Using long-term water balances to parameterize surface conductances and calculate evaporation at 0.05°spatial resolution

Yongqiang Zhang, Ray Leuning, Lindsay B. Hutley, Jason Beringer, Ian McHugh, Jeffrey P. Walker

    Research output: Contribution to journalArticle

    Abstract

    Evaporation from the land surface, averaged over successive 8 day intervals and at 0.05° (∼5 km) spatial resolution, was calculated using the Penman-Monteith (PM) energy balance equation, gridded meteorology, and a simple biophysical model for surface conductance. This conductance is a function of evaporation from the soil surface, leaf area index, absorbed photosynthetically active radiation, atmospheric water vapor pressure deficit, and maximum stomatal conductance (gsx). The novelty of this paper is the use of a "Budyko-curve" hydrometeorological model to estimate mean annual evaporation rates and hence a unique value of gsx for each grid cell across the Australian continent. First, the hydrometeorological model was calibrated using long-term water balances from 285 gauged catchments. Second, gridded meteorological data were used with the calibrated hydrometeorological model to estimate mean annual average evaporation (Ē) for each grid cell. Third, the value of gsx for each cell was adjusted to equate Ē calculated using the PM equation with Ē from the hydrometeorological model. This closes the annual water balance but allows the PM equation to provide a finer temporal resolution for evaporation than is possible with an annual water balance model. There was satisfactory agreement (0.49 < R 2 < 0.80) between 8 day average evaporation rates obtained using remotely sensed leaf area indices, the parameterized PM equation, and observations of actual evaporation at four Australian eddy covariance flux sites for the period 2000-2008. The evaporation product can be used for hydrological model calibration to improve runoff prediction studies in ungauged catchments. Copyright © 2010 by the American Geophysical Union.

    Original languageEnglish
    Pages (from-to)1-14
    Number of pages14
    JournalWater Resources Research
    Volume46
    Issue number5
    DOIs
    Publication statusPublished - May 2010

    Fingerprint Dive into the research topics of 'Using long-term water balances to parameterize surface conductances and calculate evaporation at 0.05°spatial resolution'. Together they form a unique fingerprint.

  • Cite this