The Relationship of Ocean Heat Content by Density Level to Hiatus Decadaes within the CESM

Ocean heat content not only modulates longterm climate but also plays a role on decadal timescales. Previous studies, using only one future climate scenario (RCP4.5), suggest that decadal heat content variability is related to the Interdecadal Pacific Oscillation (IPO) and can lead to hiatus decades in global temperature trends through the increase of heat reaching the deep ocean. This study investigates changes in ocean heat content during hiatus and accelerated warming periods using results from the Community Climate System Model version 4 (CCSM4) historical 20^th Century simulations and four future climate scenarios. While previous studies have used depth levels, we investigate these changes using density levels, making it possible to tie the heat content changes to water masses. In doing so, we are able to diagnose the regions in which heat is entering/leaving the ocean and tie those changes to regional climate modes of variability. We also investigate four different future scenarios to see how these relationships depend on future warming.