International Journal of Biometeorology

, Volume 60, Issue 11, pp 1775–1785 | Cite as

Validation of the mean radiant temperature simulated by the RayMan software in urban environments

Original Paper

Abstract

The RayMan software is worldwide applied in investigations on different issues in human-biometeorology. However, only the simulated mean radiant temperature (Tmrt) has been validated so far in a few case studies. They are based on Tmrt values, which were experimentally determined in urban environments by use of a globe thermometer or applying the six-directional method. This study analyses previous Tmrt validations in a comparative manner. Their results are extended by a recent validation of Tmrt in an urban micro-environment in Freiburg (southwest Germany), which can be regarded as relatively heterogeneous due to different shading intensities by tree crowns. In addition, a validation of the physiologically equivalent temperature (PET) simulated by RayMan is conducted for the first time. The validations are based on experimentally determined Tmrt and PET values, which were calculated from measured meteorological variables in the daytime of a clear-sky summer day. In total, the validation results show that RayMan is capable of simulating Tmrt satisfactorily under relatively homogeneous site conditions. However, the inaccuracy of simulated Tmrt is increasing with lower sun elevation and growing heterogeneity of the simulation site. As Tmrt represents the meteorological variable that mostly governs PET in the daytime of clear-sky summer days, the accuracy of simulated Tmrt is mainly responsible for the accuracy of simulated PET. The Tmrt validations result in some recommendations, which concern an update of physical principles applied in the RayMan software to simulate the short- and long-wave radiant flux densities, especially from vertical building walls and tree crowns.

