Upper Ocean Heat Content (0-300 m)

Upper-ocean heat content for 0 to 300 m is the heat stored in the top 300 m of the water column, computed by depth-integrating density times specific heat times temperature. It tracks the upper ocean’s response to surface heat flux and is a sensitive index of ENSO and of climate warming, since the ocean has absorbed more than 90 percent of the Earth system’s excess heat. The Argo float array, with about 4000 profilers sampling to 2000 m every 10 days, transformed this record. Warm-pool buildup at 0 to 300 m precedes El Nino, and rising heat content fuels marine heatwaves and tropical cyclones.