Vincent Dubreuil | Université Rennes 2 (original) (raw)

Papers by Vincent Dubreuil

Sociedade & Natureza

A complexidade em mensurar a água, nos diferentes estados físicos, apoia-se em instrumentos regis... more A complexidade em mensurar a água, nos diferentes estados físicos, apoia-se em instrumentos registradores pouco precisos e em um sistema climático, cuja delimitação é tênue. A exemplo da atmosfera e de sua composição variável, há vários índices para descrever um dos seus elementos, o vapor d’água. Nesta pesquisa objetivou-se estimar a umidade do ar no Parque do Ingá, em Maringá-PR, a partir de dados de umidade relativa obtidos de um registrador de temperatura e umidade inserido dentro do parque, nos intervalos temporais de abril de 2019 a janeiro de 2020 e de junho de 2020 a março de 2021. Buscou-se também verificar por sensoriamento remoto, a quantidade de vapor d’água precipitável sobre a mesma área, no intervalo temporal disponível das imagens MSI/Sentinel 2A. Concluiu-se que o Parque do Ingá possui potencial para ressaltar alguns efeitos benéficos à cidade, considerando-se sobretudo a umidade relativa e a condição de saturação mais rápida do vapor d’água naquele posto de observa...

Remote Sensing, 2022

The Amazon Basin is undergoing extensive environmental degradation as a result of deforestation a... more The Amazon Basin is undergoing extensive environmental degradation as a result of deforestation and the rising occurrence of fires. The degradation caused by fires is exacerbated by the occurrence of anomalously dry periods in the Amazon Basin. The objectives of this study were: (i) to quantify the extent of areas that burned between 2001 and 2019 and relate them to extreme drought events in a 20-year time series; (ii) to identify the proportion of countries comprising the Amazon Basin in which environmental degradation was strongly observed, relating the spatial patterns of fires; and (iii) examine the Amazon Basin carbon balance following the occurrence of fires. To this end, the following variables were evaluated by remote sensing between 2001 and 2019: gross primary production, standardized precipitation index, burned areas, fire foci, and carbon emissions. During the examined period, fires affected 23.78% of the total Amazon Basin. Brazil had the largest affected area (220,087 ...

The aim of this study was to evaluate the indicators for Water Sustainability Assessment of Agric... more The aim of this study was to evaluate the indicators for Water Sustainability Assessment of Agricultural Systems, proposed by Ferraz (2012), by conducting a study case to assess the sugarcane activity water sustainability in 10 municipalities in the southwest region of the Goias State, Brazil. These indicators are direct indexes obtained from data extracted through geoprocessing techniques from spatial models, such as: (i) Sugarcane Agroecological Zoning (Embrapa, 2009); (ii) Water contamination vulnerability by agricultural effluents model (Barbalho e Campos, 2010); (iii) Specific flow spatially model (Ferraz, 2012.). The indexes allow indicate: (i) pedoclimatic favorability areas: (ii) the surface and groundwater contamination vulnerability areas; (iii) sugarcane water sustainability level. The results show that the indicators were able to characterize and distinguish the differences between the units of analysis (municipalities) and, considering the scale and the detail level req...

Sustentabilidade em Debate, 2011

A análise do processo de sustentabilidade representa um grande desafio científico enquanto a Amaz... more A análise do processo de sustentabilidade representa um grande desafio científico enquanto a Amazônia constitui um verdadeiro laboratório onde estão sendo testadas inúmeras concepções desse conceito. Haveria pontos ou mecanismos comuns entre estas? Esse é o ponto que pesquisou o programa DURAMAZ, que teve como objetivo de desvendar fatores chaves, ou “determinantes” do desenvolvimento sustentável (DS) na Amazônia brasileira através da identificação dos impactos geográficos, demográficos e socioeconômicos de 13 projetos de DS. Apresentamos os pontos-chaves da metodologia, assim como algumas visões de síntese sobre a aplicação do conceito de desenvolvimento sustentável. Entender as dinâmicas internas de cada uma dessas experiências foi a meta principal, assim como entender as razões de um bom desempenho. O resultado final do programa de pesquisa reside na construção de um sistema de indicadores a partir de bancos de dados sistematizados (socioeconômico, demográfico/biográfico e geográ...

