アイテム詳細

要旨

The Siberian region is still sparsely covered by ecosystem observatories, which motivates to exploit existing datasets to gain spatially and temporally better-resolved carbon fluxes. The Zotino Tall Tower Observatory (ZOTTO, 60480 N, 89210 E) observations of 5 CO2 and CH4 mole fractions as well as meteorological parameters from six different heights up to 301m allow for an additional estimate of surface-atmosphere fluxes of CO2 and CH4 for the Middle-Siberian region since 2009. The total carbon flux is calculated from the storage and the turbulent flux component. The gradients between the different tower levels determine the storage flux component, which dominates the local 10 fluxes, especially during night. As a correction term, the turbulent flux component was estimated by the modified Bowen ratio method based on the sensible heat flux measurements at the top of the tower. The gained average night time fluxes (23:00 to 04:00 local time) are 2.7±1.1 μmol (m2 s)−1 for CO2 and 5.6±4.5 nmol (m2 s)−1 for CH4 during the summer months June-September in 2009 and 2011. During day, the method 15 is limited due to numeric instabilities from vanishing vertical gradients; however, the derived CO2 fluxes exhibit reasonable diurnal shape and magnitude compared to the eddy covariance technique, which become available at the site in 2012. Therefore, the tall tower data facilitates the extension of the new eddy covariance flux dataset back in time. The diurnal signal of the CH4 flux is predominantly characterized by a strong 20 morning transition, which is explained by local topographic effects.