Land use and land cover map of a semiarid region of Brazil for meteorological and climatic models

Abstract

An updated vegetation cover and land use map over a semiarid region of Brazil has been produced at a 1 km spatial resolution, using satellite data and remote sensing techniques, for application in climate modeling. The map presents the location and distribution of major vegetation types and non-vegetated land surface formations for the Northeast Brazil Region, which includes the semiarid region. In this study, Radambrasil and IBGE vegetation maps, a digital mosaic of ETM + Landsat 7, and TM Landsat 5 images from the period 1999-2000 were used. To update the map, the techniques of segmentation and unsupervised classification (ISOSEG) were applied. A total of 7 land cover and land use categories were mapped according to the "Simplified Simple Biosphere"(SSiB) model legend. This map shows that there has been a considerable increase in agricultural activities and pasture area. The vegetation in this region is an intricate combination of different life forms (e.g., trees and shrubs forming a closed cover) in this region. The semiarid region of Brazil is susceptible to desertification due to climatic and environmental conditions. This updated map should provide important input for regional stratification in climate studies. Keywords: Land use change, Biogeophysical Model, Remote Sensing, Semiarid. RESUMO: MAPA DE USO E COBERTURA DA TERRA DO SEMIÁRIDO DO BRASIL PARA MODELOS CLIMÁTICOS E METEOROLÓGICOS Através da utilização de imagens digitais e técnicas de sensoriamento remoto, foi produzido um mapa de uso e cobertura da terra da região do semiárido do Brasil para aplicação em modelagem climática. O mapa apresenta a localização e distribuição dos principais tipos de vegetação e de formações não vegetacionais da superfície da terra para a região Nordeste do Brasil. Neste estudo foram utilizadas mapas de vegetação do Radambrasil e IBGE, mosaico digital de imagens Landsat 7 ETM + e Landsat 5 TM do período de 1999-2000. Para atualizar o mapa foram aplicadas técnicas de segmentação e classificação não supervisionada (ISOSEG). Foram mapeadas um total de sete classes de uso e cobertura da terra, que foram compatibilizadas com a legenda do modelo de superfície "Simplified Simple Biosphere -SSiB" para o uso em modelos climáticos e meteorológicos. A vegetação nesta região é caracterizada por diversos padrões morfológicos, que dependem da localização geográfica e das condições climáticas. Os resultados obtidos pelo mapeamento indicam um aumento considerável nas atividades agrícolas e nas pastagens, e consequentemente, a redução da vegetação natural. Considerando que a região é susceptível a desertificação, devido as suas condições climáticas e ambientais, o mapa atualizado é de extrema importância para estudos que envolvam os impactos das mudanças dos usos e cobertura da terra no clima. Palavras-chave: Mudança de uso da terra, Modelos biofísicos, Sensoriamento Remoto, Semiárido.

Drought monitoring in the Brazilian Semiarid region

“…In 2010, the total area for pasture and agricultural activities was 1,024,621 km 2 , which represents 57% of the Northeast of Brazil (Vieira et al 2013). The Brazilian semiarid region is included in the acting area of SUDENE, covering an area of 980,323 km 2 and including 1,136 municipalities ( Figure 1).…”

Use of SMOS L3 Soil Moisture Data: Validation and Drought Assessment for Pernambuco State, Northeast Brazil

“…Its climate is tropical with annual average temperatures varying between 25 and 31 • C. The precipitation is heterogeneous, with the highest rainfalls on the coast, which decrease in the western direction where the climate is semiarid. About 80% of the territory is semiarid land with irregular precipitation associated with drought phenomenon [33].…”

“…The precipitation is heterogeneous, with the highest rainfalls on the coast, which decrease in the western direction where the climate is semiarid. About 80% of the territory is semiarid land with irregular precipitation associated with drought phenomenon [33]. The state of Pernambuco has five mesoregions: Metropolitan Region of Recife, Mata Pernambucana, Agreste, Sertão of São Francisco, and Sertão Pernambucano (Figure 1) [33].…”

“…About 80% of the territory is semiarid land with irregular precipitation associated with drought phenomenon [33]. The state of Pernambuco has five mesoregions: Metropolitan Region of Recife, Mata Pernambucana, Agreste, Sertão of São Francisco, and Sertão Pernambucano (Figure 1) [33]. To analyze the SMOS data, the five regions were grouped into three based on their climate characteristics.…”

“…Region 1 has the largest economic and demographic potential. The vegetation is characteristic of Atlantic forest with precipitation varying between 800 to greater than 2000 mm per year [33]. The Agreste mesoregion occupies 24,000 km 2 with 71 municipalities.…”