Open AccessSatellite Observations of an Unusual Cloud Formation near the Tropopause
Author(s) -
Nicolas Ferlay,
Timothy J. Garrett,
F. Minvielle
Publication year - 2014
Publication title -
journal of the atmospheric sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.853
H-Index - 173
eISSN - 1520-0469
pISSN - 0022-4928
DOI - 10.1175/jas-d-13-0361.1
Subject(s) - tropopause , cloud top , cirrus , geology , cloud height , entrainment (biomusicology) , storm , atmospheric sciences , troposphere , meteorology , climatology , cloud computing , satellite , cloud cover , astronomy , geography , physics , oceanography , computer science , rhythm , acoustics , operating system
This paper describes observations of a field of deep and regular cloud formations that spans several hundreds of kilometers at the top of a midlatitude frontal system in the North Pacific storm track. Space-based imagery of the event from active and passive measurements reveals smooth, clearly defined cloud lobes approximately 10 km across and 2–4 km deep that resemble upside-down mammatus. These observations, together with theoretical arguments and prior modeling work, suggest that the lobes were part of a deepening turbulent mixed layer that formed as a consequence of strong cloud-top radiative cooling. Over the course of a day, the cloud-top formation evolved to leave behind a sheet of cumuliform cirrus that stretched hundreds of kilometers across. The potential is for such clouds to facilitate mixing across the tropopause, much as cloud-top cooling drives the entrainment of free-tropospheric air into stratocumulus-topped boundary layers.