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| Titel |
Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data |
| VerfasserIn |
M. Otto, D. Scherer, J. Richters |
| 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 ; 15, no. 5 ; Nr. 15, no. 5 (2011-05-31), S.1713-1727 |
| Datensatznummer |
250012798
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| Publikation (Nr.) |
 copernicus.org/hess-15-1713-2011.pdf |
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| Zusammenfassung |
| High Altitude Wetlands of the Andes (HAWA) belong to a unique type
of wetland within the semi-arid high Andean region. Knowledge about HAWA
has been derived mainly from studies at single sites within different
parts of the Andes at only small time scales. On the one hand, HAWA
depend on water provided by glacier streams, snow melt or
precipitation. On the other hand, they are suspected to influence
hydrology through water retention and vegetation growth altering
stream flow velocity. We derived HAWA land cover from satellite data
at regional scale and analysed changes in connection with
precipitation over the last decade. Perennial and temporal HAWA
subtypes can be distinguished by seasonal changes of
photosynthetically active vegetation (PAV) indicating the perennial or
temporal availability of water during the year. HAWA have been
delineated within a region of 12 800 km2 situated in the
Northwest of Lake Titicaca. The multi-temporal classification method
used Normalized Differenced Vegetation Index (NDVI) and Normalized
Differenced Infrared Index (NDII) data derived from two Landsat ETM+
scenes at the end of austral winter (September 2000) and at the end of
austral summer (May 2001). The mapping result indicates an unexpected
high abundance of HAWA covering about 800 km2 of the study
region (6 %). Annual HAWA mapping was computed using NDVI 16-day
composites of Moderate Resolution Imaging Spectroradiometer
(MODIS). Analyses on the relation between HAWA and precipitation was
based on monthly precipitation data of the Tropical Rain Measurement
Mission (TRMM 3B43) and MODIS Eight Day Maximum Snow Extent data
(MOD10A2) from 2000 to 2010. We found HAWA subtype specific
dependencies on precipitation conditions. A strong relation exists
between perennial HAWA and snow fall (r2: 0.82) in dry austral
winter months (June to August) and between temporal HAWA and
precipitation (r2: 0.75) during austral summer (March to
May). Annual changes in spatial extend of perennial HAWA indicate
alterations in annual water supply generated from snow melt. |
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