Southeast Coast Of Brazil Research Articles

The effect of Oceanic South Atlantic Convergence Zone episodes on regional SST anomalies: the roles of heat fluxes and upper-ocean dynamics

The South Atlantic Convergence Zone (SACZ) is an atmospheric system occurring in austral summer on the South America continent and sometimes extending over the adjacent South Atlantic. It is characterized by a persistent and very large, northwest-southeast-oriented, cloud band. Its presence over the ocean causes sea surface cooling that some past studies indicated as being produced by a decrease of incoming solar heat flux induced by the extensive cloud cover. Here we investigate ocean–atmosphere interaction processes in the Southwestern Atlantic Ocean (SWA) during SACZ oceanic episodes, as well as the resulting modulations occurring in the oceanic mixed layer and their possible feedbacks on the marine atmospheric boundary layer. Our main interests and novel results are on verifying how the oceanic SACZ acts on dynamic and thermodynamic mechanisms and contributes to the sea surface thermal balance in that region. In our oceanic SACZ episodes simulations we confirm an ocean surface cooling. Model results indicate that surface atmospheric circulation and the presence of an extensive cloud cover band over the SWA promote sea surface cooling via a combined effect of dynamic and thermodynamic mechanisms, which are of the same order of magnitude. The sea surface temperature (SST) decreases in regions underneath oceanic SACZ positions, near Southeast Brazilian coast, in the South Brazil Bight (SBB) and offshore. This cooling is the result of a complex combination of factors caused by the decrease of solar shortwave radiation reaching the sea surface and the reduction of horizontal heat advection in the Brazil Current (BC) region. The weakened southward BC and adjacent offshore region heat advection seems to be associated with the surface atmospheric circulation caused by oceanic SACZ episodes, which rotate the surface wind and strengthen cyclonic oceanic mesoscale eddy. Another singular feature found in this study is the presence of an atmospheric cyclonic vortex Southwest of the SACZ (CVSS), both at the surface and aloft at 850 hPa near 24°S and 45°W. The CVSS induces an SST decrease southwestward from the SACZ position by inducing divergent Ekman transport and consequent offshore upwelling. This shows that the dynamical effects of atmospheric surface circulation associated with the oceanic SACZ are not restricted only to the region underneath the cloud band, but that they extend southwestward where the CVSS presence supports the oceanic SACZ convective activity and concomitantly modifies the ocean dynamics. Therefore, the changes produced in the oceanic dynamics by these SACZ events may be important to many areas of scientific and applied climate research. For example, episodes of oceanic SACZ may influence the pathways of pollutants as well as fish larvae dispersion in the region.

COVID-19-related personal protective equipment (PPE) contamination in the highly urbanized southeast Brazilian coast

This study aimed to report personal protective equipment (PPE) contamination in Santos beaches (Brazil) using standardized procedures for the first time while comparing two periods to understand the progression of PPE contamination. The occurrence of PPE items was ubiquitous in all sampled sites, although the densities were relatively low compared to those in other parts of the world. Unlike previous studies, reusable face masks were the most common type of PPE. PPE density in the studied areas was similar in both sampling seasons, probably because of the influence of tourism, urbanization, and local hydrodynamic aspects. PPE items can release microfibers into the aquatic environment and pose entanglement hazards to marine biota. A wider monitoring of PPE pollution, accompanied by surveys on PPE usage and behavior, as well as chemical characterization of the discarded PPE items, is needed to fully understand this unprecedented form of plastic pollution.

Spatio-temporal dynamics of the commercial seabob shrimp Xiphopenaeus kroyeri (Heller, 1862) and physico-chemical parameters in a marine protected area: Changes in abundance and distribution after 20 years

Studies comparing parameters before and after the establishment of protected areas in coastal environments allow improvements of management plans and recognition of alterations due to natural or anthropic effects. This study compared spatio-temporal variation in abundance of Xiphopenaeus kroyeri in two equivalent periods. The first period was 12 years before the establishment of the Marine Protected Area and the second was 8 years after. The influence of environmental factors in relation to abundance was also analyzed. Samples were conducted monthly at Ubatuba Bay, Southeast Brazilian coast in period 1 (1995–1996) and 2 (2016–2017). Five transects were sampled using the same methodology, encompassing depths from 5 to 15 meters and areas sheltered or exposed to tidal waves and currents. Abundance varied seasonally. Higher values were obtained in December, March, and June of period 1 and in April and July of period 2. These months correspond to autumn and the beginning of winter. Seasonal fluctuations in abundance seems to be a response to higher and more stable salinity and the efficacy of the closed season (March–May), favoring a higher abundance in the autumn. There was no significant difference of X. kroyeri abundance between periods. Results indicate stability of population density through time in the region, suggesting conservation measurements are aiding species’ protection is spite of a larger fishing fleet. Our study reinforces the importance of measurements to mitigate fishery resources along with other non-commercial species important to preserve local biodiversity.

A first report of decapod crustaceans (Anomura and Brachyura) from Laje de Santos: a no-take marine reserve in the southeast coast of Brazil

This study represents an unprecedented effort to assess the diversity of rocky infralittoral decapod Brachyura and Anomura from the Laje de Santos Marine State Park, a preserved and protected area along the southeastern Brazilian coast. The samples were carried out quarterly for one year, using the combination of artificial refuge substrate for the passive capture of specimens and SCUBA dive for active capture. Specimens sampled were deposited in the Crustacean Collection of the Department of Biology of FFCLRP, University of São Paulo. The abundance and richness is expressive considering the dimension of the area with a total of 987 individuals distributed into 32 species, 22 genera, and 11 families. The hermit crab Pagurus brevidactylus and the crab Mithraculus forceps were the most abundant species of Anomura and Brachyura, respectively. This is the first study focused on carcinofauna inhabiting the park on and we encourage future works focused in the monitoring of species as well as the construction of new robust checklists contents from different offshore regions in order to build biodiversity parameters to serve as baseline for future management and work plans on Brazilian protected areas since decapod crustaceans are key group on fauna composition in any subtidal ecosystem.

Assessing the Impact of Climate Change on the Fatigue Life of Offshore Structures

Abstract Design life of offshore structures is in general in the 20- to 30-year range, with some cases going up to 50 years. Fatigue is one of the major design criteria for such structures. Climate change may affect the fatigue life of offshore structures, it would be necessary to update the design procedures to take into account climate change effects on structural performance. This paper aims to investigate the impact of climate change in the long-term fatigue life of offshore structures due to wave loading. For this purpose, available environmental conditions for two locations (South East Brazilian Coast and North Atlantic Ocean) generated by the HadGEM-2S global climate model, considering representative concentration pathway (RCP) 4.5 and RCP 8.5 future scenarios and the historical (past) scenarios are considered. The assessment in both locations is performed for two structural models: an idealized stress spectrum for a generic fatigue hot-spot and a steel lazy wave riser (SLWR) connected to a floating production storage and offloading (FPSO). Fatigue life is estimated using the S–N curve approach. Results show that the impact on the fatigue life depends on the structure dynamic characteristics, on the geographic location and mainly on the greenhouse emission scenario. In general, for the Brazilian location, when compared to the historical scenario, most of the future scenarios lead to slightly higher fatigue damages (lower fatigue lives). On the other hand, for the North Atlantic location, there is not a clear trend for future climate change scenarios.

Biological affinities of Brazilian pre-colonial coastal communities explored through bootstrapped biodistances of dental non-metric traits

Based on dental morphology, it was recently suggested that the Southeast Coast of Brazil was inhabited by different biological groups throughout the Holocene. Among those that inhabited São Paulo state, coastal shellmound builders seem biologically distant from riverine shellmound builders. Additionally, individuals that later built ichthyological sites are also biologically distant from both early coastal or riverine populations. However, mainly due to low sample sizes, such conclusions may not be reliable, and require further inquiry. Here, we explore the confidence interval of biological affinities among five archaeological series (Piaçaguera, Buracão, Tenório, Mar Virado and Moraes), composed by 128 individuals from different chronological and archaeological backgrounds. We use a bootstrapping analysis of biodistances, which illustrates the expected error that results from sample sizes, by generating density estimations based on the observed biological affinities among series. Our results contradict previous claims based on dental analyses by showing that individuals from ichthyological sites cannot actually be considered distinct from Southeast coastal and riverine shellmound builders. On the other hand, it shows that early coastal and riverine shellmound builders are not biologically related, thus supporting prior assumptions of high phenotypic variation among Southeast shellmound builders, at least within the scope of São Paulo state. Finally, although shellmound builders are related to individuals from ichthyological sites to some extent, early and later coastal shellmound builders of this area do not appear to be biologically related, which further highlights the complex dynamics of population movement in the area.

New Insights into the Life-history Traits of the Night Shrimp Processa hemphilli (Caridea: Processidae) in the Western Atlantic.

We analyzed sexual dimorphism, sex ratio, relative growth, morphological sexual maturity, fecundity, embryo volume, and reproductive output of a population of the night shrimp Processa hemphilli from the Southeast coast of Brazil. Sampling was seasonally conducted, from June 2016 to April 2019 in Ubatuba, São Paulo. Our results showed the presence of sexual dimorphism in the body size, with females being larger than males. In addition, there was no difference in the overall sex ratio. However, it was possible to observe a skewed sex ratio to males in the smaller size classes, whereas females were more abundant in the larger size classes. The estimated carapace length at the onset of morphological sexual maturity of females and males was 3.6 mm and 3.2 mm, respectively. The mean fecundity of females was 285 ± 142 embryos (mean ± SD) embryos and was positively correlated with the carapace length. The embryo volume differed between the developmental stages with a constant increase in volume throughout the development between stages I and III. The mean reproductive output of females was 52.4%. Our results suggest that P. hemphilli have a pure search mating system, show sex allocation in the growth of body structures, and that females have high reproductive investment. All of these results represent the first insights into the life-history traits of the species in the western Atlantic and contribute to the knowledge about processid species.

Uncovering well-being ecosystem services bundles (WEBs) under conditions of social-ecological change in Brazil

This research examines the interplay of a 3-dimensional well-being approach of coastal communities and the ecosystem services upon which they depend, and the implications for marine protected area (MPA) governance. We use the concept of well-being ecosystem services bundles (WEBs) to refer to the links among ecosystem services and social well-being as experienced by fishing communities adjacent to MPAs. This research combines data from surveys with households (n=59) and three participatory workshops (total participation n=48). We supplement results using insights from a photovoice process with community members (n=15) and participant observation (September 2018-April 2019). We identify key WEBs, social-ecological changes, and their trade-offs and synergies in three coastal communities on the southeast coast of Brazil. In doing so, we examine core WEBs relevant to coastal communities, and the drivers of change that influence these WEBs (e.g., increased tourism, deforestation) and show their dynamism and complexity. Further, we develop a typology to reflect how individuals perceive or experience the interplay among components of WEBs, or the “pathways of interaction” that connect their well-being to ecosystem services. Results reveal three key opportunities for improving MPA governance. First, we show that WEBs play a key role in perceptions of physical and public safety experienced in coastal communities, an insight that is especially relevant to the global south and developing countries due to the inequity-related security issues. Second, trade-offs in tourism are a major area for governance interventions to improve fit to the local context, such as enhancing the well-being of locals as it is shaping local livelihoods, culture, and social relations. Third, we develop a typology that highlights overlooked experiential, observational, and visual contributions of WEBs to well-being that have the potential to reinforce conservation values and stewardship actions in communities affected by MPAs.

Geomorphic analyses of two recent debris flows in Brazil

Debris flows are one of the main geomorphic processes resulting in economic and social losses in Brazil. Due to the recurrence of these events and the damage they can cause, it is necessary to better characterize the process to mitigate new occurrences and prevent casualties. On March 11, 2011, extreme rainfall contributed to triggering debris flows and shallow landslides in the Tingidor watershed (TW), causing three deaths, destroying houses, and partially destroying the main road to the state capital. Similarly, on January 13, 2014, rainfall-induced shallow landslides triggered debris flows in the Guarda-mão watershed (GW), causing 25 deaths and destroying infrastructure. Both areas are located in the Serra do Mar, a mountain range that extends for 1500 km along the south and southeast coasts of Brazil. The main goal of this work was to investigate and compare the main triggering factors and geomorphic characteristics of these two recent events. To achieve this goal, a landslide inventory was compiled, and the main debris-flow features were mapped in detail. Flow discharges, velocities and volumes were also estimated. Despite having an initial source volume more than 30 times smaller, the GW event had a total volume of approximately 237,700 m³, compared with 196,800 m³ in the TW event. Along with differences related to runout length and topography in both areas, the results demonstrate that entrainment is an important characteristic of debris flows in the two recent occurrences evaluated in Brazil.

Dynamics and storm records on sheltered beaches: Paraty, southeast coast of Brazil

Dynamics and storm records on sheltered beaches: Paraty, southeast coast of Brazil

Extreme climatic characteristics near the coastline of the southeast region of Brazil in the last 40 years

The southeastern Brazilian coast is a vulnerable region to the development of severe storms, mainly caused by the passage of cold fronts and extratropical cyclones. In the last decades, there has been an increase in the occurrence of subtropical cyclones. This study investigates trends and climatic variations, analyzing surface meteoceanographic series at six grid points from the reanalysis databases of ERA-Interim and ERA5 (European Center for Medium-Range Weather Forecasts (ECMWF)) from 1979 to 2018 over the ocean region bounded, approximately, at 18°S, 25°S, and 37ºW, 45ºW (between the states of Espírito Santo, Rio de Janeiro, and São Paulo). Non-parametric statistical tests and the generalized extreme value distribution are employed for annual, seasonal, and daily maxima/minima. The numbers of occurrence of extreme values, as well as the extremal index, are also estimated in order to better understand the behavior of extremes. Annual maximum sea-surface temperature anomalies of the ERA-Interim databases show very low negative values, mainly at the beginning of measurements (between 1979 and 1982), leading to high positive trend values. The results are compared to the updated data from ERA5 which have anomalies that are more homogeneous with positive trends but without statistical significance. The other meteorological series of the ERA-Interim does not present discrepancies. Only the maximum anomalies of air temperature have significant annual and seasonal positive trends at grid points near the coast of Rio de Janeiro and São Paulo. Despite that the analyses for pressure and wind speed anomalies do not indicate significant trends, they present increases in the interdecadal pattern of the numbers of occurrence of extreme percentiles for almost every grid point. Return levels for 10, 25, 50, 75, and 100 years are estimated at each grid point, and many maximum/minimum peaks are close to the return levels for 100-year return periods. The extremal index suggests average cluster sizes associated with no predominance of clustering for the extreme percentiles, which represents weak dependence between the exceedances. These results characterize some independence between extreme meteorological events such as the event that has been taking place in the region. The occurrence of maximum daily wind speed peaks calculated in austral spring, whose values exceeded the previous ones, is identified at three grid points near the southeast Brazilian coast, caused by the passage of the subtropical cyclone “Deni,” which occurred in November 2016.

Patterns and drivers determining phyllostomid bat diversity in land-bridge islands off the south-east coast of Brazil

AbstractFew studies that apply the theory of island biogeography have considered the functional and phylogenetic dimensions of diversity. However, the joint use of the three diversity dimensions, i.e. taxonomic, functional and phylogenetic, can help us to gain a better understanding of the mechanisms underlying ecological and evolutionary processes. Here, we compare phyllostomid bat assemblages between five land-bridge islands off the south-east coast of Brazil and compare these islands with three sites on the mainland. For this, we have estimated the three dimensions of α- and β-diversity, nestedness and community indexes based on mean trait values for the islands and the mainland. The mainland showed higher species richness and taxonomic, functional and phylogenetic diversity. In addition, only species richness and phylogenetic diversity were positively related to island area. Taxonomically and functionally, the poorest assemblages (minor islands) were subgroups of the richer assemblages (mainland and larger islands). Taken together, our results show that bat assemblages of smaller islands tend to be more sensitive to changes in species richness than those of larger islands, with the larger islands working as a ‘source’ of species for small islands. These results demonstrate the high conservation value of the larger islands, which has direct consequences for local population dynamics of phyllostomid bats.

