The evolution of the Parisian urban climate under a changing climate is analyzed from long-term offline numerical integrations including a specific urban parameterization. This system is forced by ...meteorological conditions based on present-climate reanalyses (1970–2007), and climate projections (2071–2099) provided by global climate model simulations following two emission scenarios (A1B and A2). This study aims at quantifying the impact of climate change on air temperature within the city and in the surroundings. A systematic increase of 2-meter air temperature is found. In average according to the two scenarios, it reaches + 2.0/2.4°C in winter and + 3.5/5.0°C in summer for the minimum and maximum daily temperatures, respectively. During summer, the warming trend is more pronounced in the surrounding countryside than in Paris and suburbs due to the soil dryness. As a result, a substantial decrease of the strong urban heat islands is noted at nighttime, and numerous events with negative urban heat islands appear at daytime. Finally, a 30% decrease of the heating degree days is quantified in winter between present and future climates. Inversely, the summertime cooling degree days significantly increase in future climate whereas they are negligible in present climate. However, in terms of accumulated degree days, the increase of the demand in cooling remains smaller than the decrease of the demand in heating.
Time series studies assessing the effect of temperature on mortality generally use temperatures measured by a single weather station. In the Paris region, there is a substantial measurement network, ...and a variety of exposure indicators created from multiple stations can be tested. The aim of this study is to test the influence of exposure indicators on the temperature-mortality relationship in the Paris region. The relationship between temperature and non-accidental mortality was assessed based on a time series analysis using Poisson regression and a generalised additive model. Twenty-five stations in Paris and its three neighbouring departments were used to create four exposure indicators. These indicators were (1) the temperature recorded by one reference station, (2) a simple average of the temperatures of all stations, (3) an average weighted on the departmental population and (4) a classification of the stations based on land use and an average weighted on the population in each class. The relative risks and the Akaike criteria were similar for all the exposure indicators. The estimated temperature-mortality relationship therefore did not appear to be significantly affected by the indicator used, regardless of study zone (departments or region) or age group. The increase in temperatures from the 90ᵗʰ to the 99ᵗʰ percentile of the temperature distribution led to a significant increase in mortality over 75 years (RR = 1.10 95 % CI, 1.07; 1.14). Conversely, the decrease in temperature between the 10ᵗʰ and 1ˢᵗ percentile had a significant effect on the mortality under 75 years (RR = 1.04 95 % CI, 1.01; 1.06). In the Paris area, there is no added value in taking multiple climatic stations into account when estimating exposure in time series studies. Methods to better represent the subtle temperature variations in densely populated areas in epidemiological studies are needed.
The extremely warm summer of 2003, with its August heat wave, is taken as a prototype of future summer weather in Europe. The stagnant circulation led to accumulation of heat and pollutants, ...increased forest fires, and induced high ozone and particulate matter levels. After a description of the meteorological conditions encountered, we review here the effects of the heat-wave meteorology on photochemistry, wild fires, and particulate matter, at the continental and urban scales. We discuss the extent to which this special summer can be taken for projecting air quality in a future warmer climate, especially in the perspective of changes in regional and global emissions. For ozone, the effect of regional reduction of emissions will dominate over summer climate change, but the increase in baseline ozone should significantly raise the mean ozone levels.
Dans le cadre du projet EPICEA (Ville de Paris, Météo-France et Centre Scientifique et Technique du Bâtiment), cette étude s’intéresse à un épisode climatique extrême – la canicule d’août 2003 – en ...tant qu’extrapolation dans le futur, puisque, si l’on considère le scénario le plus pessimiste (A2), un tel phénomène concernerait l’Europe de l’Ouest en moyenne un été sur deux d’ici 2070. Une simulation à 250 m de résolution de la période allant du 08 au 13 août 2003 est effectuée en utilisant le modèle de recherche numérique MésoNH, modèle non-hydrostatique à échelle très fine préfigurant la future génération de modèles numériques de prévision du temps, et le schéma de ville Town Energy Budget (TEB). TEB représente la ville de manière théorique sous la forme d’un canyon urbain dans lequel est modélisé le bilan d’énergie des surfaces élémentaires urbaines (route, toit mur). Il est ici employé en mode « couplage » avec le modèle MésoNH pour caractériser au mieux les conditions atmosphériques urbaines. Son homologue pour la végétation, Interactions Sol-Biosphère-Atmosphère (ISBA), est également utilisé. La ville de Paris est représentée en mode « réaliste » par le biais d’une base de données du couvert urbain parisien élaborée conjointement avec l’Atelier Parisien d’Urbanisme, intégrant l’altitude, les surfaces de végétation, de voirie, d’eau, les hauteurs des bâtiments, les différents types de toits et de murs et leur surface, etc. Les données de surface issues de cette base sont retravaillées et intégrées au modèle de ville TEB via un logiciel SIG. Les résultats sont très satisfaisants : le modèle reproduit bien les observations de température et de vent, ainsi que le cycle diurne d’humidité relative et les caractéristiques du climat urbain sont clairement identifiées. Les résultats permettent de discerner des micro-ICU au sein de Paris avec des différences de température de 2 à 4°C et mettent en évidence la vulnérabilité des arrondissements périphériques et de certaines communes limitrophes en liaison avec le panache urbain engendrant des différences de température de l’ordre de 2°C. Par ailleurs, différents leviers d’action sur le climat urbain ont été préalablement identifiés. Les plus pertinents sont l’albédo des surfaces (toits, murs et voirie) et la végétalisation des surfaces urbaines. Différents tests de sensibilité sont donc envisagés en modifiant ces paramètres, dans un contexte de canicule (août 2003) : éclaircissement des façades et des toitures, verdissement et humidification de la ville. Cette étude confirme l’intérêt d’utiliser ce type de schéma urbain en intégrant les spécificités complexes de l’occupation des sols en milieu urbain dans l’optique d’études sur l’adaptation d’un territoire au changement climatique, en comparant une situation de référence – présentée ici – à différents scénarios réalisables dans le futur.
