Characteristics Of Net Ecosystem Exchange Of Carbon Dioxide And Their Driving Factors Over A Fenced Leymus Chinensis Steppe In Inner Mongolia

Long-term measurements of the exchange of CO₂ between terrestrial ecosystems and atmosphere have the potential to markedly improve understanding the role terrestrial ecosystems play in the global carbon cycle. Eddy covariance is a micrometeorological technique that allows a non-invasive measurement of the exchange of CO2 between the atmosphere and vegetation. This study was on the basis of Inner Mongolia Flux Station, and used eddy covariance technique to measure the exchange of CO₂ flux in a fenced field during 2003²005's growing seasons. We anatomized the characteristics of CO₂ flux and the driving mechanism at different temporal scale.In order to compare the results of flux data of different flux measurements, the quality of the flux data must be assessed and controlled. We analyzed the turbulence flux measurements using the open-path eddy covariance technique and the extent of energy closure of the data. We have taken advantage of an unusual drought during the summer of 2005 and the variation in precipitation pattern during three growing seasons to investigate the effects of soil water content and precipitation on the net ecosystem exchange and respiration (as measured by eddy covariance and chamber method ) in Lymus chinensis grassland. At the same time, quantitative estimation of the carbon sequestration potential of this typical grassland ecosystem level has been approached by the means of the eddy covariance technique on a three-year basis. The main results are as follows:...