Observation Study Of CO₂ Flux Based On Different Underlying Surface In The Hinterland Of Badain Jaran Desert

Carbon budget of the Earth’s terrestrial ecosystems has arouse increasing concern of the international community. Study of carbon fluxes of the terrestrial ecosystem has also become a very important scientific focus. Eddy covariance system, as a direct measurement of the physical principles has been a very important research tool throughput research. But so far, research on the vegetation scarce land surface such as gobi, desert, was still very scarce. This study, based on two eddy covariance observation systems settled in both land and lake surface in the hinterland of Badain Jaran Desert, researched the carbon flux characteristics in the hinterland of Badain Jaran Desert by a long duration comparative observational studies, and concluded as follows:1. Meteorological elements in the study area have very significant seasonal variation in which the air temperature, ground temperature and radiation showed significantly features of higher in summer and lower in winter, and their annual range is large. The annual range of daily average temperature, ground temperature were 49.41℃ and 42.09℃, the total solar radiation of 64.94 × 108J · m-2. Little precipitation with measured annual rainfall of 78.4mm in the study fields.2. Analysis from both land surface and the lake EC observing systems shows that in both of the land surface or the lake, according to the observation, were expressed as carbon sources, land surface can be calculated the total annual CO2 emissions observatory was 12.85 mol CO2 m-2 (equivalent of 565.4 g CO2 m-2), which in November to next February’s total CO2 emissions of 8.18 mol CO2 m-2, another eight months total emissions of 4.67 mol CO2 m-2. Winter carbon emissions measured value is very high, the mechanism being unknown.The yearly total CO2 emissions in lake observatory was 3.70mol CO2 m-2 (equivalent of 162.84 g CO2 m-2), with the NEE is observed negative in months 10 to 12, performance as carbon sequestration.3. The observed in-day NEE curves of land surface and the lake contrasting with the land surface observations on the overall performance of carbon emissions for the night, while the afternoon hours from noon to weak absorption or emission, while observing the lake at night for the faint displayed absorption as compared to noon pm strong emissions.4. The observed results from the land surface observation system shows that in-day NEE, daily cumulative NEE, and monthly cumulative NEE could become a good correlation with the meteorological elements (in this study are related to solar radiation Rg, relative humidity rH, temperature and ground temperature Tair Tsoil four), which negatively correlated with the relative humidity rH, and positively correlated with solar radiation, air temperature, ground temperature. However the lake system is observed NEEs have a weak negative correlation with radiation, air temperature, ground temperature, and a weak positive correlation with the relative humidity.