convective instability


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convective instability

[kən′vek·div in·stə′bil·əd·ē]
(meteorology)
The state of an unsaturated layer or column of air in the atmosphere whose wet-bulb potential temperature (or equivalent potential temperature) decreases with elevation. Also known as potential instability.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

convective instability

convective instabilityclick for a larger image
A parcel of air is stable at A and B and becomes unstable at C indicating convective instability from C onwards.
The state of the atmosphere in which there is a high relative humidity at low levels and a low relative humidity at upper levels, such that if a low layer of air is lifted bodily, the ELR (environmental lapse rate) value through the layer will gradually increase until it attains an unstable value. ELR is the lapse rate in the surrounding air within which a volume of air is being lifted. DALR, or dry adiabatic lapse rate, and SALR, or saturated adiabatic lapse rate, are lapse rates of dry and saturated air masses, respectively, when they are lifted adiabatically. The values of DALR and SALR are 3°C and 1.5°C/1000 ft, respectively. This is often seen in cold fronts, where convective instability is the major cause of instability. Also known as potential instability.
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References in periodicals archive ?
But bring tropical moisture into convective instability and we're dealing with some very high liquid water content.
Several studies have been devoted to investigating the effect of a periodic gravitational modulation on the convective instability in a fluid layer.
[18] analyzed the impact of the Kuroshio Current on mesoscale convective systems in the Meiyu front area and found that the intensified evaporation in the Kuroshio Current leads to increases in the moisture content of the air masses in the Meiyu front area, which is favorable for the maintenance of convective instability in the lower troposphere near the Meiyu front.
It is well known that the Swift-Hohenberg model was proposed to describe pattern formation in convection by Swift and Hohenberg in studying the convective instability in the Rayleigh-Benard convection [7].
The aim of this paper is to track the transition between the absolute instability and convective instability in a compressible shear layer.
Therefore, NODA contains information only on larger-scale convective instability but not on individual convective cells, which are typically resolved at O(1)-km grid spacing or smaller.
(3) We explain below two important processes to understand interaction between gravity waves and background mean zonal winds, the critical level interaction and convective instability. (26)
Muhlhaus, "Theoretical and numerical analyses of convective instability in porous media with upward throughflow," International Journal for Numerical and Analytical Methods in Geomechanics, vol.
[8] HWANG G.J., CHENG K.C., (1973), Convective instability in the thermal entrance region of a horizontal parallel plate channel heated from below, J.
Examples include his insights on magnetic island healing, curvature effects on island evolution, and convective instability of drift waves.
Secondly, we will diagnose the types of convective instability over the area of interest that are responsible for the heavy precipitation bands that create the blizzard conditions prior to cyclogenesis.