Using soil moisture as a predictor for spring convection within the state of Missouri
Abstract
Previous studies have shown that increased soil moisture can affect the overlying water vapor in the atmospheric boundary layer (ABL), potentially moistening this layer. Increased buoyancy can create more turbulence and in turn, be more conducive for severe weather. Because of the position of Missouri within the center of the United States, many factors come together to create a wide variety of weather. This position also puts the state in a transition zone, meaning both dry soils and wet soils can lead to convection. This research will attempt to show how the amount of soil moisture can be an indicator for tornado, hail, and wind activity within the state of Missouri. This study will have three main components and will focus on the period from 1980-2018 time period. The first part will use April-June soil moisture anomalies to see if there is a correlation to severe activity for the corresponding months. The second part will use soil moisture anomalies for the months of January-March to find a relationship to severe weather for the following April-June months. The third experiment will use soil moisture anomalies from September-February to assess the potential correlation to severe convection to the following April-June months. Synoptic maps, in conjunction with the ENSO phenomena, will be utilized to understand what other mechanisms may be attributing to the increase/decrease in storm reports within the state. Finally, a spectral analysis by using Fourier transforms will be conducted to see the interannual variability with respect to severe convection and soil moisture. Results showed statistical positive significance comparing April-June soil moisture with April-June tornado and wind activity. Some positive and statistical negative significance was seen with the January-March soil moisture comparison to the following April-June severe weather reports. However, no statistical significance was found within the September-February soil moisture comparison to the following April-June severe weather reports. Most of the statistically significant correlations were noticed in south central Missouri, both positive and negative. Some variability was observed with ENSO years and tornado activity, indicating that the synoptic setup may play more of a role than soil moisture. La Nina was also found to produce more tornadoes even though drier conditions were evident during this period. Overall, southern Missouri was shown to be more conducive for severe weather, mainly tornado and wind events.
Degree
M.S.
Thesis Department
Rights
OpenAccess.
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