TY - JOUR
AU - HANDLOS, ZACHARY J.
AB - AbstractNarrow, tropopause-level wind speed maxima known as jet streams or jets are among the most ubiquitous structural characteristics of the Earth’s atmosphere. Two species, the polar and subtropical jets, can be observed on any given day. The polar jet is tied, via eddy momemtum flux convergence associated with extratropical wave development, to the troposphere-deep baroclinicity of the middle latitudes while the subtropical jet is tied, by angular momentum constraints, to the poleward edge of the tropical Hadley Cell. As a consequence of their different origins, the polar and subtropical jets are separated by both latitude and elevation. However, there are times when these two usually separate features become vertically superposed to form a single, intense jet core designated as a jet superposition or superposed jet.An objective method for identifying tropopause-level jets is employed in the construction of 50-year cold season (NDJFM) synoptic-climatologies of the Northern Hemisphere polar jet, subtropical jet, and jet superpositions. The analysis demonstrates that while superposition events are relatively rare, there are clear geographical maxima. Superpositions are most frequent in the western Pacific from December through February, with a secondary peak in southern North America and along its eastern seaboard. Consistent with expectations, the spatiotemporal maxima in jet superpositions appear to be coincident with maxima in the polar and subtropical jets.
TI - A synoptic-climatology of Northern Hemisphere, cold season polar and subtropical jet superposition events
JF - Journal of Climate
DO - 10.1175/JCLI-D-16-0565.1
DA - 2017-06-20
UR - https://www.deepdyve.com/lp/american-meteorological-society/a-synoptic-climatology-of-northern-hemisphere-cold-season-polar-and-6fAF0rRxui
SP - 7231
EP - 7246
VL - preprint
IS - 2017
DP - DeepDyve
ER -