During the California Landfalling Jets Experiment (CALJET), a series of approximately 220 airborne expendable bathythermograph (AXBT) temperature soundings were made in the extra-tropical eastern Pacific off the coast of California. This data is used to calculate the upper- ocean (surface to 300 m) heat content during January-February 1998, at which time the 1997/1998 El Nino event was near its maximum amplitude. This in-situ data is then used to validate techniques to retrieve upper-ocean heat content based on statistical analyzes of TOPEX/POSEIDON satellite altimetry data. Finally, an analysis of one year of the satellite altimetry data through the intensification stage of the El Nino event is used to place the in-situ measurements in a longer term context.