Papers by Emilio Chuvieco
Fire
This paper presents a review of concepts related to wildfire risk assessment, including the deter... more This paper presents a review of concepts related to wildfire risk assessment, including the determination of fire ignition and propagation (fire danger), the extent to which fire may spatially overlap with valued assets (exposure), and the potential losses and resilience to those losses (vulnerability). This is followed by a brief discussion of how these concepts can be integrated and connected to mitigation and adaptation efforts. We then review operational fire risk systems in place in various parts of the world. Finally, we propose an integrated fire risk system being developed under the FirEUrisk European project, as an example of how the different risk components (including danger, exposure and vulnerability) can be generated and combined into synthetic risk indices to provide a more comprehensive wildfire risk assessment, but also to consider where and on what variables reduction efforts should be stressed and to envisage policies to be better adapted to future fire regimes. C...
Fire
First of all, we would like to thank the authors of the comment [...]
Religions, 2016
We analyzed the impact of religious affiliation on the ethical and environmental values of Spanis... more We analyzed the impact of religious affiliation on the ethical and environmental values of Spanish environmental activists, based on an internet survey and a working seminar held with representatives of major environmental non-government organizations (ENGO) of Spain. Respondents' religious affiliations were significantly different compared with those of Spanish society in general, with a much higher proportion of Buddhists, agnostics and atheists and a lower proportion of Catholics. Strict environmental values of ENGOs activists did not show significant differences between the religious groups, which imply that religious beliefs did not impact actual environmental values. However, they did have a significant influence on the activists' opinions on other bioethical issues. We found that Catholics and believers of other religions were more in favor than agnostics and atheists of introducing ethical limits on abortion, euthanasia or human embryo manipulation.
Science of The Total Environment, 2021
• Factors of global fire interannual variability were identified. • Regions with more burned area... more • Factors of global fire interannual variability were identified. • Regions with more burned area, burn also more frequently. • Human factors are more relevant in medium to large fire occurrence regions.
Remote Sensing, 2020
Tropical forests are known for hosting about half of the global biodiversity, and therefore are c... more Tropical forests are known for hosting about half of the global biodiversity, and therefore are considered to be a fundamental part of the Earth System. However, in the last decades, the anthropogenic pressure over these areas has been continuously increasing, mostly linked to agricultural expansion. This has created great international concern, which has crossed the limits of national policies. A clear example was the last crisis suffered this year (2019) in the Amazon, and in general, in tropical South America (SA), due to the increasing fire activity in the region, which is strongly linked to deforestation and forest degradation. International media extensively informed the world about fire activity based upon active fire data, which provided quick but incomplete information about the actual fire-affected areas. This short paper compares fire occurrence estimations derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) data of active fires and from burned area pro...
Current Forestry Reports, 2020
Purpose This paper reviews the most recent literature related to the use of remote sensing (RS) d... more Purpose This paper reviews the most recent literature related to the use of remote sensing (RS) data in wildland fire management. Recent Findings Studies dealing with pre-fire assessment, active fire detection, and fire effect monitoring are reviewed in this paper. The analysis follows the different fire management categories: fire prevention, detection, and post-fire assessment. Extracting the main trends from each of these temporal sections, recent RS literature shows growing support of the combined use of different sensors, particularly optical and radar data and lidar and optical passive images. Dedicated fire sensors have been developed in the last years, but still, most fire products are derived from sensors that were designed for other purposes. Therefore, the needs of fire managers are not always met, both in terms of spatial and temporal scales, favouring global over local scales because of the spatial resolution of existing sensors. Lidar use on fuel types and post-fire regeneration is more local, and mostly not operational, but future satellite lidar systems may help to obtain operational products. Regional and global scales are also combined in the last years, emphasizing the needs of using upscaling and merging methods to reduce uncertainties of global products. Validation is indicated as a critical phase of any new RS-based product. It should be based on the independent reference information acquired from statistically derived samples. Summary The main challenges of using RS for fire management rely on the need to improve the integration of sensors and methods to meet user requirements, uncertainty characterization of products, and greater efforts on statistical validation approaches.
