The extent and implications of the urban heat island phenomenon in Central European region Kristina Kiesel, Milena Vuckovic, and Ardeshir Mahdavi Department of building physics and building ecology, TU Vienna
EU Project (Central Europe) Investigates the UHI-phenomena in Central Europe The extent of the UHI effect in multiple cities in Central Europe Manifestation of the urban heat islands phenomena (temporal and spatial variations) Evaluation of mitigation and adaptation strategies
Participating cities The list of participating cities: Budapest, Hungary Ljubljana, Slovenia Modena, Italy Padova, Italy Prague, Czech Republic Stuttgart, Germany Vienna, Austria
UHI phenomenon Temperature difference between the urban and the rural environment Source: http://www.epa.gov/heatisland/about/index.htm
Methodology Quantifying the frequency, magnitude, and timedependent (diurnal and nocturnal) UHI intensity distribution Focus: Short-term (reference week) analyses Long-term analyses The magnitude of the UHI effect is expressed in terms of Urban Heat Island intensity ( θ)
Methodology Each participating city provided data (including air temperature, wind speed, and precipitation) from two representative weather stations (one urban and one rural) Short-term: The hourly-based UHI intensity has been derived from data sets in a course of a reference week Long-term: Mean annual (urban and rural) temperatures and UHI values were derived for a period of 30 years
Results short-term analysis Mean hourly urban temperature distribution for a reference summer day 38 36 34 32 30 28 26 24 22 20 18 16 14 12 10 VIENNA STUTTGART PADUA BUDAPEST PRAGUE MODENA WARSAW LJUBLJANA 01:00 03:00 05:00 07:00 09:00 11:00 13:00 15:00 17:00 19:00 21:00 23:00 Θ [ 0 C] TIME
Results short-term analysis Mean hourly UHI intensity distribution for a reference summer day 7 6 5 4 3 2 1 0-1 VIENNA STUTTGART PADUA BUDAPEST PRAGUE MODENA WARSAW LJUBLJANA -2 01:00 03:00 05:00 07:00 09:00 11:00 13:00 15:00 17:00 19:00 21:00 23:00 UHI intensity [K] TIME
Results short-term analysis The cumulative frequency distribution of UHI values for the participating cities for a one week summer period 100 90 80 Frequency % 70 60 50 40 30 20 10 0-5 -4-3 -2-1 0 1 2 3 4 5 6 7 8 9 10 11 12 UHI intensity [K] VIENNA STUTTGART PADUA BUDAPEST PRAGUE MODENA WARSAW LJUBLJANA
Results long-term analysis Development of (mean annual) urban and rural temperatures over a period of 30 years, respectively URBAN RURAL 16 16 15 15 θ [ 0 C] 14 13 12 11 10 9 8 7 VIENNA STUTTGART PADUA BUDAPEST PRAGUE MODENA WARSAW LJUBLJANA θ [ 0 C] 14 13 12 11 10 9 8 7 VIENNA STUTTGART PADUA BUDAPEST PRAGUE MODENA WARSAW LJUBLJANA 6 6 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 Year 2000 2002 2004 2006 2008 2010 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 Year 2000 2002 2004 2006 2008 2010
Results long-term analysis Long-term UHI intensity trend over a period of 30 years 1,5 1,4 1,3 1,2 1,1 1,0 VIENNA STUTTGART PADUA BUDAPEST PRAGUE MODENA WARSAW LJUBLJANA 0,9 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 UHI intensity [K] Year
CONCLUSION The existence and significant magnitude of the UHI effect in all participating cities. A time-dependent (diurnal and nocturnal) UHI pattern implying larger UHI intensities during the night hours. Existing variation in UHI intensity in different cities, especially in terms of peak values. Warsaw experiencing higher UHI intensity levels when compared to other cities
ONGOING WORK A systematic framework for the evaluation of urban heat island mitigation measures The framework involves the following steps: Selection of "Urban Units of Observation" (U2O) Description of the status quo of U2O in terms of a structured set of geometric and physical properties Selection of potential M&A measures Description of specified M&A measures as changes to U2O variables Evaluation of M&A measures
ONGOING WORK Defined variables of Urban Unit of Observation (U 2 O)
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