A LINEAR STUDY OF HIGH-DRAG STATES AND FLOW STAGNATION PRODUCED BY MOUNTAIN WAVES

A linear model of gravity waves generated by stratified airflow over mountains is developed. The model provides simple, closed-form formulas for the surface drag in a situation where conditions for wave resonance exist. The wind is constant near the surface and decreases linearly above. The drag normalized by its value in the absence of shear is found to depend on two parameters: the height of the interface where the shear is discontinuous and the Richardson number, Ri, in the region above. This drag attains maxima when the height of the interface induces constructive interference between the upward and downward propagating reflected waves, and minima when there is destructive interference. The amplitude of the drag modulation becomes larger for lower Ri. It is also shown that, for Ri<2.25, the locations where wave breaking is first predicted to occur in flow over a 2D ridge become displaced horizontally and vertically by an amount depending on Ri

O empirismo Delicado e o romance na Educação para a Sustentabilidade

UID/HIS/04209/2019 SFRH/BPD/100638/2014A educação para a sustentabilidade deve começar pela consciência da nossa ligação com o mundo natural. A ausência de experiência direta esensível com a natureza,dificulta a apreensão e compreensão dos fenómenos ambientais e da sua consequente relação com a vida humana. Neste texto exploramos os conceitos/métodos “empirismo delicado” de Goethe e “romance” de Whitehead, que introduzimos e aplicamos no projeto de Educação para a Sustentabilidade – ID Natura (Universidade de Évora). O trabalho desenvolvido com professores,investigadores e alunos, do ensino pré-escolar até ao ensino secundário, de Escolas de Évora, Portugal, alicerça-se numa vivência sensível em proximidade com o mundo natural, como suporte de conhecimento e desenvolvimento de uma consciência ambiental holística. Apresentamos alguns testemunhos sobre as vivências dos alunos nos quais encontramos ecos de “romance” e“empirismo delicado”.As experiências vividas e refletidas por todos  iluminam o caminho para uma educação que liga as dimensões intelectual e sensível, na aventura do conhecimento e do reconhecimento de valores fundamentais para o cuidado da nossa casa comum, a Terra.publishersversionpublishe

Exploring alternative marine lipid sources as substitutes for fish oil in Farmed Sea bass (Dicentrarchus labrax) and their influence on organoleptic, chemical, and nutritional properties during cold storage

This study evaluated the replacement of fish oil (sardine oil) by different combinations of alternative marine lipid ingredients as sources of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in European sea bass (Dicentrarchus labrax) throughout 14 days of ice storage. A practical diet (SARDINE) was used as a control, which included 9% sardine oil and 4.4% soybean oil, providing 2.3% of EPA + DHA. Two other experimental diets were formulated to achieve the same EPA + DHA values but completely devoid of soybean oil. In the ALGABLEND diet, 6.7% of salmon oil (salmon by-product) and 2% of algae biomass (Algaessence Feed™) partially replaced sardine oil. In the ALGAOIL diet, sardine oil was totally replaced with 10.1% salmon by-product oil and 3.3% algae oil (Veramaris®). All diets were equally well-accepted by European sea bass, resulting in similar growth performance, somatic indexes, and whole body composition. At the end of the trial, no significant differences were found in the EPA + DHA levels of fish muscle between dietary treatments, resulting in high values of EPA + DHA (&gt; 0.62 g 100 g−1). Furthermore, replacing fish oil did not significantly affect the organoleptic and chemical properties of the fish samples. Parameters such as pH, water holding capacity, lipid oxidation, antioxidant capacity, color and texture presented similar values to those obtained for fish fed the SARDINE diet during the 14 days of storage in ice. In conclusion, these results show that combining algal oil (Veramaris®), algae blend (Algaessence Feed™) and salmon by-product oil can be a successful strategy for the fortification of European sea bass muscle in EPA and DHA while ensuring fish freshness, nutritional quality, and consumers’ health

A LINEAR STUDY OF HIGH-DRAG STATES AND FLOW STAGNATION PRODUCED BY MOUNTAIN WAVES

A linear model of gravity waves generated by stratified airflow over mountains is developed. The model provides simple, closed-form formulas for the surface drag in a situation where conditions for wave resonance exist. The wind is constant near the surface and decreases linearly above. The drag normalized by its value in the absence of shear is found to depend on two parameters: the height of the interface where the shear is discontinuous and the Richardson number, Ri, in the region above. This drag attains maxima when the height of the interface induces constructive interference between the upward and downward propagating reflected waves, and minima when there is destructive interference. The amplitude of the drag modulation becomes larger for lower Ri. It is also shown that, for Ri<2.25, the locations where wave breaking is first predicted to occur in flow over a 2D ridge become displaced horizontally and vertically by an amount depending on Ri