Earth System Science Data, 2018
This paper presents a new global burned area (BA) product, generated from the Moderate Resolution... more This paper presents a new global burned area (BA) product, generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) red (R) and near-infrared (NIR) reflectances and thermal anomaly data, thus providing the highest spatial resolution (approx. 250 m) among the existing global BA datasets. The product includes the full times series (2001-2016) of the Terra-MODIS archive. The BA detection algorithm was based on monthly composites of daily images, using temporal and spatial distance to active fires. The algorithm has two steps, the first one aiming to reduce commission errors by selecting the most clearly burned pixels (seeds), and the second one targeting to reduce omission errors by applying contextual analysis around the seed pixels. This product was developed within the European Space Agency's (ESA) Climate Change Initiative (CCI) programme, under the Fire Disturbance project (Fire_cci). The final output includes two types of BA files: monthly full-resolution continental tiles and biweekly global grid files at a degraded resolution of 0.25 •. Each set of products includes several auxiliary variables that were defined by the climate users to facilitate the ingestion of the product into global dynamic vegetation and atmospheric emission models. Average annual burned area from this product was 3.81 Mkm 2 , with maximum burning in 2011 (4.1 Mkm 2) and minimum in 2013 (3.24 Mkm 2). The validation was based on a stratified random sample of 1200 pairs of Landsat images, covering the whole globe from 2003 to 2014. The validation indicates an overall accuracy of 0.9972, with much higher errors for the burned than the unburned category (global omission error of BA was estimated as 0.7090 and global commission as 0.5123). These error values are similar to other global BA products, but slightly higher than the NASA BA product (named MCD64A1, which is produced at 500 m resolution). However, commission and omission errors are better compensated in our product, with a tendency towards BA underestimation (relative bias −0.4033), as most existing global BA products. To understand the value of this product in detecting small fire patches (< 100 ha), an additional validation sample of 52 Sentinel-2 scenes was generated specifically over Africa. Analysis of these Published by Copernicus Publications. 2016 E. Chuvieco et al.: Global burned area product from MODIS 250 m reflectance results indicates a better detection accuracy of this product for small fire patches (< 100 ha) than the equivalent 500 m MCD64A1 product, although both have high errors for these small fires. Examples of potential applications of this dataset to fire modelling based on burned patches analysis are included in this paper. The datasets are freely downloadable from the Fire_cci website
Remote Sensing, 2016
Global burned area (BA) datasets from satellite Earth observations provide information for carbon... more Global burned area (BA) datasets from satellite Earth observations provide information for carbon emission and for Dynamic Global Vegetation Model (DGVM) benchmarking. Fire patch identification from pixel-level information recently emerged as an additional way of providing informative features about fire regimes through the analysis of patch size distribution. We evaluated the ability of global BA products to accurately represent morphological features of fire patches, in the fire-prone Brazilian savannas. We used the pixel-level burned area from LANDSAT images, as well as two global products: MODIS MCD45A1 and the European Space Agency (ESA) fire Climate Change Initiative (FIRE_CCI) product for the 2002-2009 time period. Individual fire patches were compared by linear regressions to test the consistency of global products as a source of burned patch shape information. Despite commission and omission errors respectively reaching 0.74 and 0.81 for ESA FIRE_CCI and 0.64 and 0.62 for MCD45A1 when compared to LANDSAT due to missing small fires, correlations between patch areas showed R 2 > 0.6 for all comparisons, with a slope of 0.99 between ESA FIRE_CCI and MCD45A1 but a lower slope (0.6-0.8) when compared to the LANDSAT data. Shape complexity between global products was less correlated (R 2 = 0.5) with lower values (R 2 = 0.2) between global products and LANDSAT data, due to their coarser resolution. For the morphological features of the ellipse fitted over fire patches, R 2 reached 0.6 for the ellipse's eccentricity and varied from 0.4 to 0.8 for its azimuthal directional angle. We conclude that global BA products underestimate total BA as they miss small fires, but they also underestimate burned patch areas. Patch complexity is the least correlated variable, but ellipse features appear to provide information to be further used for quality product assessment, global pyrogeography or DGVM benchmarking.
