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International Journal of Biometeorology

, Volume 63, Issue 1, pp 73–81 | Cite as

To what extent does the air flow initialisation of the ENVI-met model affect human heat stress simulated in a common street canyon?

  • Hyunjung LeeEmail author
  • Helmut Mayer
  • Wilhelm Kuttler
Original Paper
  • 102 Downloads

Abstract

This study concerns the effects of the air flow initialisation of the ENVI-met model on simulated human heat stress in a fictive E-W street canyon with different aspect ratios that is typical of Central European cities. Human heat stress is described by near-surface air temperature (Ta), mean radiant temperature (Tmrt) and physiologically equivalent temperature (PET). The numerical simulations, which are performed for a Central European heat wave day in order to consider the increase of severe heat due to regional climate change, are based on the version 4.0 BETA of ENVI-met. The simulation results in terms of grid-related Ta, Tmrt and PET values as well as mean values for both sidewalks of the street canyon are averaged over the period 10–16 CET, because they should be representative of outdoor human heat stress in Central European cities. The simulation results point to the significance of the type of inflow direction in relation to the orientation of the street canyon, i.e. whether it is flowed parallel or across. The type of inflow direction determines the modification of the inflow speed within the street canyon. Due to its physical basis, mean Tmrt does not show a noticeable impact by the inflow conditions. They also influence mean Ta relatively low. However, PET is much more affected by the inflow conditions as it depends on the local wind speed. This impact can reach the magnitude of thermal grassland effects within urban quarters, i.e. it cannot be ignored under a human-biometeorological perspective.

Keywords

Urban human-biometeorology ENVI-met model E-W street canyon Inflow initialisation Heat wave day Human heat stress 

Notes

Acknowledgements

The authors are indebted to Markus Sulzer for his assistance in basic ENVI-met simulations.

