Early December 2016 La Niña Update: Mixed Signals from NOAA and BOM

Note: See Update at the end of the post.

# # #

Last month on November 10, NOAA issued a La Niña Advisory, indicating weak La Niña conditions existed and that those conditions were “slightly favored to persist (~55% chance) through winter 2016-17.” Let’s see how things are progressing.

NOAA’S WEEKLY SATELLITE-ENHANCED REYNOLDS OI.v2 SEA SURFACE TEMPERATURE DATA SHOW A WEAKENING TO ENSO-NEUTRAL CONDITIONS

The sea surface temperature anomalies of the NINO3.4 region of the tropical Pacific (coordinates 5S-5N, 170W-120W) are a commonly used index for the timing, strength and duration of El Niño and La Niña events.

NOAA’s weekly sea surface temperature anomaly data for the NINO3.4 region based on their original Reynolds OI.v2 data show that surface temperatures there have been in ENSO neutral conditions (not La Niña, not El Niño) for 3 weeks. As of the week centered on Wednesday November 30 and for the two prior weeks, NINO3.4 sea surface temperature anomalies were at -0.4 deg C, which is above the -0.5 deg C threshold of La Niña conditions. (Rounding out the month of November, for the first week, the value was -0.7 deg C.)  See the time-series graph in Figure 1.

figure-1

Figure 1

Note that the horizontal green line is the most recent weekly value, not a trend line.

This data are based on NOAA’s original version of their Reynolds OI.v2 satellite-enhanced sea surface temperature dataset. The anomalies are referenced to the base period of 1981-2010. This is not the dataset that NOAA uses for their “official” ENSO indices.

NOAA’S MONTHLY IN SITU-ONLY ERSST.v4 SEA SURFACE TEMPERATURE DATA (WITH A FIXED SET OF BASE YEARS FOR ANOMALIES, 1981-2010) SHOW TEMPERATURES WELL WITHIN WEAK LA NIÑA CONDITIONS FOR NOVEMBER AND STRENGTHENING SLIGHTLY

Again we’re looking at sea surface temperature data for the NINO3.4 region, but this time we’re looking at a version based on NOAA’s ERSST.v4 monthly “pause buster” sea surface temperature data, which is based solely on observations from buoys and ship inlets, no satellite-based data.  This is the dataset that NOAA uses for their “official” ENSO index but it is referenced to the fixed base years of 1981-2010…while NOAA takes a few additional steps for their “official” Oceanic NINO Index.

The monthly ERSST.v4-based data for November 2016 show NINO3.4 sea surface temperature anomalies well within the realm of weak La Niña conditions, at -0.82 deg C. See Figure 2. The October value was -0.8 deg C.

figure-2

Figure 2

NOAA’S MONTHLY IN SITU-ONLY ERSST.v4 SEA SURFACE TEMPERATURE DATA (WITH SHIFTING BASE YEARS FOR ANOMALIES) SHOW SLIGHTLY STRONGER LA NIÑA CONDITIONS WITH A MORE NOTICEABLE STRENGTHENING

As opposed to using a fixed 30-year based period for the ERSST.v4-based NINO3.4 anomalies in their “official” Oceanic NINO Index, NOAA uses multiple 30-year periods that shift every 5 years.  See the NOAA explanation here. NOAA claims they’ve taken this curious approach “to remove this [global] warming trend” on the equatorial Pacific sea surface temperature data.  We revealed, however, in the 2012 post Comments on NOAA’s Recent Changes to the Oceanic NINO Index (ONI) that the global “warming trend” in NINO3.4 sea surface temperature data resulted primarily from the impact of the well-known and naturally occurring 1976 Pacific climate shift.  Apparently, NOAA does (oops) doesn’t want mother nature to be responsible for even localized warming.  This, of course, renders the Oceanic NINO Index useless for realistic climate studies.

Regardless, NOAA has adopted this odd approach to calculate the sea surface temperature anomaly values for their “official” Ocean NINO Index. The monthly NINO3.4 values that are input to the Ocean NINO Index are shown in Figure 3.  The November 2016 NINO3.4 sea surface temperature “anomaly” for this altered dataset is -0.92 deg C, which is approaching the -1.0 deg C threshold of a moderately strong La Niña.  From October to November 2016, this modified dataset shows a noticeable strengthening of -0.05 deg C.

figure-3

Figure 3

So it appears that NOAA is working hard at making the 2016/17 La Niña an “official” reality.

Note: NOAA then uses a 3-month running average of this altered monthly NINO3.4-based data for their Oceanic NINO Index.

THE SOUTHERN OSCILLATION INDEX FROM AUSTRALIA’S BOM CONTINUES TO SHOW ENSO NEUTRAL CONDITIONS

The Southern Oscillation Index (SOI) from Australia’s Bureau of Meteorology is another widely used reference for the strength, frequency and duration of El Niño and La Niña events. We discussed the Southern Oscillation Index in Part 8 of the 2014/15 El Niño series. It is derived from the sea level pressures of Tahiti and Darwin, Australia, and as such it reflects the wind patterns off the equator in the southern tropical Pacific. With the Southern Oscillation Index, El Niño events are strong negative values and La Niñas are strong positive values, which is the reverse of what we see with sea surface temperature-based indices.  The November 2016 Southern Oscillation Index shows ENSO neutral conditions exist in the tropical Pacific…with a value is -0.7, which is the sign opposite to those of La Niña conditions. (The BOM threshold for La Niña conditions is an SOI value of +8.0.)  According to the SOI, we briefly made it into La Niña conditions in September and since then, ENSO neutral. Figure 4 presents a time-series graph of the SOI data.

figure-4

Figure 4

Again, the horizontal green line is the most recent monthly value, not a trend line.

