15 research outputs found

    Urban multi-model climate projections of intense heat in Switzerland

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    This paper introduces a straightforward approach to generate multi-model climate projections of intense urban heat, based on an ensemble of state-of-the-art global and regional climate model simulations from EURO-CORDEX. The employed technique entails the empirical-statistical downscaling method quantile mapping (QM), which is applied in two different settings, first for bias correction and downscaling of raw climate model data to rural stations with long-term measurements and second for spatial transfer of bias-corrected and downscaled climate model data to the respective urban target site. The resulting products are daily minimum and maximum temperatures at five urban sites in Switzerland until the end of the 21st century under three emission scenarios (RCP2.6, RCP4.5, RCP8.5). We test the second-step QM approach in an extensive evaluation framework, using long-term observational data of two exemplary weather stations in Zurich. Results indicate remarkably good skill of QM in present-day climate. Comparing the generated urban climate projections with existing climate scenarios of adjacent rural sites allows us to represent the urban heat island (UHI) effect in future temperature-based heat indices, namely tropical nights, summer days and hot days. Urban areas will be more strongly affected by rising temperatures than rural sites in terms of fixed threshold exceedances, especially during nighttime. Projections for the end of the century for Zurich, for instance, suggest more than double the number of tropical nights (Tmin above 20 ºC) at the urban site (45 nights per year, multi-model median) compared to the rural counterpart (20 nights) under RCP8.5.This research has been partly supported by the European Commission (HEAT-SHIELD 668786). EH is supported by the German Research Foundation under project number 40805747

    Fish predation in the proximity of purse seine fishing lights: The case of Atherina boyeri (Actinopterygii: Atheriniformes: Atherinidae) in a Greek Lake

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    Background. Purse seining with the use of light is among the most common fishing practices around the world, but there is lack of studies on the effect of light on the feeding of the target species in this kind of fishery and the possible consequences for other prey species. The presently reported investigation intended to provide indications on this issue by studying the diet of Atherina boyeri Risso, 1810, which is the target species of professional purse seine fishery, conducted using light in Lake Trichonis (Greece), and by comparing the acquired results with those of previous studies where the samples were taken without using light. Materials and methods. A seven-month (June through December 2014) purse seining fishing was conducted at night around two lamp rafts: 1) a traditional lamp raft producing white LED light and 2) an autonomous photovoltaic-battery-LED lamp raft producing green LED light. Stomach content analysis was conducted on 100 randomly selected specimens from each sample and the relative prey abundance and frequency of occurrence for each prey category was estimated. Calculations of predation pressure of A. boyeri upon the fish larvae of a goby, Economidichthys trichonis Economidis et Miller, 1990, were performed. Results. The study revealed the intense effect of light on the attraction and capture of prey species rarely found in previous studies, such as the larvae of the native and endangered fish E. trichonis, amphipods, and copepod nauplii. No significant differences were observed between the two light colours. A preference shift to larger prey with the increase of ontogenetic stage of A. boyeri was observed. Several thousands of pre-recruited E. trichonis larvae may be preyed upon each night around a single lamp especially during summer. Conclusion. Fishing with light may alter the dietary preference of the target fish species and even of the entire fish community. This may have serious consequences on the younger ontogenetic stages of other fish populations, especially when it coincides with their reproductive period. Considering the lack of similar field studies, the present results may stimulate analogous investigations on the effects of fishing lights in other marine and freshwater ecosystems worldwide

    Megacity-Induced Mesoclimatic Effects in the Lower Atmosphere: A Modeling Study for Multiple Summers over Moscow, Russia

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    Urbanization leads to distinct meteorological features of urban environments, and one the best-known is the urban heat island (UHI) effect. For megacities, these features become mesoscale phenomena (scale ≥ 10 km) that are amplified by the tropospheric feedbacks, and have substantial implications on human well-being. For the first time, a three-dimensional statistical description of the megacity-induced meteorological effects extending towards the lower troposphere for summer is acquired on a quasi-climatological timescale (a decade) based on high-resolution (1 km) simulations for Moscow with the COSMO-CLM model with and without its urban canopy model TERRA_URB. Our results confirm the features from previous observational and modeling studies, including the UHI itself, the cooling effect above established by the cross-over effect, the urban dry/moist islands and the urban breeze circulation. Particularly, the UHI shows a strong diurnal variation in terms of intensity and vertical extent between daytime (≈0.5 K/≈1.5 km) and nighttime (>3 K/≈150 m). We have discovered a systematic veering in the downwind shift of the UHI spatial pattern established by the Coriolis effect, and an enhanced stable stratification of the rural surroundings established by the urban plumes further downwind. Finally, extending the analysis to multiple summers demonstrates a substantial increase in summer precipitation (up to +25%) over the city center and its leeward side. These urban-caused mesoclimatic effects need to be taken into account in weather and climate services, including the design of future megacities

    Sustainable Urban Environment through Green Roofs: A Literature Review with Case Studies

