Lorenz Atmospheric Energy Cycle in Climatic Projections

Silas Michaelides

doi:10.3390/cli9120180

Abstract

The aim of this study is to investigate whether different Representative Concentration Pathways (RCPs), as they are determined in the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC), lead to different regimes in the energetics components of the Lorenz energy cycle. The four energy forms on which this investigation is based are the zonal and eddy components of the available potential and kinetic energies. The corresponding transformations between these forms of energy are also studied. RCPs are time-dependent, consistent scenarios of concentrations of radiatively active gases and particles. In the present study, four RCPs are explored, namely, rcp26, rcp45, rcp60, rcp85; these represent projections (for the future period 2006–2100) that result in radiative forcing of approximately 2.6, 4.5, 6.0 and 8.5 Wm−2 at year 2100, respectively, relative to pre-industrial conditions. The results are presented in terms of time projections of the energetics components from 2020 to 2100 and show that the different RCPs yield diverse energetics regimes, consequently impacting the Lorenz energy cycle. In this respect, projections under different RCPs of the Lorenz energy cycle are presented.

Highlights

The study of the energetics of the atmosphere comprises a fundamental approach in the efforts to understand the dynamics of the Earth’s atmosphere
The objective of the present study is to investigate whether different Representative Concentration Pathways (RCPs) lead to different regimes in the energetics components of the Lorenz energy cycle, which would have an impact on a “rate of working” of the climate system
The available potential energy (AE) rate of change is negative with almost all scenarios, decreasing faster under the extreme all other RCPs it is positive, with the highest values noted with the rcp60 and rcp85 forcings, indicating a tendency for strengthening of the zonal flow with time with increased greenhouse gas concentrations

Summary

Introduction

The study of the energetics of the atmosphere comprises a fundamental approach in the efforts to understand the dynamics of the Earth’s atmosphere. Since the 1950s, the energetics of the atmosphere have attracted the interest of several investigations (e.g., [1,2,3]). The focus of such studies is on the fate of the available potential energy and kinetic energy. The formulation of the concept of available potential energy by Lorenz was built upon Margules’s [4] concept founded on a hypothetical adiabatic redistribution of the atmospheric mass. The concept has been widely exploited in studies of general circulation and large-scale dynamics [5]. The concept is still under examination from different perspectives (e.g., [8,9])

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Conclusion