The Experts below are selected from a list of 26844 Experts worldwide ranked by ideXlab platform
C Borrego - One of the best experts on this subject based on the ideXlab platform.
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urban resilience to future urban heat waves under a Climate Change Scenario a case study for porto urban area portugal
urban climate, 2017Co-Authors: D Carvalho, H Martins, Martinho Martaalmeida, Alfredo Rocha, C BorregoAbstract:Abstract This work aimed to assess the effectiveness of several resilience strategies to mitigate extreme urban heat episodes in Porto (Portugal). Different resilience Scenarios were studied with the WRF urban modelling system, using as case-study a future heat wave occurring in Porto urban area. The resilience factors considered were the increase of urban green areas and the application of cool (green and white) roofs. The results showed that the most effective resilience strategies to mitigate high urban temperatures are the application of cool roofs. These resilience strategies produced the strongest reduction in the average and maximum surface temperatures over Porto urban area under a future heat wave. Considering that white roofs are considerably easier and cheaper to apply in urban areas than green roofs, this resilience strategy can be seen as the most viable, cost-effective and economically attractive approach for mitigating extreme urban temperatures. This study proposed several different urban resilience strategies to extreme temperature episodes for the first time for Porto urban area, proved their effectiveness and compared their ability to reduce urban heat. Such findings can be of great importance for Porto urban planning stakeholders given the expected increase in the heat waves frequency and intensity in future Climate.
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influence of urban resilience measures in the magnitude and behaviour of energy fluxes in the city of porto portugal under a Climate Change Scenario
Science of The Total Environment, 2016Co-Authors: Sandra Rafael, D Carvalho, H Martins, C Borrego, E Sa, M LopesAbstract:Abstract Different urban resilience measures, such as the increase of urban green areas and the application of white roofs, were evaluated with the WRF-SUEWS modelling system. The case study consists of five heat waves occurring in Porto (Portugal) urban area in a future Climate Scenario. Meteorological forcing and boundary data were downscaled for Porto urban area from the CMIP5 earth system model MPI-ESM, for the Representative Concentration Pathway RCP8.5 Scenario. The influence of different resilience measures on the energy balance components was quantified and compared between each other. Results show that the inclusion of green urban areas increases the evaporation and the availability of surface moisture, redirecting the energy to the form of latent heat flux (maximum increase of + 200 W m − 2 ) rather than to sensible heat. The application of white roofs increases the solar radiation reflection, due to the higher albedo of such surfaces, reducing both sensible and storage heat flux (maximum reductions of − 62.8 and − 35 W m − 2 , respectively). The conjugations of the individual benefits related to each resilience measure shows that this measure is the most effective one in terms of improving the thermal comfort of the urban population, particularly due to the reduction of both sensible and storage heat flux. The obtained results contribute to the knowledge of the surface-atmosphere exChanges and can be of great importance for stakeholders and decision-makers.
D Carvalho - One of the best experts on this subject based on the ideXlab platform.
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urban resilience to future urban heat waves under a Climate Change Scenario a case study for porto urban area portugal
urban climate, 2017Co-Authors: D Carvalho, H Martins, Martinho Martaalmeida, Alfredo Rocha, C BorregoAbstract:Abstract This work aimed to assess the effectiveness of several resilience strategies to mitigate extreme urban heat episodes in Porto (Portugal). Different resilience Scenarios were studied with the WRF urban modelling system, using as case-study a future heat wave occurring in Porto urban area. The resilience factors considered were the increase of urban green areas and the application of cool (green and white) roofs. The results showed that the most effective resilience strategies to mitigate high urban temperatures are the application of cool roofs. These resilience strategies produced the strongest reduction in the average and maximum surface temperatures over Porto urban area under a future heat wave. Considering that white roofs are considerably easier and cheaper to apply in urban areas than green roofs, this resilience strategy can be seen as the most viable, cost-effective and economically attractive approach for mitigating extreme urban temperatures. This study proposed several different urban resilience strategies to extreme temperature episodes for the first time for Porto urban area, proved their effectiveness and compared their ability to reduce urban heat. Such findings can be of great importance for Porto urban planning stakeholders given the expected increase in the heat waves frequency and intensity in future Climate.