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    This study conducts a literature review coupled with case-study calculations comparing the thermal contribution of semi-intensive and intensive (deeper) green roofs to non-insulated and insulated building roofs, and enhancing comprehension by validating applied scenarios with published literature-based data. Mitigation of the urban heat island is crucial for reducing energy consumption and enhancing urban sustainability, especially through natural solutions such as green (i.e., planted) roofs. The energy and environmental benefits of green roofs include energy conservation, thermal comfort, noise reduction, and aesthetic improvement. Legal mandates, innovative business models, financial subsidies and incentives, regulations, etc. are all components of green roof policies. Conflicts between private property owners and the public, regulatory gaps, and high installation costs are among the challenges. Green roofs are layered and incorporate interacting thermal processes. Green roof models are either based on the calculation of thermal transmittance (U-values), an experimental energy balance, or data-driven (primarily neural network) approaches. U-values were calculated for eight hypothetical scenarios consisting of four non-insulated and four insulated roofs, with or without semi-intensive and intensive green roofs of various materials and layer thicknesses. While the non-planted, non-insulated roof had the highest U-value, planted roofs were particularly effective for non-insulated roofs. Three of these scenarios were in reasonable accord with experimental and theoretical thermal transmittance literature values. Finally, a non-insulated planted roof, particularly one with rockwool, was found to provide a certain degree of thermal insulation in comparison to a non-planted insulated roof

    From engravings to 3D. Concerns about the relationship between archaeology, memory and new technologies on the occasion of the digital promotion of the archaeological site and museum of Eleusis

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    <p>The archaeological site of Eleusis includes one of the most important sanctuaries of antiquity and is an important cultural landmark of Attica. Eleusis, as the European Capital of Culture in 2023, aspires to attract a large number of visitors and emerge as a pole of attraction alongside the traditional historical center of Athens. This development requires the upgrading of the digital presence and the formation of a digital footprint of the archaeological site and the museum. This is achieved through the myEleusis project. Its aim is to "introduce" the visitor to Eleusis and its Mysteries by offering him a comprehensive experiential experience through a set of digital applications. In this way, he becomes part of a special cultural identity that connects him with the past. At the same time, the archaeological space and the museum fit more attractively into the environment of the modern city, contributing to its tourism development. At the same time, myEleusis is added to a set of different technologies for constructing a mnemonic stratigraphy and cultural landscapes starting from European travelers and the engravings that adorned their writings and reaching modern games in digital environments that refer to antiquity. All of this will be discussed in the present announcement with the aim of showing different approaches that highlight the way of receiving, understanding and ultimately enjoying the special archaeological site of Eleusis. On the occasion of the project, an opportunity will be given for wider reflection and dialogue, around the perspectives that new technologies (3D, AR, storytelling, etc.) open up in the development of a different relationship between visitors/travelers and those included in the modern urban environment of the ancient world.</p&gt

    Financial crisis and energy consumption: A household survey in Greece

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    This research aims to investigate, analyze and characterize the relation between the economic crisis and energy consumption in Greece. A survey held in the spring and summer of 2012 collected data of the heating energy consumption for 2010-2011 and 2011-2012, from 598 households via a questionnaire. Comparing the 2010-11 winter to the harsher winter of 2011-12 showed that inhabitants consumed less energy during the winter of 2011-12 because of the rapid economic degradation. Important conclusions were drawn regarding the energy consumption of the households which during the harsh winter 2011-12 was 37% less than expected. Cluster analysis rendered two distinct clusters: three fourths of the households belonged to the lower income group that lived in a smaller space, had half the income and consumed more specific energy compared to the high income group, although much less than expected based on the degree hours of the second winter. One out of three higher-income and one out of four lower-income households adopted some conservation measures after the first winter while 2% of the higher income households and 14% of the lower-income households were below the fuel poverty threshold. Directions for further research include monitoring of low income households with sensors. © 2013 Elsevier B.V. All rights reserved

    Financial crisis and energy consumption: A household survey in Greece

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    Δημοσίευση σε επιστημονικό περιοδικόSummarization: This research aims to investigate, analyze and characterize the relation between the economic crisis and energy consumption in Greece. A survey held in the spring and summer of 2012 collected data of the heating energy consumption for 2010–2011 and 2011–2012, from 598 households via a questionnaire. Comparing the 2010–11 winter to the harsher winter of 2011–12 showed that inhabitants consumed less energy during the winter of 2011–12 because of the rapid economic degradation. Important conclusions were drawn regarding the energy consumption of the households which during the harsh winter 2011–12 was 37% less than expected. Cluster analysis rendered two distinct clusters: three fourths of the households belonged to the lower income group that lived in a smaller space, had half the income and consumed more specific energy compared to the high income group, although much less than expected based on the degree hours of the second winter. One out of three higher-income and one out of four lower-income households adopted some conservation measures after the first winter while 2% of the higher income households and 14% of the lower-income households were below the fuel poverty threshold. Directions for further research include monitoring of low income households with sensors.Παρουσιάστηκε στο: Energy and Building
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