References

  1. Ali-Toudert F, Mayer H (2006) Numerical study on the effects of aspect ratio and orientation of an urban street canyon on outdoor thermal comfort in hot and dry climate. Build Environ 41:94–108.  https://doi.org/10.1016/j.buildenv.2005.01.013
  2. Bruse M, Fleer H (1998) Simulating surface-plant-air interactions inside urban environments with a three-dimensional numerical model. Environ Model Softw 13:373–384CrossRefGoogle Scholar
  3. Fallmann J, Wagner S, Emeis S (2017) High resolution climate projections to assess the future vulnerability of European urban areas to climatological extreme events. Theor Appl Climatol 127:667–683.  https://doi.org/10.1007/s00704-015-1658-9 CrossRefGoogle Scholar
  4. Forouzandeh A (2018) Numerical modeling validation for the microclimate thermal condition of semi-closed courtyard spaces between buildings. Sust Cities Soc 36:327–345.  https://doi.org/10.1016/j.scs.2017.07.025 CrossRefGoogle Scholar
  5. Holst J, Mayer H (2011) Impacts of street design parameters on human-biometeorological variables. Meteorol Z 20:541–552.  https://doi.org/10.1127/0941-2948/2011/0254 CrossRefGoogle Scholar
  6. Huttner S (2012) Further development and application of the 3D microclimate simulation ENVI-met. Dissertation, Johannes Gutenberg-University of Mainz (Germany), http://ubm.opus.hbz-nrw.de/volltexte/2012/3112/pdf/doc.pdf. Accessed 20 April 2018
  7. Johansson L, Onomura S, Lindberg F, Seaquist J (2016) Towards the modelling of pedestrian wind speed using high-resolution digital surface models and statistical methods. Theor Appl Climatol 124:189–203.  https://doi.org/10.1007/s00704-015-1405-2 CrossRefGoogle Scholar
  8. Lee H, Mayer H (2016) Validation of the mean radiant temperature simulated by the RayMan software in urban environments. Int J Biometeorol 60:1775–1785.  https://doi.org/10.1007/s00484-016-1166-3 CrossRefGoogle Scholar
  9. Lee H, Mayer H (2018a) Thermal comfort of pedestrians in an urban street canyon is affected by increasing albedo of building walls. Int J Biometeorol 62:1199–1209.  https://doi.org/10.1007/s00484-018-1523-5 CrossRefGoogle Scholar
  10. Lee H, Mayer H (2018b) Maximum extent of human heat stress reduction on building areas due to urban greening. Urban For Urban Greening 32:154–167.  https://doi.org/10.1016/j.ufug.2018.04.010 CrossRefGoogle Scholar
  11. Lee H, Holst J, Mayer H (2013) Modification of human-biometeorologically significant radiant flux densities by shading as local method to mitigate heat stress in summer within urban street canyons. Adv Meteorol 2013:312572, 13 pages.  https://doi.org/10.1155/2013/312572 Google Scholar
  12. Lee H, Mayer H, Schindler D (2014) Importance of 3-D radiant flux densities for outdoor human thermal comfort on clear-sky summer days in Freiburg, Southwest Germany. Meteorol Z 23:315–330.  https://doi.org/10.1127/0941-2948/2014/0536 CrossRefGoogle Scholar
  13. Lee H, Mayer H, Chen L (2016) Contribution of trees and grasslands to the mitigation of human heat stress in a residential district of Freiburg, Southwest Germany. Landsc Urban Plan 148:37–50.  https://doi.org/10.1016/j.landurbplan.2015.12.004 CrossRefGoogle Scholar
  14. Mayer H (1993) Urban bioclimatology. Experientia 49:957–963.  https://doi.org/10.1007/BF02125642 CrossRefGoogle Scholar
  15. Mayer H, Höppe P (1987) Thermal comfort of man in different urban environments. Theor Appl Climatol 38:43–49.  https://doi.org/10.1007/BF00866252 CrossRefGoogle Scholar
  16. Mayer H, Holst J, Dostal P, Imbery F, Schindler D (2008) Human thermal comfort in summer within an urban street canyon in Central Europe. Meteorol Z 17:241–250.  https://doi.org/10.1127/0941-2948/2008/0285 CrossRefGoogle Scholar
  17. Müller N, Kuttler W, Barlag A-B (2014) Counteracting urban climate change: adaptation measures and their effect on thermal comfort. Theor Appl Climatol 115:243–257.  https://doi.org/10.1007/s00704-013-0890-4 CrossRefGoogle Scholar
  18. Rebetez M, Mayer H, Dupont O, Schindler D, Gartner K, Kropp JP, Menzel A (2006) Heat and drought 2003 in Europe: a climate synthesis. Ann For Sci 63:569–577.  https://doi.org/10.1051/forest:2006043 CrossRefGoogle Scholar
  19. Simon H (2016) Modeling urban microclimate - Development, implementation and evaluation of new and improved calculation methods for the urban microclimate model ENVI-met. Dissertation, Johannes Gutenberg-University of Mainz (Germany), https://publications.ub.uni-mainz.de/theses/volltexte/2016/100000507/pdf/100000507.pdf. Accessed 20 April 2018
  20. Thorsson S, Lindberg F, Eliasson I, Holmer B (2007) Different methods for estimating the mean radiant temperature in an outdoor urban setting. Int J Climatol 27:1983–1993.  https://doi.org/10.1002/joc.1537 CrossRefGoogle Scholar
  21. Wania A, Bruse M, Blond N, Weber C (2012) Analysing the influence of different street vegetation on traffic-induced particle dispersion using microscale simulations. J Environ Manag 94:91–101.  https://doi.org/10.1016/j.jenvman.2011.06.036 CrossRefGoogle Scholar
  22. Zhao Q, Sailor DJ, Wentz EA (2018) Impact of tree locations and arrangements on outdoor microclimates and human thermal comfort in an urban residential environment. Urban For Urban Green 32:81–91CrossRefGoogle Scholar

Copyright information

© ISB 2018

Authors and Affiliations

  1. 1.Department of Urban Climatology, Office for Environmental ProtectionCity of StuttgartStuttgartGermany
  2. 2.Chair of Environmental MeteorologyAlbert-Ludwigs-University of FreiburgFreiburgGermany
  3. 3.Applied Climatology, Faculty of BiologyUniversity of Duisburg-Essen, Campus EssenEssenGermany

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