Local Finite-Amplitude Rossby Wave Activity as a Diagnostic for Wave Breaking

Tuesday, 16 December 2014
Clare S Y Huang and Noboru Nakamura, University of Chicago, Department of Geophysical Sciences, Chicago, IL, United States
We generalize the zonal-mean finite-amplitude Rossby wave activity proposed by Nakamura and Zhu (2010) by allowing it to be a function of longitude. Its evolution is given by the divergence of the generalized Eliassen–Palm (E-P) flux, which is readily calculable from the wind field in the conservative limit. The relationship with the previously known finite-amplitude wave activity due to Killworth and McIntyre (1985), McIntyre and Shepherd (1987), and Haynes (1988) will be described. We will illustrate with idealized models how local wave activity may be used to define and identify the occurrence of wave breaking events. A preliminary application of the diagnostic to reanalysis products will be demonstrated and compared with previous studies of wave breaking statistics.