[ESAC Student Seminar] Paul Nicknish

“An Energy Balance Model for Orbitally Forced Perturbations to the Seasonal Cycle and Implications for Glacial Inception”

Abstract: During the latter part of the Pleistocene (1 mya to 0.01 mya), glacial cycles with a period of 100,000 years dominated Earth’s climate. However, the mechanisms driving glacial inception (the transition between the warm interglacial periods and the colder glacial periods) are not yet fully understood. In this study we couple a Budyko-type energy balance model (EBM) to an ice sheet model to better understand the relationship between the orbitally forced changes in equilibrium line altitude (ELA) and ice sheet cover. Our work has two parts. First, we demonstrate the viability of the EBM as an effective tool for understanding what controls the amplitude, phase, and annual mean of the seasonal temperature cycle, both in the present and in the past under different orbital configurations. Additionally, using modern day observations of temperature and ELA and orbital parameters of the Earth going back 5 million years, we demonstrate how to construct a time series of orbitally forced perturbations to the ELA using the EBM. Second, we then focus our study on Baffin Island in northeastern Canada, which geologic evidence suggests is the origin location of the Laurentide Ice Sheet that covered much of North America during the most recent glacial period. With our constructed time series of ELA, we drive a vertically integrated ice-sheet model over modern-day Baffin Island topography. We find that the change in ELA from orbital forcing alone leads to a transition between small glaciers persisting only in the higher elevation regions of Baffin Island and a larger ice sheet covering much of the island.

ESAC Student Seminar Series

A forum for students and postdocs to share recent research, hone presentation skills, and build community among peers, sponsored by the EAPS Student Advisory Committee. Open to current EAPS graduate and undergraduate students and postdocs. Typically hosted on Thursdays during the semester, including pizza lunch.

Contact: esac.officers@gmail.com