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Remote Estimation Of Carbon Fluxes And Carbon Sequestration Capacity Over Cropland Based On Eddy Covariance Observation

Posted on:2016-10-09Degree:MasterType:Thesis
Country:ChinaCandidate:Y N WangFull Text:PDF
GTID:2283330503955536Subject:Cartography and Geographic Information System
Abstract/Summary:PDF Full Text Request
In this paper, we use the data in four eddy covariance instruments and meteorological observation sites from HiWATER database in Heihe Daman and Zhangye basin from Heihe Plan Science Data Center. With the pre-preprocessing of flux and meteorological data to obtain complete and reliable CO2 flux and supporting meteorological data, the calculation of carbon dioxide flux(Fc), the net ecosystem exchange(NEE), and gross primary productivity(GPP) is achieved, as well as their temporal dynamic characteristics. Combine GPP with the vegetation indexes from MODIS images to correlation analysis, considering the reliability of the GPP. Build the model of LUE with the existing data and formula to estimate GPP, and combine the existing GPP with correlation analysis. The result shows that:(1) In the study area, Fc during the whole growing seasons ranged from-2.78 to0.60 mg·m-2·s-1, and the minimum Fc appeared in mid-late July; Monthly average Fc throughout the growing season showed “U” shaped curve, at 13:00 pm reached its minimum value of-1.91 mg·m-2·s-1. Nighttime ecosystem carbon flux had a significant exponential relationship with surface temperature; NEE in growing season reached the maximum carbon absorption of 16.04gC·m-2·d-1 in July 21 st. Some abnormal values was caused by the heavy rain in high temperature season; Finally GPP reached its top value of 17.74gC·m-2·d-1also in middle July. The accumulated GPP of the four observation sites were 914.68gC·m-2, 937.03gC·m-2, 984.18gC·m-2 and 1002.20gC·m-2, respectively.(2) Establish a relationship model between GPP and the data from remote images,the R2 can reach to 0.91; the R2 of GPP and LAI*VI is 0.91; the R2 between GPP and GPP-LUE is 0.93. The result proves that the model of LUE have high feasibility and applicability to estimate the GPP in maize ecosystem.
Keywords/Search Tags:remote sensing, carbon dioxide flux, maize ecosystem, net ecosystem carbon exchange, gross primary production
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