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| Titel |
Evaluation of the representation of the hydrological cycle in Western Siberia in the LMDZ general circulation model using ground-based and satellite measurements of water vapor and precipitation isotopic composition |
| VerfasserIn |
Victor Gryazin, Camille Risi, Jean Jouzel, Vyacheslav Zakharov, Konstantin Gribanov, Nikita Rokotyan, Vladislav Bastrikov, John Worden, Christian Frankenberg, Naoyuki Kurita |
| 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 |
250082941
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| Zusammenfassung |
| The hydrological and biochemical cycles in regions of peatlands and permafrost are
particularly sensitive to climate perturbations. Credible climate change projections in
these regions require a realistic representation by climate models of atmospheric
and hydrological processes specific to those regions. In this context, observations
of the water vapor and precipitation composition are emerging as an additional
constrain to better evaluate the realism of the representation of the hydrological
cycle by models. In high latitude regions, the water isotopic composition keeps an
imprint of various processes such as distillation of air masses, evaporation and
transpiration recycling air masses along trajectories, cloud processes and vertical
mixing.
In this study we evaluate the isotopic composition simulated by LMDZ general
circulation model in Western Siberia against a combination of isotopic measurements
in precipitation and in water vapor. First, the GNIP and SNIP networks provide
information on the geographical and seasonal variations of H218O and HDO composition
(yielding δD and d-excess) in precipitation. Second, in-situ measurements by a Picarro
analyzer and ground-based FTIR retrievals document hourly to seasonal variability in
δD and d-excess in low-level water vapor at the site of Ekaterinburg in Western
Siberia. Third, satellite measurements using the GOSAT and TES satellite instruments
document the geographical and temporal (intra-seasonal to seasonal) variations
of water vapor δD in the total column and at different levels of the troposphere
respectively.
To first order, observed geographical and temporal variations at different time scales are
well captured by LMDZ, though the latitudinal gradient and the daily variability in
water vapor δD are underestimated. Simulations are investigated to interpret these
model-data differences in terms of physical processes. In particular, sensitivity tests
to the representation of transport, cloud processes and continental recycling are
analyzed. Precipitation and water vapor δD and d-excess data are combined in an
attempt to better evaluate continental recycling and its pathways (evaporation vs
transpiration).
This research is conducted in the context of the WSibIso project and is supported by the
grant of Ministry of Education and Science of Russian Federation under the contract No.
11.G34.31.0064. |
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