Relationships between air temperature and ice conditions on the southern Baltic coastal lakes in the context of climate change

• Published in: Journal of Limnology
• Main Authors: Józef Piotr Girjatowicz, Małgorzata Świątek, Halina Kowalewska-Kalkowska
• Format: Article in Journal/Newspaper
• Language: English
• Published: PAGEPress Publications 2022
• Subjects: coastal lakes; southern Baltic Sea; ice conditions; air temperature; statistical relationships; trends; Geography. Anthropology. Recreation; G; Physical geography; GB3-5030; Environmental sciences; GE1-350; Sea ice
• Online Access: https://doi.org/10.4081/jlimnol.2022.2060; https://doaj.org/article/6cff700650824bcaa430da6edc0c56df

Shallow, lagoonal coastal lakes of the Southern Baltic are exceptionally susceptible to atmospheric factors. This work examines the influence of winter air temperatures in Ustka on ice parameters (dates of first ice occurrence and last ice disappearance, ice season duration, number of days with ice, and maximum ice thickness) on Southern Baltic coastal lakes (Jamno, Bukowo, Gardno, Łebsko), and trends displayed by changes in these parameters over the period spanning 1960/61-2019/20. The research data was retrieved from the archives of Institute of Meteorology and Water Management – National Research Institute. As a first step of the analysis, we investigated the statistical relationships in spatial and temporal variations in winter air temperature and coastal lake ice parameters. Correlation and regression method was employed to determine the influence of air temperature on coastal lake ice conditions. Correlation and determination coefficients were calculated, and linear regression equations were determined. The statistical significance of the observed relationships was assessed using Fisher-Snedecor test. Additionally, linear trend models were constructed. Our analysis indicates that from 1960/61 to 2019/20, the average rate of increase in winter temperature (December-March) in Ustka equalled 0.04°C ⋅year-1. The correlation coefficients for air temperature versus ice parameters were highly statistically significant (p<0.001). The strongest relationships (with correlation coefficients below -0.90) occurred between air temperature and number of days with ice. Ice season duration and number of days with ice are both closely linked with last ice disappearance date and ice thickness. Our analysis shows that a 1°C increase in average seasonal air temperature will result in the number of days with ice on the studied coastal lakes becoming reduced by 16-17 days. All trends in ice parameters indicate a mildening of ice conditions. Most of the assessed trends are statistically significant. The strongest trends were ...