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Tuesday, October 27, 2009

Preliminary October 2009 OI.v2 SST Anomaly Data Appears To Have An Error

I’ve moved to WordPress.  This post can now be found at Preliminary October 2009 OI.v2 SST Anomaly Data Appears To Have An Error
Figure 1 shows the time-series plot of the Preliminary (Unofficial) Global OI.v2 SST Anomaly data through October 2009. The preliminary October 2009 data was posted on NOMADS yesterday, October 26, 2009. The official release is not scheduled until November 9, 2009. The new data shows an upward swing for October. This is likely an error, so I wanted to illustrate it just in case there are claims about a new record Northern Hemisphere SST anomaly for October.

Figure 1 – Preliminary October 2009 Global SST Anomalies

A look at the Southern Hemisphere data, Figure 2, shows a continuation of the decline over the past few months, though the drop looks a little steep.
Figure 2 – Preliminary October 2009 Southern Hemisphere SST Anomalies

Then, obviously, the increase must be in the Northern Hemisphere, Figure 3. As you will see, this rise does not appear in the weekly Northern Hemisphere data, so it is likely an error.
Figure 3 – Preliminary October 2009 Northern Hemisphere SST Anomalies

The sudden rise in Northern Hemisphere wasn’t prompted by a rise in NINO3.4 SST anomalies, Figure 4, because they didn’t increase appreciably in October.
Figure 4 – Preliminary October 2009 NINO3.4 SST Anomalies

One thing is certain; the weekly data through October 21, 2009, which is official, DOES NOT SHOW THE RISES that are being presented in the preliminary Northern Hemisphere and Global SST anomaly data. Refer to Figures 5 through 8.
Figure 5 – Weekly Global SST Anomalies Through October 21, 2009
Figure 6 – Weekly Southern Hemisphere SST Anomalies Through October 21, 2009
Figure 7 – Weekly Northern Hemisphere SST Anomalies Through October 21, 2009
Figure 8 – Weekly NINO3.4 SST Anomalies Through October 21, 2009

NOTE: The weekly NINO3.4 SST Anomalies are above 1 deg C for the first time this year.


OI.v2 SST data is available through the NOAA NOMADS website:


John said...

The Oct 28 Northern Hemisphere reading would have to jump up to like .8 or .9c for that to actually be October's reading, right? There are at least 3 weeks of Oct reading at .46 or below and the new level for the month appears to be .56ish.

Somehow I can't see that being accurate.

Plus, how can it even be preliminary without October 28th's reading, which won't get published until Nov 2 or so anyway?

Bob Tisdale said...

John: I haven't the slightest idea how or why the preliminary data shows up over a week in advance, but it does some months. I just wanted to head off any claims by alarmists.

I have notified NOAA of the apparent error.

Unknown said...

Hi Bob,

I have been plotting the new AMSU SST channel into MS Excel. Monthly anomalies are: June 0.113, July 0.188, August 0.128, September 0.07, October 0.041 (until 24.10.) Anomalies are versus 2003-2008 baseline.
Unisys gif also does not indicate any warm-up of North Atlantic, but quite the opposite: http://weather.unisys.com/archive/sst/sst_anom_loop.gif

Juraj V.

Bob Tisdale said...

Juraj V., thanks for the confirmation. The Northern Hemisphere SST anomalies will probably drop when the official October data mkes it to NOMADS.

And thanks for the gif animation.


magellan said...

Does this apparent error affect nino 3.4?

Bob Tisdale said...

d: You asked, "Does this apparent error affect nino 3.4?"

It doesn't appear so. If there is an effect, it isn't much. Keep in mind that the weekly data is "official" and the preliminary monthly NINO3.4 SST anomalies are in line with the weekly data.

Anonymous said...


Saw this and thought of you:




Bob Tisdale said...

Robin: Thanks for the link.


John said...

A bit of an eyeball correlation and certainly just simply an observation, but their ENSO reconstruction appears to start experiencing significant variance increases around 1910, right when the temperature anomalies start their upward march (at least when looking at the 1880 - present HADSST).

I wonder what happened then.

Bob Tisdale said...

John: Here's a copy of HADISST NINO3.4 SST anomalies from 1970 to 2008.

But if we smooth it, the data shows an underlying cycle that takes an upswing in ~1915:

A problem with NINO SST measurements that you have to keep in mind: Before the opening of the Panama Canal in 1914, there wasn't a lot of ship traffic along the equatorial Pacific, so the accuracy of the early data is questionable. If they've got the timing of the big wiggles right, that would be a good thing.

John said...

So it's both an upswing in anomaly and an increase in variance of that anomaly in around 1915?


Thanks for the information.


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