scholarly journals About Validation-Comparison of Burned Area Products

2020 ◽  
Vol 12 (23) ◽  
pp. 3972
Author(s):  
Germán M. Valencia ◽  
Jesús A. Anaya ◽  
Éver A. Velásquez ◽  
Rubén Ramo ◽  
Francisco J. Caro-Lopera
Keyword(s):  
South America ◽  
Land Cover ◽  
Northern Hemisphere ◽  
Random Matrix Theory ◽  
Random Matrix ◽  
Matrix Theory ◽  
Permutation Tests ◽  
Comparison Method ◽  
Burned Area ◽  
Tropical Regions

This paper proposes a validation-comparison method for burned area (BA) products. The technique considers: (1) bootstrapping of scenes for validation-comparison and (2) permutation tests for validation. The research focuses on the tropical regions of Northern Hemisphere South America and Northern Hemisphere Africa and studies the accuracy of the BA products: MCD45, MCD64C5.1, MCD64C6, Fire CCI C4.1, and Fire CCI C5.0. The first and second parts consider methods based on random matrix theory for zone differentiation and multiple ancillary variables such as BA, the number of burned fragments, ecosystem type, land cover, and burned biomass. The first method studies the zone effect using bootstrapping of Riemannian, full Procrustes, and partial Procrustes distances. The second method explores the validation by using distance permutation tests under uncertainty. The results refer to Fire CCI 5.0 with the best BA description, followed by MCD64C6, MCD64C5.1, MCD45, and Fire CCI 4.1. It was also found that biomass, total BA, and the number of fragments affect the BA product accuracy.

scholarly journals Contrasting Post-Fire Dynamics between Africa and South America based on MODIS Observations

2019 ◽  
Vol 11 (9) ◽  
pp. 1074 ◽  
Author(s):  
Lei Zhou ◽  
Yuhang Wang ◽  
Yonggang Chi ◽  
Shaoqiang Wang ◽  
Quan Wang
Keyword(s):  
South America ◽  
Land Cover ◽  
Northern Hemisphere ◽  
Vegetation Dynamics ◽  
Fire Regime ◽  
High Density ◽  
Forest Recovery ◽  
Burned Area ◽  
Fire Dynamics ◽  
The Impact

Fire is an important driver of land cover change throughout the world, affecting processes such as deforestation, forest recovery and vegetation transition. Little attention has been given to the role of fire in shaping the temporal and spatial land cover changes among continents. This study has integrated two MODIS products (MCD64A1: Burned area and MCD12Q1: Land cover) over Africa and South America from 2001–2013 to explore the vegetation dynamics after fires. The results indicated that while Africa suffered from repeated fires, more than 50% of the total burned area in South America experienced only one fire. The vegetation dynamics of the high-density vegetated regions in the 10 years after a fire showed that the forest losses in the first year after a fire in Africa were slightly larger than that in South America (Africa: 17.2% vs. South America: 14.5% in the Northern Hemisphere). The continental comparison suggested that early successional forests in Africa recovered relatively fast (northern part: 10.2 years; southern part: 12.8 years) than in South America, which recovered (18.4 years) slowly in Northern Hemisphere or ever with no recovery in the Southern Hemisphere. No clear information of the recoveries of other vegetation types (i.e., shrub, grass and crop) in Africa or South America could be identified from the satellite data. In addition, we also analyzed the changes of high-density vegetation in non-burned regions in both continents. These findings highlighted the impact of the fire regime on the vegetation changes in Africa, which appear resilient to fire, but there were complex systems in South America related to fires.

SSA, Random Matrix Theory, and Noise-Reduced Correlations

2016 ◽  
Author(s):  
Jan W Dash ◽  
Xipei Yang ◽  
Mario Bondioli ◽  
Harvey J. Stein
Keyword(s):  
Random Matrix Theory ◽  
Random Matrix ◽  
Matrix Theory

History—an overview

2018 ◽  
Author(s):  
Oriol Bohigas ◽  
Hans A. Weidenmüller
Keyword(s):  
Random Matrix Theory ◽  
Random Matrix ◽  
Matrix Theory ◽  
Rapid Development ◽  
The Past ◽  
History Of ◽  
And Mathematics

An overview of the history of random matrix theory (RMT) is provided in this chapter. Starting from its inception, the authors sketch the history of RMT until about 1990, focusing their attention on the first four decades of RMT. Later developments are partially covered. In the past 20 years RMT has experienced rapid development and has expanded into a number of areas of physics and mathematics.

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