Quantification of turbulent heat fluxes for adaptation strategies within urban planning

With the objective of quantifying turbulent heat fluxes in areas with various types of urban land use to improve living and environmental conditions through better urban planning, comparative energy balance measurements using the eddy‐covariance (EC) technique were conducted in Oberhausen (Germany) between 15 August 2010 and 15 April 2011. The results of this paper show that the sensible heat flux (QH) is 20% higher and that the latent heat flux (QE) is 90% lower at an urban site (URB) compared to a suburban site (SUB). Green spaces in cities counteract the growing thermal stresses on city dwellers and therefore represent a possible urban climate mitigation measure. This positive effect may be reduced or lost entirely during long periods of drought. The Bowen ratio (QH/QE) increased from 0.65 to 2.8 with decreasing soil moisture at the SUB, and the monthly average QE value decreased from 94 W m−2 (August 2010, heavy precipitation) to only 47 W m−2 (March 2011, dry period), providing impressive evidence of this relationship. Considering the aspects of urban climate, the creation of urban green spaces can only be effective if an optimum water supply is provided. Furthermore, additional planning recommendations are given for urban planners within cities located at mid‐latitudes, as derived from the measured results. Copyright © 2012 Royal Meteorological Society

[1]  A. Mahmoud.  Analysis of the microclimatic and human comfort conditions in an urban park in hot and arid regions , 2011 .

[2]  L. Shashua-Bar,et al.  The influence of trees and grass on outdoor thermal comfort in a hot‐arid environment , 2011 .

[3]  W. Kuttler.  Climate change in urban areas. Part 2, Measures , 2011 .

[4]  W. Kuttler.  Klimawandel im urbanen Bereich, Teil 1, Wirkungen , 2011 .

[5]  Amauri Pereira de Oliveira,et al.  Anthropogenic heat in the city of São Paulo, Brazil , 2011 .

[6]  M. Rosson,et al.  The state of the art in end-user software engineering , 2011, ACM Comput. Surv..

[7]  W. Kuttler.  Climate change in urban areas, Part 1, Effects , 2011 .

[8]  B. Lamb,et al.  Energy balance in urban Mexico City: observation and parameterization during the MILAGRO/MCMA-2006 field campaign , 2011 .

[9]  Nina Schwarz,et al.  Assessing climate impacts of planning policies—An estimation for the urban region of Leipzig (Germany) , 2011 .

[10]  Joseph P. McFadden,et al.  Seasonal contributions of vegetation types to suburban evapotranspiration , 2011 .

[11]  Eberhard Parlow,et al.  Flux measurements in Cairo. Part 1: in situ measurements and their applicability for comparison with satellite data , 2011 .

[12]  T. Williamson,et al.  Urban Microclimate: Designing the Spaces Between Buildings , 2010 .

[13]  Stephan Weber,et al.  Comparison of atmospheric turbulence characteristics and turbulent fluxes from two urban sites in Essen, Germany , 2010 .

[14]  Julia N. Georgi,et al.  The contribution of urban green spaces to the improvement of environment in cities: Case study of Chania, Greece , 2010 .

[15]  K. Gallo,et al.  Surface Energy Balance Measurements Above an Exurban Residential Neighbourhood of Kansas City, Missouri , 2009 .

[16]  D. Pearlmutter,et al.  The role of evaporation in the energy balance of an open‐air scaled urban surface , 2009 .

[17]  Eero Nikinmaa,et al.  Surface–atmosphere interactions over complex urban terrain in Helsinki, Finland , 2008 .

[18]  T. Oke,et al.  The suburban energy balance in miami, florida , 2007 .

[19]  V. Masson,et al.  Anthropogenic heat release in an old European agglomeration (Toulouse, France) , 2007 .

[20]  Matthias Roth,et al.  Review of atmospheric turbulence over cities , 2007 .

[21]  D. Groleau,et al.  Modeling the influence of vegetation and water pond on urban microclimate , 2006 .

[22]  C. S. B. Grimmond,et al.  Temporal variations in heat fluxes over a central European city centre , 2006 .

[23]  Ingegärd Eliasson,et al.  Urban Modification of the Surface Energy Balance in the West African Sahel: Ouagadougou, Burkina Faso , 2005 .

[24]  Michael Schatzmann,et al.  BUBBLE – an Urban Boundary Layer Meteorology Project , 2005 .

[25]  Dennis D. Baldocchi,et al.  Objective threshold determination for nighttime eddy flux filtering , 2005 .

[26]  Timothy R. Oke,et al.  Flux and turbulence measurements at a densely built‐up site in Marseille: Heat, mass (water and carbon dioxide), and momentum , 2004 .

[27]  Christoph Schär,et al.  Climate change: Hot news from summer 2003 , 2004, Nature.

[28]  P. Stott,et al.  Human contribution to the European heatwave of 2003 , 2004, Nature.

[29]  M. Kanda,et al.  Seasonal and Diurnal Fluxes of Radiation, Heat, Water Vapor, and Carbon Dioxide over a Suburban Area , 2004 .

[30]  A. Christen,et al.  Energy and radiation balance of a central European city , 2004 .

[31]  David J. Sailor,et al.  A top-down methodology for developing diurnal and seasonal anthropogenic heating profiles for urban areas , 2004 .

