Coral reef detection using SAR/RADARSAT-1 images at Costa dos Corais, PE/AL, Brazil

The present work aimed to examine the potentials of SAR RADARSAT-1 images to detect emergent coral reefs at the Environmental Protection Area of "Costa dos Corais". Multi-view filters were applied and tested for speckle noise reduction. A digital unsupervised classification based on image segmentation was performed and the classification accuracy was evaluated by an error matrix built between the SAR image classification and a reference map obtained from a TM Landsat-5 classification. The adaptative filters showed the best results for speckle suppression and border preservation, especially the Kuan, Gamma MAP, Lee, Frost and Enhanced Frost filters. Small similarity and area thresholds (5 and 10, respectively) were used for the image segmentation due to the reduced dimensions and the narrow and elongated forms of the reefs. The classification threshold of 99% had a better user's accuracy, but a lower producer's accuracy because it is a more restrictive threshold; therefore, it may be possible that it had a greater omission on reef classification. The results indicate that SAR images have a good potential for the detection of emergent coral reefs.O presente trabalho examinou o potencial de imagens SAR do RADARSAT-1 na detecção de recifes de coral expostos na Área de Proteção Ambiental das Costa dos Corais. Filtros de multi-visada foram aplicados e testados para redução do ruído speckle. Uma classificação não supervisionada baseada em uma imagem segmentada foi realizada e a acurácia da classificação foi avaliada através de uma matriz de erro construída entre a imagem classificada e o mapa de referência. Os filtros adaptativos apresentaram os melhores desempenhos para supressão de speckle e preservação de bordas, especialmente os filtros Kuan, Gamma MAP, Lee, Frost and Enhanced Frost. Os pequenos limiares de similaridade e de área (10 e 5, respectivamente) foram melhores devido à forma fina e alongada dos recifes. O limiar de classificação de 99% apresentou uma melhor acurácia do produtor, mas uma menor acurácia do usuário, porque este limiar é mais restritivo; portanto, é possível que tenha havido uma maior omissão na classificação de recifes. Os resultados indicam que imagens SAR têm um bom potencial para a detecção de recifes expostos

Patrones oceánicos y atmosféricos durante períodos de puesta previos a capturas extremas de la sardina brasilera (Sardinella brasiliensis) en el océano Atlántico sudoeste

Relative maxima and minima of landings of Brazilian sardine captured in the Southeast Brazil Bight (SBB) were compared with oceanic and atmospheric composites relative to the spawning period in December and January, prior to these landings. Atmospheric and oceanic variables such as wind stress, Ekman transport, mixing index, sea surface temperature (SST), precipitation, outgoing long wave radiation and geopotential height were analyzed, revealing distinct climatological patterns in the SBB for these extreme catches that have not been described before. The system could be characterized by cooler SST composite anomaly (SSTA) along the SBB as a response to increased cloud cover and reduced incidence of short-wave radiation, predominating one year before the Brazilian sardine catch maxima. This system can take on a different configuration in which positive SSTA condition in the SBB is associated with a less intense South Atlantic Convergence Zone displaced southwards one year before the period of minimum catch. Our results indicate that the spatial structure of the spawning habitat is influenced by specific ocean-atmosphere interactions rather than simply resulting from the choice of a stable environment. This climatic constraint strongly affects the interannual variability of the Brazilian sardine production.Los desembarcos máximos y mínimos de capturas de la sardina brasileña en la Plataforma Sudeste Brasilera (SBB) se compararon con los patrones climáticos oceánicos y atmosféricos durante períodos de puesta, en diciembre y enero. Se analizó el comportamiento climático de variables oceanicas y atmosféricas como la influencia del viento, el transporte de Ekman, el índice de mezcla, la temperatura superficial del mar (SST), las precipitaciones, la radiación ascendente de ondas largas (OLR) y la altura geopotencial. Este análisis permitió la identificación de patrones climatológicos característicos sobre la SBB, no observados en trabajos previos. Los análisis revelaron que el sistema se caracteriza por SSTA más fríos sobre la sardina como respuesta a un incremento de la nebulosidad y la reducción de la incidencia de las radiaciones de onda corta, que predominan un año antes de las máximas capturas de sardina. Este sistema puede asumir una configuración distinta en la que SSTA positivos sobre la SBB se asocian con una SACZ desplazada hacia el sur un año antes del periodo de capturas mínimas. Nuestros resultados indican que la estructura espacial del hábitat de puesta es una consecuencia de las interacciones específicas océano-atmósfera, más que de una elección de ambiente estable y que ello influencia fuertemente la variabilidad interanual en la producción de sardina brasileña

Modeling the spawning strategies and larval survival of the Brazilian\ud sardine (Sardinella brasiliensis)

