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| Titel |
Evaluation of surface properties and atmospheric disturbances caused by post-dam alterations of land use/land cover |
| VerfasserIn |
A. T. Woldemichael, F. Hossain, R. Pielke Sr. |
| 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. 9 ; Nr. 18, no. 9 (2014-09-26), S.3711-3732 |
| Datensatznummer |
250120476
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| Publikation (Nr.) |
 copernicus.org/hess-18-3711-2014.pdf |
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| Zusammenfassung |
| This study adopted a differential land-use/land-cover (LULC) analysis to
evaluate dam-triggered land–atmosphere interactions for a number of LULC
scenarios. Two specific questions were addressed: (1) can
dam-triggered LULC heterogeneities modify surface and energy budget, which, in
turn, change regional convergence and precipitation patterns? (2) How extensive is the modification in surface moisture and energy
budget altered by dam-triggered LULC changes occurring in different climate
and terrain features? The Regional Atmospheric Modeling System (RAMS,
version 6.0) was set up for two climatologically and topographically
contrasting regions: the American River watershed (ARW), located in
California, and the Owyhee River watershed (ORW), located in eastern Oregon. For the
selected atmospheric river precipitation event of 29 December 1996 to 3 January 1997,
simulations of three pre-defined LULC scenarios are performed. The definition
of the scenarios are (1) the "control" scenario, representing the
contemporary land use, (2) the "pre-dam" scenario, representing the
natural landscape before the construction of the dams and (3) the
"non-irrigation" scenario, representing the condition where previously
irrigated landscape in the control is transformed to the nearby
land-use type. Results indicated that the ARW energy and moisture fluxes were
more extensively affected by dam-induced changes in LULC than the ORW. Both
regions, however, displayed commonalities in the modification of
land–atmosphere processes due to LULC changes, with the control–non-irrigation
scenario creating more change than the control–pre-dam
scenarios. These commonalities were: (1) the combination of
a decrease in temperature (up to 0.15 °C) and an increase at dew point (up
to 0.25 °C) was observed; (2) there was a larger fraction of energy
partitioned to latent heat flux (up to 10 W m−2) that increased the
amount of water vapor in the atmosphere and resulted in a larger convective
available potential energy (CAPE); (3) low-level wind-flow variation was found
to be responsible for pressure gradients that affected localized
circulations, moisture advection and convergence. At some locations, an
increase in wind speed up to 1.6 m s−1 maximum was observed; (4) there were also
areas of well-developed vertical motions responsible for moisture transport
from the surface to higher altitudes that enhanced precipitation patterns in
the study regions. |
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