 |
| Titel |
Trends in ice formation at Lake Neusiedl since 1931 and large-scale oscillation patterns |
| VerfasserIn |
Anna-Maria Soja, Karl Maracek, Gerhard Soja |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250077229
|
|
|
|
|
|
| Zusammenfassung |
| Ice formation at Lake Neusiedl (Neusiedler See, FertÅ tó), a shallow steppe lake (area 320
km2, mean depth 1.2 m) at the border of Austria/Hungary, is of ecological and economic
importance. Ice sailing and skating help to keep a touristic off-season alive. Reed harvest to
maintain the ecological function of the reed belt (178 km2) is facilitated when lake surface is
frozen.
Changes in ice formation were analysed in the frame of the EULAKES-project (European
Lakes under Environmental Stressors, www.eulakes.eu), financed by the Central Europe
Programme of the EU. Data records of ice-on, ice duration and ice-off at Lake
Neusiedl starting with the year 1931, and air temperature (nearby monitoring station
Eisenstadt - Sopron (HISTALP database and ZAMG)) were used to investigate
nearly 80 winters. Additionally, influences of 8 teleconnection patterns, i.e. the
Atlantic Multidecadal Oscillation (AMO), the East Atlantic pattern (EAP), the East
Atlantic/West Russia pattern (EA/WR), the Eastern Mediterranean Pattern (EMP), the
Mediterranean Oscillation (MO) for Algiers and Cairo, and for Israel and Gibraltar,
resp., the North Atlantic Oscillation (NAO) and the Scandinavia pattern (SCA) were
assessed.
Ice cover of Lake Neusiedl showed a high variability between the years (mean duration
71±27 days). Significant trends for later ice-on (p=0.02), shorter ice duration (p=0.07) and
earlier ice-off (p=0.02) for the period 1931-2011 were found by regression analysis and trend
analysis tests. On an average, freezing of Lake Neusiedl started 2 days later per decade and
ice melting began 2 days earlier per decade.
Close relationships between mean air temperature and ice formation could be found: ice-on
showed a dependency on summer (R=+0.28) and autumn air temperatures (R=+0.51), ice
duration and ice off was related to autumn (R=-0.36 and -0.24), winter (R=-0.73 and -0.61)
and concurrent spring air temperatures (R=-0.44).
Increases of air temperature by 1Ë C caused an 8.4 days later timing of ice-on, a decrease of
ice duration by 11.0 days and a 5.8 days earlier ice-off. The sensitivity of ice duration and
ice-off to rising air temperatures was increasing at Lake Neusiedl. This effect of warming
could not be verified for the timing of ice-on.
Ice-on at Lake Neusiedl showed a significant relation to EAP (yearly index; R=0.33). Ice
duration and ice-off were influenced significantly by the winter indices of MO for Algiers and
Cairo (R=-0.48 and -0.45), NAO (R=-0.42 and -0.37), and EAP (R=-0.31 and -0.48). |
|
|
|
|
|
|