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influence of urban resilience measures in the magnitude and behaviour of energy fluxes in the city of porto portugal under a Climate Change Scenario
Science of The Total Environment, 2016Co-Authors: Sandra Rafael, D Carvalho, H Martins, C Borrego, E Sa, M LopesAbstract:Abstract Different urban resilience measures, such as the increase of urban green areas and the application of white roofs, were evaluated with the WRF-SUEWS modelling system. The case study consists of five heat waves occurring in Porto (Portugal) urban area in a future Climate Scenario. Meteorological forcing and boundary data were downscaled for Porto urban area from the CMIP5 earth system model MPI-ESM, for the Representative Concentration Pathway RCP8.5 Scenario. The influence of different resilience measures on the energy balance components was quantified and compared between each other. Results show that the inclusion of green urban areas increases the evaporation and the availability of surface moisture, redirecting the energy to the form of latent heat flux (maximum increase of + 200 W m − 2 ) rather than to sensible heat. The application of white roofs increases the solar radiation reflection, due to the higher albedo of such surfaces, reducing both sensible and storage heat flux (maximum reductions of − 62.8 and − 35 W m − 2 , respectively). The conjugations of the individual benefits related to each resilience measure shows that this measure is the most effective one in terms of improving the thermal comfort of the urban population, particularly due to the reduction of both sensible and storage heat flux. The obtained results contribute to the knowledge of the surface-atmosphere exChanges and can be of great importance for stakeholders and decision-makers.
Samuel Somot - One of the best experts on this subject based on the ideXlab platform.
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biogeochemical response of the mediterranean sea to the transient sres a2 Climate Change Scenario
Biogeosciences, 2019Co-Authors: Samuel Somot, Camille Richon, J C Dutay, Laurent Bopp, Briac Le Vu, Francois DulacAbstract:Abstract. The Mediterranean region is a Climate Change hotspot. Increasing greenhouse gas emissions are projected to lead to a substantial warming of the Mediterranean Sea as well as major Changes in its circulation, but the subsequent effects of such Changes on marine biogeochemistry are poorly understood. Here, our aim is to investigate how Climate Change will affect nutrient concentrations and biological productivity in the Mediterranean Sea. To do so, we perform transient simulations with the coupled high-resolution model NEMOMED8-PISCES using the high-emission IPCC Special Report on Emissions Scenarios (SRES) A2 socioeconomic Scenario and corresponding Atlantic, Black Sea, and riverine nutrient inputs. Our results indicate that nitrate is accumulating in the Mediterranean Sea over the 21st century, while phosphorus shows no tendency. These contrasting Changes result from an unbalanced nitrogen-to-phosphorus input from riverine discharge and fluxes via the Strait of Gibraltar, which lead to an expansion of phosphorus-limited regions across the Mediterranean. In addition, phytoplankton net primary productivity is reduced by 10 % in the 2090s in comparison to the present state, with reductions of up to 50 % in some regions such as the Aegean Sea as a result of nutrient limitation and vertical stratification. We also perform sensitivity tests to separately study the effects of Climate and biogeochemical input Changes on the future state of the Mediterranean Sea. Our results show that Changes in nutrient supply from the Strait of Gibraltar and from rivers and circulation Changes linked to Climate Change may have antagonistic or synergistic effects on nutrient concentrations and surface primary productivity. In some regions such as the Adriatic Sea, half of the biogeochemical Changes simulated during the 21st century are linked with external Changes in nutrient input, while the other half are linked to Climate Change. This study is the first to simulate future transient Climate Change effects on Mediterranean Sea biogeochemistry but calls for further work to characterize effects from atmospheric deposition and to assess the various sources of uncertainty.
