On Applied Thermodynamics in Atmospheric Modeling

Yıl 2000, Cilt: 3 Sayı: 4, 171 - 180, 01.12.2000

Sean Wright David Scott James Haddow Marc Rosen

Öz

Recently some atmospheric researchers have turned to thermodynamics to avoid the complexity of conventional atmospheric models. This approach has resulted in a search for an entropy production extremum principle that governs circulation. Research has focused on the maximum dissipation theorems of Paltridge and Zeigler and the minimum entropy production principle of Prigogine. Stephens and O’Brien have calculated the entropy production rate of Earth based on satellite energy measurements and have concluded that its value supports the maximum dissipation conjecture. In this paper, we present evidence that Prigogine’s minimum entropy production principle is not applicable to atmospheric circulation. The calculation of the extremum simply shows that the entropy production rate is minimum with respect to any force when the corresponding flux has ceased. The force-flux equations completely govern the response of the system, under certain constraints, to applied external forces or radiative sources and sinks. Secondly, it is shown that for a number of reasons the conclusion of Stephens and O’Brien that the calculated entropy production rate supports the maximum dissipation conjecture is not justified. Thirdly, an improved radiative model of the planet is presented that provides insight into the thermodynamic behaviour of the Earth system. For example, the results from this model show, surprisingly, that the Earth’s mean temperature has a tendency to be independent of planetary albedo (or independent of the fraction of sunlight absorbed) while being dependent on phenomena like the greenhouse effect.

•  This paper was presented at the ECOS'00 Conference in Enschede, July 5-7, 2000

Anahtar Kelimeler

irreversible thermodynamics, atmospheric modeling, entropy production principles, radiative planetary model