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Seasonal, synoptic, and diurnal‐scale variability of biogeochemical trace gases and O 2 from a 300‐m tall tower in central Siberia
Author(s) -
Kozlova Elena A.,
Manning Andrew C.,
Kisilyakhov Yegor,
Seifert Thomas,
Heimann Martin
Publication year - 2008
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1029/2008gb003209
Subject(s) - biogeochemical cycle , trace gas , environmental science , atmospheric sciences , amplitude , orography , climatology , geology , precipitation , chemistry , meteorology , geography , environmental chemistry , physics , quantum mechanics
We present first results from 19 months of semicontinuous concentration measurements of biogeochemical trace gases (CO 2 , CO, and CH 4 ) and O 2 , measured at the Zotino Tall Tower Observatory (ZOTTO) in the boreal forest of central Siberia. We estimated CO 2 and O 2 seasonal cycle amplitudes of 26.6 ppm and 134 per meg, respectively. An observed west‐east gradient of about −7 ppm (in July 2006) between Shetland Islands, Scotland, and ZOTTO reflects summertime continental uptake of CO 2 and is consistent with regional modeling studies. We found the oceanic component of the O 2 seasonal amplitude (Atmospheric Potential Oxygen, or APO) to be 51 per meg, significantly smaller than the 95 per meg observed at Shetlands, illustrating a strong attenuation of the oceanic O 2 signal in the continental interior. Comparison with the Tracer Model 3 (TM3) atmospheric transport model showed good agreement with the observed phasing and seasonal amplitude in CO 2 ; however, the model exhibited greater O 2 (43 per meg, 32%) and smaller APO (9 per meg, 18%) amplitudes. This seeming inconsistency in model comparisons between O 2 and APO appears to be the result of phasing differences in land and ocean signals observed at ZOTTO, where ocean signals have a significant lag. In the first 2 months of measurements on the fully constructed tower (November and December 2006), we observed several events with clear vertical concentration gradients in all measured species except CO. During “cold events” (below −30°C) in November 2006, we observed large vertical gradients in CO 2 (up to 22 ppm), suggesting a strong local source. The same pattern was observed in CH 4 concentrations for the same events. Diurnal vertical CO 2 gradients in April to May 2007 gave estimates for average nighttime respiration fluxes of 0.04 ± 0.02 mol C m −2 d −1 , consistent with earlier eddy covariance measurements in 1999–2000 in the vicinity of the tower.