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| Titel |
Attribution of satellite-observed vegetation trends in a hyper-arid region of the Heihe River basin, Western China |
| VerfasserIn |
Y. Wang, M. L. Roderick, Y. Shen, F. Sun |
| 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 (2014-09-09), S.3499-3509 |
| Datensatznummer |
250120463
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| Publikation (Nr.) |
 copernicus.org/hess-18-3499-2014.pdf |
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| Zusammenfassung |
| Terrestrial vegetation dynamics are closely influenced by both climate and
by both climate and by land use and/or land cover change (LULCC) caused by human activities.
Both can change over time in a monotonic way and it can be difficult to
separate the effects of climate change from LULCC on vegetation. Here we
attempt to attribute trends in the fractional green vegetation cover to
climate variability and to human activity in Ejina Region, a hyper-arid
landlocked region in northwest China. This region is dominated by extensive
deserts with relatively small areas of irrigation located along the major
water courses as is typical throughout much of Central Asia. Variations of
fractional vegetation cover from 2000 to 2012 were determined using Moderate
Resolution Imaging Spectroradiometer (MODIS) vegetation index data with 250 m
spatial resolution over 16-day intervals. We found that the fractional
vegetation cover in this hyper-arid region is very low but that the mean
growing season vegetation cover has increased from 3.4% in 2000 to
4.5% in 2012. The largest contribution to the overall greening was due to
changes in green vegetation cover of the extensive desert areas with a
smaller contribution due to changes in the area of irrigated land.
Comprehensive analysis with different precipitation data sources found that
the greening of the desert was associated with increases in regional
precipitation. We further report that the area of land irrigated each year
can be predicted using the runoff gauged 1 year earlier. Taken together,
water availability both from precipitation in the desert and runoff inflow
for the irrigation agricultural lands can explain at least 52% of the
total variance in regional vegetation cover from 2000 to 2010. The results
demonstrate that it is possible to separate the satellite-observed changes
in green vegetation cover into components due to climate and human
modifications. Such results inform management on the implications for water
allocation between oases in the middle and lower reaches and for water
management in the Ejina oasis. |
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