Sustainability, 2020

This study examines how key stakeholders in agriculture in a number of municipalities in the Braz... more This study examines how key stakeholders in agriculture in a number of municipalities in the Brazilian Amazon state of Mato Grosso are incorporating and adapting to public policies on climate change. Fieldwork and semi-structured interviews conducted in 2014 and 2018 with key stakeholders in the region were analyzed to assess the effectiveness of public policies incorporating climate change factors. Data obtained from documents from national institutions complemented these interviews. The results show that although local government claims that its mission is economic, social and sustainable development, and although public institutions and stakeholders repeat internationally recognized protocols and agreements in their communications, in actual fact, these are not reflected by any change in institutional behavior.

Atmosphere, 2020

Understanding the long-term behavior of rainfall and potential evapotranspiration (PET) over wate... more Understanding the long-term behavior of rainfall and potential evapotranspiration (PET) over watersheds is crucial for the monitoring of hydrometeorological processes and climate change at the regional scale. The São Francisco watershed (SFW) in Brazil is an important hydrological system that transports water from humid regions throughout the Brazilian semiarid region. However, long-term, gapless meteorological data with good spatial coverage in the region are not available. Thus, gridded datasets, such as the Climate Research Unit TimeSeries (CRU TS), can be used as alternative sources of information, if carefully validated beforehand. The objective of this study was to assess CRU TS (v4.02) rainfall and PET data over the SFW, and to evaluate their long-term (1942–2016) climatological aspects. Point-based measurements retrieved from rain gauges and meteorological stations of national agencies were used for validation. Overall, rainfall and PET gridded data correlated well with poin...

Global Environmental Change, 2019

The Amazon region has been undergoing profound transformations since the late '70s through forest... more The Amazon region has been undergoing profound transformations since the late '70s through forest degradation, land use changes and effects of global climate change. The perception of such changes by local communities is important for risk analysis and for subsequent societal decision making. In this study, we compare and contrast observations and perceptions of climate change by selected Amazonian communities particularly vulnerable to alterations in precipitation regimes. Two main points were analysed: (i) the notion of changes in the annual climate cycle and (ii) the notion of changes in rainfall patterns. About 72% of the sampled population reports perceptions of climate changes, and there is a robust signal of increased perception with age. Other possible predictive parameters such as gender, fishing frequency and changes in/planning of economic activities do not appear overall as contributing to perceptions. The communities' perceptions of the changes in 2013-2014 were then compared to earlier results (2007-2008), providing an unprecedented cohort study of the same sites. Results show that climate change perceptions and measured rainfall variations differ across the basin. It was only in the southern part of the Amazon that both measured and perceived changes in rainfall patterns were consistent with decreased precipitation. However, the perception of a changing climate became more widespread and frequently mentioned, signalling an increase in awareness of climate risk.

Remote Sensing, 2018

Knowledge and studies on precipitation in the Amazon Basin (AB) are determinant for environmental... more Knowledge and studies on precipitation in the Amazon Basin (AB) are determinant for environmental aspects such as hydrology, ecology, as well as for social aspects like agriculture, food security, or health issues. Availability of rainfall data at high spatio-temporal resolution is thus crucial for these purposes. Remote sensing techniques provide extensive spatial coverage compared to ground-based rainfall data but it is imperative to assess the quality of the estimates. Previous studies underline at regional scale in the AB, and for some years, the efficiency of the Tropical Rainfall Measurement Mission (TRMM) 3B42 Version 7 (V7) (hereafter 3B42) daily product data, to provide a good view of the rainfall time variability which is important to understand the impacts of El Nino Southern Oscilation. Then our study aims to enhance the knowledge about the quality of this product on the entire AB and provide a useful understanding about his capacity to reproduce the annual rainfall regi...

Remote Sensing, 2017

Satellite-derived estimates of precipitation are essential to compensate for missing rainfall mea... more Satellite-derived estimates of precipitation are essential to compensate for missing rainfall measurements in regions where the homogeneous and continuous monitoring of rainfall remains challenging due to low density rain gauge networks. The Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks-Climate Data Record (PERSIANN-CDR) is a relatively new product (released in 2013) but that contains data since 1983, thus enabling long-term rainfall analysis. In this work, we used three decades (1983-2014) of PERSIANN-CDR daily rainfall data to characterize precipitation patterns in the southern part of the Amazon basin, which has been drastically impacted in recent decades by anthropogenic activities that exacerbate the spatio-temporal variability of rainfall regimes. We computed metrics for the rainy season (onset date, demise date and duration) on a pixel-to-pixel basis for each year in the time series. We identified significant trends toward a shortening of the rainy season in the southern Amazon, mainly linked to earlier demise dates. This work thus contributes to monitoring possible signs of climate change in the region and to assessing uncertainties in rainfall trends and their potential impacts on human activities and natural ecosystems.

