A long meridional section at 137°E in the western North Pacific has been routinely made in January since 1967. The results obtained from 1967 to 1974 indicate that there are fairly big differences between years in temperature and salinity of the upper water and steric sea level in the tropical or equatorial region. An anomalous state of oceanographic characteristics in the western equatorial Pacific, which is suggested by the 137°E section in July 1972 and in January 1973, may be associated with the El Niño off South America...
Masuzawa, Jotaro, and Koichi Nagasaka. 1975. "The 137°E oceanographic section." Journal of Marine Research 33, (S). https://elischolar.library.yale.edu/journal_of_marine_research/1339