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21st century Climate Change Scenario for the mediterranean using a coupled atmosphere ocean regional Climate model
Global and Planetary Change, 2008Co-Authors: Samuel Somot, Michel Deque, Florence Sevault, Michel CreponAbstract:Abstract The SAMM (Sea Atmosphere Mediterranean Model) has been developed to study the Climate evolution of the Mediterranean and European regions for the 21st Century. SAMM is a new concept of AORCM (Atmosphere–Ocean Regional Climate Model), where a global atmosphere model is locally coupled with a regional ocean circulation model. It consists of the global spectral AGCM ARPEGE-Climate model, whose variable resolution is maximum in the Mediterranean region (50 km), which has been coupled to the Mediterranean Sea limited area OGCM OPAMED (10 km). A 140-year numerical experiment starting in 1960 was run with the AORCM. Up to year 2000, forcing was prescribed from observed values, whereas forcing following a SRES-A2 Scenario was applied beyond 2000. In order to ensure the model stability, a simple monthly heat flux correction on air–sea exChanges was applied. The present-Climate validation proves that the AORCM is comparable to the state-of-the-art European Atmosphere Regional Climate Models (ARCM) at the same resolution. At first order, the Climate Change impact over Europe simulated by the AORCM is comparable with ARCM simulations. However the AORCM significantly amplifies the Climate Change signal over large parts of Europe with respect to the corresponding ARCM: the warming is higher in all seasons and in many areas of Europe (up to 25% of the signal), winters are wetter over northern Europe and summers drier over southern and eastern Europe (up to 50% of the signal). These differences are highly significant and the choice between coupled and non-coupled regional models could be an additional source of uncertainty when evaluating the Climate Change response over Europe. The factors responsible for these differences are discussed. Among them, the response of the Mediterranean SST, better simulated by the high resolution Mediterranean Sea model of the AORCM, seems to be preponderant. Further mechanism studies and model inter-comparisons are however required to legitimate the present results.
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transient Climate Change Scenario simulation of the mediterranean sea for the twenty first century using a high resolution ocean circulation model
Climate Dynamics, 2006Co-Authors: Samuel Somot, Florence Sevault, Michel DequeAbstract:A Scenario of the Mediterranean Sea is performed for the twenty-first century based on an ocean modelling approach. A Climate Change IPCC-A2 Scenario run with an atmosphere regional Climate model is used to force a Mediterranean Sea high-resolution ocean model over the 1960–2099 period. For comparison, a control simulation as long as the Scenario has also been carried out under present Climate fluxes. This control run shows air–sea fluxes in agreement with observations, stable temperature and salinity characteristics and a realistic thermohaline circulation simulating the different intermediate and deep water masses described in the literature. During the Scenario, warming and saltening are simulated for the surface (+3.1°C and + 0.48 psu for the Mediterranean Sea at the end of the twenty-first century) and for the deeper layers (+1.5°C and + 0.23 psu on average). These simulated trends are in agreement with observed trends for the Mediterranean Sea over the last decades. In addition, the Mediterranean thermohaline circulation (MTHC) is strongly weakened at the end of the twenty-first century. This behaviour is mainly due to the decrease in surface density and so the decrease in winter deep-water formation. At the end of the twenty-first century, the MTHC weakening can be evaluated as −40% for the intermediate waters and −80% for the deep circulation with respect to present-Climate conditions. The characteristics of the Mediterranean Outflow Waters flowing into the Atlantic Ocean are also strongly influenced during the Scenario.
H Martins - One of the best experts on this subject based on the ideXlab platform.
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urban resilience to future urban heat waves under a Climate Change Scenario a case study for porto urban area portugal
urban climate, 2017Co-Authors: D Carvalho, H Martins, Martinho Martaalmeida, Alfredo Rocha, C BorregoAbstract:Abstract This work aimed to assess the effectiveness of several resilience strategies to mitigate extreme urban heat episodes in Porto (Portugal). Different resilience Scenarios were studied with the WRF urban modelling system, using as case-study a future heat wave occurring in Porto urban area. The resilience factors considered were the increase of urban green areas and the application of cool (green and white) roofs. The results showed that the most effective resilience strategies to mitigate high urban temperatures are the application of cool roofs. These resilience strategies produced the strongest reduction in the average and maximum surface temperatures over Porto urban area under a future heat wave. Considering that white roofs are considerably easier and cheaper to apply in urban areas than green roofs, this resilience strategy can be seen as the most viable, cost-effective and economically attractive approach for mitigating extreme urban temperatures. This study proposed several different urban resilience strategies to extreme temperature episodes for the first time for Porto urban area, proved their effectiveness and compared their ability to reduce urban heat. Such findings can be of great importance for Porto urban planning stakeholders given the expected increase in the heat waves frequency and intensity in future Climate.
