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| Content Provider | IEEE Xplore Digital Library |
|---|---|
| Author | Mingzhu He Yanlian Zhou Gaohuan Liu Weimin Ju Xianfeng Li Gaolong Zhu |
| Copyright Year | 2010 |
| Description | Author affiliation: School of Geographic and Oceanographic Sciences, Nanjing University, Nanjing, China (Mingzhu He; Yanlian Zhou) || Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China (Gaohuan Liu) || International Institute for Earth System Science, Nanjing University, Nanjing, China (Weimin Ju; Xianfeng Li; Gaolong Zhu) |
| Abstract | Terrestrial carbon cycle plays an important role in global climate change. As a key component of terrestrial carbon cycle, gross primary productivity (GPP) is a major determinant of the exchange of carbon between the atmosphere and terrestrial ecosystems. 8-day global GPP estimated from ground meteorological data and remotely sensed fraction of photosynthetic active radiation (fPAR) by MODIS using the light use efficiency approach is currently provided as MOD17 product. Previous studies indicated that MODIS GPP has large uncertainties in some ecosystems. In this study, GPP of a subtropical coniferous plantation at Qianyanzhou Experimental Station in southern China was firstly calculated using the MODIS GPP algorithm (MOD17 algorithm) driven by MODIS fPAR and measured meteorological data. Calculated GPP was validated using GPP measured during 2003 and 2004 with the eddy covariance technique. Then the potential to better MODIS GPP was investigated through comparing GPP calculated using the MOD17 algorithm and improved fPAR or/and maximum light use efficiency (εmax) calibrated with measured GPP. The results indicated that the MODIS GPP product significantly underestimated measured GPP at this planted forest. The $R^{2}$ of MODIS GPP with measured GPP was 0.72 and 0.67 in 2003 and 2004, respectively. And the calculated annual GPP was 33% and 47% lower than measured values in these two years. The improvement on fPAR through using LAI data estimated with photosynthetic active radiation (PAR) measured above and below canopy can definitely remedy underestimation of annual GPP. The application of εmax determined through model calibration improved annual GPP more significantly, indicating that the errors in MODIS GPP at this site can be mainly attributed to the underestimation of fPAR and εmax. When the improved fPAR and εmax were used, the agreement between calculated and measured 8-day GPP improved significantly, with $R^{2}$ equals to 0.78 and 0.85 for years 2003 and 2004, respectively. And the calculated annual GPP was only 3.5% lower and 1.3% higher than measured values in these two years. Through this study, it can be concluded that accurate εmax and LAI from which fPAR is calculated are required for reliably calculating regional/global GPP with the MOD17 algorithm. The fusion of flux data with remote sensing data can provide the accurate estimate of εmax andhas a great potential to control uncertainties in calculated regional/global GPP. |
| Starting Page | 1 |
| Ending Page | 4 |
| File Size | 281377 |
| Page Count | 4 |
| File Format | |
| ISBN | 9781424473014 |
| e-ISBN | 9781424473038 |
| DOI | 10.1109/GEOINFORMATICS.2010.5567700 |
| Language | English |
| Publisher | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Publisher Date | 2010-06-18 |
| Publisher Place | China |
| Access Restriction | Subscribed |
| Rights Holder | Institute of Electrical and Electronics Engineers, Inc. (IEEE) |
| Subject Keyword | Productivity Algorithm design and analysis Maximum light use efficiency Ecosystems LAI Vegetation Gross primary productivity FPAR Carbon MODIS Remote sensing Qianyanzhou |
| Content Type | Text |
| Resource Type | Article |
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