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Relationships between the Baltic Sea ice extent and ice parameters in the sheltered basins of the southern Baltic coast

Girjatowicz Józef P., Świątek Małgorzata

Oceanological and Hydrobiological Studies

2020

Vol. 49, No. 3

291--303

In the study, archive data on the maximum annual ice extent in the Baltic Sea (MIB) for the period 1961–2018 were used. They were obtained from the FIMR database. Data on ice parameters for the four largest southern Baltic coastal lakes: Jamno, Bukowo, Gardno and Łebsko, and for Szczecin, Puck, and Vistula Lagoons, come from the Maritime Branch of Institute of Meteorology and Water Management – National Research Institute (in Polish: Instytut Meteorologii i Gospodarki Wodnej – Panstwowy Instytut Badawczy, IMGW-PIB) in Gdynia. The time series for the lakes cover the years from 1960 to 2018, and for the lagoons – from 1946 to 2018. Three ice parameters were selected for this study: the number of days with ice, the duration of the ice season and the maximum ice thickness for a given winter. Relationships between the selected ice parameters for the studied basins and the MIB were examined using correlation and regression methods. Correlations between the MIB and values of the ice parameters for the lakes and the southern Baltic coastal lagoons do not differ significantly. Considerable differences are observed amongst the correlation coefficients for individual ice parameters and the MIB. Larger differences are found in relationships between the values of individual ice parameters in the sheltered basins and the MIB. The strongest correlation with the MIB is observed for the maximum ice thickness and the number of days with ice.

Korelacja parametrów lodowych z parametrami termicznymi zimy i jej przestrzenne zróżnicowanie w rejonie ujścia Odry

Girjatowicz J.P., Olechwir T.

Zeszyty Naukowe. Marine Sciences / Uniwersytet Szczeciński

1998

Nr 4

37-52

The aim of the study is the examination of relations between ice and winter thermal parameters and the division of waters of the mouth of the Odra river into regions basing on differential values of computed correlation coefficients. Relations between ice (S, L, H) and thermal (T, Z) parameters were examinated with the correlation and regression analysis. There were examinated many regression functions as linear, logarythmic, polynomial, exponential and multiplicative. There were computed correlation coefficients (r). There was also performed the estimation od statistical significance of these relations using Fisher-Snedecor's significance test (F). Statistical significance of ice relations with winter thermal conditions is depended not only on the kind of chose ice thermal parameters but also on the kind of function and differential physiographical conditions of the water area. It was proved that amond different examined functions the function of polynomial of order 2 (W) approximates in the best way the empirical points in the system of rectangular coordinates. In some cases natural logarithm (Ln) and linear (P) functions approximate them well enough as well. All these relations (204) are high statistical significant ones, even on significance level a = 0,01. The ice parameter which correlates with thermal parameter the best is maximum ice thickness (H). The lenght of season (S) correlates the worst. The influence of thermal parameters on significance of ice relations is sufficiently differential and is depended on the kind of chosen function, ice parameters and of the water area. In the water area in the mouth of the Odra the higest correlation coefficients are calculated for Szczecin Bay. It is shallow sheltered water area, which is characterized by the weakest water motion. For deeper areas with stronger water motion (sea, straits, rivers, fairway, canal) the coefficients are lower, that indirectly show the marked influence of not thermal factors (water motion, wind, anthropogenic activity). There were divided three types of regions which are characterized by distinct differentiation of correlation coefficients: 1) rivers and straits which are characterized by the lowest values of correlation coefficients; 2) the Pomeranian Gulf , characterized by the higher than for rivers and straits values of correlation coefficients; 3) the Szczecin Bay and adjacent lakes which are characterized by the highest values of correlation coefficients. The distinct differentiation of correlation coefficients of ice relations indirectly tells about the differential hydrological regime, with ice system included, of those regions.