Undergrad Research Study by Katarena Jarrell Does the El Nino Southern Oscillation Play a role in the Spatial distribution of Tornadoes IN the united States? Undergrad Research Study by Katarena Jarrell

What are Tornadoes? Large, violent column of rotating air from the cloud base to the ground. Often found in violent rotating thunderstorms called supercells. Deep Moisture Convection, unstable air, and wind shear are key factors in tornado formation. Tornadoes measure in the Fujita Scale(F), recently Enhanced Fujita(EF) scale has been used. Scale from EF0 to EF5. Normally found in Tornado Alley and Dixie Alley. Dixion et al 2014 study showed that Birmingham, AL had the highest risk of tornado damage.

Tornado Alley & Dixie Alley Photo By: http://www.nzpchasers.com/apps/blog/categories/show/1945564-weather-

What is the El Nino Southern Oscillation (Enso)? The interchanging years between El Nino, La Nina, and Neutral years. Changes of sea surface temperatures of South America's west coast. El Nino- warmer water that usual La Nina- colder water than usual Neutral when the sea surface temperatures are normal La Nina will follow El Nino Weather pattern changes EL Nino I increased the font here and reshaped the size of the text box. That allowed me to pull the maps out of the bottom corner – see if you can imitate this type of visual balance on other slides as well. Watch out for capitalization (check all slides). La Nina

How do Tornadoes and ENsO relate? Changes in water = changes in the Air Pressure above the water Changes in air pressure=change of the Jet stream in the Pacific Jet Stream Change = Weather pattern changes in the United States Example is El Nino years Texas tends to have a wetter winter. Photos by: http://www.srh.noaa.gov/jetstream/tropics/enso_impacts.html El Nino Dec-Feb La Nina Dec-Feb

Cook and Schaefer 2008 Study Study found that there was no link to ENSO and Winter Tornado Outbreak. Used historical Tornado data to map tornado outbreaks (1950-2003). Two different maps for Tornado days and violent tornado days. Mapped tornadoes from January to March. Also incorporated storm patterns in with their model. My Study is based off this study.

Methods Tornado Data from National Ocean and Atmosphere Administration (NOAA) Storm Prediction Center. from the year 1964 to 2014. Tornadoes with a strength of EF/F2 or higher. ENSO Data from NOAA(http://www.esrl.noaa.gov/psd/enso/past_events.html ) Split the Tornado Data into the three separate group of years. El Nino(EN), La Nina(LN), and Neutral(N). Spatial Distribution was mapped in ArcGIS. Lower 48 States

EnsO Years

Results

Discussion How closely do each of the maps correlate to Cook and Schaefer's maps that they produced in 2008? Compare Cook and Schaefer historical winter outbreak maps to this study. Examine tornado distribution in form of a density analysis. Mean Coordinates for EN, LN, and N years.

Cook and Schaefer 2008 El Nino Year El Nino:12 years This Study

Cook and Schaefer 2008 La Nina:17 years La Nina Years This Study

Cook and Schaefer 2008 Neutral Years Neautral:25 years This Study

Mean Coordinate

Shift in Mean Coordinates See next slide.

Conclusion Majority of the shifts shows a high significance in the shift of tornado spatial distribution in the three type of years. Geographically it may seem close but statistically there is a highly significant shift. Correlation shows that ENSO may have an impact on tornado spatial distribution with this study. Further study and other factors may need to be added. It is important because National Weather Services can use these maps to predict future storm events and maybe save lives.

What’s next? Mapping out Tornadoes with a magnitude of EF/F3 and greater. Analyzing more recent studies that relate to this topic. Possibly including the Jet Stream Data in the study.

Questions?