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 CO 2 concentration was observed. The seasonal cycles 1996-1997 were similar, with a peak-to-peak amplitude of the selected and smoothed CO 2 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 CO 2 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 CO 2 cycle by the recent El Niño event. The mean CH 4 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 CO 2 and CH 4 are strongly correlated during winter months: the average monthly mean slope of the linear relationship between CH 4 and CO 2 was 10.7 ± 0.3 ppbCH 4 per ppmCO 2 . During summer months this strong correlation breaks down. Diurnal changes of CO 2 and CH 4 mixing ratios observed at Kasprowy Wierch are typical for continental mountain sites, with a distinct minimum of CO 2 during afternoon hours in summer and maximum during winter. For CH 4 , 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 CO 2 and 30 ppb for CH 4 , whereas during winter (February) they diminished to 1.5 ppm and 10 ppb, respectively.

Anthropogenic changes of CO2, CH4, N2O, CFCl3, CF2Cl2, CCl2FCClF2, CHCl3, CH3CCl3, CCl4, SF6 and SF5CF3 mixing ratios in the atmosphere over southern Poland

“…Shown are daily means of the mea sured mix ing ra tios, cal cu lated af ter ap pro priate data se lec tion pro ce dure. A three-step pro ce dure was applied to se lect the data rep re sent ing back ground con di tions at the sta tion (Necki et al, 2003). Daily mean val ues were fur ther smoothed us ing the rou tine rec om mended by NOAA (CCGvu 4.40; Thoning et al, 1989).…”

“…At mo spheric mix ing ra tios of car bon di ox ide and meth ane are mea sured at Kasprowy Wierch and in Kraków us ing au to matic gas chromatographs (Hewlet Packard 5890 and Agilent 6890N, re spec tively) equipped with a flame ion iza tion de tec tor (FID), a 3 m col umn (Porapak QS) and nickel cat a lyst con vert ing car bon di ox ide to meth ane (Necki et al, 2003). Ni trous ox ide is mea sured at Kasprowy Wierch us ing an elec tron cap ture de tec tor (ECD) and dou ble-col umn sys tem con fig ured in a back-flush mode (2 m pre-col umn Hysep Q 80/100 and 4 m an a lyt i cal col umn Hysep Q 80/100).…”

“…60% were re corded. At Kasprowy Wierch such daily fluc tu a tions are much weaker and are shifted in-phase, with the min ima dur ing night-time and the max ima dur ing early af ter noon (Necki et al, 2003). Fig ure 7 shows a com par i son of SF 6 mix ing ra tios measured at Kasprowy Wierch and in Kraków dur ing the pe riod 2011-2012.…”

“…Since Kasprowy Wierch is sit u ated within the tran si tion zone be tween the free tro po sphere and the plan e tary bound ary layer (PBL) and is rel a tively free of lo cal in flu ences, this site is con sid ered a re gional ref er ence sta tion for trace gas mea surements in the lower at mo sphere over Cen tral and East ern Europe. Since 1994, reg u lar ob ser va tions of at mo spheric mix ing ra tios of CO 2 and CH 4 have been per formed at this site (Necki et al, 2003;Chmura et al, 2008;Nêcki et al, 2013). From Septem ber 1994 till June 1996 weekly com pos ite sam ples of air were col lected and the CO 2 and CH 4 con cen tra tion was measured at the In sti tute of En vi ron men tal Phys ics, Uni ver sity of Hei del berg, Ger many.…”

“…The data points rep re sent flask sam ples col lected at both sites. At Kasprowy Wierch site the sam ples were collected dur ing night hours (2-4 a.m.) when the free tro po sphere is sam pled by the sta tion and the data rep re sent re gional background con di tions (Necki et al, 2003). In Kraków, sam pling was typ i cally done dur ing mid day when ver ti cal mix ing of the lo cal at mo sphere is the most in tense.…”