The exceptionally warm waters of the tropical Pacific Ocean have surpassed yet another milestone, pushing this El Niño one step closer to becoming the strongest on record.
The strength of El Niño is measured by how abnormally warm the ocean water is in the equatorial Pacific. There are many zones in the Pacific that are used to quantify the strength of an El Niño, including the often-cited Niño 3.4 zone. Ocean surface temperature is measured and averaged over the entire region in periods of a week, a month and three months. The records in this region are typically broken by fractions of degrees.
In mid-November, the Niño 3.4 region set a new record for weekly temperature — 3 degrees Celsius, or 5.4 degrees Fahrenheit, above average. It was the highest temperature departure ever recorded in the region on the scale of one week.
Now the data for the entire month of November are in, and it eked out November 1997, the previous record-high, by 0.02 degrees Celsius. It is not a huge margin, but a remarkable achievement nonetheless against what is remembered as the most intense, most influential El Niño since records began in 1950.