Advertisement

Theoretical and Applied Climatology

, Volume 117, Issue 3–4, pp 363–376 | Cite as

Transmissivity of solar radiation through crowns of single urban trees—application for outdoor thermal comfort modelling

  • Janina KonarskaEmail author
  • Fredrik Lindberg
  • Annika Larsson
  • Sofia Thorsson
  • Björn Holmer
Original Paper

Abstract

Trees play an important role in mitigating heat stress on hot summer days, mainly due to their ability to provide shade. However, an important issue is also the reduction of solar radiation caused by trees in winter, in particular at high latitudes. In this study, we examine the transmissivity of total and direct solar radiation through crowns of single street trees in Göteborg, Sweden. One coniferous and four deciduous trees of species common in northern European cities were selected for case study. Radiation measurements were conducted on nine clear days in 2011–2012 in foliated and leafless tree conditions using two sunshine pyranometers—one located in shade of a tree and the other one on the roof of an adjacent building. The measurements showed a significant reduction of total and direct shortwave radiation in the shade of the studied trees, both foliated and leafless. Average transmissivity of direct solar radiation through the foliated and defoliated tree crowns ranged from 1.3 to 5.3 % and from 40.2 to 51.9 %, respectively. The results confirm the potential of a single urban tree to reduce heat stress in urban environment. However, the relatively low transmissivity through defoliated trees should be considered while planning street trees in high latitude cities, where the solar access in winter is limited. The results were used for parameterisation of SOLWEIG model for a better estimation of the mean radiant temperature (Tmrt). Measured values of transmissivity of solar radiation through both foliated and leafless trees were found to improve the model performance.

Keywords

Thermal Comfort Shortwave Radiation Direct Component Direct Solar Radiation Urban Tree 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

The project is being funded by the Swedish Research Council Formas, the Swedish Energy Agency, the Swedish Environmental Protection Agency, the Swedish National Heritage Board and the Swedish Transport Administration.

