Development of Temperature Patterns during Clear Nights

Torbjörn Gustavsson Laboratory of Climatology, Department of Physical Geography, Göteborg University, Goteborg, Sweden

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Maria Karlsson Laboratory of Climatology, Department of Physical Geography, Göteborg University, Goteborg, Sweden

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Jörgen Bogren Laboratory of Climatology, Department of Physical Geography, Göteborg University, Goteborg, Sweden

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Sven Lindqvist Laboratory of Climatology, Department of Physical Geography, Göteborg University, Goteborg, Sweden

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Abstract

This paper examines nocturnal air temperature structure development in complex terrain. Clear nights were studied in order to compare the cooling rate in different topographical areas with a variety of land cover. It was found that large variations in temperature developed over a very short time period after sunset and that in situ cooling was the dominant factor causing this in valleys and other wind-sheltered locations. Shelter can be provided both from valley sides and from nearby trees with the main effect being to reduce the vertical mixing.

The nighttime increase in temperature difference between valley bottoms and nearby reference areas was interpreted to be due to cold airflows. This was also shown by the increasing lateral extension of cold air accumulating in valleys. This development was found only in open valley locations. Sheltered areas cooled at a much faster rate than exposed sites during early evening. Further cooling did not increase the lateral extension of cold air or result in larger temperature differences. This is attributed to lack of cold airflow. The rapid cooling was supported due to reduced mixing of warmer air from above. This hypothesis was further confirmed in this study by analysis of clear nights with low regional wind speed when it was found that sheltered locations differed significantly in temperature compared to wind-exposed areas.

Corresponding author address: Dr. Torbjörn Gustavsson, Department of Physical Geography, Earth Sciences Centre, Göteborg University, Box 460, SE 405 30 Göteborg, Sweden.

torbjorng@gvc.gu.se

Abstract

This paper examines nocturnal air temperature structure development in complex terrain. Clear nights were studied in order to compare the cooling rate in different topographical areas with a variety of land cover. It was found that large variations in temperature developed over a very short time period after sunset and that in situ cooling was the dominant factor causing this in valleys and other wind-sheltered locations. Shelter can be provided both from valley sides and from nearby trees with the main effect being to reduce the vertical mixing.

The nighttime increase in temperature difference between valley bottoms and nearby reference areas was interpreted to be due to cold airflows. This was also shown by the increasing lateral extension of cold air accumulating in valleys. This development was found only in open valley locations. Sheltered areas cooled at a much faster rate than exposed sites during early evening. Further cooling did not increase the lateral extension of cold air or result in larger temperature differences. This is attributed to lack of cold airflow. The rapid cooling was supported due to reduced mixing of warmer air from above. This hypothesis was further confirmed in this study by analysis of clear nights with low regional wind speed when it was found that sheltered locations differed significantly in temperature compared to wind-exposed areas.

Corresponding author address: Dr. Torbjörn Gustavsson, Department of Physical Geography, Earth Sciences Centre, Göteborg University, Box 460, SE 405 30 Göteborg, Sweden.

torbjorng@gvc.gu.se

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  • Barr, S., and M. M. Orgill, 1989: Influence of external meteorology on nocturnal valley drainage winds. J. Appl. Meteor.,28, 497–517.

  • Bogren, J., and T. Gustavsson, 1989: Modelling of local climate for prediction of road slipperiness. Phys. Geogr.,10, 147–164.

  • ——, and ——, 1991: Nocturnal air and road surface temperature variations in complex terrain. Int. J. Climatol.,11, 443–455.

  • Catchpole, A. J. W., 1963: The Houghall frost hollow. Meteor. Mag.,92, 121–129.

  • Coleman, A. M., 1969: An objective method for minimum temperature forecasting at Hobart. Meteor. Note 29, Bureau of Meteorology, Hobart, Australia, 9 pp.

  • Dight, F. H., 1967: The diurnal range of temperature in Scottish glens. Meteor. Mag.,99, 327–334.

  • Fleagle, R. G., 1950: Radiation theory of local temperature differences. J. Meteor.,7, 114–120.

