Search

Recent modeling studies have proposed different scenarios to explain the slowdown in surface temperature warming in the most recent decade. Some of these studies seem to support the idea of internal variability and/or rearrangement of heat between the surface and the ocean interior. Others suggest that radiative forcing might also play a role. Our examination of observational data over the past two decades shows some significant differences when compared to model results from reanalyses and provides the most definitive explanation of how the heat was redistributed. We find that cooling in the top 100-meter layer of the Pacific Ocean was mainly compensated for by warming in the 100- to 300-meter layer of the Indian and Pacific Oceans in the past decade since 2003., (Copyright © 2015, American Association for the Advancement of Science.)

During the 1975 El Niño expedition an array of conventional and electric field type near-bottom current recorders was deployed at the equator 300 kilometers west of the Galápagos Islands. While hydrographic observations were indicating El Niño activity off the South American coast, the current meters recorded an oscillation with a 25-day period, a wavelength of about 1000 kilometers, and an amplitude of 0.04 meter per second propagating westward at approximately 0.5 meter per second. These characteristics agree with theoretical models of a first-mode baroclinic Rossby wave trapped at the equator.

The Shuttle Experiment conducted between Hawaii and Tahiti from January 1979 to June 1980 was designed to observe the changing equatorial ocean structure and circulation, to study the variations and interactions of the four major equatorial ocean currents, and to develop a scientific basis for their monitoring by simple observations of thermal structure and sea level. Preliminary analyses of the results show that the equatorial thermal structure remains intact during a normal year and that only the positions and intensities of the currents are subject to change. The water transport of the equatorial undercurrent varied from 25 x 10(6) cubic meters per second in January to 51 x 10(6) cubic meters per second in July, but also exhibited strong short-term pulsations. The equatorial surface flow responded strongly to the winds at periods of 1 month and longer. An array of drifter buoys in the equatoral countercurrent was subject to very little dispersion while traveling over 4500 kilometers in 4 months. Low-frequency fluctuations in the North Equatorial Countercurrent can be monitored by means of the difference in sea level between Fanning and Majuro.