An Individual Based Model (IBM), coupled with a hydrodynamic model (ROMS), was used to investigate\ud the spawning strategies and larval survival of the Brazilian Sardine in the South Brazil Bight (SBB). ROMS\ud solutions were compared with satellite and field data to assess their representation of the physical\ud environment. Two spawning experiments were performed for the summer along six years, coincident\ud with ichthyoplankton survey cruises. In the first one, eggs were released in spawning habitats inferred\ud from a spatial model. The second experiment simulated a random spawning to test the null hypothesis\ud that there are no preferred spawning sites. Releasing eggs in the predefined spawning habitats increases\ud larval survival, suggesting that the central-southern part of the SBB is more suitable for larvae development\ud because of its thermodynamic characteristics. The Brazilian sardine is also capable of exploring\ud suitable areas for spawning, according to the interannual variability of the SBB. The influence of water\ud temperature, the presence of Cape Frio upwelling, and surface circulation on the spawning process\ud was tested. The Cape Frio upwelling plays an important role in the modulation of Brazilian sardine\ud spawning zones over SBB because of its lower than average water temperature. This has a direct influence\ud on larval survival and on the interannual variability of the Brazilian sardine spawning process. The\ud hydrodynamic condition is crucial in determining the central-southern part of SBB as the most suitable\ud place for spawning because it enhances simulated coastal retention of larvaeCAPESCNPq - PQ (CNPq) Project Number 304633/2012-

Potential changes in the connectivity of marine protected areas driven by extreme ocean warming

Projected future climate scenarios anticipate a warmer tropical ocean and changes in surface currents that will likely influence the survival of marine organisms and the connectivity of marine protected areas (MPAs) networks. We simulated the regional effects of climate change on the demographic connectivity of parrotfishes in nine MPAs in the South Atlantic through downscaling of the HadGEM2-ES Earth System Model running the RCP 8.5 greenhouse gas trajectory. Results indicate a tropicalization scenario over the tropical southwest Atlantic following an increase of sea surface temperature (SST) between 1.8 and 4.5 °C and changes in mean surface currents between − 0.6 to 0.5 m s−1 relative to present conditions. High mortality rates will reduce demographic connectivity and increase the isolation of oceanic islands. The simulation of organismal response to ocean warming shows that acclimation can significantly improve (p < 0.001) particle survival, promoting connectivity and tropicalization of MPAs, with potential impacts on their functional integrity and long-term resilience.publishedVersio

Atlas de Sensibilidade Ambiental ao Óleo da Bacia Marítima do Espírito Santo

Number of Pages: 8

Mapeamento de recifes costeiros utilizando imagens orbitais

A new methodology is being proposed for the mapping of all Brazilian coastal reefs, using TM Landsat and HRV SPOT images. This is a joint effort involving researchers from Diretoria de Áreas Protegidas/Ministério do Meio Ambiente, Programa HIDRO/INPE and Projeto Recifes Costeiros/UFPE-IBAMA-BID. This methodology is built upon the experience gathered during the mapping of coastal reefs from na environmental protected area called Costa dos Corais, located between the States of Pernambuco and Alagoas (Northeast Brazil). Initially, remote sensing images were classified using segmentation techniques to identify and map the following themes: 1)water; 2)sand flat environments; 3)shoals; 4)""breaker zone""; 5)river plume; 6)beach; 7)intertidal and shallow subtidal reefs; and 8)reef surfaces partially covered by sediments. Segmentation of LANDSAT bands TM1, 2 e 5 reached the highest mapping precision (74). Segmentation of band TM1 followed by the classification of bands TM1, 2 e 5 resulted in the most cost effective mapping (69), demanding less computer time and interaction with the analyst. However, visual interpretation of TM LANDSAT images allowed the identification of most themes and showed to be the most efficient way to map the reefs. Based on the above results, a mapping strategy will be applied where TM LANDSAT images will be appropriately filtered and resampled to the best spatial resolution possible and visually interpreted. Whenever possible, local managers will be invited to be trained on GIS and mapping techniques using digital images. This effort aims at improving the coastal zone management skills of people involved in the management of reef protected areas.Pages: 759-76

Determination of the Set of Feasible Investment Rates to Achieve Pre-specified Goals of Forecasted Carbon Emissions

Pages: 1-1

The relationship between multi-sensor satellite data and Bayesian estimates for skipjack tuna catches in the South Brazil Bight

In this study we tested a Bayesian model based on a conjugate gamma/Poisson pair associated with environmental variables derived from satellite data such as sea surface temperature (SST) and its derived gradient fields from Moderate Resolution Imaging Spectroradiometer (MODIS)/Terra, chlorophyll-a concentration from Sea Viewing Wide field of View Sensor (SEAWiFS)/SeaStar and surface winds and Ekman pumping from SeaWinds/Quick Scatterometer (QuikSCAT) to predict weekly catch estimates of the skipjack tuna in the South Brazil Bight. This was achieved by confronting the fishery data with model estimates and regressing the results on the satellite data. The fishery data were expressed by an index of catch per unit effort (CPUE) calculated as the weight of fish caught (in tonnes) by fishing week, and were divided into two series, called historical series (1996-1998; 2001), and validation year (2002). The output of model CPUE estimates is in good agreement with the historical weekly CPUE and generated updated weekly estimates that explained up to 62% of weekly CPUE from 2002. In general, the best proxy for the Bayesian weekly estimates is the gradient zonal SST field. The results refined previous knowledge of the influence of SST on the occurrence of skipjack tuna.Pages: 4049-406