This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Has El Niño reached the West Coast? After all, the ocean off Southern and Central California is unusually warm.
But that warmth is from a recent marine heat wave that predates the current El Niño. Much of the Pacific Coast is experiencing relatively normal conditions while still awaiting the impacts of what could be a very strong El Niño. In June, NOAA's National Weather Service declared that El Niño had developed.
That finding, however, is based on ocean temperatures from the tropical Pacific Ocean near the equator, which warm ahead of El Niño's impact on the Americas. While eastern tropical Pacific temperatures have already risen more than 2°C (about 3.6°F) above normal, El Niño-related warming along the West Coast typically lags that increase by a few months. NOAA Fisheries scientists are tracking West Coast conditions as part of our Integrated Ecosystem Assessment.
Here are some of the changes in ocean conditions and marine life that typically signal the arrival of El Niño's influence along the West Coast. During El Niño, winds that typically blow westward along the equator weaken and periodically reverse in "westerly wind bursts." These wind bursts set off oceanic Kelvin waves that travel east along the equator. After reaching Central and South America, the waves travel north as "coastal trapped waves" along the North American coast.
This creates a link between the tropics and the United States known as an oceanic teleconnection. These waves travel underwater but produce relatively small changes in sea level (approximately 15 cm or 6 inches) that are measurable at tide gauges along the coast and from satellites. Kelvin waves originating along the equator this spring and summer first reached California in May–June.
However, their impacts on the West Coast will likely be minor compared with those this fall and winter, said Nate Mantua, a research scientist with NOAA's Southwest Fisheries Science Center based in Santa Cruz, California. As these Kelvin waves move north along the coast, they deepen the thermocline—an underwater boundary at which temperatures drop rapidly at greater depths. Additionally, an atmospheric teleconnection allows El Niño conditions in the tropics to modify atmospheric pressure patterns over the North Pacific.
Extract — continue reading at the source.
