严凯等:Evaluation of MODIS LAI/FPAR Product Collection 6. Part 1: Consistency and Improvements
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2016-08-06
Evaluation of MODIS LAI/FPAR Product Collection 6. Part 1: Consistency and Improvements
作者:Yan, K (Yan, Kai)[ 1,2 ] ; Park, T (Park, Taejin)[ 2 ] ; Yan, GJ (Yan, Guangjian)[ 1 ] ; Chen, C (Chen, Chi)[ 2 ] ; Yang, B (Yang, Bin)[ 2,3 ] ; Liu, Z (Liu, Zhao)[ 2 ] ; Nemani, RR (Nemani, Ramakrishna R.)[ 4 ] ; Knyazikhin, Y (Knyazikhin, Yuri)[ 2 ] ; Myneni, RB (Myneni, Ranga B.)[ 2 ]
 
REMOTE SENSING
卷: 8  期: 5
文献号: 359
DOI: 10.3390/rs8050359
出版年: MAY 2016
 
摘要
As the latest version of Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) products, Collection 6 (C6) has been distributed since August 2015. This collection is evaluated in this two-part series with the goal of assessing product accuracy, uncertainty and consistency with the previous version. In this first paper, we compare C6 (MOD15A2H) with Collection 5 (C5) to check for consistency and discuss the scale effects associated with changing spatial resolution between the two collections and benefits from improvements to algorithm inputs. Compared with C5, C6 benefits from two improved inputs: (1) L2G-lite surface reflectance at 500 m resolution in place of reflectance at 1 km resolution; and (2) new multi-year land-cover product at 500 m resolution in place of the 1 km static land-cover product. Global and seasonal comparison between C5 and C6 indicates good continuity and consistency for all biome types. Moreover, inter-annual LAI anomalies at the regional scale from C5 and C6 agree well. The proportion of main radiative transfer algorithm retrievals in C6 increased slightly in most biome types, notably including a 17% improvement in evergreen broadleaf forests. With same biome input, the mean RMSE of LAI and FPAR between C5 and C6 at global scale are 0.29 and 0.091, respectively, but biome type disagreement worsens the consistency (LAI: 0.39, FPAR: 0.102). By quantifying the impact of input changes, we find that the improvements of both land-cover and reflectance products improve LAI/FPAR products. Moreover, we find that spatial scale effects due to a resolution change from 1 km to 500 m do not cause any significant differences.
 
通讯作者地址: Yan, K (通讯作者)
Beijing Normal Univ, Sch Geog, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China.
通讯作者地址: Yan, K; Park, T (通讯作者)
Boston Univ, Dept Earth & Environm, Boston, MA 02215 USA.
地址:
[ 1 ] Beijing Normal Univ, Sch Geog, State Key Lab Remote Sensing Sci, Beijing 100875, Peoples R China
[ 2 ] Boston Univ, Dept Earth & Environm, Boston, MA 02215 USA
[ 3 ] Peking Univ, Beijing Key Lab Spatial Informat Integrat & Its A, Inst RS & GIS, Beijing 100871, Peoples R China
[ 4 ] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA