Automatic near real-time selection of flood water levels from high resolution Synthetic Aperture Radar images for assimilation into hydraulic models: a case study

Flood extents caused by fluvial floods in urban and rural areas may be predicted by hydraulic models. Assimilation may be used to correct the model state and improve the estimates of the model parameters or external forcing. One common observation assimilated is the water level at various points along the modelled reach. Distributed water levels may be estimated indirectly along the flood extents in Synthetic Aperture Radar (SAR) images by intersecting the extents with the floodplain topography. It is necessary to select a subset of levels for assimilation because adjacent levels along the flood extent will be strongly correlated. A method for selecting such a subset automatically and in near real-time is described, which would allow the SAR water levels to be used in a forecasting model. The method first selects candidate waterline points in flooded rural areas having low slope. The waterline levels and positions are corrected for the effects of double reflections between the water surface and emergent vegetation at the flood edge. Waterline points are also selected in flooded urban areas away from radar shadow and layover caused by buildings, with levels similar to those in adjacent rural areas. The resulting points are thinned to reduce spatial autocorrelation using a top-down clustering approach. The method was developed using a TerraSAR-X image from a particular case study involving urban and rural flooding. The waterline points extracted proved to be spatially uncorrelated, with levels reasonably similar to those determined manually from aerial photographs, and in good agreement with those of nearby gauges

Evidence of a topographic signal in surface soil moisture derived from ENVISAT ASAR wide swath data

The susceptibility of a catchment to flooding is affected by its soil moisture prior to an extreme rainfall event. While soil moisture is routinely observed by satellite instruments, results from previous work on the assimilation of remotely sensed soil moisture into hydrologic models have been mixed. This may have been due in part to the low spatial resolution of the observations used. In this study, the remote sensing aspects of a project attempting to improve flow predictions from a distributed hydrologic model by assimilating soil moisture measurements are described. Advanced Synthetic Aperture Radar (ASAR) Wide Swath data were used to measure soil moisture as, unlike low resolution microwave data, they have sufficient resolution to allow soil moisture variations due to local topography to be detected, which may help to take into account the spatial heterogeneity of hydrological processes. Surface soil moisture content (SSMC) was measured over the catchments of the Severn and Avon rivers in the South West UK. To reduce the influence of vegetation, measurements were made only over homogeneous pixels of improved grassland determined from a land cover map. Radar backscatter was corrected for terrain variations and normalized to a common incidence angle. SSMC was calculated using change detection. To search for evidence of a topographic signal, the mean SSMC from improved grassland pixels on low slopes near rivers was compared to that on higher slopes. When the mean SSMC on low slopes was 30–90%, the higher slopes were slightly drier than the low slopes. The effect was reversed for lower SSMC values. It was also more pronounced during a drying event. These findings contribute to the scant information in the literature on the use of high resolution SAR soil moisture measurement to improve hydrologic models

Large scale grain mantle disruption in the Galactic Center

We present observations of C2H5OH toward molecular clouds in Sgr A, Sgr B2 and associated with thermal and non-thermal features in the Galactic center. C2H5OH emission in Sgr A and Sgr B2 is widespread, but not uniform. C2H5OH emission is much weaker or it is not detected in some molecular clouds in both complexes, in particular those with radial velocities between 70 and 120 km/s. While most of the clouds associated with the thermal features do not show C2H5OH emission, that associated with the Non-Thermal Radio Arc shows emission. The fractional abundance of C2H5OH in most of the clouds with radial velocities between 0 and 70 km/s in Sgr A and Sgr B2 is relatively high, of few 1e-8. The C2H5OH abundance decreases by more than one order of magnitude (aprox. 1e-9) in the clouds associated with the thermal features. The large abundance of C2H5OH in the gas-phase indicates that C2H5OH has formed in grains and released to gas-phase by shocks in the last aprox. 1e5 years.Comment: In press in Astrophysical Journal Letters 7 pages, 1 table, 1 figur

Efeito da aplicação de altas pressões em chouriço de frango sem aditivos

A procura de produtos com carne de aves e sem aditivos é cada vez mais acentuada por parte dos consumidores. As indústrias alimentares tentam corresponder a estas exigências com o desenvolvimento de produtos isentos de aditivos mas garantindo a segurança alimentar. As altas pressões são uma alternativa interessante face aos métodos tradicionais de conservação de alimentos, uma vez que permitem aumentar a segurança microbiológica. O objetivo deste trabalho foi estudar o efeito das altas pressões em chouriço de frango sem adição de aditivos, produzido numa unidade industrial. Após o tratamento (600MPa por 8 min) as amostras foram armazenadas a 4 °C. O controlo microbiológico foi realizado no dia 0, 2 e 4 meses de conservação. Efetuaram-se contagens de bactérias lácticas mesófilas, bolores e leveduras, bactérias coliformes, Clostridium perfringens, estafilococos coagulase positivos, Escherichia coli ß-glucuronidase positiva, mesófilos, e psicrotróficos, e pesquisas de Listeria monocytogenes, Salmonella spp., segundo as normas internacionais. Os resultados apontam a ausência de Salmonella spp. e de Listeria monocytogenes em 25 g de produto. As contagens de Escherichia coli, bolores e leveduras, bactérias coliformes, Clostridium perfringens, e estafilococos coagulase positivos foram inferiores a 10 UFC g-1 em todas as amostras. As análises microbiológicas revelaram que as amostras com tratamento obtiveram contagens de bactérias lácticas mesófilas, mesófilos e psicrotróficos inferiores às contagens das amostras sem tratamento, com uma redução de 2 log. Esta redução poderá estar associada ao efeito das altas pressões ao nível da estrutura e integridade funcional da membrana citoplasmática dos microrganismos. Em suma, as altas pressões são uma técnica de grande interesse na indústria alimentar.info:eu-repo/semantics/publishedVersio

