| Wetland ecosystem is the second large carbon pool in the world, and plays a fundamental role in the global carbon cycle. In order to understand the carbon cycle in the wetland ecosystem, the methods of flux data's processing and evaluation, the aerodynamic parameters and flux source, the flux dynamics of carbon, water and heat fluxes and their controlling factors were studied in Panjin reed wetland ecosystem, in terms of the data from eddy covariance system, micro-meteorological observation system and ecophysiological observations. The main conclusions were listed as follows:(1) The energy balance ratio (EBR) was 0.92 in 2005, with the data quality control of flux measurement from eddy covariance systems. Turbulent flux showed a low estimation in the night. The appropriate friction velocity (u* ) for flux data quality control could be about 0.15 m?s-1.(2) Two fundamental aerodynamic parameters: zero-plane displacement ( ) and roughness length ( ) of Panjin reed wetland were estimated based on Martano's method. and had obvious seasonal variations; their highest values appeared in September and the lowest in December. The maximum values for and were 1.85m and 0.24m, respectively. Their seasonal variations were close related with vegetation characteristics (height, canopy height ( ) and leaf area index (h LAI )) and wind speed. and had a close linear relationship; the variations of with could be expressed by quadric curves; and were nearly correlated with LAI. Moreover, atmospheric stability parameter and wind direction would also affect the aerodynamic parameters.(3) Based on FSAM model (Schmid, 1994), the footprint and source area were calculated in Panjin reed wetland ecosystem. Under unstable conditions, the source areas were smaller than those under the stable conditions. In the dormant season, the source areas under stable conditions were larger than those in the growing season, and the smaller under unstable conditions. In the prevailing wind direction (180°~270°), the upwind range of the source areas was in the magnitude of 0~150m and vertical upwind range was -50~50 m at a 0.9 significant level under unstable conditions in the growing season. Under stable conditions, they were 0~300 m and -60~60 m respectively; in the dormant season, the upwind range of source areas was in the magnitude of 0~120m and vertical upwind range was -40~ 40 m at a 0.9 significant level under unstable conditions, and under stable conditions, they were 0~350 m and -65 ~65 m respectively.(4) The Panjin reed wetland was a strong carbon sink. The diurnal variations of the carbon exchange had obviously seasonal variations, which appeared to be active in summer, and the weakest in winter. The diurnal variations of CO2 flux in different months showed the same trend, which could be expressed as inverted bell. The energy balance components had obviously diurnal variation, net radiation (Rn)> latent heat flux (LE)> sensible heat flux (H)> soil heat flux (G). In the early growing season (April-May), the sensible heat flux was dominant, the latent heat flux accounted for the dominant position of late growing season. The upper canopy temperature, soil temperature, vapour pressure dificit (VPD), photosynthetically active radiation, soil evaporation and plant transpiration were important factors in carbon sequestration in Panjin reed wetlands.(5) Profile gradient method, Bowen ratio energy balance method (BREB) were used to estimated the fluxes in Panjin reed wetland ecosystem. There was a consistency of the sensible and latent heat fluxes estimating by Profile gradient method, Bowen ratio energy balance method and Eddy covariance method (EC). Application of these methods to estimate wetland water heat flux was feasible. In the growing season, the results of Profile gradient method was closer to the EC values; while in the dormant season, Bowen ratio energy balance method was better. Therefore, the different methods should be available to estimate more accurately the water and heat flux based on the different growth stages.
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