Does the subtropical jet catalyze the mid-latitude atmospheric regimes?
Abstract
Understanding the atmospheric low-frequency variability is of crucial importance in fields such as climate studies, climate change detection, and extended-range weather forecast. The Northern Hemisphere climate features the planetary waves as a relevant ingredient of the atmospheric variability. Several observations and theoretical arguments seem to support the idea that winter planetary waves indicator obey a non-Gaussian statistics and may present a multimodal probability density function, thus characterizing the low-frequency portion of the climate system. We show that the upper tropospheric jet strength is a critical parameter in determining whether the planetary waves indicator exhibits a uni- or bimodal behavior, and we determine the relevant threshold value of the jet. These results are obtained by considering the data of the NCEP-NCAR and ECMWF reanalyses for the overlapping period. Our results agree with the non-linear orographic theory, which explains the statistical non-normality of the low-frequency variability of the atmosphere and its possible bimodality.
Cite
@article{arxiv.physics/0508193,
title = {Does the subtropical jet catalyze the mid-latitude atmospheric regimes?},
author = {Paolo M. Ruti and Valerio Lucarini and Alessandro Dell'Aquila and Sandro Calmanti and Antonio Speranza},
journal= {arXiv preprint arXiv:physics/0508193},
year = {2007}
}
Comments
Final version of the paper