Article Type:
Research Article

Effect of Dewfall and Frostfall on Nighttime Cooling in a Small, Closed Basin

C. David Whiteman Meteorology Department, University of Utah, Salt Lake City, Utah

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Stephan F. J. De Wekker National Center for Atmospheric Research, Boulder, Colorado

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Thomas Haiden Central Institute for Meteorology and Geodynamics, Vienna, Austria

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Print Publication:
01 Jan 2007
DOI:
https://doi.org/10.1175/JAM2453.1
Page(s):
3–13
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Abstract

Series of tethered balloon soundings of temperature and humidity in Austria’s Gruenloch basin (floor elevation 1270 m MSL) on two June days showed that the water vapor mixing ratio fell by 2–3 g kg−1 overnight as dew or frost formed in the basin. After sunrise, the basin atmosphere remoistened as higher humidity was brought down into the basin from above and as evapotranspiration occurred from the basin floor and sidewalls. The latent heat released at night by the dewfall/frostfall was 33%–53% of the overall observed basin sensible heat loss, illustrating the important role of dew and frost formation on the nighttime heat budget of the basin atmosphere. An energy budget equation illustrates the decreasing importance of the latent heat release on the overall basin heat budget as ambient temperatures fall from summer to winter. Because the diurnal temperature range is frequently larger than the late-afternoon dewpoint depression, fog and clouds often form in this basin. The extreme temperature minima that have been previously observed in this basin are expected to be attained only if such cloud moisture is removed. Calculations show that several cloud moisture removal processes may be effective in removing this moisture.

* Current affiliation: Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia

+ The National Center for Atmospheric Research is sponsored by the National Science Foundation

Corresponding author address: Dr. C. David Whiteman, Meteorology Department, University of Utah, 135 S 1460E, Rm. 819, Salt Lake City, UT 84112-0110. Email: whiteman@met.utah.edu

Abstract

Series of tethered balloon soundings of temperature and humidity in Austria’s Gruenloch basin (floor elevation 1270 m MSL) on two June days showed that the water vapor mixing ratio fell by 2–3 g kg−1 overnight as dew or frost formed in the basin. After sunrise, the basin atmosphere remoistened as higher humidity was brought down into the basin from above and as evapotranspiration occurred from the basin floor and sidewalls. The latent heat released at night by the dewfall/frostfall was 33%–53% of the overall observed basin sensible heat loss, illustrating the important role of dew and frost formation on the nighttime heat budget of the basin atmosphere. An energy budget equation illustrates the decreasing importance of the latent heat release on the overall basin heat budget as ambient temperatures fall from summer to winter. Because the diurnal temperature range is frequently larger than the late-afternoon dewpoint depression, fog and clouds often form in this basin. The extreme temperature minima that have been previously observed in this basin are expected to be attained only if such cloud moisture is removed. Calculations show that several cloud moisture removal processes may be effective in removing this moisture.

* Current affiliation: Department of Environmental Sciences, University of Virginia, Charlottesville, Virginia

+ The National Center for Atmospheric Research is sponsored by the National Science Foundation

Corresponding author address: Dr. C. David Whiteman, Meteorology Department, University of Utah, 135 S 1460E, Rm. 819, Salt Lake City, UT 84112-0110. Email: whiteman@met.utah.edu

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Cover Journal of Applied Meteorology and Climatology
Journal of Applied Meteorology and Climatology

  • Clements, C. B., C. D. Whiteman, and J. D. Horel, 2003: Cold-air-pool structure and evolution in a mountain basin: Peter Sinks, Utah. J. Appl. Meteor., 42 , 752–768.

    • Search Google Scholar
    • Export Citation

  • Cotton, W. R., and R. A. Anthes, 1989: Storm and Cloud Dynamics. Academic Press, 880 pp.

  • Fletcher, N. H., 1966: The Physics of Rainclouds. Cambridge University Press, 390 pp.

  • Freytag, C., 1985: Atmosphärische Grenzschicht in Alpentälern während der Experimente HAWEI, DISKUS und MERKUR (Atmospheric boundary layer in mountain valleys during the experiments HAWEI, DISKUS and MERKUR). Meteorologisches Institut, Universität München, Wissenschaftliche Mitteilung 52, 131 pp.

  • Freytag, C., and B. Hennemuth, Eds. 1979: Hangwind-experiment Innsbruck Oktober 1978—Datensammlung (Innsbruck slope wind experiment, October 1978—Data volume). Meteorologisches Institut, Universität München, Wissenschaftliche Mitteilung 36, 261 pp.

  • Freytag, C., and B. Hennemuth, Eds. 1981: DISKUS, Gebirgswind-experiment im Dischmatal—Datensammlung Teil 1: Sondierungen (DISKUS, Mountain wind experiment in the Dischma Valley—Data volume Part 1: Soundings). Meteorologisches Institut, Universität München, Wissenschaftliche Mitteilung 43, 250 pp.

