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Downstream development and Kona low genesis
Author(s) -
Moore R. W.,
Martius O.,
Davies H. C.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl035502
Subject(s) - tropopause , cyclogenesis , potential vorticity , extratropical cyclone , climatology , geology , tropical cyclogenesis , atmospheric sciences , troposphere , forcing (mathematics) , cyclone (programming language) , geophysics , vorticity , vortex , physics , meteorology , field programmable gate array , computer science , computer hardware
A composite analysis of 43 Kona lows in conjunction with a case study of a particularly damaging Kona low indicate that downstream development is dynamically important to the subtropical cyclogenesis. It takes the form of eastward propagating, statistically significant upstream potential vorticity (PV) anomalies with accompanying meridional wind anomalies at the tropopause level prior to the formation of a Kona low. The downstream development culminates in the formation of a PV streamer, a meridionally‐elongated stratospheric intrusion of high PV air into the troposphere, associated with a breaking wave on the dynamical tropopause. Subsequently, the streamer ‘cuts off’ from the stratospheric reservoir of high PV and translates equatorward, thereby providing a necessary dynamical forcing for the subtropical surface cyclogenesis.