LAUSR

Abstract The changes in temperature and dissolved oxygen concentration in the Pacific Ocean in the northern region of the shallow oxygen minimum zone (OMZ) off Mexico were analyzed on the basis of the Word Ocean Database and a series of oceanographic cruises (LEGOZ-Mex). In order to test the changes in both parameters between two similar oceanographic scenarios according to the Pacific Decadal Oscillation (PDO), a comparison was made between the last two cool PDO phases of 1962–1974 and 2002–2012 when conditions might be expected to be relatively similar. Results show that the surface layer (upper layer of 50 m depth) has been warming significantly in two of the three areas included in this study: 1) the southern end of the California Current (0.8 °C; p