Global Ecology and Biogeography, 2016
Aim This paper presents a new global burned area (BA) product developed within the framework of t... more Aim This paper presents a new global burned area (BA) product developed within the framework of the European Space Agency's Climate Change Initiative (CCI) programme, along with a first assessment of its potentials for atmospheric and carbon cycle modelling. Innovation Methods are presented for generating a new global BA product, along with a comparison with existing BA products, in terms of BA extension, fire size and shapes and emissions derived from biomass burnings. Main conclusions Three years of the global BA product were produced, accounting for a total BA of between 360 and 380 Mha year 21. General omission and commission errors for BA were 0.76 and 0.64, but they decreased to 0.51 and 0.52, respectively, for sites with more than 10% BA. Intercomparison with other existing BA datasets found similar spatial and temporal trends, mainly with the BA included in the Global Fire Emissions Database (GFED4), although regional differences were found (particularly in the 2006 fires of eastern Europe). The simulated carbon emissions from biomass burning averaged 2.1 Pg C year 21 .
International Journal of Wildland Fire, 2016
Wildland fires are one of the main alleged examples of Self-Organised Criticality (SOC), with sim... more Wildland fires are one of the main alleged examples of Self-Organised Criticality (SOC), with simple SOC models resulting in the expectation of a power-law fire size frequency distribution. Here, we test whether fire size distributions systematically follow a power law and analyse their spatial variation for eight distinct areas over the globe. For each of the areas, we examine the fire size frequency distribution using two types of plots, maximum likelihood estimation and chi-square tests. Log-normal emerges as a suitable option to fit the fire size distribution in this variety of environments. In only two of eight areas was the power law (which is a particular case of the log-normal) not rejected. Notably, the two parameters of log-normal are related to each other, displaying a general linear relation, which extends to the sites that can be described with a power law. These results do not necessarily refute the SOC hypothesis, but reveal the presence of other processes that are, a...
Biogeosciences Discussions, 2015
This study presents the methods for the generation of the first global fuel dataset, containing a... more This study presents the methods for the generation of the first global fuel dataset, containing all the parameters required to be input in the Fuel Characteristic Classification System (FCCS). The dataset was developed from different spatial variables, both based on satellite Earth observation products and fuel databases, and is comprised by a global fuelbed map and a database that includes the parameters of each fuelbed that affect fire behavior and effects. A total of 274 fuelbeds were created and parameterized, and can be input into FCCS to obtain fire potentials, surface fire behavior and carbon biomass for each fuelbed. To assess the results, FCCS was used to calculate the carbon biomass of each fuelbed, and the results were compared to the values obtained for four other regional or global biomass products. The results showed reasonable agreement both in terms of geographical distribution and biomass loads when compared to other biomass data, with the best results found for Tropical and Boreal forests (Spearman's coefficient of 0.79 and 0.77). This global fuel dataset could be used for a varied range of applications, including fire danger assessment, fire behavior estimations, fuel consumption calculations and emissions inventories.
La quema de biomasa cada vez cobra mayor importancia en los modelos predictivos de cambio climati... more La quema de biomasa cada vez cobra mayor importancia en los modelos predictivos de cambio climatico al ser una de las principales fuentes de emisiones de gases de efecto invernadero y aerosoles artificiales a la atmosfera, equivalente al 20% de las emisiones anuales. Con la informacion obtenida por teledeteccion se han generado diversos productos de area quemada global como son el L3JRC, GBA2000, GLOBSCAR, GLOBCARBON, MCD45A1, M CD64A1, con diferencias en la deteccion y estimacion de la superficie de area quemada. El objetivo de esta inve stigacion fue generar areas globales de validacion, que permitan, posteriormente, la optima comparacion y validacion espacial de los productos de area que- mada actuales y futuros a nivel de biomas terrestres, generando una fuente de informacion escasa o nula para algunas zonas del planeta. La generacion de las ar eas globales de validacion se realizo a traves de una reclasificacion de los14 biomas existentes en 7 grupos, en los cuales se distribuyeron 100 zonas de validacion en funcion del total de superficie quemada durante el 2008. El bioma con mayor representativi- dad es la sabana tropical con 49 puntos y el menor fue el Bosque Mediterraneo con 7 puntos. En cada una de estas zonas, la cobertura vectorial de area quemada se desarrollo con el programa ABAMS a traves del analisis multitemporal de imagenes Landsat TM y ETM+.
