PACIFIC-NORTH AMERICAN TELECONNECTIVE PATTERNS AND THE HYDROCLIMATE OF NORTHEASTERN INDIANA

Teleconnections are recognized atmospheric patterns that occur at identified intervals and are representative of Earth’s dynamic atmospheric system. Known for providing a link between pressure centers, teleconnections allow for the reallocation of large cold or warm air masses and consequently create anomalous patterns of weather and climate over massive distances. Teleconnections are forced by fluctuations in sea surface temperature and the vertical or lateral movement of upper atmospheric waves. Depending on the particular pattern, teleconnections operate periodically meaning that they can occur on a seasonal, annual, or decadal scale. Understanding the periodicity of a teleconnective pattern allows for scientists to accurately assess climatic variability using the pattern as an index for change while also providing a more comprehensive understanding of fluctuations to regional hydroclimate. One of the most important processes operating within the northern hemisphere is the Pacific-North American (PNA) teleconnective process. Because synoptic upper atmospheric variation, like PNA, can alter regional patterns of temperature and precipitation and thus produce extreme weather events, it is imperative that the pattern and its periodicity be understood. PNA significantly impacts temperature and precipitation in the continental United States and, as such, it can be used as an index to forecast future fluctuations in regional temperature and precipitation. To better predict large-scale weather events in the future, weather and climate scientists must know how the pattern functioned in the past. This can be done paleolimnologically, using varved sediments from long-lived lake environments. I plan to utilize the remains of fossilized diatoms from varved sediments in Pretty Lake, a varved kettle lake in northeastern Indiana, to analyze the effect that positive and negative phases of PNA have on the hydroclimate of the Midwestern United States.