The surface temperature of water in Polish and Belarusian lakes during the period of climate change

Abstract

The paper presents the results of surface water temperature measurements from 17 lakes located in northern Poland and Belarus over the period of 50 years (1971-2020). Using the Excel computer program, Corel Quattro Pro 8 and the graphic Draw 9, annual and monthly averages, extreme values, annual and monthly trends were calculated and presented. It is supplemented by the monthly average air temperatures for 13 weather stations. The research showed that the temperature in all lakes is characterized by a positive trend at the level of 0.044°C year–1. The largest lake is characteristic for Chervonoe Lake – 0.066°C year–1, and the smallest 0.029°C year–1 for the deep Lake Hańcza. In the course of the average monthly surface water temperatures, a positive trend is also observed, ranging from 0.015°C year–1 in January to 0.069°C year–1 in May. These values correlate with the average air temperatures in the winter months (December-March) and with the winter NAO index (DJFM).