Intradiurnal and seasonal variability of soil temperature, heat flux, soil moisture content, and thermal properties under forest and pasture in Rondonia.

R.C.S. Alvala, R. Gielow, H.R. Rocha, H.C. Freitas, J.M. Lopes, A.O. Manzi, C. von Rondow, M.A.F.S. Dias, O.M.R. Cabral, M.J. Waterloo

    Research output: Contribution to JournalArticleAcademicpeer-review

    255 Downloads (Pure)

    Abstract

    Soil temperatures depend on the soil heat flux, an important parameter in meteorological and plant growth-energy balance models. Thus, they were measured, together with soil moisture contents, within the LBA program at forest (Reserva Jaru) and pasture (Fazenda Nossa Senhora) sites in Rondônia, Brazilian Amazonia during wet (February) and dry (August) periods of 1999. The wet period showed maxima of the heat flux into the soil around five to six times smaller at the forest than at the pasture, except for some spikes that are related to stronger solar forcing, such as those due to sunspecks in the forest. This pattern remained during the dry period, but with doubled maximum values. Also the soil heat flux and the soil temperatures responded very significantly to the passage of cold fronts in both periods at both sites. Temperature profiles measured in the 0.10-0.40 m soil layer showed daily averages and ranges smaller at the forest than at the pasture. The daily average of the soil moisture content in the same layer, during the wet season, increased with depth at both sites, with consistently lower values at the forest. However, their ranges were smaller at the pasture, except for the 0.40 m depth. During the dry period, these ranges were much higher at the pasture, but with nearer average values. Finally, the computed daily apparent soil thermal diffusivities, volumetric heat contents, and thermal conductivities are presented, with the first ones crossed with the measured soil moisture content. Copyright 2002 by the American Geophysical Union.
    Original languageEnglish
    Pages (from-to)2001
    Number of pages1029
    JournalJournal of Geophysical Research. Atmospheres
    Volume107
    Issue numberD20
    DOIs
    Publication statusPublished - 2002

    Fingerprint

    Dive into the research topics of 'Intradiurnal and seasonal variability of soil temperature, heat flux, soil moisture content, and thermal properties under forest and pasture in Rondonia.'. Together they form a unique fingerprint.

    Cite this