An Isopycnally Averaged North Pacific Climatology

Abstract

Approximately a quarter of a million hydrographic stations extracted from the North Pacific World Ocean Atlas 1994 have been subjected to a statistical quality control to produce a Pacific climatology in the spirit of the Atlantic hydrobase. The CTD casts from the publicly available World Ocean Circulation Experiment (WOCE) and pre-WOCE cruises have also been included, and where available, nutrient data have been retained. Particular attention has been paid to the quality control of the 200?000 stations that lie within the region surrounding Japan as it was determined that much of these data contained suspicious salinity values. A comparison with the gridded World Ocean Atlas 1994 confirms expectations that within deep waters over much of the North Pacific the relatively flat isopycnal surfaces produce only small differences between the two climatologies. Closer to surface, however, the differences between the datasets are far more apparent. The major differences (as large as 1.3°C and 0.2 psu at 500 db) occur in the region of the Kuroshio where isopycnals are strongly sloping. Differences also occur in the regions containing the suspicious salinity values as in the Sea of Japan, as well as over a broad region centered at about 15°N. The horizontal, vertical, and temporal distribution of the data make basin-scale temporal analysis problematic; however, regional analyses are possible and under way.