On Eddy Heat Fluxes and Entropy Production in the Jet Flow Region and the Earth’s Surface in the Climate Model of the Marchuk Institute of Numerical Mathematics

• Published in: Izvestiya. Atmospheric and oceanic physics Vol. 61; no. 3; pp. 340 - 348
• Main Authors: Krupchatnikov, V. N., Gochakov, A. V., Antokhina, O. Yu, Gradov, V., Borovko, I. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.06.2025; Springer Nature B.V
• Subjects: Atmosphere; Climate; Climate models; Climate system; Climatology; Convection; Earth and Environmental Science; Earth Sciences; Earth surface; Energy transfer; Entropy; Entropy production; Geophysics/Geodesy; Heat flux; Heat transfer; Irreversible processes; Jet flow; Jet stream; Jet streams (meteorology); Land cover; Mathematics; Northern Hemisphere; Planetary waves; Rivers; Rossby wave propagation; Rossby waves; Subtropical jet stream; Temperature gradients; Thermodynamics; Wave propagation; entropy balance and production; climate modeling; jet currents; turbulence; eddy heat fluxes; Rossby wave breaking
• ISSN: 0001-4338; 1555-628X
• DOI: 10.1134/S0001433825700677

This paper discusses some results of the study of eddy heat fluxes in the vicinity of a subtropical jet stream. Many large-scale dynamical phenomena in the Earth’s atmosphere are associated with Rossby wave propagation and collapse processes. Here we focus on regions of countergradient eddy heat fluxes in the region of the subtropical jet stream in the Northern Hemisphere associated with Rossby wave overturning. In these regions, we observe meridional energy transfer on the northern flank of the jet stream in the equatorial direction from the ERA-5 reanalysis data and simulation data with the INM-CM4-8 climate model of the Marchuk Institute of Numerical Mathematics of the Russian Academy of Sciences (INM RAS). The entropy production due to horizontal heat transfer becomes negative, because heat is transferred against the temperature gradient, but this is not a violation of the second law of thermodynamics, since the main part of entropy production occurs due to the processes of vertical heat transfer, such as convection, and other irreversible processes. Entropy production is sensitive to land cover, the entropy balance being most related to radiation at the surface. Quantifying the thermodynamic balance of entropy and entropy production is a useful metric for evaluating the interactions of the atmosphere–surface system. Some estimates of entropy production by the surface are presented in this paper. The traditional approach to studying the climate system focuses on the dynamic mechanisms and physical processes responsible for the conversion of energy from one form to another, but an approach based on analyzing the entropy balance of the climate system and especially entropy production is also important.