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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.earscirev.2008.12.002 Byline: Charles Harris (a), Lukas U. Arenson (b), Hanne H. Christiansen (c), Bernd Etzelmuller (d), Regula Frauenfelder (d), Stephan Gruber (e), Wilfried Haeberli (e), Christian Hauck (f), Martin Holzle (e), Ole Humlum (d), Ketil Isaksen (g), Andreas Kaab (d), Martina A. Kern-Lutschg (a), Michael Lehning (h), Norikazu Matsuoka (i), Julian B. Murton (j), Jeanette Notzli (e), Marcia Phillips (h), Neil Ross (k), Matti Seppala (l), Sarah M. Springman (m), Daniel Vonder Muhll (n) Keywords: European permafrost; climate change; geothermal monitoring; geothermal modelling; geophysics; slope stability; permafost hazards; permafrost engineering Abstract: We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empirical-statistical models, and physically based process-oriented models, is described, and it is shown that, though more complex and data dependent, process-oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography. Mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed. We report on recent research into ground ice formation, including ice segregation within bedrock and vein ice formation within ice wedge systems. The potential impacts of climate change on rock weathering, permafrost creep, landslides, rock falls, debris flows and slow mass movements are also discussed. Recent engineering responses to the potentially damaging effects of climate warming are outlined, and risk assessment strategies to minimise geological hazards are described. We conclude that forecasting changes in hazard occurrence, magnitude and frequency is likely to depend on process-based modelling, demanding improved understanding of geomorphological process-response systems and their impacts on human activity. Author Affiliation: (a) School of Earth and Ocean Sciences, Cardiff University, CF10 3YE, UK (b) Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2W2 (c) Department of Geology, The University Centre in Svalbard, 9171 Longyearbyen, Norway (d) Department of Geosciences, University of Oslo, Blindern, NO-0316 Oslo, Norway (e) Department of Geography, University of Zurich, CH-8057 Zurich, Switzerland (f) Institute for Meteorology and Climate Reasearch, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany (g) The Norwegian Meteorological Institute, Blindern, 0313 Oslo, Norway (h) WSL,Swiss Federal Institute for Snow and Avalanche Research, SLF Davos, CH-7260 Davos Dorf, Switzerland (i) Graduate School of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8572, Japan (j) Department of Geography, University of Sussex, Brighton, BN1 9SJ, UK (k) School of Geosciences, University of Edinburgh, West Mains Road, Edinburgh EH9 3JW, UK (l) Department of Geography, University of Helsinki, Helsinki, FIN-00014, Finland (m) Geotechnical Institute, ETH Zurich, CH-8093 Zurich, Switzerland (n) The Swiss Initiative in Systems Biology, ETH-Zurich, CH-8092 Zurich, Switzerland Article History: Received 13 July 2007; Accepted 5 December 2008

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.solener.2005.06.015 Byline: Mirela Robitu (a)(b), Marjorie Musy (b), Christian Inard (a), Dominique Groleau (b) Keywords: Urban climate; Vegetation; Water pond; Thermal comfort Abstract: The beneficial influence of trees and water ponds on summer comfort in urban spaces was studied experimentally in situ and in wind tunnels but the modeling needs further development to become effective in practical applications. This paper introduces a numerical approach based on coupling the CFD model of airflow, in which the influence of trees is considered as source terms, and the radiation exchange, completed with thermal conduction. The CFD, radiation and thermal conduction models use the same discretization grid at their common boundaries. The model was used to estimate the influence of trees and water ponds in a real town square. Comparison of results between two situations, with and without vegetation and water pond, indicate that surface temperatures are reduced in presence of trees and the comfort is improved. Author Affiliation: (a) LEPTAB University of La Rochelle, Avenue Michel CREPEAU, 17042 La Rochelle, France (b) CERMA -- Architectural School of Nantes, Rue Massenet, BP 81931, 44319 Nantes, France Article History: Received 3 January 2005; Revised 31 May 2005; Accepted 28 June 2005 Article Note: (miscellaneous) Communicated by: Associate Editor Matheos Santamouris