  • Freytag, C., and B. Hennemuth, Eds. 1982: DISKUS, Gebirgswind-experiment im Dischmatal—Datensammlung Teil 2: Bodennahe Messungen und Flugzeugmessungen (DISKUS, Mountain wind experiment in the Dischma Valley—Data volume Part 2: Near-ground and airplane measurements). Meteorologisches Institut, Universität München, Wissenschaftliche Mitteilung 46, 192 pp.

  • Freytag, C., and B. Hennemuth, Eds. 1983: MERKUR: Mesoskaliges Experiment in Raum Kufstein-Rosenheim (MERKUR: Mesoscale experiment in the area between Kufstein and Rosenheim). Meteorologisches Institut, Universität München, Wissenschaftliche Mitteilung 48, 132 pp.

  • Garratt, J. R., and M. Segal, 1988: On the contribution of atmospheric moisture to dew formation. Bound.-Layer Meteor., 45 , 209–236.

  • Geiger, R., 1965: The Climate near the Ground. Harvard University Press, 611 pp. (Translated by Scripta Technica, Inc., from the German 4th edition, 1961.).

    • Search Google Scholar
    • Export Citation

  • Halbsguth, G., M. J. Kerschgens, H. Kraus, G. Meindl, and E. Schaller, 1984: Energy fluxes in an Alpine valley. Arch. Meteor. Geophys. Bioclimatol., 33A , 11–20.

    • Search Google Scholar
    • Export Citation

  • Hennemuth, B., and U. Köhler, 1984: Estimation of the energy balance of the Dischma Valley. Arch. Meteor. Geophys. Bioclimatol., 34B , 97–119.

    • Search Google Scholar
    • Export Citation

  • Hennemuth, B., and I. Neureither, 1986: Das Feuchtefeld in einem alpinen Endtal (The humidity field in an Alpine end valley). Meteor. Rundsch., 39 , 233–239.

    • Search Google Scholar
    • Export Citation

  • Mahrt, L., 1986: Nocturnal topoclimatology. World Meteorological Organization Tech. Doc. WCP-117, WMO/TD-No. 132, 76 pp.

  • Mahrt, L., D. Vickers, R. Nakamura, M. R. Soler, J. Sun, S. Burns, and D. H. Lenschow, 2001: Shallow drainage flows. Bound.-Layer Meteor., 101 , 243–260.

    • Search Google Scholar
    • Export Citation

  • Monteith, J. L., 1957: Dew. Quart. J. Roy. Meteor. Soc., 83 , 322–341.

  • Oke, T. R., 1987: Boundary Layer Climates. 2d ed. Routledge, 435 pp.

  • Reiter, R., H. Müller, R. Sladkovic, and K. Munzert, 1984: Aerologische Untersuchungen des tagesperiodischen Windsystems im Inntal während MERKUR (Aerological investigations of diurnal wind systems in the Inn Valley during MERKUR). Meteor. Rundsch., 37 , 176–190.

    • Search Google Scholar
    • Export Citation

  • Steinacker, R., M. Dorninger, S. Eisenbach, A. M. Holzer, B. Pospichal, C. D. Whiteman, and E. Mursch-Radlgruber, 2002: A sinkhole field experiment in the Eastern Alps. Preprints, 10th Conf. on Mountain Meteorology, Park City, UT, Amer. Meteor. Soc., 91–92.

  • Stull, R. B., 2000: Meteorology for Scientists and Engineers. 2d ed. Brooks/Cole, 502 pp.

  • Whiteman, C. D., 2000: Mountain Meteorology: Fundamentals and Applications. Oxford University Press, 355 pp.

  • Whiteman, C. D., K. J. Allwine, L. J. Fritschen, M. M. Orgill, and J. R. Simpson, 1989: Deep valley radiation and surface energy budget microclimates. Part II: Energy budget. J. Appl. Meteor., 28 , 427–437.

    • Search Google Scholar
    • Export Citation

  • Whiteman, C. D., T. B. McKee, and J. C. Doran, 1996: Boundary layer evolution within a canyonland basin. Part I: Mass, heat, and moisture budgets from observations. J. Appl. Meteor., 35 , 2145–2161.

    • Search Google Scholar
    • Export Citation

  • Whiteman, C. D., T. Haiden, B. Pospichal, S. Eisenbach, and R. Steinacker, 2004: Minimum temperatures, diurnal temperature ranges, and temperature inversions in limestone sinkholes of different size and shape. J. Appl. Meteor., 43 , 1224–1236.

    • Search Google Scholar
    • Export Citation

  • Zängl, G., 2005: Formation of extreme cold-air pools in elevated sinkholes: An idealized numerical process study. Mon. Wea. Rev., 133 , 925–941.

    • Search Google Scholar
    • Export Citation
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