Applied Geography, 2017

The recent decoupling of deforestation and soybean production has raised optimistic expectations ... more The recent decoupling of deforestation and soybean production has raised optimistic expectations towards enhanced land use sustainability in the SouthEastern Amazon agricultural frontier. Nonetheless, assessing land use sustainability implies not only the consideration of how agricultural activities affect natural ecosystems but also how they impact on society and how society can cope with them. We review some of the forthcoming challenges that the agricultural sector should address to confirm its significant progress towards land use sustainability. Firstly, we assess the recent efforts to adopt environmentally friendly practices with regard to the ongoing intensification process mainly based on double cropping systems. Secondly, while rapid agricultural development has brought major social advances, we evidence a recent trend towards a decoupling of soy production and the Human Development Index at municipality level. We then put this result into perspective considering that the trend towards agricultural intensification based on the use of large amounts of agrochemicals could lead to major health concerns which are still too rarely considered. Finally, we discuss how the recent efficient policies to contain deforestation in the Amazon can cause indirect land use changes in the Brazilian Cerrados and in African Savannas, thus potentially leading to an "illusion of preservation" at global scale. We conclude that new indicators involving social sciences are necessary to better address the complexity of land use sustainability on the still very dynamic agricultural frontier in the SouthEastern Amazon.

Environment, Development and Sustainability, 2016

Agricultural landscapes of the Southern Brazilian Amazon are the result of eighty years of govern... more Agricultural landscapes of the Southern Brazilian Amazon are the result of eighty years of governmental policies to install a powerful agricultural sector. Yet, this rapid expansion raised important environmental considerations especially with regard to deforestation. The agricultural frontier is thus now facing a huge challenge: to combine socioeconomic development with environmental conservation in a context of frontier expansion. Based on a conceptual model of the agricultural frontier, we review historical changes in environmental and development policies in the Brazilian state of Mato Grosso and emphasize their ambivalent trend to both encourage and control the progress of the frontier. We then extend this model with an integration stage where environmental governance and economic development evolve from competing to complementary concepts. At this stage, the efforts to slow down deforestation are accompanied with programs to promote new agricultural practices and support industrialization. Finally, we put into perspective this recent evolution with regards to the underlying reasons for changing the agricultural model, thus considering the agricultural frontier to be at a tipping point where first positive results need to be confirmed in spite of an unstable economic and political situation.

Revista Brasileira de Climatologia, 2014

Com o intuito de contribuir com os estudos climato-hidrológicos no sitio Ramsar PARNA Pantanal, c... more Com o intuito de contribuir com os estudos climato-hidrológicos no sitio Ramsar PARNA Pantanal, conforme as recomendações da Convenção de Ramsar, o presente trabalho analisou séries anuais de dados observados de chuva, temperatura e cotas no período de 1971 a 2011 de estações da sub-bacia do Alto Paraguai. Os dados foram analisados com os testes de Mann-Kendall e Regressão linear para identificação de tendências e Pettitt para verificação de rupturas. Foram constatadas diminuição pluviométrica anual na porção que se estende da Amazônia ao centro do Pantanal e aumento das temperaturas máxima e mínima nas estações de Cáceres (MT) e Cuiabá (MT). O nível d’ água dos rios localizados nas Ottobacias responsáveis pela manutenção do sistema hídrico do sítio Ramsar PARNA Pantanal variou no período estudado. O estudo demonstra o alto grau de vulnerabilidade do sítio Ramsar PARNA Pantanal à variabilidade do clima.