Also see the BOM Recent (preliminary) Southern Oscillation Index (SOI) values webpage. The current 30-day running average and the 90-day average are still in ENSO neutral conditions.

CLOSING

As noted in the title, we’re getting mixed signals from NOAA and BOM, and from NOAA itself, about the existence of La Niña conditions on the tropical Pacific.

WANT TO LEARN HOW EL NIÑO AND LA NIÑA EVENTS CONTRIBUTE TO LONG-TERM GLOBAL WARMING?

I published On Global Warming and the Illusion of Control (25MB .pdf) back in November 2015. The introductory post is here. That 700+ page climate change reference is free. Chapter 3.7 includes detailed discussions of El Niño events and their aftereffects…though not as detailed as in Who Turned on the Heat?

My ebook Who Turned on the Heat? – The Unsuspected Global Warming Culprit: El Niño-Southern Oscillation (23MB .pdf) goes into a tremendous amount of detail to explain El Niño and La Niña processes and the long-term global-warming aftereffects of strong El Niño events. It too is free. See the introductory post here. Who Turned on the Heat? weighs in at a whopping 550+ pages, about 110,000+ words. It contains somewhere in the neighborhood of 380 color illustrations. In pdf form, it’s about 23MB. It includes links to more than a dozen animations, which allow the reader to view ENSO processes and the interactions between variables.

UPDATE:

Within hours of my publishing this post, Australia’s BOM has cancelled their La Niña watch. They write in their December 6th ENSO Update:

La Niña no longer likely in the coming months

The El Niño–Southern Oscillation (ENSO) in the tropical Pacific Ocean remains neutral (neither El Niño nor La Niña). Although some very weak La Niña-like patterns continue (such as cooler than normal ocean temperatures and reduced cloudiness in the central and eastern Pacific), La Niña thresholds have not been met. Climate models and current observations suggest these patterns will not persist. The likelihood of La Niña developing in the coming months is now low, and hence the Bureau’s ENSO Outlook has shifted from La Niña WATCH to INACTIVE.

Will NOAA follow?

About Bob Tisdale

Research interest: the long-term aftereffects of El Niño and La Nina events on global sea surface temperature and ocean heat content. Author of the ebook Who Turned on the Heat? and regular contributor at WattsUpWithThat.
This entry was posted in ENSO Update, Uncategorized. Bookmark the permalink.

6 Responses to Early December 2016 La Niña Update: Mixed Signals from NOAA and BOM

  1. Hi Bob,
    This an interesting period when it comes to natural variance impacts on the progression of the Current Warm Period. The reason is that we are just off an El Niño event that had characteristics vry similar to that of 1997/98, and that was followed by a period where warming was not evident and given a whole lot of euphamistic names.
    – There’s chatter anticipating a resumption of the period of no evident warming again.
    – Looking at UAH prepublished by Roy Spencer, there is a hint of a step-up from the plateau prior to the recent ElNino that will likely be addressed in your next review.
    – There’s a hesitancy to announce whether there’s a La Niña in progress

    Overall, it is rather amusing to watch for *anticipated* machinations to explain another plateau of warmth, a different experience to last time as we watched the unfolding of an aghast realisation a plateau was being experienced.

    In Australia there’s three observations worth noting.
    – BoM is keen to say La Nina like patterns (of increased Spring rainfall) can occur ‘ even if thresholds are not met.’ – note the threshold is +7 and ‘sustained’ is required (no +8 as in article).
    This is worth noting because we experienced considerable flooding recently at the time immediately after El Niño finalised.
    – The Australian government is reviewing its climate policy with the usual, expected media coverage; just as the Murray-Darling Basin review of water usage is underway, intriguing (potentially sensible) solar-wind-with-battery-storage farms are being constructed, and the Australian National Farmers Federation has adopted a “climate change” sympathetic stance under its new president (read eg: read http://www.stockandland.com.au/story/4325760/nff-modernises-climate-change-thinking/?cs=4590 )
    The impact of Natural variation on Australian multi-year and decadal conditions would have been a better and more important place to devote resources (even locally politically advantageous, apart from economic imperatives and stewardship of the natural resouces and wildlife) rather than the political IPCC “climate change” as elegantly portrayed in your previous post.
    -Lastly as an entertainment, the Australian Govt’s Figure 4 (element b): ‘Example air temperature over 50 years’ at https://www.pacificclimatefutures.net/en/help/climate-projections/understanding-climate-variability-and-change/ by how its selection of an example warming trend deliberately used the 1970s.

    Looking forward to the November review.
    regards, John

  2. charlieskeptic says:

    Thanks, again, for your informative work.

    I guess the climate warriors on both sides have to wait a bit longer for their supporting trends.

    Dave Fair

  3. Pingback: UN-Weltklimakonferenz erfolgreich: Die globalen Temperaturen gehen 2016 stark zurück! „Global Warming“ Reality Check November 2016 – wobleibtdieglobaleerwaermung

  4. Kathleen says:

    This is so thorough and interesting! Thanks for the update at the end!!!

    From, an avid amateur

  5. Pingback: La Niña kühlt die Erde ab! Kein neuer globaler Wärmerekord 2016 trotz El Niño! „Global Warming“ Reality Check Dezember 2016 – wobleibtdieglobaleerwaermung

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