## Abstract

The finite-amplitude wave activity diagnostic developed for quasigeostrophic (QG) flows in Part I is extended to the global primitive equation system in the isentropic coordinate. The Rossby wave activity density *A* is proportional to Kelvin’s circulation around the wavy potential vorticity (PV) contour minus that around the zonal circle that encloses the same isentropic mass. A quasi-conservative, eddy-free reference state flow *u*_{REF} is constructed from the observed Kelvin’s circulation by zonalizing the PV contours conservatively while enforcing gradient balance. The departure of the observed zonal-mean flow of the atmosphere from the reference state *u* is further partitioned into the direct eddy drag −*A* and the residual impulse Δ*u _{R}* consistent with the time-integrated transformed Eulerian mean (TEM) zonal-wind equation.

The analyzed climatological-mean wave activity in the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) is similar to that in Part I. The net adjustment Δ*u* is mainly due to the direct eddy drag (Δ*u* ≈ −*A*) in the winter polar stratosphere and can reach approximately −60 m s^{−1} in the Northern Hemisphere. In the extratropical troposphere Δ*u* is a small residual (Δ*u _{R}* ≈

*A*), yet it clearly reveals a 5–6 m s

^{−1}eddy driving of the Southern Hemisphere jet as well as a 7–8 m s

^{−1}eddy drag in the subtropical upper troposphere of both hemispheres. The local maxima in wave activity in the equatorial upper troposphere and the extratropical lower stratosphere found in Part I are undetected, while negative wave activity is found where the isentropes intersect the ground. As in the QG case,

*u*

_{REF}exhibits significantly less transient and interannual variability than

*Corresponding author address:*Noboru Nakamura, Department of Geophysical Sciences, University of Chicago, 5734 South Ellis Ave., Chicago, IL 60637. E-mail: nnn@uchicago.edu