Degree Type

Dissertation

Date of Award

2016

Degree Name

Doctor of Philosophy

Department

Geological and Atmospheric Sciences

Major

Meteorology

First Advisor

Tsing-Chang Chen

Abstract

Mesoscale Convective Systems (MCSs) produce the majority of the precipitation over the area east of the United States’ Rocky Mountains. These systems are responsible for the majority of the flash flooding and severe weather, which can have a significant impact on crops. MCSs are vitally important in crop growing areas and, in particular, the Corn Belt where almost half of the World’s corn supply is produced. Studying the changes in MCS initiation could lead to better prediction of corn yields. For this study, the warm season (April-September) MCS initiations over the United States Corn Belt are analyzed to determine significant MCS initiation conditions when compared to cases where no initiation occurred in the years 1979 to 2013. The Corn Belt is defined as Kansas, Nebraska, South Dakota, North Dakota, Minnesota, Iowa, Missouri, Illinois, Indiana, and Ohio. Changes in MCS initiation by initiation hour, month, half warm season, year, decade, and half of the database are also examined to determine what fluctuations occurred throughout the database. MCS initiation activity is studied because of the shortage of available literature. To determine the changes in MCS initiation, significance testing and logistic regressions were analyzed for the six hours prior to initiation through the three hours after initiation. For select time periods, a Bayes’ Theorem application was also completed. The statistical analyses, when coupled with meteorology, indicate the majority of the changes in MCS initiation can be attributed to the rise in global/regional temperatures. A large scale analysis, accomplished with spatial statistics, was also completed in the form to an intensity/cluster analysis and a teleconnection pattern analysis. The intensity/cluster analysis shows that there is clustering of the MCS initiation locations over the Corn Belt with MCS initiation locations particularly concentrated to Nebraska, Kansas, Missouri, and Iowa. For the teleconnection pattern analysis, each of the six teleconnection patterns studied do have an effect on initiation with the Pacific-North American Pattern and the West Pacific Pattern having the most profound effect. From this study, it can be concluded that MCS initiations are affected by climate change and specific teleconnection patterns.

Copyright Owner

Elisabeth Callen

Language

en

File Format

application/pdf

File Size

708 pages

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