The first graph shows that the temperature at Manilla NSW agreed very closely with El Niño and La Niña temperatures for a good part of the last sixteen years.
The El Nino – Southern Oscillation (ENSO) is shown by NINO3.4 monthly anomaly values, and temperature at Manilla, NSW is smoothed monthly mean daily maximum temperature anomalies. (See the Note below.)
Values of Manilla temperatures agree with those of ENSO through the major temperature peaks and troughs in the spring seasons of 2002, 2006, 2007, 2009, and 2010. In the two highest peaks of 2002 and 2009 and the deep trough of 2010, Manilla temperature extremes were more than a month ahead of ENSO temperature extremes.
Since mid-2011, the two curves do not agree well:
* A La Nina in summer 2011-12 that was very weak produced the deepest of all troughs in Manilla temperature.
* An El Nino in winter 2012 resulted in heat at Manilla, but not until four months later.
* In spring 2013, when there was no El Nino at all, Manilla had a heat wave just like those with the El Nino’s of 2002 and 2009, .
The record for ENSO since January 2013 is unlike that earlier this century: it flutters rather than cycles.
To show slower changes, I have drawn cubic trend lines for both of the variables. These also agree closely, with ENSO going from a maximum (2004) to a minimum (2011) seven years later. Manilla temperature trends remained ahead of ENSO temperature trends by one or two years.
The second graph shows that higher rainfall at Manilla was often associated with La Niña events, and lower rainfall with El Niño events. The graphs are scaled to make the best match: 20 mm of monthly rainfall deficit at Manilla, NSW, matches one degree of excess temperature in the NINO3.4 region 7000 km away in the mid-Pacific Ocean.
The rainfall curve (when inverted) is very like that for maximum temperature, but the match with ENSO is not quite as good. Rainfall troughs (negative anomalies (up)) are not sharp: perhaps a linear anomaly is not the best measure. Peaks and troughs of rainfall generally come a month or two earlier than those of ENSO. Again, the match is poor after mid-2011. In particular, the very weak La Nina of summer 2011-12 came at the time of extreme rainfall, with an anomaly that was twice as high as any other shown here. Later, there was an extreme rainfall deficiency in summer 2013-14 without an El Nino.
The cubic trend line for Manilla rainfall anomalies (inverted) is similar to that of Manilla maximum temperature. It, too, leads the ENSO trend by one or two years.
I presented data of this kind up to April 2011 in earlier posts, the last being this one.
I noted that, compared to peaks in ENSO:
* Peaks of Manilla daily maximum temperature come one month earlier;
* Peaks of Manilla rainfall come two months earlier;
* Peaks of Manilla dew point come three months earlier.
Predicting weather from ENSO
This extension of data out to sixteen years relating Manilla’s climate to ENSO suggests even more caution about predicting weather from ENSO than I did earlier. Perhaps we have entered a phase when the weather (at least here) relates less to ENSO events than it did in the recent past.
These are monthly data values. The El Niño – Southern Oscillation (ENSO) is represented by NINO3.4 monthly anomaly values, as published on this web-site.
Because they need a little smoothing, I have applied the same smoothing function that was routinely applied to the previously-authoritative data, the ONI, that is, (1:1:1)/3.
Values at Manilla, NSW are monthly mean daily maximum temperature anomalies, taken in my Gill screen, and monthly rainfall totals from Manilla Post Office, Station 055031. Both are smoothed with a Gaussian function of half-width six months. This function requires six more monthly readings after a given date, which makes December 2014 the latest available date.