Freshwater and heat changes in the North and South Pacific Oceans between the 1960s and 1985-94

Comparisons of hydrographic conditions in the North and South Pacific Ocean s in the 1960s and 1985-94 have been made along five World Ocean Circulatio n Experiment sections. Below the seasonal mixed layer, statistically signif icant temporal differences in salinity and temperature have been detected i n the water masses that occur in the upper 2000 dbar of the water column. T hese water mass property differences have been used to estimate the freshwa ter and heat storage trends in the Pacific over the study period. Along 24 degreesN, 10 degreesN, and 17 degreesS, where either North Pacific Intermed iate Water or Antarctic Intermediate Water is present, the upper waters hav e increased in salinity, while the intermediate and deep waters have decrea sed in salinity. Although the depth-integrated salinity changes observed al ong these sections are small, the regional redistribution of freshwater ass ociated with the water mass changes is significant and implies significant redistribution of surface freshwater fluxes over the Pacific. Heat loss has occurred along 47 degreesN and 17 degreesS, but significant warming has oc curred along 24 degrees and 10 degreesN, giving the Pacific a net heat gain of 1.79 x 10(8) J m(-2). The resulting steric sea level change for the are a in the Pacific between 60 degreesN and 31.5 degreesS over the roughly 20- yr study period is estimated to be a rise of 0.85 mm yr(-1), consistent wit h those in existing literature, but larger than that estimated from numeric al models reported in the Intergovernmental Panel on Climate Change Second Assessment Report.