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| Titel |
Assimilation of GRACE and hydro-meteorological information for improving large-scale total water storage changes |
| VerfasserIn |
Christof Lorenz, Harald Kunstmann, Balaji Devaraju, Nico Sneeuw |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081322
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| Zusammenfassung |
| Due to a high noise content especially in the higher frequency part of the spherical harmonic
spectrum, filter techniques have to be applied to data from the Gravity Recovery and Climate
Experiment (GRACE) in order to reveal realistic patterns of terrestrial water storage changes
(TWSC). However, as the spatial resolution of the filtered fields is poorer than 300 km, using
GRACE data for local, regional and even basin-scale applications is still delicate, especially if
the spatial distribution or patterns of TWSC is of interest. The objective of this study is
the assimilation of GRACE-derived TWSC with other hydro-meteorological and
hydrological (independent) data sources like atmospheric reanalysis models and/or global
and regional hydrological models to improve the spatial resolution of basin-scale
TWSC fields. As there are significant differences between the models and every
model has its own advantages and disadvantages, respectively, we do not rely on a
single model but use an ensemble-based estimate to obtain reliable information on
the time-evolution and the stochastics of TWSC. These model estimates together
with observation based data are then assimilated with GRACE derived TWSC in a
Kalman-Smoother-Scheme. We assume that the advantages of GRACE is in the
large-scale information of TWSC, while models can provide reliable small scale
time-evolution estimates due to their physical origin. First investigations over the
Mississippi basin show that the assimilated fields still contain the typical GRACE patterns,
but also a significantly increased level of detail on smaller scales. An independent
evaluation with observed soil moisture further shows that the assimilation improves the
agreement with in situ observations in terms of correlation and RMSE. The resulting
product provides important information on the spatial distribution of water storage
variations on basin-scales and helps in further understanding the regional water cycle. |
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