The Dynamical and Microphysical Structure of an Occluded Frontal System and its Modification by Orography

摘要: Abstract An occluded front moving over Washington State was investigated with serial rawinsonde ascents, aircraft penetrations, raingage measurements and conventional observations. The data showed that the frontal system contained alternate mesoscale tongues of air low high values wet–bulb potential temperature (θω). These included a pre–frontal surge low–θω aloft, centered at about 700 mb level, low–evel high–θω tongue along front, two post–frontal tongues. low– were order 50–100 km in width. precipitation confined to band, 80 width, front. cloud associated this hand characterized by vertical circulation similar to, but much less vigorous than, an organized convective system. Cloud microphysical indicated narrow cumulus–scale updraft zone located near leading edge cloud. concentrations ice particles fronta...