Dissertations and Theses

Date of Award


Document Type



Earth and Atmospheric Sciences

First Advisor

Z. Johnny Luo


convection, CAPE, convective available potential energy, temporal, convective system, ISCCP


In 1983, the World Climate Research Programme launched its first project: the International Satellite Cloud Climatology Project (ISCCP). While the ISCCP has succeeded in many of its cataloging and analytical goals, one of its flagship products, the Convection Tracking (CT) Database does not contain certain environmental parameters that are essential in understanding how, and when, convection is initiated or intensified. The development of mesoscale convection – notably, convective systems (CS) – is also largely dependent on parameters like convective available potential energy (CAPE) which the ISCCP CT Database does not record. By tying information on CAPE to CS, discoveries in convective development have been made. These results have been useful in ascertaining that strong CAPE environments intensify convection, but less illuminating on the temporal co-variation of CAPE and convective evolution. To that end, this study focuses on examining both the time difference between realization of maximum CAPE and the peak intensity of nearby convection, and at what local time of day each of these occurrences takes place. This study specifically explores the diurnal variations in CAPE in the continental United States (also known as the CONUS) in seasons of intense tornadic activity and relatively higher CAPE. It also examines diurnal changes in the evolutionary lifecycle of CS for these respective seasons. Findings of this study include the recognition that CS reach their peak intensity 3 to 6 hours after the ambient environment reaches its maximum CAPE. Furthermore, the time of day and location of maximum ambient CAPE and greatest convective intensity vary by warm season of interest. In the spring, maximum ambient CAPE takes place in the evening hours, but maximum convective intensity is more diffuse throughout the day. These findings are localized to “Tornado Alley.” In the summer, both maximum convective intensity and maximum ambient CAPE tend to take place in the evening hours just east of the Rocky Mountains. An understanding of the diurnal variations of CAPE generation and convective development in specific regions could be of great interest to the atmospheric science community.


This study is supported and monitored by The National Oceanic and Atmospheric Administration—Cooperative Science Center for Earth System Sciences and Remote Sensing Technologies (NOAA-CESSRST) under the Cooperative Agreement Grant #: NA16SEC4810008.


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