Los datos de puntos de calor (HS) MODIS han sido utilizados ampliamente como fuente de datos para... more Los datos de puntos de calor (HS) MODIS han sido utilizados ampliamente como fuente de datos para estudiar la ocurrencia de incendios a escala global. Para mejorar el entendimiento y la caracterizacion de estos datos se ha hecho una co mparacion entre los HS de MODIS y mapas de areas quemadas de alta resolucion para 9 zonas del mundo. Los errores de comision observados son bajos para todas las areas de estudio (<4%), con los valores mayores en areas con alta cobertura de zonas agricolas (6,5%). Los errores de omision son relativamente altos considerando todos los incendios, disminuyendo para incendios mas grandes. Los errores de omision son mas altos para incendios que afectan a pastizales y zonas agricol as. Los resultados presentados en ese estudio ayudan a entender la variabilidad espacial de los errores y contribuyen a un mejor uso de los HS en el futuro.
Earth Observation of Wildland Fires in Mediterranean Ecosystems, 2009
... in Mediterranean Ecosystems of California: Vegetation type, Density, Invasive Species, and Fi... more ... in Mediterranean Ecosystems of California: Vegetation type, Density, Invasive Species, and Fire Frequency Susan L. Ustin, David Riaño, Alexander Koltunov, Dar A ... to have more extreme weather in the future and could face periods of even more extended drought (Hayhoe et al. ...
Global Ecology and Biogeography, 2014
Aim In order to understand fire's impacts on vegetation dynamics, it is crucial that the distribu... more Aim In order to understand fire's impacts on vegetation dynamics, it is crucial that the distribution of fire sizes be known. We approached this distribution using a power-law distribution, which derives from self-organized criticality theory (SOC). We compute the global spatial variation in the power-law exponent and determine the main factors that explain its spatial distribution. Location Global, at 2°grid resolution. Methods We use satellite-derived MODIS burned-area data (MCD45) to obtain global individual fire size data for 2002-2010, grouped together for each 2°grid. A global map of fire size distribution was produced by plotting the exponent of the power law. The drivers of the spatial trends in fire size distribution, including vegetation productivity, precipitation, population density and net income, were analysed using a generalized additive model (GAM). Results The power law gave a good fit for 93% of the global 2°grid cells with important fire activity. A global map of the fire size distribution, as approached by the power law shows strong spatial patterns. These are associated both with climatic variables (precipitation and evapotranspiration) and with anthropogenic variables (cropland cover and population density). Main conclusions Our results indicate that the global fire size distribution changes over gradients of precipitation and aridity, and that it is strongly influenced by human activity. This information is essential for understanding potential changes in fire sizes as a result of climate change and socioeconomic dynamics. The ability to improve SOC fire models by including these human and climatic factors would benefit fire projections as well as fire management and policy.
Advances in forest fire research, 2014
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitali... more A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença. Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso.
Remote Sensing of Environment, 2015
The accuracies of six global burned area (BA) products for year 2008 were compared using the same... more The accuracies of six global burned area (BA) products for year 2008 were compared using the same validation methods and reference data to quantify accuracy of each product. The selected products include MCD64, MCD45 and Geoland2, and three products developed within *Revised Manuscript with no Changes Highlighted Click here to download Revised Manuscript with no Changes Highlighted: CPA_global_v17.docx 2 the Fire Disturbance project (fire_cci), which is part of the European Space Agency's (ESA) Climate Change Initiative (CCI) program. The latter three products were derived from MERIS and VEGETATION sensors (one product from each sensor separately, and a third one from the merging of MERIS and VGT products). The reference fire perimeters were mapped from two multi-temporal Landsat TM/ETM+ images at 103 non-overlapping Thiessen scene areas (TSA) selected with a stratified random sampling design. The validation results were based on cross tabulated error matrices from which six accuracy measures were computed following the requirements of end-users of burned area products. While overall accuracy (OA) exceeded 99% for all products, overall accuracy was lower for the burned class. Burned area commission error ratio was above 40% for all products and omission error ratio was above 65% for all products. The statistical significance of differences in accuracy between pairs of products was evaluated based on theory of the stratified combined ratio estimator. Statistical tests identified the MCD64 as the most accurate product, followed by MCD45 and the MERIS product.
Advances in forest fire research, 2014
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitali... more A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos. Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença. Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso.
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Papers by Emilio Chuvieco