Six-year record of atmospheric carbon dioxide and methane at a high-altitude mountain site in Poland

Abstract

Carbon dioxide and methane observations from the continental mountain station Kasprowy Wierch in the Tatra Mountains, southern Poland, are presented. They cover a six‐year period from 1994 to 2000. Significant year‐to‐year variability of CO2 concentration was observed. The seasonal cycles 1996–1997 were similar, with a peak‐to‐peak amplitude of the selected and smoothed CO2 record of approximately 20 ppm and no significant increase of the annual mean values. For 1998 and 1999 large increases of the annual mean values by 3.3 and 4.0 ppm per year, respectively, were observed. This increase was accompanied by a reduction of the seasonal amplitude of the smoothed record to approximately 15 ppm in 1998 and 16 ppm in 1999. In 2000 the seasonal amplitude increased again to a value similar as in 1996/1997, whereas the mean annual value remained close to that recorded for 1999. Similar features can also be traced in the selected and smoothed CO2 record for Schauinsland station, Germany, located ca. 1000 km west of Kasprowy Wierch. These similarities strongly suggest that both stations are capturing the same large‐scale European phenomena, most probably related to a disturbance of the CO2 cycle by the recent El Niño event. The mean CH4 mixing ratio at Kasprowy Wierch for the period 1996–1999 was about 30 ppb higher than over the Atlantic Ocean, confirming previous observations that the European continent is a net source of methane throughout the year. No significant seasonal cycle of methane has been observed at Kasprowy Wierch. The short‐term changes of CO2 and CH4 are strongly correlated during winter months: the average monthly mean slope of the linear relationship between CH4 and CO2 was 10.7 ± 0.3 ppbCH4 per ppmCO2. During summer months this strong correlation breaks down. Diurnal changes of CO2 and CH4 mixing ratios observed at Kasprowy Wierch are typical for continental mountain sites, with a distinct minimum of CO2 during afternoon hours in summer and maximum during winter. For CH4, diurnal cycles have similar shape throughout the year, with a broad maximum during daytime. The mean peak‐to‐peak amplitudes for summer (July) were 4.5 ppm for CO2 and 30 ppb for CH4, whereas during winter (February) they diminished to 1.5 ppm and 10 ppb, respectively.

Three years of semicontinuous greenhouse gas measurements at the Puy de Dôme station (central France)

“…The mean diurnal cycles of the long-lived GHGs and 222 Rn observed in this study are typical of mountain sites, as previously described by Schmidt et al (1996) for the Schauinsland station (1205 m a.s.l.) or Necki et al (2003) for the Kasprowy Wierch station (Poland, 1987 m a.s.l.). The PBL height is a key atmospheric factor, particularly for mountain sites where measurements alternate between the free troposphere and the PBL.…”

Pollution Events at the High-Altitude Mountain Site Zugspitze-Schneefernerhaus (2670 m a.s.l.), Germany

“…), Germany, with a mean ratio of 7.8 ± 1.0 ppb/ppm [52], and the Kasprowy Wierch (1987 m a.s.l. ), Poland, with 10.7 ± 0.3 ppm/ppb [51]). Schmidt et al [52] list a single diurnal cycle of CH 4 and CO 2 at the JFJ in December 1988, where the emission ratio was 5.3 ± 0.9 ppb/ppm.…”

“…Occasionally the emission ratios are calculated as ∆CO/∆CO 2 or ∆CH 4 /∆CO 2 , where ∆ denotes the difference of the total concentration to the background concentration (which is individually defined using particular techniques (e.g., [49,50])). In some studies, the emission ratio is calculated as CO/∆CO 2 , whereas sometimes no background is removed (e.g., [51,52]). In this paper, in order to be consistent with the Keeling plot data selection, we calculated emission ratios on the total emission ratios for periods from the minimum (when the CO 2 mixing ratio started to increase) to the maximum (when the highest value of the CO 2 mixing ratio was reached).…”

Comparison of the regional CO<sub>2</sub> mole fraction filtering approaches at a WMO/GAW regional station in China

“…Indeed, the positive coefficients still suggest that the anthropogenic emissions dominate the carbon cycle at the LAN station. In remote areas, an uncorrelated or negatively correlated relationship is generally observed (e.g., Necki et al, 2003). As described above, we also used the robust extraction of baseline signal (REBS) method to filter the CH 4 data because it has proven to be suitable for extracting the background mole fractions of CH 4 at remote sites (Cunnold et al, 2002).…”

“…For this purpose, lots of groundbased stations have been set up to monitor the CO 2 mole fractions around the world. So far, there are more than 150 sites worldwide where greenhouse gas mole fractions are measured (Artuso et al, 2009;Dlugokencky et al, 1995;Necki et al, 2003;Sirignano et al, 2010;Tans et al, 1990;WMO, 2015). Due to technical and logistical constraints like access to the measurement site, power supply or internet connection, very few monitoring stations are sufficiently remote to be permanently exposed to pristine air masses, while many Global Atmosphere Watch (GAW) stations are occasionally too frequently affected by local sources or sinks (Tsutsumi Published by Copernicus Publications on behalf of the European Geosciences Union.…”