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| Titel |
Hydrometeorological effects of historical land-conversion in an ecosystem-atmosphere model of Northern South America |
| VerfasserIn |
R. G. Knox, M. Longo, A. L. S. Swann, K. Zhang, N. M. Levine, P. R. Moorcroft, R. L. Bras |
| 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 ; 19, no. 1 ; Nr. 19, no. 1 (2015-01-15), S.241-273 |
| Datensatznummer |
250120591
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| Publikation (Nr.) |
 copernicus.org/hess-19-241-2015.pdf |
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| Zusammenfassung |
This work investigates how the integrated land use of northern South America
has affected the present day regional patterns of hydrology. A model of the
terrestrial ecosystems (ecosystem demography model 2: ED2) is combined with
an atmospheric model (Brazilian Regional Atmospheric Modeling System:
BRAMS). Two realizations of the structure and composition of terrestrial
vegetation are used as the sole differences in boundary conditions that drive
two simulations. One realization captures the present day vegetation
condition that includes deforestation and land conversion, the other is an
estimate of the potential structure and composition of the region's
vegetation without human influence. Model output is assessed for differences
in resulting hydrometeorology.
The simulations suggest that the history of land conversion in northern South
America is not associated with a significant precipitation bias in the
northern part of the continent, but has shown evidence of a negative bias in
mean regional evapotranspiration and a positive bias in mean regional runoff.
Also, negative anomalies in evaporation rates showed pattern similarity
with areas where deforestation has occurred. In the central eastern Amazon
there was an area where deforestation and abandonment had lead to an overall
reduction of above-ground biomass, but this was accompanied by a shift in
forest composition towards early successional functional types and
grid-average-patterned increases in annual transpiration.
Anomalies in annual precipitation showed mixed evidence of consistent
patterning. Two focus areas were identified where more consistent
precipitation anomalies formed, one in the Brazilian state of Pará where
a dipole pattern formed, and one in the Bolivian Gran Chaco, where a negative
anomaly was identified. These locations were scrutinized to understand the
basis of their anomalous hydrometeorologic response. In both cases,
deforestation led to increased total surface albedo, driving decreases in
net radiation, boundary layer moist static energy and ultimately decreased
convective precipitation. In the case of the Gran Chaco, decreased
precipitation was also a result of decreased advective moisture transport,
indicating that differences in local hydrometeorology may manifest via
teleconnections with the greater region. |
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