Urban Climate Strategies against future Heat Stress Conditions Prof. Dr. Lutz Katzschner University Kassel /Germany
Urban Climatology and Global Climate Change - air pollution aspect (toxic health risks), change of radiation followed by change in the chemical reactions in the atmosphere (NOx and Ozone) - thermal aspect, urban heat island (health risks through heat stress) - meteorological extremes (rain, duration of hot days) Climate Protection Emissions (green house effect) Global effects Regional climate Climate Adaptation global climate change Regional effects Urban climate (buildings/orientation/density)
Outside Human Comfort places were you like to go + places were you like to stop when passing by Thermal Comfort is part of this aspect (variation in time and space!)
Thermal Comfort Index: PET (physiolocical equivalent temperature) = f (ta, u, tmrt, v) based on a steady state human energy balance
Visualization of the differences concerning the cut points in the answering categories 1,0 0,9 0,8 geschätzte Wahrscheinlichkeiten 0,7 0,6 0,5 0,4 0,3 0,2 0,1 0,0 0 3 6 9 13 16 19 22 25 28 32 35 38 41 44 47 51 54 57 60 PET ( C) sehr heiß heiß sehr warm warm okay kühl zu kühl kalt
Qualitative distribution of urban heat load in Hong Kong and Frankfurt based on an urban climatic map 16 Increase of hot days in urban areas: days with heat stress 14 12 10 8 6 4 2 0 period 1950 to 2005 Calculation by the DWD (German Weatherservice) on base of urban climate map in the city of / Germany T air > 25 C Annual heat stress today in 46 days Scenario 2050 increase at airport 3 days increase city parks 4 days Increase residential areas 6 days Increase in dense structures 11 days
Classifi cation Name Description /PET C Evaluation 1 fresh air productions or air path minor roughness and minor heat capacity mainly agricultural areas; PET 22 very important for climate High protection 2 fresh air production on slopes Forests and trees; PET 24 important for circulation to keep and maintain 3 mixed climates with local circulation pattern parks, gardens ; PET 26 important linkage areas, forsee the orientation and denisty 4 heat island potentials Urban areas with roughness but vegetation links; PET 28 thermal importance ; vegetation improvement 5 heat island dense built up areas with considerable roughness and heat load; PET 30 thermal and air pollution prpblems; mitigation through ventilation and vegetation; heat stress increasing 6 heat island max Extremly dense areas nor vegetation (city centre); PET 32 heavy thermal load should be mitigated, heat stress problems, extremely increasing
Urban Heat Island Kassel 2009 plannig climate change 2030
Comparision of modelling results (mean radiation temperature) SOLWEIGH ENVIMET
Spatial avarages at point 4 in a daily value of mean radiation temperatures Tmrt in C SOLWEIG ENVIMET mean vertical and horizontal globe measurements 45 43 47 44
Calibration of PET ( C) in Germany (n = 776), Hong Kong (n = 1958) and Brazil (n = 706) based on empirical data PET ( C) PET ( C) PET ( C) subjective (Germany) (Belo Horizonte) (Hong Kong) perception level of stress more than 42 more than 43 more than 45 very hot extreme heat stress 35-41 35-42 35-45 hot strong heat stress 29-34 31-35 30-35 warm moderate heat stress 18-28 15-30 12-30 comfortable no thermal stress 13-17 13-15 9-12 slightly cool weak cold stress less than 13 less than 13 less than 8 cool cold stress
Future urban design?
perspective: to reduce the income energy in cities using adaptative matierials using adaptative city structures Urban strategies and urban design guidelines to reduce health risks in cities are needed
Bioclimatic design proposals
Thermal conditions at the Opernplatz in Kassel indicated by the PET value (above) and the spatial distribution of interviews on Opernplatz linked to th Thermal conditions at the Opernplatz in Kassel indicated by the PET value (left) and the spatial distribution of interviews on Opernplatz linked to their subjective perception (right), both figures representing 3 pm (CET)
Comparison of thermal comfort evaluation by interviews (left) and BotWorld (right)
Heat stress from interviews with linear interpolation (left) and calculated with BotWorld (right)
Planning usage of ENVIMET simulations from KLIMES project Universities in Mainz and Kassel (2009)
Use of thermal calculations microclimate conditions in 2009 Energieaufwand kwh Gebäudehülle Heizwärmebedarf Kühlkältebedarf inside outside
calculated microlimate for 2030 Energieaufwand kwh Gebäudehülle Heizwärmebedarf Kühlkältebedarf inside outside
KLIMZUG NORDHESSEN climate change Szenarios need for adaptation Scientific projects R,E,M,H,T solutions 18 Projects Scientific projects society behavioural / social changes Practical projects implementation 9 Projects (+) transfer www.klimzug-nordhessen.de
Development of strategies to mitigate enhanced heat stress in urban quarters due to regional climate change in Central Europe (KLIMES) Helmut Mayer 1), Lutz Katzschner 2), Christl Drey 3), Michael Bruse 4) 1) Meteorological Institute, Albert-Ludwigs-University of Freiburg, Germany 2) Department of Environmental Meteorology, University of Kassel, Germany 3) Department of Urban Development, University of Kassel, Germany 4) Geomatics Group, Geography Department, Ruhr-University Bochum, Germany funded by within the scope of the research initiative Sustainable Neighbourhood from Lisbon to Leipzig through Research (L2L), Leipzig, May 2007 Meteorological Institute, Albert-Ludwigs-Universitäty of Freiburg,
Definition of an ideal urban climate (Katzschner 1999) The ideal urban climate is an atmospheric situation within the UCL with a high variation in time and space to develop inhomogeneous thermal conditions for man within a distance of 150 m. It should be free from air pollution and thermal stress considering the differences in regional climates by means of more shadow and ventilation (tropical and warm climates) or wind protection (moderate and cold climates). It should also taking into account possible climate adaptations of people. Thank you!