Most of those involved with ONI ( Ocean Nino Index) understand the sequence of events that lead to regions within the Pacific Ocean warming or cooling, and it's Terminology El Nino Or La Nina.
But what are NOAA's Indexes based upon? Lets take a look at their web site (https://www.ncdc.noaa.gov/teleconnections/enso/indicators/sst/)
*El Niño (La Niña) is a phenomenon in the equatorial Pacific Ocean characterized by a five consecutive 3-month running mean of sea surface temperature (SST) anomalies in the Niño 3.4 region that is above (below) the threshold of +0.5°C (-0.5°C). This standard of measure is known as the Oceanic Niño Index (ONI). You will note there is no mean SST mentioned.
*Studies have shown that a necessary condition for the development and
persistence of deep convection (enhanced cloudiness and precipitation) in the Tropics is that the local SST be 28°C or greater.
*A SST anomaly of +0.5°C in the Niño 3.4 region is sufficient to reach this threshold from late March to mid-June. During the remainder of the year a larger SST anomaly, up to +1.5°C in November-December-January, is required in order to reach the threshold to support persistent deep convection in that region.
WE can now see from above NOAA's OWN expression of the ONI (Ocean Nino Index) above note the Summer index of 0.5°c is confined to March-Mid June. and the UP TO +1.5c relates to the winter value November through January. *please remember these values as we progress through this blog*.
**Again there is no specific value in Celsius given to the mean SST in NINO regions so we MUST assume 28°c is the given threshold of +.5°c.
27.5°c must be the mean value to give a plus .5c threshold reached. ok.
With this information we should be able to provide a graph of ONI using the above.. correct? ok let us now plot this using the data that NOAA provide here (https://www.esrl.noaa.gov/psd/data/correlation/nina34.data
In order Jan-Dec.
The above is actual data from the above web site.
We shall now plot the last 15 months SST based on 5x3 month rolling avg as suggested by NOAA BUT TO SIMPLIFY graph 2018 index only using 27.5°c as the MEAN SST.
Now i shall present NOAA's ONI graph.
As you can see 2018 (according to NOAA) has had a positive anomaly throughout Jan/October recently going passed the threshold of El Nino .6°c above.
Let's look at the last 3 rolling months SST in region 3.4.
2018 - SST in region 3.4 from Jan -October are 25.57 25.97 26.48 27.31 27.74 27.78 27.42 26.95 + 27.19 + 27.58 = 81.72 div 3= 27.24°c. The last number in this equation 27.24 is .34 lower than the value given by NOAA for october (Above) and certainly NOT above the threshold of 28c ( given 27.5°c is mean). Now go back to MY GRAPH and see where El Nino is on my ONI plot.. pretty close isn't it?.
Lets look at current SST's in region 3.4 at 1st November 2018..
We see SST's of 28 and 26 throughout region 3.4 with a mean of.. yes you guessed it 27°c (28+26 is a round number it may be 28.3 and 26.2 ect).
NOAA'S own data says 27.58°c for october ( noted above) very good i agree!!! oh hang on David this is not above the nino threshold? Absolutely correct it does not even if we use a single monthly running total or a running 3 month anomaly. THE MATH DOESN'T WORK.
Now let us take a look at 2016 Super El Nino, registering +2.5 above threshold on NOAA's ONI USING Data presented from NOAA.
2015 ... 28.93 29.08 29.42 29.26
2016... 29.11 29.01 28.90 28.72 28.23 27.69 26.82 26.28 26.14 25.98 25.94 26.10.
Sep - Nov.... 2015 -28.93+29.08+29.42=87.43 div 3 =29.14
Oct-Dec ..... 2015- 29.08+29.42+29.26=87.76 div 3 =29.25
Nov-Jan ....... 2016- 29.42+29.26+29.11=87.79 div 3 =29.26
Dec-Feb........ 2016- 29.26+29.11+29.01=87.38 div 3 =29.12
Jan-Mar........ 2016- 29.11+29.01+28.90=87.02 div 3 =29.00
Feb-Apr......... 2016- 29.01+28.90+28.72=86.63 div 3 =28.87
index Sep-Nov of 1.14°c Index Oct-Dec of 1.25°c
Index Nov-Jan of 1.26°c Index Dec-Feb of 1.12°c
Index Jan-Mar of 1.00°c Index Feb-Apr of .87°c
As you can see we did see an El nino during 2015/16 however Using the data NOAA has presented above the threshold did not exceed 1.26°c Giving a Moderate/ strong El Nino, at NO POINT did the threshold reach 2+ on the ONI as suggested.
We can perform the same 5x3 month rolling average on the La Nina of 2010/11 an indeed CAN see an ONI breaking the -2 index,however NOAA's graph does not represent such (above). The figures above are for any member of the public to do their own investigations into the findings i present, this is not a witch hunt and was never intended to be, however the biased findings suggested here is remarkable given the current climate debate. Presenting such findings -there is no doubt in my mind that officials within this agency are manipulating trend lines to portray an unjustified outlook which only emphasises a skeptical view point.
Thank you for dropping by, i hope you got something out of this blog.
David I Birch. 08.11.2018
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