Atmosphere Ocean Science Friday Seminar

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Characterizing the impacts of bathymetry on sea level variability using clustering

Speaker: Andrew Brettin, CAOS

Location: Warren Weaver Hall 1314

Date: Friday, October 8, 2021, 7 p.m.

Notes:

Sea level extremes, such as those arising from storm surge, can incur large economic damages and result in loss of human life. Understanding how various drivers impact probability distributions of sea level can help us determine how frequently such extreme sea level events will occur in a future climate. Here, we investigate the effects of bathymetry—a time-independent geographical driver—on coastal sea level distributions simulated by a coupled climate model, GFDL CM2.6. The high resolution in CM2.6 (1/10° in the ocean and 1/2° in the atmosphere) allows the simulation of processes impacting sea level variability which are not present in many coarser models, such as ocean mesoscale eddies and category 3 hurricanes. We characterize sea level distributions by applying k-means clustering to the leading statistical moments of sea level anomalies and examine how distributions differ across different ocean depths. We show that the continental shelf drives sea level towards distributions with higher kurtosis, and higher standard deviation or skewness, indicating how broad and shallow continental slopes are conducive for extreme values. This work highlights how understanding of the coastal geometry—a constant under a changing climate—can help constrain estimates for the frequency of sea level extremes under an altered climate.