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| Titel |
Simulation of semi-arid biomass plantations and irrigation using the WRF-NOAH model – a comparison with observations from Israel |
| VerfasserIn |
O. Branch, K. Warrach-Sagi, V. Wulfmeyer, S. Cohen |
| 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 ; 18, no. 5 ; Nr. 18, no. 5 (2014-05-15), S.1761-1783 |
| Datensatznummer |
250120356
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| Publikation (Nr.) |
 copernicus.org/hess-18-1761-2014.pdf |
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| Zusammenfassung |
A 10 × 10 km irrigated biomass plantation was simulated in an arid
region of Israel to simulate diurnal energy balances during the summer of
2012 (JJA). The goal is to examine daytime horizontal flux gradients between
plantation and desert. Simulations were carried out within the coupled
WRF-NOAH atmosphere/land surface model. MODIS land surface data was adjusted
by prescribing tailored land surface and soil/plant parameters, and by
adding a controllable sub-surface irrigation scheme to NOAH. Two model cases
studies were compared – Impact and Control. Impact simulates the irrigated plantation.
Control simulates the existing land surface, where the predominant land surface is
bare desert soil. Central to the study is parameter validation against land
surface observations from a desert site and from a 400 ha Simmondsia chinensis (jojoba)
plantation. Control was validated with desert observations, and Impact with Jojoba
observations. Model evapotranspiration was validated with two
Penman–Monteith estimates based on the observations.
Control simulates daytime desert conditions with a maximum deviation for surface 2 m air temperatures (T2)
of 0.2 °C, vapour pressure deficit (VPD) of 0.25 hPa, wind
speed (U) of 0.5 m s−1, surface radiation (Rn) of 25 W m−2,
soil heat flux (G) of 30 W m−2 and 5 cm soil temperatures (ST5) of
1.5 °C. Impact simulates irrigated vegetation conditions with a maximum deviation for T2 of 1–1.5 °C,
VPD of 0.5 hPa, U of 0.5 m s−1, Rn of 50 W m−5,
G of 40 W m−2 and ST5 of 2 °C.
Latent heat curves in Impact correspond closely with Penman–Monteith estimates,
and magnitudes of 160 W m−2 over the plantation are usual. Sensible heat
fluxes, are around 450 W m−2 and are at least 100–110 W m−2
higher than the surrounding desert. This surplus is driven by reduced albedo
and high surface resistance, and demonstrates that high evaporation rates
may not occur over Jojoba if irrigation is optimized. Furthermore, increased
daytime T2 over plantations highlight the need for hourly as well as daily
mean statistics. Daily mean statistics alone may imply an overall cooling
effect due to surplus nocturnal cooling, when in fact a daytime warming
effect is observed. |
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