### 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 (g_{sx}). 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 g_{sx} 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 g_{sx} 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 language | English |
---|---|

Pages (from-to) | 1-14 |

Number of pages | 14 |

Journal | Water Resources Research |

Volume | 46 |

Issue number | 5 |

DOIs | |

Publication status | Published - May 2010 |

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*Water Resources Research*,

*46*(5), 1-14. https://doi.org/10.1029/2009WR008716

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*Water Resources Research*, vol. 46, no. 5, pp. 1-14. https://doi.org/10.1029/2009WR008716

**Using long-term water balances to parameterize surface conductances and calculate evaporation at 0.05°spatial resolution.** / Zhang, Yongqiang; Leuning, Ray; Hutley, Lindsay B.; Beringer, Jason; McHugh, Ian; Walker, Jeffrey P.

Research output: Contribution to journal › Article › Research › peer-review

TY - JOUR

T1 - Using long-term water balances to parameterize surface conductances and calculate evaporation at 0.05°spatial resolution

AU - Zhang, Yongqiang

AU - Leuning, Ray

AU - Hutley, Lindsay B.

AU - Beringer, Jason

AU - McHugh, Ian

AU - Walker, Jeffrey P.

PY - 2010/5

Y1 - 2010/5

N2 - 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.

AB - 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.

KW - Annual average

KW - Annual water balance

KW - Atmospheric water vapor

KW - Biophysical model

KW - Eddy covariance

KW - Energy balance equations

KW - Evaporation products

KW - Evaporation rate

KW - Grid cells

KW - Hydrological models

KW - Land surface

KW - Leaf Area Index

KW - Meteorological data

KW - Parameterized

KW - Penman-Monteith

KW - Photosynthetically active radiation

KW - Runoff prediction

KW - Soil surfaces

KW - Spatial resolution

KW - Stomatal conductance

KW - Surface conductance

KW - Temporal resolution

KW - Ungauged catchment

KW - Water balance

KW - Catchments

KW - Climate models

KW - Evaporation

KW - Forestry

KW - Image resolution

KW - Plants (botany)

KW - Remote sensing

KW - Runoff

KW - Water vapor

KW - Climatology

KW - biophysics

KW - calibration

KW - catchment

KW - eddy covariance

KW - energy balance

KW - evaporation

KW - hydraulic conductivity

KW - hydrological modeling

KW - hydrometeorology

KW - leaf area index

KW - numerical model

KW - parameterization

KW - Penman-Monteith equation

KW - photosynthetically active radiation

KW - remote sensing

KW - runoff

KW - soil surface

KW - spatial resolution

KW - stomatal conductance

KW - water budget

KW - water vapor

KW - Australia

UR - http://www.scopus.com/inward/record.url?scp=77952271240&partnerID=8YFLogxK

U2 - 10.1029/2009WR008716

DO - 10.1029/2009WR008716

M3 - Article

VL - 46

SP - 1

EP - 14

JO - Water Resources Research

JF - Water Resources Research

SN - 0043-1397

IS - 5

ER -