Makarieva A.M., Gorshkov V.G., Nefiodov A.V., Sheil D., Nobre A.D., Li B.-L. (2016) Quantifying the global atmospheric power budget. arXiv:1603.03706v2 [physics.ao-ph]
Abstract
The power of atmospheric circulation W is a key measure of the Earth's climate system. The mismatch between predictions and observations for atmospheric circulation under a warming climate calls for a reassessment of how atmospheric power is defined, estimated and constrained. Here we review published formulations for W to show how they differ; the differences are associated with integration of material derivatives in the presence of moisture sources and sinks in the continuity equation. We discuss how estimates of W are affected by these differences. Starting from the thermodynamic definition of mechanical work, we present a novel derivation linking global atmospheric power to measurable atmospheric parameters. The resulting formulation distinguishes three components of W: the kinetic power associated with horizontal motion, the kinetic power associated with vertical motion and the gravitational power of precipitation (WP). Unlike previous approaches, our formulation allows evaluation of WP without knowledge of atmospheric moisture or precipitation. This allows the terms of the atmospheric power budget to be estimated from re-analyses. We use daily and monthly mean MERRA and NCAR/NCEP data and 3-hourly instantaneous MERRA data for 1979-2015. While our estimates of kinetic power are consistent across the databases, the resulting estimates for W and WP differ. We explain how data resolution and the inherent uncertainty in the determination of vertical velocity cause these discrepancies. We also discuss how independent precipitation-based estimates of WP could reduce such uncertainties. Finally, we discuss the physical constraints on global atmospheric power and how considering the dynamic effects of water vapor condensation offers new opportunities. In particular, analyses indicate that kinetic power increases with temporal resolution approaching our theoretical estimate for condensation-induced circulation in the limit when all convective motion is fully resolved.

Notes

This paper stemmed from a short Technical Comment on the work of Laliberte et al. (2015) in Science (it was not published). Here is the review that we received.

Макарьева А.М., Горшков В.Г., Нефёдов А.В., Шейл Д., Нобре А.Д., Ли Б.-Л. (2016) К расчёту мощности глобальной циркуляции. arXiv:1603.03706v2 [physics.ao-ph] [на англ. яз.]
Аннотация
The power of atmospheric circulation W is a key measure of the Earth's climate system. The mismatch between predictions and observations for atmospheric circulation under a warming climate calls for a reassessment of how atmospheric power is defined, estimated and constrained. Here we review published formulations for W to show how they differ; the differences are associated with integration of material derivatives in the presence of moisture sources and sinks in the continuity equation. We discuss how estimates of W are affected by these differences. Starting from the thermodynamic definition of mechanical work, we present a novel derivation linking global atmospheric power to measurable atmospheric parameters. The resulting formulation distinguishes three components of W: the kinetic power associated with horizontal motion, the kinetic power associated with vertical motion and the gravitational power of precipitation (WP). Unlike previous approaches, our formulation allows evaluation of WP without knowledge of atmospheric moisture or precipitation. This allows the terms of the atmospheric power budget to be estimated from re-analyses. We use daily and monthly mean MERRA and NCAR/NCEP data and 3-hourly instantaneous MERRA data for 1979-2015. While our estimates of kinetic power are consistent across the databases, the resulting estimates for W and WP differ. We explain how data resolution and the inherent uncertainty in the determination of vertical velocity cause these discrepancies. We also discuss how independent precipitation-based estimates of WP could reduce such uncertainties. Finally, we discuss the physical constraints on global atmospheric power and how considering the dynamic effects of water vapor condensation offers new opportunities. In particular, analyses indicate that kinetic power increases with temporal resolution approaching our theoretical estimate for condensation-induced circulation in the limit when all convective motion is fully resolved.

Примечания

This paper stemmed from a short Technical Comment on the work of Laliberte et al. (2015) in Science (it was not published). Here is the review that we received.