Keywords

RayMan software package Validations Tmrt PET Urban environment 

References

  1. Acero JA, Herranz-Pascual K (2015) A comparison of thermal comfort conditions in four urban spaces by means of measurements and modelling techniques. Build Environ 93:245–257. doi:10.1016/j.buildenv.2015.06.028 CrossRefGoogle Scholar
  2. Andrade H, Alcoforado M-J (2008) Microclimatic variation of thermal comfort in a district of Lisbon (Telheiras) at night. Theor Appl Climatol 92:225–237. doi:10.1007/s00704-007-0321-5 CrossRefGoogle Scholar
  3. Blazejczyk K, Epstein Y, Jendritzky G, Staiger H, Tinz B (2012) Comparison of UTCI to selected thermal indices. Int J Biometeorol 56:515–535. doi:10.1007/s00484-011-0453-2 CrossRefGoogle Scholar
  4. Bruse M, Fleer H (1998) Simulating surface-plant-air interactions inside urban environments with a three-dimensional numerical model. Environ Model Softw 13:373–384. doi:10.1016/S1364-8152(98)00042-5 CrossRefGoogle Scholar
  5. Carter JG, Cavan G, Connelly A, Guy S, Handley J, Kazmierczak A (2015) Climate change and the city: building capacity for urban adaptation. Prog Plann 95:1–66. doi:10.1016/j.progress.2013.08.001 CrossRefGoogle Scholar
  6. Charalampopoulos I, Tsiros I, Chronopoulou-Sereli A, Matzarakis A (2013) Analysis of thermal bioclimate in various urban configurations in Athens, Greece. Urban Ecosyst 16:217–233. doi:10.1007/s11252-012-0252-5 CrossRefGoogle Scholar
  7. Chen Y-C, Matzarakis A (2014) Modification of physiologically equivalent temperature. J Heat Island Inst Intern 9-2:26–32Google Scholar
  8. Chen Y-C, Lin T-P, Matzarakis A (2014) Comparison of mean radiant temperature from field experiment and modelling: a case study in Freiburg, Germany. Theor Appl Climatol 118:535–551. doi:10.1007/s00704-013-1081-z CrossRefGoogle Scholar
  9. Fanger PO (1972) Thermal comfort. McGraw-Hill, New YorkGoogle Scholar
  10. Fröhlich D, Matzarakis A (2013) Modeling of changes in thermal bioclimate: examples based on urban spaces in Freiburg, Germany. Theor Appl Climatol 111:547–558. doi:10.1007/s00704-012-0678-y CrossRefGoogle Scholar
  11. Gulyás Á, Unger J, Matzarakis A (2006) Assessment of the microclimatic and human comfort conditions in a complex urban environment: modelling and measurements. Build Environ 41:1713–1722. doi:10.1016/j.buildenv.2005.07.001 CrossRefGoogle Scholar
  12. Höppe P (1992) A new method to determine the mean radiant temperature outdoors. Wetter und Leben 44:147–151 (in German)Google Scholar
  13. Höppe PR (1993) Heat balance modelling. Experientia 49:741–746CrossRefGoogle Scholar
  14. Höppe P (1999) The physiological equivalent temperature—a universal index for the biometeorological assessment of the thermal environment. Int J Biometeorol 43:71–75. doi:10.1007/s004840050118 CrossRefGoogle Scholar
  15. Holst J, Mayer H (2010) Urban human-biometeorology: investigations in Freiburg (Germany) on human thermal comfort. Urban Climate News 38:5–10Google Scholar
  16. Holst J, Mayer H (2011) Impacts of street design parameters on human-biometeorological variables. Meteorol Z 20:541–552. doi:10.1127/0941-2948/2011/0254 CrossRefGoogle Scholar
  17. Huang J, Cedeño-Laurent JG, Spengler JD (2014) CityComfort+: a simulation-based method for predicting mean radiant temperature in dense urban areas. Build Envir 80:84–95. doi:10.1016/j.buildenv.2014.05.019 CrossRefGoogle Scholar
  18. Hwang R-L, Lin T-P, Matzarakis A (2011) Seasonal effects of urban street shading on long-term outdoor thermal comfort. Build Envir 46:863–870. doi:10.1016/j.buildenv.2010.10.017 CrossRefGoogle Scholar
  19. Jendritzky G, de Dear R, Havenith G (2012) UTCI—why another thermal index? Int J Biometeorol 56:421–428. doi:10.1007/s00484-011-0513-7 CrossRefGoogle Scholar
  20. Jendritzky G, Menz G, Schirmer H, Schmidt-Kessen W (1990) Methodology for the spatial evaluation of the thermal component of the human bioclimate: updated Klima-Michel-model. Akad Raumforsch Landesplan, no. 114 (in German)Google Scholar
  21. Ketterer C, Matzarakis A (2014) Human-biometeorological assessment of the urban heat island in a city with complex topography - the case of Stuttgart, Germany. Urban Climate 10:573–584. doi:10.1016/j.uclim.2014.01.003
  22. Krüger EL, Minella FO, Matzarakis A (2014) Comparison of different methods of estimating the mean radiant temperature in outdoor thermal comfort studies. Int J Biometeorol 58:1727–1737. doi:10.1007/s00484-013-0777-1 CrossRefGoogle Scholar
  23. Lau KK-L, Lindberg F, Rayner D, Thorsson S (2015) The effect or urban geometry on mean radiant temperature under future climate change: a study of three European cities. Int J Biometeorol 59:799–814. doi:10.1007/s00484-014-0898-1 CrossRefGoogle Scholar
  24. Lee H (2015) Increasing heat waves require human-biometeorological analyses on the planning-related potential to mitigate human heat stress within urban districts. Dissertation, Faculty of Environment and Natural Resources, Albert-Ludwigs-University of Freiburg (Germany), pp. 114. doi: 10.6094/UNIFR/10428.Google Scholar
  25. Lee H, Mayer H (2013) Urban human-biometeorology supports urban planning to handle the challenge by increasing severe heat. Proc. 29th International PLEA Conference, Session I.3, 1–6.Google Scholar
  26. Lee H, Mayer H (2015) Green coverage changes within an ESE-WNW street canyon as a planning measure to maintain human thermal comfort on a heat wave day. Proc. 31st International PLEA Conference, PU 84, 1–8Google Scholar
