ozone precursor emissions during this period.…”

Section: Sampling Effect On Ozone Trendssupporting

confidence: 83%

Impact of sampling frequency in the analysis of tropospheric ozone observations

et al. 2012

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Abstract. Measurements of ozone vertical profiles are valuable for the evaluation of atmospheric chemistry models and contribute to the understanding of the processes controlling the distribution of tropospheric ozone. The longest record of ozone vertical profiles is provided by ozone sondes, which have a typical frequency of 4 to 12 profiles a month. Here we quantify the uncertainty introduced by low frequency sampling in the determination of means and trends. To do this, the high frequency MOZAIC (Measurements of OZone, water vapor, carbon monoxide and nitrogen oxides by inservice AIrbus airCraft) profiles over airports, such as Frankfurt, have been subsampled at two typical ozone sonde frequencies of 4 and 12 profiles per month. We found the lowest sampling uncertainty on seasonal means at 700 hPa over Frankfurt, with around 5 % for a frequency of 12 profiles per month and 10 % for a 4 profile-a-month frequency. However the uncertainty can reach up to 15 and 29 % at the lowest altitude levels. As a consequence, the sampling uncertainty at the lowest frequency could be higher than the typical 10 % accuracy of the ozone sondes and should be carefully considered for observation comparison and model evaluation. We found that the 95 % confidence limit on the seasonal mean derived from the subsample created is similar to the sampling uncertainty and suggest to use it as an estimate of the sampling uncertainty. Similar results are found at six other Northern Hemisphere sites. We show that the sampling substantially impacts on the inter-annual variability and the trend derived over the period 1998-2008 both in magnitude and in sign throughout the troposphere. Also, a tropical case is discussed using the MOZAIC profiles taken over Windhoek, Namibia between 2005 and 2008. For this site, we found that the sampling uncertainty in the free troposphere is around 8 and 12 % at 12 and 4 profiles a month respectively.

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Section: Sampling Effect On Ozone Trendssupporting

confidence: 83%

Impact of sampling frequency in the analysis of tropospheric ozone observations

et al. 2012

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“…We only used data for which the correction factor belong to the range 0.9-1.35, as recommended by Logan (1994). More details on this ozonesonde data, measurements procedures, are given by Jeannet et al (2007) and the references therein. Marenco et al (1994) exploited ancient measurements at the Pic du Midi (PDM) station, and showed that the mean ozone concentration in the free troposphere has increased by a factor of 5 since the end of the 19th century, to reach between 47 and 48 ppb in the early 1990s.…”

Section: Balloon Soundingsmentioning

confidence: 99%

Influence of altitude on ozone levels and variability in the lower troposphere: a ground-based study for western Europe over the period 2001–2004

