scholarly journals Analysis of a multiyear global vegetation leaf area index data set

2002 ◽  
Vol 107 (D22) ◽  
Author(s):  
Wolfgang Buermann
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Data Set ◽  
Area Index ◽  
Index Data ◽  
Global Vegetation

scholarly journals A Semiprognostic Phenology Model for Simulating Multidecadal Dynamics of Global Vegetation Leaf Area Index

2020 ◽  
Vol 12 (7) ◽  
Author(s):  
Qinchuan Xin ◽  
Xuewen Zhou ◽  
Nan Wei ◽  
Hua Yuan ◽  
Zurui Ao ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Area Index ◽  
Phenology Model ◽  
Global Vegetation

scholarly journals A leaf area index data set acquired in Sahelian rangelands of Gourma in Mali over the 2005–2017 period

2019 ◽  
Vol 11 (2) ◽  
pp. 675-686
Author(s):  
Eric Mougin ◽  
Mamadou Oumar Diawara ◽  
Nogmana Soumaguel ◽  
Ali Amadou Maïga ◽  
Valérie Demarez ◽  
...  
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Land Surface ◽  
Model Development ◽  
Land Surface Model ◽  
Product Evaluation ◽  
Tree Canopy ◽  
Surface Model ◽  
Data Set ◽  
Area Index

Abstract. The leaf area index of Sahelian rangelands and related variables such as the vegetation cover fraction, the fraction of absorbed photosynthetically active radiation and the clumping index were measured between 2005 and 2017 in the Gourma region of northern Mali. These variables, known as climate essential variables, were derived from the acquisition and the processing of hemispherical photographs taken along 1 km linear sampling transects for five contrasted canopies and one millet field. The same sampling protocol was applied in a seasonally inundated Acacia open forest, along a 0.5 km transect, by taking photographs of the understorey and the tree canopy. These observations collected over more than a decade, in a remote and not very accessible region, provide a relevant and unique data set that can be used for a better understanding of the Sahelian vegetation response to the current rainfall changes. The collected data can also be used for satellite product evaluation and land surface model development and validation. This paper aims to present the field work that was carried out during 13 successive rainy seasons, the measured vegetation variables, and the associated open database. Finally, a few examples of data use are shown. DOI of the referenced data set: https://doi.org/10.17178/AMMA-CATCH.CE.Veg_Gh.

scholarly journals Observed Vegetation Greening and Its Relationships with Cropland Changes and Climate in China

Land ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 274
Author(s):  
Yuzhen Zhang ◽  
Shunlin Liang ◽  
Zhiqiang Xiao
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Boosted Regression Trees ◽  
Trend Detection ◽  
Area Index ◽  
Vegetation Greenness ◽  
Detection Algorithms ◽  
Index Data

Chinese croplands have changed considerably over the past decades, but their impacts on the environment remain underexplored. Meanwhile, understanding the contributions of human activities to vegetation greenness has been attracting more attention but still needs to be improved. To address both issues, this study explored vegetation greening and its relationships with Chinese cropland changes and climate. Greenness trends were first identified from the normalized difference vegetation index and leaf area index from 1982–2015 using three trend detection algorithms. Boosted regression trees were then performed to explore underlying relationships between vegetation greening and cropland and climate predictors. The results showed the widespread greening in Chinese croplands but large discrepancies in greenness trends characterized by different metrics. Annual greenness trends in most Chinese croplands were more likely nonlinearly associated with climate compared with cropland changes, while cropland percentage only predominantly contributed to vegetation greening in the Sichuan Basin and its surrounding regions with leaf area index data and, in the Northeast China Plain, with vegetation index data. Results highlight both the differences in vegetation greenness using different indicators and further impacts on the nonlinear relationships with cropland and climate, which have been largely ignored in previous studies.

Improving the Consistency and Continuity of MODIS 8 Day Leaf Area Index Products

2012 ◽  
Vol 58 (2) ◽  
pp. 141-146 ◽  
Author(s):  
Sivasathivel Kandasamy ◽  
Philippe Neveux ◽  
Aleixandre Verger ◽  
Samuel Buis ◽  
Marie Weiss ◽  
...  
Keyword(s):  
Time Series ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Singular Spectrum Analysis ◽  
Area Index ◽  
Standard Methods ◽  
Error Metrics ◽  
Mode Decomposition ◽  
Low Pass ◽  
Global Vegetation

Improving the Consistency and Continuity of MODIS 8 Day Leaf Area Index Products Time Series Analysis of Leaf Area Index (LAI) is vital to the understanding of global vegetation dynamics. The LAI time series derived from satellite observations are usually not complete and noisy due to cloud contamination and uncertainties in the retrieval techniques. In this paper, the continuity and consistency of the MODIS 8 day LAI products are improved using a method based on Caterpillar Singular Spectrum Analysis. The proposed method is compared with other standard methods: Savitzky-Golay filter, Empirical Mode Decomposition, Low Pass filtering and Asymmetric Gaussian fitting. The experiment demonstrates the smoothing and gapfilling ability of the developed method, which is more robust across the biomes both in terms of root mean square error metrics and bias metrics as compared to the standard methods.

Evaluation of the observation operator Jacobian for leaf area index data assimilation with an extended Kalman filter

2010 ◽  
Vol 115 (D9) ◽  
Author(s):  
Christoph Rüdiger ◽  
Clément Albergel ◽  
Jean-François Mahfouf ◽  
Jean-Christophe Calvet ◽  
Jeffrey P. Walker
Keyword(s):  
Kalman Filter ◽  
Data Assimilation ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Extended Kalman Filter ◽  
Area Index ◽  
Observation Operator ◽  
Index Data

Evaluation of the Utility of Satellite-Based Vegetation Leaf Area Index Data for Climate Simulations

2001 ◽  
Vol 14 (17) ◽  
pp. 3536-3550 ◽  
Author(s):  
Wolfgang Buermann ◽  
Jiarui Dong ◽  
Xubin Zeng ◽  
Ranga B. Myneni ◽  
Robert E. Dickinson
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Area Index ◽  
Index Data ◽  
Climate Simulations
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