[32]  D. Lüthi,et al.  The role of increasing temperature variability in European summer heatwaves , 2004, Nature.

[33]  M. Beniston.  The 2003 heat wave in Europe: A shape of things to come? An analysis based on Swiss climatological data and model simulations , 2004 .

[34]  H. Saaroni,et al.  The impact of a small lake on heat stress in a Mediterranean urban park: the case of Tel Aviv, Israel , 2003, International journal of biometeorology.

[35]  Rachel Spronken-Smith,et al.  Comparison of summer‐ and winter‐time suburban energy fluxes in Christchurch, New Zealand , 2002 .

[36]  David Fowler,et al.  Micrometeorological measurements of the urban heat budget and CO2 emissions on a city scale. , 2002, Environmental science & technology.

[37]  D. Nowak,et al.  Local-scale fluxes of carbon dioxide in urban environments: methodological challenges and results from Chicago. , 2002, Environmental pollution.

[38]  Thomas Foken,et al.  New Equations For Sonic Temperature Variance And Buoyancy Heat Flux With An Omnidirectional Sonic Anemometer , 2001 .

[39]  W. Kuttler.  On the detection of intra-urban global radiation differences by mobile measurements , 2000 .

[40]  T. Oke,et al.  The energy balance of central Mexico City during the dry season , 1999 .

[41]  E. Jáuregui,et al.  Energy balance measurements in a suburban vegetated area in Mexico City , 1999 .

[42]  Keisuke Hanaki,et al.  Impact of anthropogenic heat on urban climate in Tokyo , 1999 .

[43]  Timothy R. Oke,et al.  Aerodynamic Properties of Urban Areas Derived from Analysis of Surface Form , 1999 .

[44]  Hans Peter Schmid,et al.  Experimental design for flux measurements: matching scales of observations and fluxes , 1997 .

[45]  Dean Vickers,et al.  Quality Control and Flux Sampling Problems for Tower and Aircraft Data , 1997 .

[46]  K. Kłysik.  Spatial and seasonal distribution of anthropogenic heat emissions in Lodz, Poland , 1996 .

[47]  Ingegärd Eliasson,et al.  Urban nocturnal temperatures, street geometry and land use , 1996 .

[48]  C. Grimmond,et al.  Influence of tree cover on summertime surface energy balance fluxes, San Gabriel Valley, Los Angeles , 1996 .

[49]  Timothy R. Oke,et al.  Comparison of heat fluxes from summertime observations in the suburbs of four North American cities , 1995 .

[50]  R. Stull.  An Introduction to Boundary Layer Meteorology , 1988 .

[51]  C. J. Moore.  Frequency response corrections for eddy correlation systems , 1986 .

[52]  Frans T. M. Nieuwstadt,et al.  Temperature measurement with a sonic anemometer and its application to heat and moisture fluxes , 1983 .

[53]  T. Oke.  The energetic basis of the urban heat island , 1982 .

[54]  J. Monteith,et al.  Boundary Layer Climates. , 1979 .

[55]  Kazuo Yamamoto,et al.  THE LOCAL STRUCTURE OF ISOTROPIC TURBULENCE , 1974 .

[56]  Taha,et al.  ORLANDO LAWRENCE NATIONAL LABORATORY ERNEST BERKELEY Heat Island and Oasis Effects of Vegetative Canopies : Micro-Meteorological Field-Measurements , 2013 .

[57]  Liang Chen,et al.  A study on the cooling effects of greening in a high-density city: An experience from Hong Kong , 2012 .

[58]  Eberhard Parlow,et al.  Flux Measurements in Cairo , 2011 .

[59]  Tzu-Ping Lin,et al.  Shading effect on long-term outdoor thermal comfort , 2010 .

[60]  C. Grimmond,et al.  Intraurban Differences of Surface Energy Fluxes in a Central European City , 2006 .

[61]  Helen A. Cleugh,et al.  The impact of suburban design on water use and microclimate , 2005 .

[62]  J. Chamie,et al.  World Urbanization Prospects: The 2003 Revision , 2004 .

[63]  G. Pyle,et al.  Toxicity of uranium mine receiving waters to early life stage fathead minnows (Pimephales promelas) in the laboratory. , 2002, Environmental pollution.

[64]  Ü. Rannik,et al.  Estimates of the annual net carbon and water exchange of forests: the EUROFLUX methodology , 2000 .

[65]  T. Oke,et al.  The thermal regime of urban parks in two cities with different summer climates , 1998 .

[66]  T. Foken,et al.  Tools for quality assessment of surface-based flux measurements , 1996 .

[67]  P. Mason.  Atmospheric boundary layer flows: Their structure and measurement , 1995 .

[68]  H. Schmid.  Source areas for scalars and scalar fluxes , 1994 .

[69]  R. Spronken-Smith.  Energetics and cooling in urban parks , 1994 .

[70]  Timothy R. Oke,et al.  The role of "rural" in comparisons of observed suburban-rural flux differences , 1993 .

[71]  I. Saito,et al.  Study of the effect of green areas on the thermal environment in an urban area , 1990 .

[72]  W. Kuttler.  Spatial and Temporal Structures of the Urban Climate — A Survey , 1988 .

[73]  E. K. Webb,et al.  Correction of flux measurements for density effects due to heat and water vapour transfer , 1980 .