This study is part of the EPICEA project (joint collaboration between the City of Paris, Météo-France and the Scientific and Technical Centre for Building). It is focused on an extreme meteorological episode such as the 2003 heat wave that is considered as representative of future summers: regarding the pessimistic scenario A2, this may concern Western Europe on alternate summers as from 2070. A simulation of the period from 08/08/2003 to 13/08/2003 (corresponding to the highest mortality) with a 250 m high resolution is conducted, using the atmospheric model Méso-NH, the model Interaction between Soil, Biosphere, and Atmosphere (ISBA) for the natural covers and the specific urban canopy model Town Energy Budget (TEB) for built-up covers. TEB is aimed to simulate the turbulent fluxes into the atmosphere at the surface of a mesoscale atmospheric model covered by buildings, roads, or any artificial material, and calculates the urban energy budget of three urban surfaces (one for the roofs, roads, and walls). The city of Paris is represented as a realistic one, using datas from a specific database of the Parisian urban canopy that has been elaborate with the Parisian Urban Planning Agency (APUR). These datas include altitude, surface vegetation, roads, water, heights of buildings, different types of roofs and walls and their surface, etc.). They have been re-analysed and incorporated into the TEB urban model via a GIS software. One can then be confident in the results: The model compares correctly against observation for temperature and wind and reproduces correctly the diurnal humidity cycle, and the different processes involved in the urban climate are highlighted. The results shows micro-UHI inside of Paris from 2 to 4°C and the vulnerability of the peripheral districts of Paris and some surrounding cities due to urban plume (up to 2°C warmer). Various actions on the built environment are identified besides, which have a potential impact on urban climate. The most relevant are the modification of the surfaces albedo (roofs, walls and roads) and the greening of urban surfaces. Several sensitivity tests are therefore planned with different settings of Paris in the context of the 2003 heat wave: walls and roofs whitening, greening, and wetting of the city. This study confirms the usefullness of such urban schemes and informations about the complex specificites of land use in urban locations for adaptation to climate change studies by comparing a reference situation, such as the one described here, to different future scenarios.
Desplat Julien, Dandin Philippe, Jacq V., Balaguer S., Chapnik B., Croux S., Chassagneux P., Rambaldelli B. Le site Internet Pluies Extrêmes sur la France Métropolitaine. In: Evénements extrêmes ...fluviaux et maritimes. Leurs variabilités spatiales et chronologiques dans l'ouest de l’Europe. 34èmes journées de l’hydraulique Paris, 1 et 2 février 2012. 2012.
Abstract
Uveal melanoma is a rare and aggressive cancer that originates in the eye. Currently, there are no approved targeted therapies and very few effective treatments for this cancer. Although ...activating mutations in the G protein alpha subunits, GNAQ and GNA11, are key genetic drivers of the disease, few additional drug targets have been identified. Recently, studies have identified context-specific roles for the mammalian SWI/SNF chromatin remodeling complexes (also known as BAF/PBAF) in various cancer lineages. Here, we find evidence that the SWI/SNF complex is essential through analysis of functional genomics screens and further validation in a panel of uveal melanoma cell lines using both genetic tools and small-molecule inhibitors of SWI/SNF. In addition, we describe a functional relationship between the SWI/SNF complex and the melanocyte lineage–specific transcription factor Microphthalmia-associated Transcription Factor, suggesting that these two factors cooperate to drive a transcriptional program essential for uveal melanoma cell survival. These studies highlight a critical role for SWI/SNF in uveal melanoma, and demonstrate a novel path toward the treatment of this cancer.
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