RESULTS OF THE DUE THERMOPOLIS CAMPAIGN WITH REGARD TO THE URBAN HEAT ISLAND (UHI) EFFECT IN ATHENS Ioannis A. Daglis (1) , Spyridon Rapsomanikis (2) , Konstantinos Kourtidis (2) , Dimitrios Melas (3) , Alexandros Papayannis (4) , Iphigenia Keramitsoglou (1) , Theodoros Giannaros (3) , Vassilis Amiridis (1) , Georgios Petropoulos (1) , Aristeidis Georgoulias (2) , José Antonio Sobrino (5) , Paolo Manunta (6) , Julian Gröbner (7) , Marc Paganini (8) , Remo Bianchi (8) 1 Institute for Space Applications & Remote Sensing, National Observatory of Athens, Greece 2 Department of Environmental Engineering, Democritus University of Thrace, Greece 3 Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki, Greece 4 Department of Physics, National Technical University of Athens, Greece 5 Global Change Unit, University of Valencia, Spain 6 Planetek Italia srl, Italy 7 Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Switzerland 8 European Space Research Institute (ESRIN), European Space Agency ABSTRACT The Urban Heat Island (UHI) effect is a typical phenomenon of urban climate, where the temperature of central urban locations is several degrees higher than that of surrounding rural areas of similar elevation; the temperature difference is especially pronounced during night-time. Although the UHI effect has long been studied through ground-based observations, the possibility of thermal remote sensing using spacecraft and/or airborne platforms has become available only relatively recently, providing innovative ways for the observation and study of the UHI effect. Following an initiative of the European Space Agency (ESA) to improve our understanding of the complexities of how urban heat islands arise, a relevant project entitled “Urban Heat Islands and Urban Thermography” has been under way to study the UHI effect in major European cities through the combination of ground-based observations and spacecraft remote sensing. In this paper we report preliminary results of this project pertaining to the metropolitan area of Athens, Greece, where also airborne remote sensing observations became available through the ESA-funded Thermopolis 2009 campaign, coordinated by the Democritus University of Thrace and implemented by a wide consortium. 1. INTRODUCTION In November 2008 a consortium of seven institutes and companies from five European countries started the implementation of the project Urban Heat Islands and Urban Thermography (UHI), funded by the European Space Agency (ESA). The consortium consists of Planetek Italia srl as the coordinator, the Institute for Space Applications and Remote Sensing of the National Observatory of Athens (NOA-ISARS, Greece), the Flemish institute for technological research (Vlaamse Instelling voor Technologisch Onderzoek – VITO, Belgium), and the companies Indra (Spain), EDISOFT S.A. (Portugal) and EUROSENSE (Belgium). Furthermore, the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki (Greece) participates in the project through a partnership with NOA-ISARS. The main goal of the UHI project is the integration of satellite remote sensing observations – acquired mainly in the Thermal Infrared (TIR) part of electromagnetic radiation – with weather and ancillary ground measurements (e.g. temperature, relative humidity and wind speed) into urban meteorological and climate modelling. The long-term aim is to help decision and policy makers in better forecasting, preventing and mitigating the impact of Urban Heat Islands during heat waves, through appropriate alert systems, and in reducing the risk through dedicated urban land planning. Another important objective of the project is to study the mission requirements for a high resolution thermal infrared (TIR) satellite sensor that could serve at best the needs of all public administrations requesting more adequate UHI observations in metropolitan areas. The third objective of the project is to study how TIR observations from space can support the implementation of urban energy efficiency policies. In order to support the implementation of Earth Observation Programmes the European Space Agency regularly carries out coordinated ground-based and airborne campaigns. In the framework of the UHI project, the Thermopolis 2009 campaign was run with the purpose to complement the proposed activities for Athens, Greece. This campaign combined concurrently-acquired observed airborne hyper- spectral, space-borne and in-situ ground measurements to generate spectrally and geometrically representative _________________________________________________ Proc. ‘ESA Living Planet Symposium’, Bergen, Norway 28 June – 2 July 2010 (ESA SP-686, December 2010)