Evaluation of a Limited-area Energy Budget Cycle of an Extratropical Storm Under Lagrangian and Eulerian Frameworks
Abstract To conceptualize the uncertainties regarding the mechanisms of extratropical cyclones (EC), a study of their energy cycle can provide key information of their fundamental structure. This study applies a set of equations built from earlier works for a limited-area energy decomposed into temporal mean and deviations. It compares the results obtained with a reference frame that tracks an EC through its eddy kinetic energy with those obtained with a larger but fixed frame. A specific storm that occurred throughout the period of December 10-18th 2004 and simulated by the Canadian Regional Climate Model (CRCM – version 5) was studied. Results support the notion that the moving reference results in larger amplitudes for all temporal deviation components of the cycle than for the fixed reference. A time tendency analysis of the energetic reservoirs reveals noteworthy phases in the storm’s energy, with an increase and decrease occurring during the periods of 10-14 December and 14-18 December, respectively. The energy budget is overall fairly well balanced, with the exception of a lateral boundary term, hkTV , with considerable negative values; this term exhibits a spatially larger scale than the other contributions in the EC. An evaluation of the sensibility of the tracking scheme related to its size and positioning was also performed to determine its influence on the boundary term hkTV.