Late Pleistocene Sea Levels and Resulting Changes in Global Land Distributions

Abstract

Over the past 120,000 years global sea level has fluctuated through multiple cycles of rises and falls, ranging from a few meters above current level to 139 meters below. This thesis analyzes the resulting distributions of terrestrial and submerged lands at regular intervals of 1,000 years. Global mean sea level change is derived from 12 in situ database interpolated temporally with various fitting models. Some sea levels are based on single in situ observations at specific time windows. The fitting models including Fourier series, sum of sine, smoothing spline, and central tendency measurements are used for predicting data curves. Two methods, employed to see if a trend exists throughout the past 120,000 years, are linear regression and TFPW Mann-Kendall trend test. An animation about terrestrial vs. submerged land change is made to show global changes in the extent of aquaterra, defined as the lands that were alternately exposed and inundated as ice sheets advanced and retreated over the last 120,000. From ETOPO1 data and sea level values, the total land area and land distribution change with time was calculated by spherical geometry using Matlab (matrix laboratory, a multi-paradigm numerical computing environment). The greatest change in aggregate terrestrial land area occurred between 23.5° N and 66.5° N (12.6%), and 23.5° S to 23.5° N (15.6%). Over 56% of the aquaterra is located between equator and 66.5° N.