References

  1. Akbari H, Pomerantz M, Taha H (2001) Cool surfaces and shade trees to reduce energy use and improve air quality in urban areas. Solar Energy 70(3):295–310CrossRefGoogle Scholar
  2. Ali-Toudert F, Mayer H (2005) Thermal comfort in urban streets with trees under hot summer conditions. In: Proc. 22th Conference on Passive and Low Energy Architecture (PLEA), Beirut, Lebanon, 13–16 November 2005. pp 699–704Google Scholar
  3. Anderson MC (1964) Studies of the Woodland light climate. 1. The photographic computation of light conditions. J Ecol 52(1):27–41CrossRefGoogle Scholar
  4. Bowler DE, Buyung-Ali L, Knight TM, Pullin AS (2010) Urban greening to cool towns and cities: a systematic review of the empirical evidence. Landsc Urban Plann 97(3):147–155CrossRefGoogle Scholar
  5. Bruse M (2004) ENVI-met 3.0: Updated Model Overview. http://www.envi-met.com/documents/papers/overview30.pdf. Accessed on 7 January 2013
  6. Bruse M, Fleer H (1998) Simulating surface-plant-air interactions inside urban environments with a three dimensional numerical model. Environ Model Software 13(3–4):373–384CrossRefGoogle Scholar
  7. Cantón MA, Cortegoso JL, Derosa C (1994) Solar permeability of urban trees in cities of western Argentina. Energy and Buildings 20(3):219–230CrossRefGoogle Scholar
  8. Chapman L (2007) Potential applications of near-infrared hemispherical imagery in forest environments. Agricultural & Forest Meteorology 143:151–156CrossRefGoogle Scholar
  9. de Abreu LV, Labaki LC (2008) 648: Evaluation of the radius of influence of different arboreal species on microclimate provided by vegetation. In: PLEA 2008 - 25th Conference on Passive and Low Energy Architecture, DublinGoogle Scholar
  10. Dimoudi A, Nikolopoulou M (2003) Vegetation in the urban environment: microclimatic analysis and benefits. Energy and Buildings 35(1):69–76CrossRefGoogle Scholar
  11. Dragoni D, Schmid HP, Wayson CA, Potter H, Grimmond CSB, Randolph JC (2011) Evidence of increased net ecosystem productivity associated with a longer vegetated season in a deciduous forest in south-central Indiana, USA. Global Change Biol 17(2):886–897CrossRefGoogle Scholar
  12. Gardner TJ, Sydnor TD (1984) Interception of summer and winter insolation by 5 shade tree species. J Am Soc Hortic Sci 109(4):448–450Google Scholar
  13. Gay LW, Knoerr KR, Braaten MO (1971) Solar radiation variability on the floor of a pine plantation. Agr Meteorol 8:39–60CrossRefGoogle Scholar
  14. Hardy JP, Melloh R, Koenig G, Marks D, Winstral A, Pomeroy JW, Link T (2004) Solar radiation transmission through conifer canopies. Agric For Meteorol 126(3–4):257–270CrossRefGoogle Scholar
  15. Heisler GM (1986) Effects of individual trees on the solar-radiation climate of small buildings. Urban Ecol 9(3–4):337–359CrossRefGoogle Scholar
  16. Jauregui E (1991) Influence of a large urban park on temperature and convective precipitation in a tropical city. Energy and Buildings 15(3–4):457–463Google Scholar
  17. Liakatas A, Proutsos N, Alexandris S (2002) Optical properties affecting the radiant energy of an oak forest. Meteorol Appl 9(4):433–436CrossRefGoogle Scholar
  18. Lindberg F (2012) The SOLWEIG-model. http://www.gvc.gu.se/Forskning/klimat/stadsklimat/gucg/software/solweig/. Accessed on 7 January 2013
  19. Lindberg F, Grimmond CSB (2011) The influence of vegetation and building morphology on shadow patterns and mean radiant temperatures in urban areas: model development and evaluation. Theor Appl Climatol 105(3–4):311–323CrossRefGoogle Scholar
  20. 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(7):697–713CrossRefGoogle Scholar
  21. Matzarakis A, Rutz F, Mayer H (2007) Modelling radiation fluxes in simple and complex environments—application of the RayMan model. Int J Biometeorol 51(4):323–334CrossRefGoogle Scholar
  22. Mayer H, Hoppe P (1987) Thermal comfort of man in different urban environments. Theor Appl Climatol 38(1):43–49CrossRefGoogle Scholar
  23. Mayer H, Kuppe S, Holst J, Imbery F, Matzarakis A (2009) Human thermal comfort below the canopy of street trees on a typical Central European summer day. Ber Meteor Inst Univ Freiburg 18:211–219Google Scholar
  24. Ni WG, Li XW, Woodcock CE, Roujean JL, Davis RE (1997) Transmission of solar radiation in boreal conifer forests: measurements and models. J Geophys Res-Atmos 102(D24):29555–29566CrossRefGoogle Scholar
  25. Norman JM, Jarvis PG (1974) Photosynthesis in Sitka Spruce (Picea-sitchensis (Bong.) Carr.). III. Measurements of canopy structure and interception of radiation. J Appl Ecol 11(1):375–398CrossRefGoogle Scholar
  26. Oke TR (1987) Boundary layer climates. 2nd edn. Methuen, London; New YorkGoogle Scholar
  27. Oke TR (1989) The micrometeorology of the urban forest. Philosophical Transactions of the Royal Society of London Series B-Biological Sciences 324(1223):335–349CrossRefGoogle Scholar
  28. Pomeroy JW, Dion K (1996) Winter radiation extinction and reflection in a boreal pine canopy: measurements and modelling. Hydrological Processes 10(12):1591–1608CrossRefGoogle Scholar
  29. Rich PM, Clark DB, Clark DA, Oberbauer SF (1993) Long-term study of solar-radiation regimes in a tropical wet forest using quantum sensors and hemispherical photography. Agr Forest Meteorol 65(1–2):107–127CrossRefGoogle Scholar
  30. Robitu M, Musy M, Inard C, Groleau D (2006) Modeling the influence of vegetation and water pond on urban microclimate. Solar Energy 80(4):435–447CrossRefGoogle Scholar
  31. Shashua-Bar L, Hoffman ME (2000) Vegetation as a climatic component in the design of an urban street—an empirical model for predicting the cooling effect of urban green areas with trees. Energy and Buildings 31(3):221–235CrossRefGoogle Scholar
  32. Shashua-Bar L, Pearlmutter D, Erell E (2011) The influence of trees and grass on outdoor thermal comfort in a hot-arid environment. Int J Climatol 31(10):1498–1506CrossRefGoogle Scholar
  33. Simpson JR, McPherson EG (1996) Potential of tree shade for reducing residential energy use in California. J Arboric 22(1):10–18Google Scholar
  34. Thayer RL, Maeda BT (1985) Measuring street tree impact on solar performance: a five-climate computer modeling study. J Arboric 11:1–11Google Scholar
  35. 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(14):1983–1993CrossRefGoogle Scholar
  36. Thorsson S, Lindberg F, Bjorklund J, Holmer B, Rayner D (2011) Potential changes in outdoor thermal comfort conditions in Gothenburg, Sweden due to climate change: the influence of urban geometry. Int J Climatol 31(2):324–335CrossRefGoogle Scholar
  37. Upmanis H, Eliasson I, Lindqvist S (1998) The influence of green areas on nocturnal temperatures in a high latitude city (Goteborg, Sweden). Int J Climatol 18(6):681–700CrossRefGoogle Scholar
  38. Wilkinson DM (1991) Can photographic methods be used for measuring the light attenuation characteristics of trees in leaf? Landsc Urban Plann 20(4):347–349CrossRefGoogle Scholar
  39. Wood J (2007) User Manual for the Sunshine Pyranometer Type SPN1. http://www.delta-t.co.uk/product-downloads.asp?$=Product%20Manuals. Accessed on 26 July 2013
  40. Yates D, McKennan G (1988) Solar architecture and light attenuation by trees: conflict or compromise? Landscape Research 13(1):19–23CrossRefGoogle Scholar
  41. Youngberg RJ (1983) Shading effects of deciduous trees. J Arboric 9(11):295–297Google Scholar
  42. Zipperer WC, Sisinni SM, Pouyat RV, Foresman TW (1997) Urban tree cover: an ecological perspective. Urban Ecosyst 1:229–246CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Wien 2013

Authors and Affiliations

  • Janina Konarska
    • 1
    Email author
  • Fredrik Lindberg
    • 1
  • Annika Larsson
    • 2
  • Sofia Thorsson
    • 1
  • Björn Holmer
    • 1
  1. 1.Department of Earth SciencesUniversity of GothenburgGothenburgSweden
  2. 2.Faculty of Landscape Planning, Horticulture and Agricultural ScienceSwedish University of Agricultural ScienceAlnarpSweden

Personalised recommendations