A reader asked for a time representation… a tricky problem via a web site, the data is large…
Here are three different views, two from the UK Met Office and one from UAH, the newly released version. These run from January 1996 through December 2000.
Firstly here is an overview an Hovmoller plot for the same time span. These are widely used but rarely for earth whole views. Here are some I prepared earlier as a 2012 article (includes ) elsewhere which might help understanding on what I am doing for this article.
Figure 1, Hovmoller diagram of 1998 El Nino, UAH TLT V5.6  (as PDF 142kB)
The 1998 El Niño event was similar to the less known ~1876 event, both seeming increasingly muted in the Met Office data. The El Niño form is a pulse of warmth primarily in tropical regions followed by a cool period. The warmth gradually disappearing apparently flowing poleward, producing a characteristic sideways V shape in Hovmoller graphics. The cool in inside the V. Perhaps preceeded by coolish. This pattern has repeated over the years.
If instead of folding all longitudes into a mean as above a plain XY map for a month gives a different view, so we may be able to see from where on the globe there are contributions.
This new work showcases one month available for all datasets, February 2015. The image above, lower troposphere from UAH V6 beta is merely a picture, the true work is in a PDF for local display. The intent is information, not hitting you in the face, so whilst as such green is a colour few people like that is how it has turned out. New geographic map, new colours.
Combined images, PDF (2.9MB), the cover page explains more.
I leave the reader to draw conclusions. As I get accused, understating, some surprises are inside.