Home – Home – Jornals – Earth’s Cryosphere 2025 number 3

In the Middle and Late Pleistocene, in the areas of the source and sink of radiative heat in the Northern hemisphere, the effect of dividing the intensity of seasonal irradiation by phases of changes in the intensity of annual irradiation is manifested. The average values of the intensity of summer radiation in the phase of increasing annual exposure exceed those in the phases of decreasing annual exposure. The average values of the intensity of winter radiation in the phases of increasing annual exposure are inferior to those in the phases of decreasing annual exposure. The effect of phase separation manifests itself in different ways in the areas of the source and sink of radiation heat. In the areas of the heat source, the phase separation of the intensity of summer and winter irradiation, on average, in the stages of high-amplitude oscillations of a  400-millennial cycle exceeds the phase separation in the stages of low-amplitude oscillations. In the areas of radiative heat runoff, on average, the phase separation of the intensity of summer and winter irradiation in the stage of low-amplitude oscillations exceeds the phase separation in the stages of high-amplitude oscillations. The values of the phase separation of the intensity of summer irradiation in the stages of high-amplitude and low-amplitude fluctuations in 5-degree latitude zones vary in different directions, and the intensity of winter irradiation is unidirectional. The phase separation is most noticeable in the area of radiative heat runoff of the Northern Hemisphere (the area of the cryolithozone) in the summer half of the year at the stage of low-amplitude oscillations of a  400-millennial cycle. This is typical for the beginning of the Middle Pleistocene (solar epoch 16), the Likhvin interglacial (solar epochs 8 and 9) and the present (solar epoch 1).