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| Titel |
Large Trajectory Ensembles for understanding Snow Accumulation over the Ross Ice Shelf |
| VerfasserIn |
Ethan Dale, Adrian McDonald, Wolfgang Rack |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250147203
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| Publikation (Nr.) |
 EGU/EGU2017-11327.pdf |
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| Zusammenfassung |
| We investigate how differing synoptic weather patterns over Antarctica affect the rate of
precipitation. During the 2015/16 field season a 16m firn core was drilled on the Ross Ice
Shelf (80.7o S 174.5o E). Oxygen (δ18O) and Deuterium (δ2H) isotope analysis of this core
allow a 40 year record of snow accumulation and therefore precipitation over the Ross
Ice Shelf to be produced. The resulting precipitation record differs significantly in
magnitude and trend from climate model precipitation over a similar period of
time.
In an effort to interpret this core we have attempted to identify distinctive weather patterns
impacting snow accumulation. Lagrangian back trajectories are calculated from reanalysis
wind fields to examine the origin of the air. The spatial distribution of trajectories as a
function of time over the period of the ice core record are examined in an attempt to relate
specific periods of large and small snow accumulation to particular pathways. We also
examine how large scale modes of variability (Southern Annular Mode, El Nino Southern
Oscillation and the Amundsen Sea Low) impact the spatial distribution of trajectories.
Re-analysis humidity data along each trajectory is also considered allowing a more
comprehensive identification of the origin of moist air, also helping to identify a
representative ‘residence time’ of moisture for which our trajectory analysis is completed.
Similar to previous studies we find that during periods of precipitation, air over
the Ross Ice Shelf more frequently originates in the Ross and Amundsen Seas.
While during dry periods over the Ross Ice Shelf we find the air originates more
frequently from the Bellingshausen and Weddell seas, as well as continental Antarctica. |
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