We examine the diurnal cycles of deep convection and precipitation in the Southern Amazon region,... more We examine the diurnal cycles of deep convection and precipitation in the Southern Amazon region, using mainly the Advanced Microwave Sounding Unit, contrasting a year of drought (2004-2005) with a "normal" year (2005-2006). MODIS 550nm aerosol optical thickness data and TRMM 3B42 precipitation products were also used to investigate whether a significant relationship between these two parameters can be identified. We use a simple, tractable method to identify convective areas based on humidity channels of AMSU. We found through comparisons with independent ground precipitation data that the diurnal cycle of convection in regional scale can be realistically described by this method. We observe that deep convective areas have a slow build-up early in the rainy season of the dry year, and rapid in the normal year, and in both cases, convection starts around midday. As the rainy season advances, the peak hour of maximum convective activity shifts towards mid-afternoon, and eventually spreads towards the night. During the peak of rainy season (December through February) convective activity was up to 12% larger in the "normal" year. Convective overshooting was found to be 50% less frequent in the drought year compared to the following year. A simple spatial correlation analysis of MODIS 550nm and TRMM 3B42 monthly mean data showed that by the end of dry season, aerosol loading and precipitation amounts have a positive (albeit low) significant correlation.

Confins, 2009

Avertissement Le contenu de ce site relève de la législation française sur la propriété intellect... more Avertissement Le contenu de ce site relève de la législation française sur la propriété intellectuelle et est la propriété exclusive de l'éditeur. Les oeuvres figurant sur ce site peuvent être consultées et reproduites sur un support papier ou numérique sous réserve qu'elles soient strictement réservées à un usage soit personnel, soit scientifique ou pédagogique excluant toute exploitation commerciale. La reproduction devra obligatoirement mentionner l'éditeur, le nom de la revue, l'auteur et la référence du document. Toute autre reproduction est interdite sauf accord préalable de l'éditeur, en dehors des cas prévus par la législation en vigueur en France. Revues.org est un portail de revues en sciences humaines et sociales développé par le CLEO, Centre pour l'édition électronique ouverte (CNRS, EHESS, UP, UAPV).

Revista de geografía Norte Grande, 2009

Este trabalho tem como objetivo analisar a estrutura térmica do clima urbano com base na interpre... more Este trabalho tem como objetivo analisar a estrutura térmica do clima urbano com base na interpretação do canal termal do satélite Landsat 7 e de medidas de superfície. Identificou também como se processa a produção do clima urbano, partindo de uma análise das formas de estruturação do espaço, das características do uso do solo e dos materiais construtivos na geração de ilhas de calor e suas implicaçıes no conforto ambiental de uma cidade média de clima tropical no Brasil. Para a verificação das temperaturas do ar intra-urbana realizaramse medidas em transectos móveis nos percursos norte-sul e leste-oeste. Os dados do canal termal do Landsat-7, foram convertidos para valores de temperatura de superfície. Os resultados mostraram que o padrão de urbanização e as características do uso do solo são os responsáveis pela distribuição da temperatura gerando ilhas de calor no centro da cidade e nos bairros populares densamente construídos. Nestes últimos, devido ao elevado grau de segregação social, as altas temperaturas também provocam aumento no número de casos de doenças e morbidade, principalmente do aparelho respiratório.

International Journal of Climatology, 2013

ABSTRACT Assessing the impact/adaptation of human activities on/to climate change is a key issue,... more ABSTRACT Assessing the impact/adaptation of human activities on/to climate change is a key issue, especially in the tropics that concentrate major anthropogenic dynamics such as deforestation and nearly two-thirds of the planetary rainfall. However, this task is often made tough because human activities such as agricultural dynamics are usually analysed at local or regional scale whereas climate related studies are led at large to global scales due to a lack of reliable data, especially in the tropics. In this article we argue that the increased spatial resolution of remote sensing-based rainfall estimates enables assessing the spatiotemporal variability of rainfall regimes at regional and local scales, thus allowing fine analysis of the interactions with human activities. We processed Tropical Rainfall Measuring Mission (TRMM) 3B42 daily rainfall estimates over the state of Mato Grosso (southern Brazilian Amazon) for the 1998–2012 study period in order to compute rainfall metrics such as annual rainfall and duration, onset and end dates of the rainy season based on the Anomalous Accumulation methodology (at a 0.25° spatial resolution). We then crossed these metrics with agricultural maps (produced at a 250 m spatial resolution) and proved that the adoption of intensive agricultural practices such as double cropping systems is partly the result of a strategy to adapt practices to local climatic conditions. Finally, we discuss how such results raise important issues regarding the sustainability of the agricultural development model in the Southern Amazon.