Some people wonder when El Niño will show up in the lower troposphere. It takes some months before the temperature of the lower troposphere peaks - up to three months later than the peak in surface temperatures. That means that it will still be a couple of months before the El Niño shows up strongly in lower troposphere temperatures.
Roy Spencer has posted an update of UAH lower troposphere temperature. Here is an update of the chart from a few weeks ago, with November 2015 included. This version is 6.04 beta which is slightly different to previous beta versions in the detail. The shaded area covers the general period of an El Niño - from around April in year 1 to March in year 2. The lower troposphere temperature doesn't normally peak till the end of the El Niño:
|Fig 1 | Lower troposphere temperature anomaly - global. Data source: UAH|
I've also plotted the chart just for the tropics. It is important to remember that air moves about a lot more than the oceans, so the air above the tropics in the lower troposphere isn't the only place that El Niño will affect.
|Fig 2 | Lower troposphere temperature anomaly - tropics. Data source: UAH|
I was planning to write a more extensive article on ENSO and the troposphere, but that will have to wait for another time. If you are interested in the subject, one article worth reading is by Geert Jan van Oldenborgh, KNMI at Ed Hawkin's ClimateLabBook. The article, "Is there a pause in the temperature of the lower troposphere?" is mainly about the slowdown in surface warming that occurred this century, but it touches on ENSO as well, pointing out that "the effects of El Niño are stronger in the TLT than in the near-surface temperature". What this means is that we can expect that Christopher Monckton and all the deniers at WUWT will have to press the restart button soon, when they want to claim that global warming has stopped. As Geert Jan van Oldenborgh concluded last December:
I conclude that beyond the effects of El Niño there is no pause in the warming in TLT either. As there is no evidence for a long-term trend in the Niño3.4 index, this means it will revert to normal before long and by that time the trend will pick up in the full TLT series as well. I think that may well be next year (2015), due to the (very small) El Niño this winter, but that may be overwhelmed by other natural variability. The TLT series looks so similar to the near-surface temperature series only because of a cancellation between the differences in the tropics and the high latitudes. However, neither shows that global warming stopped.
To complete the picture, below is a chart of surface temperatures in El Niño years, with this year's temperature anomaly up to and including October 2015:
|Fig 3 | Global mean surface temperature anomaly in El Niño years. Data source: GISS NASA|
References and further reading
There was a paper published a couple of years ago - it's quite technical so I'll be addressing some of the points it makes in a future article (maybe, I shouldn't make promises).
Scherllin‐Pirscher, B., C. Deser, S‐P. Ho, C. Chou, W. Randel, and Y‐H. Kuo. "The vertical and spatial structure of ENSO in the upper troposphere and lower stratosphere from GPS radio occultation measurements." Geophysical Research Letters 39, no. 20 (2012). DOI: 10.1029/2012GL053071 (open access)
Is there a pause in the temperature of the lower troposphere? - article by Geert Jan van Oldenborgh, KNMI at Ed Hawkin's ClimateLabBook
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