The influence of the North Atlantic Oscillation on ice conditions in coastal lakes of the Southern Baltic Sea

Abstract

This paper focuses on relationships between the North Atlantic Oscillation Index (NAO) and the ice conditions in coastal lakes (Jamno, Bukowo, Gardno and ebsko) of the southern Baltic Sea. The data on ice conditions included : date of first ice appearance (F), date of last ice disappearance (D), number of days with ice (N), length of the ice season (in days ; S) and maximum ice thickness (H) during the given winter. The period examined covers the winters from 1960/61 to 1999/2000. The monthly values of the NAO index for the same period were applied in accordance with Jones et al. (1997). Correlation and regression analysis methods were applied to determine and study the relationships between NAO (independent variable) and the parameters of ice conditions (dependent variables). The strongest relationships, with a linear correlation coefficient exceeding -0.80, were obtained for the date of the last ice disappearance (D) in ebsko Lake (-0.853) and Gardno Lake (-0.828) for the JanuaryMarch period. In contrast, the relationships between the NAO index and the date of first ice appearance (F) are much weaker. They are statistically significant only in November and early winter (Nov.-Dec., Nov.-Jan.). The correlation coefficients in the coastal lakes of the Southern Baltic Sea coasts generally increase eastwards, a phenomenon related to the severity of winters and to the increasing continuity of ice phenomena during a given winter in this direction.

Variability and course of occurrence of ice cover on selected lakes of the Gnieźnieńskie Lakeland (Central Poland) in the period 1976–2015

“…In research on 75 lakes on the Northern Hemisphere, Benson et al [14] determined later freezing of lakes (0.3-1.6 day·dec -1 ), earlier disappearance of ice (0.5-1.9 day·dec -1 ), and its shorter duration (0.7-4.3 day·dec -1 ). In the case of lakes in Poland, the issue concerning ice conditions on lakes is popular among researchers [15][16][17][18], and the results obtained in the paper correspond with earlier publications referring to long-term changes [19,20]. Marszelewski and Skowron [21] treat changes in the course of ice phenomena on lakes in Poland as an indicator of climate warming.…”

Effect of the North Atlantic Oscillation on Ice Phenomena on Selected Lakes in Poland Over the Years 1961–2010

“…Tendencies of change in the duration of ice cover Focusing on lakes located in Poland, Marszelewski and Skowron (2005) analysed the pattern of ice phenomena for six of them in the years 1961-2000. Among their findings was that the Girjatowicz (2003) for the coastal lakes on the southern shore of the Baltic. When examining four of them on the basis of the 1960-2000 data, he found that the relations between the NAO index and the start of ice phenomena were weaker than between the index and their end.…”

“…There have been many studies documenting the effect of the North Atlantic Oscillation on the ice regimes of rivers and lakes. In the years with a positive NAO DJFM index, ice cover disappears from rivers and lakes markedly earlier in northern Europe (yoo, D'Odorico 2002), in the Alpine region (livingstone 1997(livingstone , livingstone, Dokulil 2001, and in Poland (Girjatowicz 2003, Marszelewski, Skowron 2006, Choiński et al 2009). …”

Ice conditions in coastal lakes of the southern Baltic Sea

“…Bluthgen 1953, «Eishandbuch»... 1972, Girjatowicz 1990. In coastal lakes and lagoons, ice conditions grow in intensity and their frequency increases eastwards; ice parameter coefficients of variation decrease, and correlations between thermal and circulation conditions and ice parameters assume higher coefficients (Girjatowicz 2001b(Girjatowicz , 2003.…”