Bioaccumulation of mercury is equal between sexes but different by age in seabird (Sula leucogaster) population from southeast coast of Brazil

Since several seabird species have sexual size dimorphism, in which one sex is larger than the other, and may consume bigger prey, this size difference may affect the contamination concentration in the seabird’s tissues depending on their sex and age. In this study, mercury contamination was investigated in brown booby (Sula leucogaster) adults and juveniles during their breeding season at the Santana Archipelago, on the southeast coast of Brazil. Two hypotheses were evaluated: 1. As females consume larger prey than males due to the reverse sexual dimorphism, higher total mercury (THg) and methylmercury (MeHg) concentrations are expected in females tissues than in males; 2. Adult seabirds have more time to accumulate mercury than juveniles, so it is expected that adults will show higher THg and MeHg concentrations than juveniles in their feathers, but none in blood since the last indicates the exposure of short time (30–60 days), as it is a constantly synthesized tissue. Feathers and blood were sampled from 20 individuals of each group (males, females and juveniles). Also, 10 eggs of the brown booby and muscle tissue samples of their main prey were collected, from February to October 2018. Females and males had similar THg concentrations in the tissues with no statistical differences between sexes. Thus, the sexual size dimorphism did not influence mercury concentrations among the tissues and both genders can be used as a biomonitor. Brown booby juveniles had low THg and MeHg concentrations compared to adults due to a shorter time of exposure for mercury to bioaccumulate in their tissues. This is the first study, to the best of our knowledge, analyzing methylmercury in feathers, blood and eggs of a tropical seabird, which can be a useful baseline for future studies on the effects of contaminants on this species in tropical regions.

Drone-Monitoring: Improving the Detectability of Threatened Marine Megafauna

Unmanned aerial vehicles (UAVs; or drones) are an emerging tool to provide a safer, cheaper, and quieter alternative to traditional methods of studying marine megafauna in a natural environment. The UFES Nectology Laboratory team developed a drone-monitoring to assess the impacts on megafauna related to the Fundão dam mining tailings disaster in the Southeast Brazilian coast. We have developed a systematic pattern to optimize the available resources by covering the largest possible area. The fauna observer can monitor the environment from a privileged angle with virtual reality and subsequently analyzes each video captured in 4k, allowing to deepening behavioral ecology knowledge. Applying the drone-monitoring method, we have observed an increasing detectability by adjusting the camera angle, height, orientation, and speed of the UAV; which saved time and resources for monitoring turtles, sea birds, large fish, and especially small cetaceans efficiently and comparably.

Evaluation of the ABI/GOES-16 SST Product in the Tropical and Southwestern Atlantic Ocean

