*Satoru Okajima1, Hisashi Nakamura1, Yohai Kaspi2
(1.Research Center for Advanced Science and Technology, 2.Weizmann Institute of Science)
Keywords:transient eddy, storm track
Transient eddies are of quite importance for weather and climate in extratropics, because they play a significant role in maintaining the westerly jets, which act as a basic state for atmospheric circulation variabilities, by systematically transporting momentum and heat as well as account for a large fraction of extratropical daily weather variability. Studies on their activity have been carried out from two perspectives: a “Lagrangian” perspective, in which individual (anti)cyclones are tracked, and an “Eulerian” perspective, in which statistics of local atmospheric variables are utilized. These perspectives have pros and cons. Nevertheless, few studies have attempted to incorporate these perspectives.
Here we introduce a methodology to investigate transient eddy activity from a “hybrid” perspective, by partially incorporating the above perspectives. Focusing on the “midwinter minimum” of the North Pacific transient eddy activity as a test case, we demonstrate that our understanding of midlatitude storm track activity may be further deepened through investigation from the multiple and “hybrid” perspectives.