Intensywność cyrkulacji termohalinowej na Atlantyku Północnym a susze w Polsce
Intensity of Thermohaline Circulation in the North Atlantic and Droughts in Poland

Summary/Abstract: The work considers the cause of the frequency of droughts occurrence variability in Poland. It was proven, that the frequency of droughts shows statistically significant relationship with intensity of thermohaline circulation (THC) in the North Atlantic. In periods of occurrence of positive phase the THC frequency of droughts’ occurrence in Poland grows up and it is about 3.6 times greater, than in periods of occurrence of negative phase the THC. The sign and the value of coefficient characterizing the THC determines the drought occurrence and its duration time. Changeability of the THC is not however the only factor influencing on droughts’ occurrence. The analyses show, that the probability of the Spring and Summer droughts’ occurrence in a year with a positive THC phase is considerably larger, if in period of Winter preceding the drought, the sign of NAO index will be positive. At present (the year 2019) we are presumably already after the culmination of the positive phase of the THC, lasting from the year 1989. As the long-term course of the THC changeability shows the quasi- periodicity, we can presume, that the strong positive trend of occurrence of droughts, lasting from the 80’ of 20th century, will undergo break down.

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