A Compositing Approach for Preserving Significant Features in Atmospheric Profiles

Abstract

Composite profiles of thermodynamic and kinematic variables are prepared to represent the characteristics of the environment within which a particular atmospheric phenomenon occurs. During the averaging process, it is desirable to retain the dominant features and associated gradients found in the individual profiles so that representative values of quantities such as flux parameters, energy budgets, convective available potential energy, and various stability indices can be computed from the composite profiles. The conventional compositing approach, where averages are computed at common heights, reduces or even smooths out a significant feature when the height and vertical extent of the feature differ from one individual profile to the next. To retain a desirable feature in the composite profile, it is necessary to compute averages at the heights where the feature occurs and to compute the average height of the feature itself. As an example of the capabilities of this scaling or feature-preserving approach, the technique was applied to a set of 33 hodographs from supercell thunderstorm environments as documented in the literature. The feature-preserving technique retained realistic wind-shear values, including a midlatitude minimum-shear layer that disappeared when the conventional compositing technique was used.