Instead of Surface temperature, might not a truer measure of the strength of an El Nino be the total amount of extra heat in the upper ocean (top 300m) in the area with significant deviaitons from the mean. It seems the 2015 may far outstrip the 1997 event on that basis, given the total volume of affected water, and the higher anomalies at depth of up to +6 deg. C. The graphs I've been able to find on your site seem to indicate the 97 event was a much shallower event. And of course the whole NE Pacific is way above normal this time as well...that equates to a lot of extra energy does it not? thanks, Peter