@Article{MakarievaGoNeShNoLi:2017:QuGlAt,
               author = "Makarieva, Anastassia M. and Gorshkov, Victor G. and Nefiodov, 
                         Andrei V. and Sheil, Douglas and Nobre, Antonio Donato and Li, 
                         Bai-Lian",
          affiliation = "{Petersburg Nuclear Physics Institute} and {Petersburg Nuclear 
                         Physics Institute} and {Petersburg Nuclear Physics Institute} and 
                         {Norwegian University of Life Sciences} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {University of California}",
                title = "Quantifying the global atmospheric power budget",
              journal = "Atmospheric Chemistry and Physics Discussion",
                 year = "2017",
               volume = "17",
                pages = "1--52",
             abstract = "The power of atmospheric circulation is a key measure of the 
                         Earths climate system. The mismatch between predictions and 
                         observations under a warming climate calls for a reassessment of 
                         how atmospheric power W is defined, estimated and constrained. 
                         Here we review published formulations for W and show how they 
                         differ when applied to a moist atmosphere. Three factors, a 
                         non-zero source/sink in the continuity equation, the difference 
                         between velocities of gaseous air and condensate, and interaction 
                         between the gas and condensate modifying the equations of motion, 
                         affect the formulation of W. Starting from the thermodynamic 
                         definition of mechanical work, we derive an expression for W from 
                         an explicit consideration of the equations of motion and 
                         continuity. Our analyses clarify how some past formulations are 
                         incomplete or invalid. Three caveats are identified. First, W 
                         critically depends on the boundary condition for gaseous air 
                         velocity at the Earths surface. Second, confusion between gaseous 
                         air velocity and mean velocity of air and condensate in the 
                         expression for W results in gross errors despite the observed 
                         magnitudes of these velocities are very close. Third, W expressed 
                         in terms of measurable atmospheric parameters, air pressure and 
                         velocity, is scale-specific; this must be taken into account when 
                         adding contributions to W from different processes. We further 
                         present a formulation of the atmospheric power budget, which 
                         distinguishes three components of W: the kinetic power associated 
                         with horizontal pressure gradients (WK), the gravitational power 
                         of precipitation (WP ) and the condensate loading (Wc). This 
                         formulation is valid with an accuracy of the squared ratio of the 
                         vertical to horizontal air velocities. Unlike previous approaches, 
                         it allows evaluation of WP + Wc without knowledge of atmospheric 
                         moisture or precipitation. This formulation also highlights that 
                         WP and Wc are the least certain terms in the power budget as they 
                         depend on vertical velocity; WK depending on horizontal velocity 
                         is more robust. We use MERRA and NCAR/NCEP re-analyses to evaluate 
                         the atmospheric power budget at different scales. Estimates of WK 
                         are found to be consistent across the re-analyses, while estimates 
                         for W and WP drastically differ. We then estimate independent 
                         precipitation-based values of WP and discuss how such estimates 
                         could reduce uncertainties. Our analyses indicate that WK 
                         increases with temporal resolution approaching our theoretical 
                         estimate for condensation-induced circulation when all convective 
                         motion is resolved. Implications of these findings for 
                         constraining global atmospheric power are discussed.",
                  doi = "10.5194/acp-2017-17",
                  url = "http://dx.doi.org/10.5194/acp-2017-17",
                 issn = "1680-7367",
             language = "en",
           targetfile = "makarieva_quantifying.pdf",
        urlaccessdate = "05 maio 2024"
}