The Exchange of Energy, Water and Carbon Dioxide between Wet Arctic Tundra and the Atmosphere at the Lena River Delta, Northern Siberia

• Main Author: Kutzbach, Lars
• Format: Thesis
• Language: unknown
• Published: Universität Hamburg 2006
• Subjects: Arctic; Arctic Ocean; Ice; lena river; permafrost; Tundra; Siberia
• Online Access: https://epic.awi.de/id/eprint/45207/; https://epic.awi.de/id/eprint/45207/1/Dissertation_Kutzbach_2006.pdf; http://ediss.sub.uni-hamburg.de/volltexte/2007/3177/; https://hdl.handle.net/10013/epic.51369; https://hdl.handle.net/10013/epic.51369.d001

The ecosystem-scale exchange fluxes of energy, water and carbon dioxide (CO2) between wet arctic tundra and the atmosphere were investigated by the micrometeoro-logical eddy covariance method. The investigation site was situated in the centre of the Lena River Delta in Northern Siberia (72°22'N, 126°30'E). The micrometeorological campaigns were performed from July to October 2003 and from May to July 2004. The study region is characterised by a polar and distinctly continental climate, very cold and ice-rich permafrost and its position at the interface between the Eurasian continent and the Arctic Ocean. The measurements were performed on the surface of a Holocene river terrace, which is characterised by wet polygonal tundra. The soils at the site are characterised by high organic matter content, low nutrient availability and pronounced water logging. The vegetation is dominated by sedges and mosses. The fluctuations of the wind velocity components and the sonic temperature were determined with a three-dimensional sonic anemometer, and the fluctuations of the H2O and CO2 concentrations were measured with a closed-path infrared gas analyser. The measurement height was 3.65 m. The fast-response eddy covariance measurements were supplemented by a set of slow-response meteorological and soil-meteorological measurements. The relative energy balance closure was around 90 % on the hourly basis and around 96 % on the daily basis, indicating a good performance of the complete flux measurement set-up. The combined datasets of the two campaigns 2003 and 2004 were used to characterise the seasonal course of the energy, water and CO2 fluxes and the underlying processes for the synthetic measurement period May 28…October 21 2004/2003 which included the period of snow and soil thawing as well as the beginning of refreezing. The synthetic measurement period 2004/2003 was characterised by a long snow ablation period (until June 17) and a late start of the growing season. On the other hand, the growing season ended also late due ...