Sea surface temperature (SST) is an essential climate variable used for ocean and weather monitoring and forecasting. The NOAA’s next generation geostationary satellite GOES-16 was declared operational at the east position (75°W) in December 2017, carrying onboard an Advanced Baseline Imager (ABI). The hyperspectral ABI sensor now allows SST estimates every 10–15 min at both day and nighttime, with advanced options for cloud screening and water vapor correction. In the present work, we compare the first operational ABI SST product (OSI SAF, 2018) with an in situ match-up database (MDB) across the Tropical and Southwestern Atlantic Ocean, off the Brazilian coast, throughout the year of 2018. The MDB was obtained from two long-term programs, i.e., PIRATA moored buoys (FOLTZ et al., 2016) and PNBoia moored and drifting buoys (MARINHA DO BRASIL, 2017). Separate comparisons were made for each data set, analyzing the uncertainties according to the program (i.e., buoy type and region), satellite SST quality level and influence of diurnal heating. We also compare the ABI product with the OSTIA analysis L4 SST (DONLON et al., 2012) to increment our analyses on the spatio-temporal biases within the study region. The results show that the OSI SAF ABI SST L3C has a mean bias (0.1 °C) and error (RMSE, 0.5 °C) within the GHRSST standards, with an exception being coastal waters off the southeast Brazilian coast (RMSE, 0.65 °C), which are subjected to sharp thermal fronts. The highest biases are for regions/seasons subjected to persistent cloud coverage and high water-vapor content, i.e., the Intertropical and South Atlantic Convergence Zones, as well as highly dynamic frontal zones, i.e., the Brazil Malvinas Confluence Zone, the Subtropical Front and coastal waters. The ABI SST product is suitable for operational use, and applications should explore more deeply the new set of information provided.

Avaliação de um biossorvente à base de fibra de ráfia na sorção de hidrocarbonetos

Oil spills and discharges of petroleum products have severely polluted aquatic ecosystems, oceans, rivers, groundwater and even soil. In August 2019, more than 2,000 km of the northeast and southeast coast of Brazil were struck by a major oil spill in the country’s largest ever environmental disaster. Spill remediation is a significant environmental challenge and the economic and socioenvironmental impacts of these events are diverse. Oil spills in oceans and rivers severely affect the fishing and tourism industries of the areas in question, with damage including severe short and long-term effects on plants and animals, such as respiratory and digestive disorders, reduced growth and reproductive capacity as well as weakened immunity due to the bioaccumulation of toxic contaminants. There are several proposed strategies for removing crude oil and petroleum products from surface water. Contaminated areas can be remediated in-situ or ex-situ, with the former considered the best option in terms of cost and efficiency. In this respect, absorbent materials obtained from biomass have received widespread attention due to their ease of use, buoyancy and low cost. Raffia is a natural fiber abundant in eastern Africa with excellent physical properties, such as low specific weight, good liquid sorption and low conductivity. As such, the present study investigated the application of raffia fiber with different particle sizes ( 300 µm, 300 - 850 µm, 850 - 1000 µm, 1000 - 1400 µm and 1400 - 2000 µm) and fiber/hydrocarbon ratios (1, 2, 3 and 4% w/v) as an absorbent for hydrocarbons, using n-heptane as a model molecule. Microscopic analysis of micronized raffia fiber indicated the presence of honeycomb-shaped cells with well-defined borders and an irregular geometry. These honeycomb structures are preserved, especially in large particle size ranges. Among the granulometries assessed, the highest sorption capacities were obtained for 1000 to 1400 µm raffia fibers, suggesting that honeycomb-shaped structures favor hydrocarbon sorption. Additionally, the fact that smaller particles do not require micronization is economically beneficial and facilitates application of the absorbent material to remediate hydrocarbon-contaminated areas. The results obtained under the conditions studied indicate that sorption capacity increases as the absorbent content rises. Comparison of fiber contents of 1% and 3% w/v for 1000 - 1400 µm particles showed an increase of approximately 43% in sorption capacity when content rose to 3% w/v. The results of the present study demonstrate the potential of natural raffia fiber as an alternative absorbent for hydrocarbons.

Quantifying anthropogenic threats affecting Marine Protected Areas in developing countries