Aplicação de altas pressões em chouriço de peru sem aditivos - segurança alimentar

As tecnologias emergentes de conservação dos alimentos têm como objetivo a segurança microbiológica, preservando a qualidade nutricional e sensorial ao longo do armazenamento. As altas pressões hidrostáticas são um método de conservação, alternativo aos processos térmicos existentes mais agressivos. O objetivo deste trabalho foi avaliar a aplicação de altas pressões em chouriço de peru produzido sem adição de aditivos numa unidade fabril e submetido a altas pressões (600MPa durante 8 min). As amostras foram armazenadas a 4 °C. Analisadas no dia da aplicação do tratamento e após 2 e 4 meses. Os parâmetros microbiológicos, designadamente contagens de bactérias lácticas mesófilas, bolores e leveduras, bactérias coliformes, Clostridium perfringens, estafilococos coagulase positivos, Escherichia coli ß-glucuronidase positiva, mesófilos, psicrotróficos, e pesquisa de Listeria monocytogenes, e de Salmonella spp., foram analisados recorrendo às metodologias definidas segundo as normas internacionais. Na pesquisa de patogénicos todas as amostras analisadas apresentaram um resultado de ausência em 25 g de produto. As contagens de Escherichia coli, bolores e leveduras, bactérias coliformes, Clostridium perfringens, e estafilococos coagulase positivos revelaram-se inferiores a 10 UFC g-1. As amostras submetidas a altas pressões hidrostáticas obtiveram contagens de bactérias lácticas mesófilas, mesófilos e psicrotróficos inferiores às contagens das amostras sem tratamento, desde o dia da aplicação do tratamento, com uma redução de 2 log. Perante os resultados obtidos, o fabrico de chouriço de peru sem aditivos e com aplicação de altas pressões hidrostáticas surge como um método de conservação do produto.N/

Pineapple by-products integrated valorisation towards functional foods

This work was financially supported by CBQF under the FCT – Fundação para a Ciência e a Tecnologia through project Multibiorefinery – Multi-purpose strategies for the valorisation of a wide range of agroforestry by-products and fisheries: A step forward in the creation of an integrated biorefinery, (POCI-01-0145- FEDER-0066) and the project UID/Multi/50016/2019 and by PhD grant SFRH/BD/104074/2014 to Débora Campos.info:eu-repo/semantics/publishedVersio

Observation impact, domain length and parameter estimation in data assimilation for flood forecasting

Accurate inundation forecasting provides vital information about the behaviour of fluvial flood water. Using data assimilation with an Ensemble Transform Kalman Filter we combine forecasts from a numerical hydrodynamic model with synthetic observations of water levels. We show that reinitialising the model with corrected water levels can cause an initialisation shock and demonstrate a simple novel solution. In agreement with others, we find that although assimilation can accurately correct water levels at observation times, the corrected forecast quickly relaxes to the open loop forecast. Our new work shows that the time taken for the forecast to relax to the open loop case depends on domain length; observation impact is longer-lived in a longer domain. We demonstrate that jointly correcting the channel friction parameter as well as water levels greatly improves the forecast. We also show that updating the value of the channel friction parameter can compensate for bias in inflow

Widespread HCO emission in the M82's nuclear starburst

We present a high-resolution (~ 5'') image of the nucleus of M82 showing the presence of widespread emission of the formyl radical (HCO). The HCO map, the first obtained in an external galaxy, reveals the existence of a structured disk of ~ 650 pc full diameter. The HCO distribution in the plane mimics the ring morphology displayed by other molecular/ionized gas tracers in M82. More precisely, rings traced by HCO, CO and HII regions are nested, with the HCO ring lying in the outer edge of the molecular torus. Observations of HCO in galactic clouds indicate that the abundance of HCO is strongly enhanced in the interfaces between the ionized and molecular gas. The surprisingly high overall abundance of HCO measured in M82 (X(HCO) ~ 4x10^{-10}) indicates that its nuclear disk can be viewed as a giant Photon Dominated Region (PDR) of ~ 650 pc size. The existence of various nested gas rings, with the highest HCO abundance occurring at the outer ring (X(HCO) ~ 0.8x10^{-9}), suggests that PDR chemistry is propagating in the disk. We discuss the inferred large abundances of HCO in M82 in the context of a starburst evolutionary scenario, picturing the M82 nucleus as an evolved starburst.Comment: 13 pages, 3 figures, to appear in ApJ Letters; corrected list of author