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Titel |
A global water cycle reanalysis (2003-2012) merging satellite gravimetry and altimetry observations with a hydrological multi-model ensemble |
VerfasserIn |
A. I. J. M. Van Dijk, L. J. Renzullo, Y. Wada, P. Tregoning |
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. 8 ; Nr. 18, no. 8 (2014-08-12), S.2955-2973 |
Datensatznummer |
250120431
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Publikation (Nr.) |
copernicus.org/hess-18-2955-2014.pdf |
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Zusammenfassung |
We present a global water cycle reanalysis that merges water balance
estimates derived from the Gravity Recovery And Climate Experiment (GRACE) satellite mission, satellite water level
altimetry and off-line estimates from several hydrological models. Error
estimates for the sequential data assimilation scheme were derived from
available uncertainty information and the triple collocation technique.
Errors in four GRACE storage products were estimated to be 11–12 mm over
land areas, while errors in monthly storage changes derived from five global
hydrological models were estimated to be 17–28 mm. Prior and posterior water storage
estimates were evaluated against independent observations of river water
level and discharge, snow water storage and glacier mass loss. Data
assimilation improved or maintained agreement overall, although results
varied regionally. Uncertainties were greatest in regions where glacier mass
loss and subsurface storage decline are both plausible but poorly
constrained. We calculated a global water budget for 2003–2012. The main
changes were a net loss of polar ice caps (−342 Gt yr−1) and mountain
glaciers (−230 Gt yr−1), with an additional decrease in seasonal snowpack
(−18 Gt yr−1). Storage increased due to new impoundments (+16 Gt yr−1),
but this was compensated by decreases in other surface water
bodies (−10 Gt yr−1). If the effect of groundwater depletion (−92 Gt yr−1)
is considered separately, subsurface water storage increased by
+202 Gt yr−1 due particularly to increased wetness in northern
temperate regions and in the seasonally wet tropics of South America and
southern Africa. The reanalysis results are publicly available via www.wenfo.org/wald/. |
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