Conservation's capacity to deal with anthropogenic environmental threats within Marine Protected Areas (MPAs) varies enormously, especially in developing countries that are often immersed in weak enforcement, ineffective management and shortages of resources. A deeper understanding of the causes of these threats is fundamental for identifying effective management solutions. Here, we investigate the presumptive drivers of environmental threats across 40 Brazilian MPAs. We categorized and quantified environmental threats from two independent sources: i) the results of systematic social surveys carried out as part of WWF's RAPPAM assessment, as primary data source, and; ii) data gathered from news media articles related to the MPAs (secondary data source). We identified 461 reports of threats that we classified into three general categories: overexploitation, urbanization and land use threats. The presence of overexploitation threats was strongly associated with extreme poverty of local communities close to the MPAs. Threats also seem to be more frequent in category V MPAs, which in Brazil are Environmental Protection Areas (EPA), with multiple use objectives. Threats were concentrated on the North and Southeast coasts of Brazil. We found that data from news media can be used for qualitative assessment of threats, but has limited potential for quantification. Our findings highlight the need for policy makers and MPA managers to adopt a broader perspective that considers the role of social inequalities in promoting and exacerbating environmental threats. While recognizing that conservation has limited capacity to address the widespread social inequalities found in many tropical developing countries, if the socioeconomic context of local communities is significantly compromising conservation efforts it may be necessary to target and prioritize social interventions as a prerequisite for effective MPA management and governance.

Fieldwork in the Southeast Coast of Brazil

Fieldwork in the Southeast Coast of Brazil

Meteotsunamis at global scale: problems of event identification, parameterization and cataloguing

Meteorological tsunamis (meteotsunamis) are defined as anomalous long-period (2 to 120 min) sea-level oscillations resulting from atmospheric forcing. In the current version of the Global Historical Tsunami Database covering almost 4000 years and including about 2500 tsunamis and tsunami-like events, meteotsunamis constitute a very small fraction of all events (4.1%). In the twenty-first century, when digital instruments for sea-level recording became widely available, identified meteotsunamis still only constitute 5.8% of all catalogued tsunami events. At the same time, there are many regions (Great Lakes, northeastern Gulf of Mexico, US East coast, southern Britain, Balearic Islands, Adriatic Sea, Yellow Sea, south-west coast of Japan, south-east coast of Brazil), where meteotsunamis dominate over all the other types of tsunamigenic events. Cataloguing of meteotsunami events, as reported in mass media, and described in scientific publications, faces the problems of their correct parameterization within the adopted format of the tsunami database. This format was developed in the late 1980s primarily for parameterization of seismogenic tsunamis, which at that time constituted more than 90% of the database’s content. As a result, most of the meteotsunamis included in the database lack some basic parameters, such as time of origin, location of source as well as run-up heights. The present paper addresses these issues and discusses the ways for their possible resolution. Several well-known cases of recent meteotsunamis are considered from the standpoint of their parameterization and hazard assessment.

Classification of Oil Slicks and Look-Alike Slicks: A Linear Discriminant Analysis of Microwave, Infrared, and Optical Satellite Measurements

We classify low-backscatter regions observed in Synthetic Aperture Radar (SAR) measurements of the surface of the ocean as either oil slicks or look-alike slicks (radar false targets). Our proposed classification algorithm is based on Linear Discriminant Analyses (LDAs) of RADARSAT-1 measurements (402 scenes off the southeast coast of Brazil from July 2001 to June 2003) and Meteorological-Oceanographic (MetOc) data from other earth observation sensors: Advanced Very High Resolution Radiometer (AVHRR), Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), Moderate Resolution Imaging Spectroradiometer (MODIS), and Quick Scatterometer (QuikSCAT). Oil slicks are sea-surface expressions of exploration and production oil, ship- and orphan-spills. False targets are associated with environmental phenomena, such as biogenic films, algal blooms, upwelling, low wind, or rain cells. Both categories have been interpreted by domain-experts: mineral oil (n = 350; 45.5%) and petroleum free (n = 419; 54.5%). We explore nine size variables (area, perimeter, etc.) and three types of MetOc information (sea surface temperature, chlorophyll-a, and wind speed) that describe the 769 samples analyzed. Seven attribute–domain combinations are tested with three non-linear transformations (none, cube root, log10), with and without MetOc, adding to 39 attribute subdivisions. Classification accuracies are independent of data transformation and improve when selected size attributes are combined with MetOc, leading to overall accuracies of ~80% and sound levels of sensitivity (~90%), specificity (~80%), positive (~80%) and negative (~90%) predictive values. The effectiveness of this data-driven attempt supports further commercial or academic implementation of our LDA algorithm.