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| Titel |
Evaluating Hydrological Model Outputs with Satellite derived Land Surface Temperature |
| VerfasserIn |
M. Zink, L. Samaniego, M. Cuntz, R. Kumar |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250069723
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| Zusammenfassung |
| A combined investigation of the water and energy balance in hydrologic models is needed
for a better understanding of exchange, transport, and feedback processes in the
soil-vegetation-atmosphere system. These models, however, are often only evaluated at
gauging stations. While this evaluation does not provide any information about the spatial
distribution of hydrological variables, such as evapotranspiration and soil moisture, additional
methods have to be found.
The objective of this study is to indirectly evaluate such variables using satellite derived
Land Surface Temperature (LST) fields. Therefore, we calculate the Land Surface
Temperature with the hydrological model mHM from the sensible heat formulation. The
sensible heat is determined as residual of the energy balance, assuming that the soil heat
flux and the storage term is negligible at the daily time scale. Additionally, the
evapotranspiration is determined due to solving the water balance with mHM. Furthermore,
the remaining term of the energy balance, the net radiation, is obtained by solving the
radiation budget using long and shortwave incoming radiation, albedo and emissivity
data from the Land Surface Analysis - Satellite Application Facility (LSA-SAF,
landsaf.meteo.pt). Finally, to determine the LST, the aerodynamic resistance is
parameterized to solve the sensible heat formulation. The calculated fields of land surface
temperature are evaluated against those provided by LSA-SAF for a period from
2005-2010.
The study is carried out in Germany, whereas sets of good performing global transfer
parameters are estimated in seven German river basins: Danube, Ems, Main, Mulde, Neckar,
Saale and Weser. The average Nash Sutcliffe Efficiencies exceeds 0.7 in the validation period
from 2005 to 2010.
Preliminary results indicate that the estimated mHM LST agrees quite well
with the satellite observations. This result indirectly indicates that the simulated
evapotranspiration and corresponding soil moisture fields are reasonable estimates.
This assertion will be corroborated by comparison with hourly evapotranspiration
fluxes obtained at nine eddy covariance measurement stations (www.fluxdata.org). |
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