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Cloud‐resolving model simulations of multiply‐banded frontal clouds
Author(s) -
Pizzamei M.,
Gray S. L.,
Browning K. A.
Publication year - 2005
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1256/qj.04.175
Subject(s) - convection , parametrization (atmospheric modeling) , troposphere , geology , cold front , instability , atmospheric convection , meteorology , atmospheric sciences , mechanics , physics , optics , radiative transfer
An idealized two‐dimensional cloud‐resolving model is used to investigate the formation and temporal evolution of multiply‐banded clouds in frontal zones. Radar observations often show both upright and slantwise convection in the circulations associated with such bands. The aim is to examine the interaction between upright and slantwise convection and to determine the mechanisms leading to multiple banding. A warm bubble is used to initiate convection in the frontal zone, which has an initial thermodynamic profile based on observations. Further triggering occurs and banded clouds evolve. The initially upright plumes become tilted due to the so‐called Δ M adjustment process (upscale development). Observed multiple bands in frontal zones are frequently attributed to the release of conditional symmetric instability (CSI). However, in these simulations, there is no evidence of the release of CSI despite the fragmentation of slantwise bands into multiple layers in the mid‐troposphere. Successive triggering of upright convection is instead associated with a spreading cold pool driven by evaporative cooling in the slanted downdraughts. Triggering can occur on both the warm‐ and cold‐air sides of the frontal zone, and is sensitive to the microphysical parametrization used. Copyright © 2005 Royal Meteorological Society.