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Limited polar low sensitivity to sea‐surface temperature
Author(s) -
Linders T.,
Saetra Ø.,
Bracegirdle T. J.
Publication year - 2011
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 - 10.1002/qj.718
Subject(s) - polar , sensitivity (control systems) , intensity (physics) , sea surface temperature , convection , hydrostatic equilibrium , atmospheric sciences , azimuth , geology , environmental science , climatology , mechanics , physics , optics , astronomy , electronic engineering , quantum mechanics , engineering
Abstract The sensitivity of the intensity of polar lows to changes in the sea‐surface temperature (SST) is investigated. This is done by using an axisymmetric non‐hydrostatic numerical model. It is found that the intensity of the simulated polar lows responds linearly to SST perturbations, with positive perturbations leading to deeper sea‐level pressure (SLP) depressions and higher azimuthal winds. The numerical simulations give an SLP depression sensitivity of only about −0.6 hPa K −1 and a sensitivity of the maximum azimuthal wind of only about +0.6 m s −1 K −1 . This is about one order of magnitude less than the sensitivity of the theoretical maximum intensity. It is suggested that the very limited sensitivity can be explained within the wind‐induced surface heat exchange (WISHE) theory. The limited sensitivity can thus be attributed, in roughly equal parts, to the limited efficiency with which the polar low extracts heat from the ocean and the limited mean height of the convection. Copyright © 2011 Royal Meteorological Society