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influence of urban resilience measures in the magnitude and behaviour of energy fluxes in the city of porto portugal under a Climate Change Scenario
Science of The Total Environment, 2016Co-Authors: Sandra Rafael, D Carvalho, H Martins, C Borrego, E Sa, M LopesAbstract:Abstract Different urban resilience measures, such as the increase of urban green areas and the application of white roofs, were evaluated with the WRF-SUEWS modelling system. The case study consists of five heat waves occurring in Porto (Portugal) urban area in a future Climate Scenario. Meteorological forcing and boundary data were downscaled for Porto urban area from the CMIP5 earth system model MPI-ESM, for the Representative Concentration Pathway RCP8.5 Scenario. The influence of different resilience measures on the energy balance components was quantified and compared between each other. Results show that the inclusion of green urban areas increases the evaporation and the availability of surface moisture, redirecting the energy to the form of latent heat flux (maximum increase of + 200 W m − 2 ) rather than to sensible heat. The application of white roofs increases the solar radiation reflection, due to the higher albedo of such surfaces, reducing both sensible and storage heat flux (maximum reductions of − 62.8 and − 35 W m − 2 , respectively). The conjugations of the individual benefits related to each resilience measure shows that this measure is the most effective one in terms of improving the thermal comfort of the urban population, particularly due to the reduction of both sensible and storage heat flux. The obtained results contribute to the knowledge of the surface-atmosphere exChanges and can be of great importance for stakeholders and decision-makers.
Camille Richon - One of the best experts on this subject based on the ideXlab platform.
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biogeochemical response of the mediterranean sea to the transient sres a2 Climate Change Scenario
Biogeosciences, 2019Co-Authors: Samuel Somot, Camille Richon, J C Dutay, Laurent Bopp, Briac Le Vu, Francois DulacAbstract:Abstract. The Mediterranean region is a Climate Change hotspot. Increasing greenhouse gas emissions are projected to lead to a substantial warming of the Mediterranean Sea as well as major Changes in its circulation, but the subsequent effects of such Changes on marine biogeochemistry are poorly understood. Here, our aim is to investigate how Climate Change will affect nutrient concentrations and biological productivity in the Mediterranean Sea. To do so, we perform transient simulations with the coupled high-resolution model NEMOMED8-PISCES using the high-emission IPCC Special Report on Emissions Scenarios (SRES) A2 socioeconomic Scenario and corresponding Atlantic, Black Sea, and riverine nutrient inputs. Our results indicate that nitrate is accumulating in the Mediterranean Sea over the 21st century, while phosphorus shows no tendency. These contrasting Changes result from an unbalanced nitrogen-to-phosphorus input from riverine discharge and fluxes via the Strait of Gibraltar, which lead to an expansion of phosphorus-limited regions across the Mediterranean. In addition, phytoplankton net primary productivity is reduced by 10 % in the 2090s in comparison to the present state, with reductions of up to 50 % in some regions such as the Aegean Sea as a result of nutrient limitation and vertical stratification. We also perform sensitivity tests to separately study the effects of Climate and biogeochemical input Changes on the future state of the Mediterranean Sea. Our results show that Changes in nutrient supply from the Strait of Gibraltar and from rivers and circulation Changes linked to Climate Change may have antagonistic or synergistic effects on nutrient concentrations and surface primary productivity. In some regions such as the Adriatic Sea, half of the biogeochemical Changes simulated during the 21st century are linked with external Changes in nutrient input, while the other half are linked to Climate Change. This study is the first to simulate future transient Climate Change effects on Mediterranean Sea biogeochemistry but calls for further work to characterize effects from atmospheric deposition and to assess the various sources of uncertainty.