  27. 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. doi:10.1155/2013/312572
  28. 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. doi:10.1127/0941-2948/2014/0536 CrossRefGoogle Scholar
  29. 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. doi:10.1016/j.landurbplan.2015.12.004 CrossRefGoogle Scholar
  30. Lin T-P (2009) Thermal perception, adaptation and attendance in a public square in hot and humid regions. Build Environ 44:2017–2026. doi:10.1016/j.buildenv.2009.02.004 CrossRefGoogle Scholar
  31. Lin T-P, Matzarakis A, Hwang R-L (2010) Shading effect on long-term outdoor thermal comfort. Build Environ 45:213–221. doi:10.1016/j.buildenv.2009.06.002 CrossRefGoogle Scholar
  32. Lindberg F, Holmer B, Thorsson S (2008) SOLWEIG 1.0—modelling spatial variations of 3D radiant fluxes and mean radiant temperature in complex urban settings. Int J Biometeorol 52:697–713. doi:10.1007/s00484-008-0162-7 CrossRefGoogle Scholar
  33. Lindberg F, Holmer B, Thorsson S, Rayner D (2014) Characteristics of the mean radiant temperature in high latitude cities—implications for sensitive climate planning applications. Int J Biometeorol 58:613–627. doi:10.1007/s00484-013-0638-y CrossRefGoogle Scholar
  34. Mahmoud AHA (2011) Analysis of the microclimatic and human comfort conditions in an urban park in hot and arid regions. Build Environ 46:2641–2656. doi:10.1016/j.buildenv.2011.06.025 CrossRefGoogle Scholar
  35. Martinelli L, Lin T-P, Matzarakis A (2015) Assessment of the influence of daily shadings pattern on human thermal comfort and attendance in Rome during summer period. Build Envir 92:30–38. doi:10.1016/j.buildenv.2015.04.013 CrossRefGoogle Scholar
  36. Matzarakis A, Mayer H (1997) Regionalisation of the physiologically equivalent temperature in Greece. Annal Meteorol 33:113–118 (in German)Google Scholar
  37. Matzarakis A, Rutz F, Mayer H (2007) Modelling radiation fluxes in simple and complex environments—application of the RayMan model. Int J Biometeorol 51:323–334. doi:10.1007/s00484-006-0061-8 CrossRefGoogle Scholar
  38. Matzarakis A, de Rocco M, Najjar G (2009) Thermal bioclimate in Strasbourg - the 2003 heat wave. Theor Appl Climatol 98:209–220. doi:10.1007/s00704-009-0102-4 CrossRefGoogle Scholar
  39. Matzarakis A, Rutz F, Mayer H (2010) Modelling radiation fluxes in simple and complex environments: basics of the RayMan model. Int J Biometeorol 54:131–139. doi:10.1007/s00484-009-0261-0 CrossRefGoogle Scholar
  40. Mayer H (1993) Urban bioclimatology. Experientia 49:957–963CrossRefGoogle Scholar
  41. Mayer H (2008) KLIMES - a joint research project on human thermal comfort in cities. Rep Meteor Inst Univ Freiburg 17:101–117Google Scholar
  42. Mayer H, Höppe P (1987) Thermal comfort of man in different urban environments. Theor Appl Climatol 38:43–49. doi:10.1007/BF00866252 CrossRefGoogle Scholar
  43. 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. doi:10.1127/0941-2948/2008/0285 CrossRefGoogle Scholar
  44. Nastos PT, Matzarakis A (2013) Human bioclimatic conditions, trends, and variability in the Athens University Campus, Greece. Adv Meteorol, article ID 976510. doi: 10.1155/2013/976510Google Scholar
  45. Nastos PT, Polychroni ID (2016) Modeling and in situ measurements of biometeorological conditions in microenvironments within the Athens University campus, Greece. Int J Biometeorol. doi:10.1007/s00484-016-1137-8 Google Scholar
  46. Taleghani M, Sailor D, Ban-Weiss GA (2016) Micrometeorological simulations to predict the impacts of heat mitigation strategies on pedestrian thermal comfort in a Los Angeles neighborhood. Environ Res Lett 11:024003. doi:10.1088/1748-9326/11/2/024003 CrossRefGoogle Scholar
  47. 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. doi:10.1002/joc.1537 CrossRefGoogle Scholar
  48. Valko P (1966) The sky radiation in its relationship to different parameters. Arch Meteorol Geophys Bioclimatol, Ser B 14:336–359 (in German)CrossRefGoogle Scholar
  49. VDI (1994) Environmental meteorology - interactions between atmosphere and surfaces: calculation of the short- and long-wave radiation. VDI guideline 3789, part 2. Beuth Publ., BerlinGoogle Scholar
  50. VDI (1998) Environmental meteorology - methods for the human-biometeorological evaluation of climate and air quality for the urban and regional planning, part I: climate. VDI guideline 3787, part 1. Beuth Publ., BerlinGoogle Scholar
  51. VDI (2001) Environmental meteorology - interactions between atmosphere and surfaces: calculation of spectral irradiances in the solar wavelength range. VDI guideline 3789, part 3. Beuth Publ., BerlinGoogle Scholar
  52. Yang X, Zhao L, Bruse M, Meng Q (2013) Evaluation of a microclimate model for predicting the thermal behavior of different ground surfaces. Build Environ 60:93–104. doi:10.1016/j.buildenv.2012.11.008 CrossRefGoogle Scholar
  53. Zeng Y, Dong L (2015) Thermal human biometeorological conditions and subjective thermal sensation in pedestrian streets in Chengdu, China. Int J Biometeorol 59:99–108. doi:10.1007/s00484-014-0883-8 CrossRefGoogle Scholar

Copyright information

© ISB 2016

Authors and Affiliations

  1. 1.Chair of Environmental MeteorologyAlbert-Ludwigs-University of FreiburgFreiburgGermany

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