  • Geiger, R., 1971: The Climate Near the Ground. Harvard University Press, 611 pp.

  • Gross, G., 1987: Some effects of deforestation on nocturnal drainage flow and local climate—A numerical study. Bound.-Layer Meteor.,38, 315–337.

  • Gudiksen, P. H., J. M. Leone Jr., C. W. King, D. Ruffieux, and W. D. Neff, 1992: Measurements and modeling of the effects of ambient meteorology on nocturnal drainage flows. J. Appl. Meteor.,31, 1023–1032.

  • Gustavsson, T., 1990: Variation in road surface temperature due to topography and wind. Theor. Appl. Meteor.,41, 227–236.

  • ——, 1995: A study of air and road surface temperature variations during clear windy nights. Int. J. Climatol.,15, 919–932.

  • Harrison, A. A., 1969: A discussion of the temperature of inland Kent with particular reference to night minima in the lowlands. Meteor. Mag.,100, 97–111.

  • Heywood, G. S. P., 1933: Katabatic winds in a valley. Quart. J. Roy. Meteor. Soc.,59, 47–58.

  • Hogan, A., and M. Ferrick, 1997: Winter morning air temperature. J. Appl. Meteor.,36, 52–69.

  • Kalma, J. D., G. P. Laughlin, A. A. Green, and M. T. O’Brien, 1986:Minimum temperature surveys based on near-surface air-temperature measurements and airborne thermal scanner data. J. Climatol.,6, 413–430.

  • Kondo, J., and T. Sato, 1988: A simple model of drainage flow on a slope. Bound.-Layer Meteor.,43, 103–123.

  • ——, and N. Okusa, 1990: A simple numerical prediction model of nocturnal cooling in a basin with various topographic parameters. J. Appl. Meteor.,29, 604–619.

  • Laughlin, G. P., 1982: Minimum temperature and lapse rate in complex terrain: Influencing factors and prediction. Arch. Meteor. Geophys. Bioclimatol.,30B, 141–152.

  • ——, and J. D. Kalma, 1990: Frost risk mapping for landscape planning: A methodology. Theor. Appl. Climatol.,42, 41–51.

  • Lee, I. Y., R. L. Coulter, H. M. Park, and J.-H. Oh, 1995: Numerical simulations of nocturnal drainage flow properties in a rugged canyon. Bound.-Layer Meteor.,72, 305–321.

  • Magono, C., C. Nakamura, and Y. Yoshida, 1982: Nocturnal cooling of the Moshiri basin, Hokkaido, in midwinter. J. Meteor. Soc. Japan,60, 1106–1116.

  • Mahrt, L., 1986: Nocturnal Topoclimatology. World Meteor. Assoc., 76 pp.

  • McKee, T. B., and R. D. O’Neal, 1989: The role of valley geometry and energy budget in the formation of nocturnal valley winds. J. Appl. Meteor.,28, 445–456.

  • Müller, H., and C. D. Whiteman, 1988: Breakup of a nocturnal temperature inversion in the Dishma Valley during DISKUS. J. Appl. Meteor.,27, 188–194.

  • Neff, W. D., and C. W. King, 1989: The accumulation and pooling of drainage flows in a large basin. J. Appl. Meteor.,28, 518–530.

  • Sakiyama, S., 1990: Drainage flow characteristics and inversion break-up in two Alberta mountain valleys. J. Appl. Meteor.,29, 1015–1030.

  • Tabony, R. C., 1985: Relations between minimum temperature and topography in Great Britain. J. Climatol.,5, 503–520.

  • Thompson, A. H., and C. R. Dickman, 1958: Ground layer temperature inversions in an interior valley and canyon. Final Rep. U.S. Army, DA 9-129-QM-399, Project No. 7–83–05–004Be.

  • Thompson, B. W., 1986: Small-scale katabatics and cold hollows. Weather,41, 146–153.

  • Toritani, H., 1990: A local climatological study on the mechanics of nocturnal cooling in plains and basins. Environmental Research Center Papers, No. 13, University of Tsukuba, 1–62.

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