The video shows satellite measurements of sea surface height, which scientists can use as a proxy for temperature. This year’s El Niño exploded across the equatorial Pacific Ocean in March and April, while the 1997 version was still getting its legs. Interestingly, sea surface temperature in the far eastern Pacific is running closer to average so far this year, with the warmest water focused in the central Pacific. But in 1997, the warmest water sloshed very far east through the end of the year, right up against coastal South America.
It will be interesting to see how El Niño continues to morph this year, since some studies have shown that it only takes slight variations in strength and extent to change the way it affects our weather.