A roadmap to climate data rescue services

Quantitative approaches to climate risk management such as mapping or impact modelling rely on past meteorological data with daily or sub‐daily resolution, a large fraction of which have not yet been digitized. Over the last decade or so, a number of projects have contributed to the rescue of some of these data. Here we provide a summary of a survey we have undertaken of several meteorological and climate data rescue projects, in order to identify the needs of climate data rescue services. To make these efforts more sustainable, additional integrated activities are needed. We argue that meteorological and climate data rescue must be seen as a continuous, coordinated long‐term effort. Technical developments (e.g. data assimilation), new scientific questions (e.g. process understanding of extreme events) and new social (e.g. risk assessment, health) or economic (e.g. new renewable energy sources, agriculture and forestry, tourism, infrastructure, etc.) services are highlighting the immense value of data previously neglected or never considered. This continuous effort is currently undertaken by projects of various sizes, structure, funding and staffing, as well as by dedicated programmes, ranging from those within many national weather services down to “grassroots” initiatives. These activities are often not sufficiently coordinated, staffed, or funded at an international level and will benefit considerably from climate data rescue services being established within the Copernicus Climate Change Service (C3S) (https://climate.copernicus.eu/)

The International Surface Pressure Databank version 2

The International Surface Pressure Databank (ISPD) is the world's largest collection of global surface and sea-level pressure observations. It was developed by extracting observations from established international archives, through international cooperation with data recovery facilitated by the Atmospheric Circulation Reconstructions over the Earth (ACRE) initiative, and directly by contributing universities, organizations, and countries. The dataset period is currently 1768–2012 and consists of three data components: observations from land stations, marine observing systems, and tropical cyclone best track pressure reports. Version 2 of the ISPD (ISPDv2) was created to be observational input for the Twentieth Century Reanalysis Project (20CR) and contains the quality control and assimilation feedback metadata from the 20CR. Since then, it has been used for various general climate and weather studies, and an updated version 3 (ISPDv3) has been used in the ERA-20C reanalysis in connection with the European Reanalysis of Global Climate Observations project (ERA-CLIM). The focus of this paper is on the ISPDv2 and the inclusion of the 20CR feedback metadata. The Research Data Archive at the National Center for Atmospheric Research provides data collection and access for the ISPDv2, and will provide access to future versions

Towards a more reliable historical reanalysis: improvements for version 3 of the Twentieth Century Reanalysis system

Historical reanalyses that span more than a century are needed for a wide range of studies, from understanding large‐scale climate trends to diagnosing the impacts of individual historical extreme weather events. The Twentieth Century Reanalysis (20CR) Project is an effort to fill this need. It is supported by the National Oceanic and Atmospheric Administration (NOAA), the Cooperative Institute for Research in Environmental Sciences (CIRES), and the U.S. Department of Energy (DOE), and is facilitated by collaboration with the international Atmospheric Circulation Reconstructions over the Earth initiative. 20CR is the first ensemble of sub‐daily global atmospheric conditions spanning over 100 years. This provides a best estimate of the weather at any given place and time as well as an estimate of its confidence and uncertainty. While extremely useful, version 2c of this dataset (20CRv2c) has several significant issues, including inaccurate estimates of confidence and a global sea level pressure bias in the mid‐19th century. These and other issues can reduce its effectiveness for studies at many spatial and temporal scales. Therefore, the 20CR system underwent a series of developments to generate a significant new version of the reanalysis. The version 3 system (NOAA‐CIRES‐DOE 20CRv3) uses upgraded data assimilation methods including an adaptive inflation algorithm; has a newer, higher‐resolution forecast model that specifies dry air mass; and assimilates a larger set of pressure observations. These changes have improved the ensemble‐based estimates of confidence, removed spin‐up effects in the precipitation fields, and diminished the sea‐level pressure bias. Other improvements include more accurate representations of storm intensity, smaller errors, and large‐scale reductions in model bias. The 20CRv3 system is comprehensively reviewed, focusing on the aspects that have ameliorated issues in 20CRv2c. Despite the many improvements, some challenges remain, including a systematic bias in tropical precipitation and time‐varying biases in southern high‐latitude pressure fields