Advertisement

Theoretical and Applied Climatology

, Volume 44, Issue 2, pp 123–138 | Cite as

Heat island and oasis effects of vegetative canopies: Micro-meteorological field-measurements

  • H. Taha
  • H. Akbari
  • A. Rosenfeld
Article

Summary

Dry-bulb temperature, dew-point, wind speed, and wind direction were measured in and around an isolated vegetative canopy in Davis CA from 12 to 25 October 1986. These meteorological variables were measured 1.5 m above ground along a transect of 7 weather stations set up across the canopy and the upwind/downwind open fields. These variables were averaged every 15 minutes for a period of two weeks so we could analyze their diurnal cycles as well as their spatial variability. The results indicate significant nocturnal heat islands and daytime oases within the vegetation stand, especially in clear weather. Inside the canopy within 5 m of its upwind edge, daytime temperature fell by as much as 4.5 °C, whereas the nighttime temperature rose by 1 °C. Deeper into the canopy and downwind, the daytime drop in temperature reached 6 °C, and the nighttime increase reached 2 °C. Wind speed was reduced by ~ 2 ms−1 in mild conditions and by as much as 6.7 ms−1 during cyclonic weather when open-field wind speed was in the neighborhood of 8 ms−1. Data from this project were used to construct correlations between temperature and wind speed within the canopy and their corresponding ambient, open-field values.

Keywords

Waste Water Wind Speed Open Field Wind Direction Spatial Variability 
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.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Akbari, H., Taha, H., Huang, J., Rosenfeld, A., 1986: Undoing uncomfortable summer heat islands can save gigawatts of peak power.Proceedings of the ACEEE Summer Study on Energy Efficiency in Buildings, August 1986, Santa Cruz, California 2, 7–22.Google Scholar
  2. Barnston, A. G., Schickedanz, P. T., 1984: The effect of irrigation on warm season precipitation in the southern great plains.J. Climate Appl. Meteor. 23, 865–888.Google Scholar
  3. Bernatzky, A., 1982: The contribution of trees and green spaces to a town climate.Energy and Buildings 5, 1–10.Google Scholar
  4. Budyko, M. I., 1977:Climatic Changes. American Geophysical Union, Washington, DC.Google Scholar
  5. Davenport, D. C., Hudson, J. P., 1967a: Changes in evaporation rates along a 17-km transect in the Sudan gezira.Agric. Meteor. 4, 339–352.Google Scholar
  6. Davenport, D. C., Hudson, J. P., 1967b: Meteorological observations and Penman estimates along a 17-km transect in the Sudan gezira.Agric. Meteor. 4, 405–414.Google Scholar
  7. DeVries, D. A., 1959: The influence of irrigation on the energy balance and the climate near the ground.J. Meteor. 16, 256–270.Google Scholar
  8. Geiger, R., 1957:The Climate Near the Ground. Boston: Harvard University Press, 611 pp.Google Scholar
  9. Huang, J., Akbari, H., Taha, H., Rosenfeld, A., 1987: The potential of vegetation in reducing summer cooling loads in residential buildings.J. Climate Appl. Meteor. 26, 1103–1116.Google Scholar
  10. Lemon, E. R., Glaser, A. H., Satterwhite, L. E., 1957: Some aspects of the relationship of soil, plant, and meteorological factors to evapotranspiration.Soil Sci. Soc. Am. Proc. 21, 464–468.Google Scholar
  11. Sebba, R., Enis, R., Hoffman, M. E., 1984: The Kibbutz landscape in arid zones.Energy and Buildings 7, 205–211.Google Scholar
  12. Taha, H., Akbari, H., Rosenfeld, A., Huang, J., 1988: Residential cooling loads and the urban heat island: the effects of albedo.Building and Environment 23, 271–283.Google Scholar
  13. Taha, H., Akbari, H., Rosenfeld, A., 1989: Vegetation canopy micro-climate: a field-project in Davis, California. Lawrence Berkeley Laboratory Report LBL 24593, Berkeley, California.Google Scholar

Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • H. Taha
    • 1
  • H. Akbari
    • 1
  • A. Rosenfeld
    • 1
  1. 1.Heat Island Project, Applied Science Division, Lawrence Berkeley LaboartoryUniversity of California-BerkeleyUSA

Personalised recommendations