Date of Award
Doctor of Philosophy (PhD)
Jennifer E. Kay
In recent decades, a rapidly warming lower atmosphere has been observed in the Arctic. Consequently, we wish to address a fundamental question: how do weather patterns in the northern hemisphere respond to these significant changes in the Arctic, especially sea ice loss? To gain insight about the possible linkage between warming Arctic conditions and the resultant atmospheric responses, changes in cyclone activity and synoptic weather patterns were investigated in this study. Given that precipitation can also affect weather patterns, a newly developed reanalysis precipitation was evaluated over Greenland for future hydrological cycle research in the Arctic.
First, the Arctic System Reanalysis version 1 precipitation generally showed good agreement with gauge-based precipitation measured in coastal areas. However, precipitation at Summit, Greenland, a higher continental environment, indicated overestimated amounts with respect to Doppler radar measurements.
Secondly, no robust changes in cyclone activity were observed, despite the changes in moisture availability, regional baroclinicity, and vertical stability.
Lastly, we confirmed that persistent warm surface signals can generate a ridge at 500 hPa and a surface high-pressure system downstream of the ridge. When the Arctic surface forcing has a sufficiently long persistence over a moderately large area, it can induce mid-latitude cold-air advection.
Koyama, Tomoko, "Atmospheric Responses to Arctic Climate Warming: Precipitation, Cyclone, and Synoptic Patterns" (2018). Atmospheric & Oceanic Sciences Graduate Theses & Dissertations. 78.