The Carbon Fluxes Estimation For Phyllostachys Praecox Forest Based On Eddy Covariance Method And Wireless Sensor Networks

Forest ecosystems is the most important part of terrestrial ecosystems. It plays an important role in carbon storage and carbon cycle. According to the results of continuous forest inventory, bamboo number and its area increase year after year, with increasing importance in the ecosystem, gradually. The eddy covariance method which bases on micrometeorology is an internationally recognized method to the estimation regional carbon flux. With the development of wireless sensor technology, wireless sensor networks(WSN) has become a widely used method in obtaining environmental factors.The study calculated the carbon fluxes and flux contribution area of Phyllostachys praecox forest using the data obtained from the Taihuyuan flux observation system during the year of 2013. Combining with the landuse information of the observation area, the fluxes of different land type are extracted. In addition, on the vertical direction of the study area of the study area, the study installed several wireless sensor nodes on the flux tower. According to the CO2 concentration, humidity and barometric pressure and other data the CO2 flux is calculated. The main conclusions are:1) Under 90% contribution level, the flux contributions area has little difference under different atmospheric conditions in the directions of 0°~90°,90°~180°,180°~270°,270°~360°. Under stable atmospheric conditions the range is during 96.19~941.63 m, and under unstable atmospheric conditions it is during 28.62~313.54 m. In conclusion, the flux contribution area is within the range of 2km × 2km which centered by observation center.2) The landuse under the study area is mainly composed of Phyllostachys praecox, non-Lei bamboo forest(coniferous forest, broadleaf forest and mixed wood), other landtype(villages and farmland), road and water. Within 2km × 2km of the observation area, the Phyllostachys praecox is 67.28% of the total area, the non-Lei bamboo forest accounted for 17.33%, the other landtype accounted for 11.97%, water accounted for 2.4%, and the last is road which accounted for 1%. The flux under observation area isn’t completely from the Phyllostachys praecox ecosystems. Thus, the present study presents a flux information extraction methods. The total net flux sequestration of the underlying surface observed by flux tower is 148.93gC?m-2?a-1. Through decomposition, the total net flux sequestration of pure Phyllostachys praecox Ecosystem is 115.98gC?m-2?a-1, and when the underlying surface are all non-Phyllostachys praecox stands, it is 181.32gC?m-2?a-1. As for the monthly average NEE, the pure Phyllostachys praecox <observing flux < when the underlying surface are all non-Phyllostachys praecox stands. But as the non-Lei bamboo forest accounted for small proportion of the study area, it has little contribution to the overall flux.3) The CO2 fluxes calculated with the data obtained from wireless sensor network has better consistency in trends with those calculated by eddy covariance system. The correlation analysis results between the wireless sensor networks and eddy correlation data are r = 0.834, p <0.05, that means there is significant correlation.