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| Titel |
Modifying a dynamic global vegetation model for simulating large spatial scale land surface water balances |
| VerfasserIn |
G. Tang, P. J. Bartlein |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 8 ; Nr. 16, no. 8 (2012-08-07), S.2547-2565 |
| Datensatznummer |
250013412
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| Publikation (Nr.) |
 copernicus.org/hess-16-2547-2012.pdf |
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| Zusammenfassung |
| Satellite-based data, such as vegetation type and fractional vegetation
cover, are widely used in hydrologic models to prescribe the vegetation state
in a study region. Dynamic global vegetation models (DGVM) simulate land
surface hydrology. Incorporation of satellite-based data into a DGVM may
enhance a model's ability to simulate land surface hydrology by reducing the
task of model parameterization and providing distributed information on land
characteristics. The objectives of this study are to (i) modify a DGVM for
simulating land surface water balances; (ii) evaluate the modified model in
simulating actual evapotranspiration (ET), soil moisture, and surface runoff
at regional or watershed scales; and (iii) gain insight into the ability of
both the original and modified model to simulate large spatial scale land
surface hydrology. To achieve these objectives, we introduce the
"LPJ-hydrology" (LH) model which incorporates satellite-based data into the
Lund-Potsdam-Jena (LPJ) DGVM. To evaluate the model we ran LH using
historical (1981–2006) climate data and satellite-based land covers at 2.5
arc-min grid cells for the conterminous US and for the entire world using
coarser climate and land cover data. We evaluated the simulated ET, soil
moisture, and surface runoff using a set of observed or simulated data at
different spatial scales. Our results demonstrate that spatial patterns of
LH-simulated annual ET and surface runoff are in accordance with previously
published data for the US; LH-modeled monthly stream flow for 12 major
rivers in the US was consistent with observed values respectively during the
years 1981–2006 (R2 > 0.46, p < 0.01;
Nash-Sutcliffe Coefficient > 0.52). The modeled mean annual
discharges for 10 major rivers worldwide also agreed well (differences
< 15%) with observed values for these rivers. Compared to a
degree-day method for snowmelt computation, the addition of the solar
radiation effect on snowmelt enabled LH to better simulate monthly stream
flow in winter and early spring for rivers located at mid-to-high latitudes.
In addition, LH-modeled monthly soil moisture for the state of Illinois (US)
agreed well (R2 = 0.79, p < 0.01) with observed data for the
years 1984–2001. Overall, this study justifies both the feasibility of
incorporating satellite-based land covers into a DGVM and the reliability of
LH to simulate land-surface water balances. To better estimate surface/river
runoff at mid-to-high latitudes, we recommended that LPJ-DGVM considers the
effects of solar radiation on snowmelt. |
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