Estimation of direct, diffuse, and total FPARs from Landsat surface reflectance data and ground-based estimates over six FLUXNET sites
文献类型：SCI/SSCI论文
| 作者 | Li W. J.; Fang, H. L. |
| 发表日期 | 2015 |
| 关键词 | direct FPAR diffuse FPAR total FPAR APAR Landsat TM photosynthetically active radiation gross primary productivity canopy reflectance radiance data time-series remote estimation vegetation index transfer model sail model modis data |
| 英文摘要 | The fraction of photosynthetically active radiation (PAR) absorbed by green elements (FPAR) is an essential climate variable in quantifying canopy absorbed PAR (APAR) and gross and net primary production. Current satellite FPAR products typically correspond to black-sky FPAR under direct illumination only, but the radiation transfer and vegetation absorption processes differ for direct and diffuse PARs. To address this, the present study developed a new approach to estimate direct, diffuse, and total FPARs, separately, from Landsat surface reflectance data. Field-measured direct and diffuse FPARs were first derived for crops, deciduous broadleaf forests, and evergreen needleleaf forests at six FLUXNET sites. Then, a coupled soil-leaf-canopy radiative transfer model (SLC) was used to simulate surface reflectance under direct and diffuse illumination conditions. Direct, diffuse, and total FPARs were estimated by comparing Landsat-5 Thematic Mapper (TM) data and simulated surface reflectances using a lookup table approach. The differences between the Landsat-estimated and the field-measured FPARs are less than 0.05 (10%). The diffuse FPAR is higher than the direct FPAR by up to 19.38%, whereas the total FPAR is larger than the direct FPAR by up to 16.07%. The direct APAR is higher than the diffuse APAR under clear-sky conditions, but underestimates the total APAR by -277.72 mu mols(-1)m(-2) on average. The approach described here can be extended to estimate direct, diffuse, and total FPARs from other satellite data and the obtained FPAR variables could be helpful to improve modeling of vegetation processes. |
| 出处 | Journal of Geophysical Research-Biogeosciences |
| 卷 | 120 |
| 期 | 1 |
| 页 | 96-112 |
| 收录类别 | SCI |
| 语种 | 英语 |
| ISSN号 | 2169-8953 |
| 源URL | [http://ir.igsnrr.ac.cn/handle/311030/38704]  |
| 专题 | 地理科学与资源研究所_历年回溯文献 |
| 推荐引用方式 GB/T 7714 | Li W. J.,Fang, H. L.. Estimation of direct, diffuse, and total FPARs from Landsat surface reflectance data and ground-based estimates over six FLUXNET sites. 2015. |
入库方式： OAI收割
来源：地理科学与资源研究所
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