et al. 2007

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Abstract. The PAES (French acronym for synoptic scale atmospheric pollution) network focuses on the chemical composition (ozone, CO, NOx/y and aerosols) of the lower troposphere (0–3000 m). Its high-altitude surface stations located in different mountainous areas in France complete the low-altitude rural MERA stations (the French contribution to the european program EMEP, European Monitoring and Evaluation Program). They are representative of pollution at the scale of the French territory because they are away from any major source of pollution. This study deals with ozone observations between 2001 and 2004 at 11 stations from PAES and MERA, in addition to 16 elevated stations located in mountainous areas of Switzerland, Germany, Austria, Italy and Spain. The set of stations covers a range of altitudes between 115 and 3550 m. The comparison between recent ozone mixing ratios to those of the last decade at Pic du Midi (2877 m), as well as trends calculated over 14-year data series at three high-altitude sites in the Alps (Jungfraujoch, Sonnblick and Zugspitze) reveal that ozone is still increasing but at a slower rate than in the 1980s and 1990s. The 2001–2004 mean levels of ozone from surface stations capture the ozone stratification revealed by climatological profiles from the airborne observation system MOZAIC (Measurement of OZone and water vapour by Airbus In-service airCraft) and from ozone soundings above Payerne (Switzerland). In particular all data evidence a clear transition at about 1000–1200 m a.s.l. between a sharp gradient below (of the order of +30 ppb/km) and a gentler gradient (+3 ppb/km) above. The same altitude (1200 m) is also found to be a threshold regarding how well the ozone levels at the surface stations agree with the free-tropospheric reference (MOZAIC or soundings). Below the departure can be as large as 40%, but suddenly drops within 15% above. For stations above 2000 m, the departure is even less than 8%. Ozone variability also reveals a clear transition between boundary-layer and free-tropospheric regimes around 1000 m a.s.l. Below, diurnal photochemistry accounts for about the third of the variability in summer, but less than 20% above – and at all levels in winter – where ozone variability is mostly due to day-to-day changes (linked to weather conditions or synoptic transport). In summary, the altitude range 1000–1200 m clearly turns out in our study to be an upper limit below which specific surface effects dominate the ozone content. Monthly-mean ozone mixing-ratios show at all levels a minimum in winter and the classical summer broad maximum in spring and summer – which is actually the superposition of the tropospheric spring maximum (April–May) and regional pollution episodes linked to persistent anticyclonic conditions that may occur from June to September. To complement this classical result it is shown that summer maxima are associated with considerably more variability than the spring maximum. This ensemble of findings support the relevance of mountain station networks such as PAES for the long-term observation of free-tropospheric ozone over Europe.

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“…Payerne has higher correction or scaling factors (CF) than MOHp, probably because the pump temperature was assumed constant at 280 K instead of 300 K (see also Jeannet et al, 2007). The CF is determined as the ratio between the total O 3 column measured by the ozonesonde and a nearby independent column measurement, such as from Dobson or Brewer spectrometers.…”

Section: Ozonesondesmentioning

confidence: 99%

Trajectory matching of ozonesondes and MOZAIC measurements in the UTLS – Part 2: Application to the global ozonesonde network

et al. 2014

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Abstract. Both balloon-borne electrochemical ozonesondes and MOZAIC (measurements of ozone, water vapour, carbon monoxide and nitrogen oxides by in-service Airbus aircraft) provide very valuable data sets for ozone studies in the upper troposphere/lower stratosphere (UTLS). Although MOZAIC's highly accurate UV-photometers are regularly inspected and recalibrated annually, recent analyses cast some doubt on the long-term stability of their ozone analysers. To investigate this further, we perform a 16 yr comparison (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)) of UTLS ozone measurements from balloon-borne ozonesondes and MOZAIC. The analysis uses fully three-dimensional trajectories computed from ERA-Interim (European Centre for Medium-Range Weather Forecasts Re-analysis) wind fields to find matches between the two measurement platforms. Although different sensor types (Brewer-Mast and Electrochemical Concentration Cell ozonesondes) were used, most of the 28 launch sites considered show considerable differences of up to 25 % compared to MOZAIC in the mid-1990s, followed by a systematic tendency to smaller differences of around 5-10 % in subsequent years. The reason for the difference before 1998 remains unclear, but observations from both sondes and MOZAIC require further examination to be reliable enough for use in robust long-term trend analyses starting before 1998. According to our analysis, ozonesonde measurements at tropopause altitudes appear to be rather insensitive to changing the type of the Electrochemical Concentration Cell ozonesonde, provided the cathode sensing solution strength remains unchanged. Scoresbysund (Greenland) showed systematically 5 % higher readings after changing from Science Pump Corporation sondes to ENSCI Corporation sondes, while a 1.0 % KI cathode electrolyte was retained.

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Ozone balloon soundings at Payerne (Switzerland): Reevaluation of the time series 1967–2002 and trend analysis

Cited by 34 publications

References 46 publications

Impact of sampling frequency in the analysis of tropospheric ozone observations

Impact of sampling frequency in the analysis of tropospheric ozone observations

Influence of altitude on ozone levels and variability in the lower troposphere: a ground-based study for western Europe over the period 2001–2004

Trajectory matching of ozonesondes and MOZAIC measurements in the UTLS – Part 2: Application to the global ozonesonde network

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