Assessing the vertical distribution of convective available potential energy

Abstract Comparisons of convective available potential energy (CAPE) with standard instability indices for evaluating the convective potential of the atmosphere such as the lifted index (LI) reveal only moderate correlations. This is because the LI is a measure of single-level buoyancy while CAPE is a measure of both integration depth and the buoyancy. Normalizing the CAPE values by the depth over which the integration takes place provides an index (NCAPE) that is independent of the depth and is a convenient measure of the mean parcel buoyancy. This normalization effectively distinguishes between environments with similar CAPE but exhibiting different buoyancy and integration depth. Also, because the vertical distribution of CAPE can have an important effect on convective updraft strength, it is advantageous to vertically partition CAPE and NCAPE into multiple layers. NCAPE may provide a more useful indicator of buoyancy in environments in which the depth of free convection is shallow and total CAPE is sm...

[1]  P. Kennedy,et al.  Single-Doppler Radar Observations of a Mini-Supercell Tornadic Thunderstorm , 1993 .

[2]  Alan R. Moller,et al.  The Operational Recognition of Supercell Thunderstorm Environments and Storm Structures , 1994 .

[3]  D. Atlas.  severe local storms , 1976 .

[4]  M. Lemone,et al.  Vertical velocity in oceanic convection off tropical Australia , 1994 .

[5]  M. Moncrieff,et al.  The dynamics and simulation of tropical cumulonimbus and squall lines , 1976 .

[6]  J. G. Galway,et al.  The Lifted Index as a Predictor of Latent Instability , 1956 .

[7]  Joseph B. Klemp,et al.  The Dependence of Numerically Simulated Convective Storms on Vertical Wind Shear and Buoyancy , 1982 .

[8]  Grant L. Darkow,et al.  The Total Energy Environment of Severe Storms , 1968 .

[9]  Randy A. Peppier.  A REVIEW OF STATIC STABILITY INDICES AND RELATED THERMODYNAMIC PARAMETERS , 1988 .

[10]  J. Edwards.  The use of computers. , 1982, Birth defects original article series.

[11]  J. Fritsch,et al.  Numerical Prediction of Convectively Driven Mesoscale Pressure Systems. Part I: Convective Parameterization , 1980 .

[12]  E. Rasmussen,et al.  A Baseline Climatology of Sounding-Derived Supercell and Tornado Forecast Parameters , 1998 .

[13]  A. K. Showalter,et al.  A stability index for thunderstorm forecasting , 1953 .

[14]  Frank P. Colby,et al.  Convective Inhibition as a Predictor of Convection during AVE-SESAME II , 1984 .

[15]  Edward J. Zipser,et al.  Cumulonimbus Vertical Velocity Events in GATE. Part II: Synthesis and Model Core Structure , 1980 .

[16]  Robert C Miller,et al.  Notes on Analysis and Severe-Storm Forecasting Procedures of the Air Force Global Weather Central , 1972 .

[17]  M. Lemone,et al.  Convective Available Potential Energy in the Environment of Oceanic and Continental Clouds: Correction and Comments , 1994 .

[18]  R. Johns,et al.  Severe Local Storms Forecasting , 1992 .

[19]  Erik N. Rasmussen,et al.  The Effect of Neglecting the Virtual Temperature Correction on CAPE Calculations , 1994 .