Thursday, February 4, 2016

Satellites, surface temperatures up in January

The satellite temperatures for January are out now, and also the Mohyu NCEP/NCAR index. All increased, quite significantly. UAH Ver 6 beta was up by 0.09°C, to 0.54°C. RSS-MSU was up from 0.543 to 0.663°C. In both indices, Jan 2016 was the highest ever, making four such months in a row. However, the jump from Dec to Jan was rather smaller than in 1997/8. I have an eye here on the implications for the RSS "pause". February will have to be a lot warmer (0.88) to erase the pause in that month. OTOH, the January warmth, if sustained, will ensure there are only positive trends after March data.

The NCEP/NCAR index rose from 0.621 to 0.665°C. Again, very warm, but not as big a rise as might have been expected. In fact, the first half of January was very warm indeed, but then came a relatively cool period. February is starting warm again.

Monday, February 1, 2016

Any news on the GWPF International Temperature Data Review?

I mentioned the revised state of this project in September. The project was announced in April. The news page hasn't updated since September. And the submissions seem to remain unpublished.

I'll check back around the anniversary of the announcement in April.

Wednesday, January 27, 2016

The fleeting pause

At WUWT, there is a monthly post (latest here recording the duration of the Pause, which Lord Monckton defines as the maximum time back that a satellite index, RSS, can be found to have trend less than zero. The choice of that index, which measures an average of troposphere temperature by a complex analysis of data from several satellites, is necessary because all of the better known surface temperature indices have rising trends for all recent periods.

So there is lots of cherry picking. You can see what is actually going on in this calculation in the following back trend graph (from this active plotter).

The graph shows, for various indices, the trend from the year on the x axis to present (Dec 2015). You can see the cherry picking in the choice of index. RSS is the lowest green curve. It now has UAH V6 beta for company, but only recently; V5.6, still being published, was up with the surface indices. The Pause starts from the first crossing of the x-axis, which I've marked with a red circle. But you'll see that even so, most of the curve is positive. The excursions below the axis are brief and shallow, and about to come to an end. In fact the shape is not too far from an inverted image of the time series itself. The big temperature peak in 1998 shows as a dip, while the following trough shows as a local peak in trend. That is why the "pause" has persisted - because of the very big 1998 peak which depresses subsequent trends.

I'll show later how the troposphere measures respond strongly but late to an El Nino. So much higher readings are expected in the coming months. But already those curves are rising rapidly, and I expect them to clear the axis within two or three months. In fact, I'll show a fairly easy way of measuring this, in terms of temperatures to come. Specifically:
  • If the January anomaly exceeds about 1.3°C, the Pause is gone. This is unlikely.
  • If the Jan and Feb anomalies exceed on average about 0.77°C, the curve will be above the axis. For reference, the Dec anomaly was 0.543°C. I think this is quite likely.
  • If the first three months exceed 0.59°C on average, that would suffice to extinguish the pause. That is barely above the December value, and I think very likely indeed.
  • If Jan-April exceed 0.5°C, that will also suffice.
I'll explain the arithmetic below the fold.

Saturday, January 23, 2016

History of record warm years.

Last year, I posted plots of the progress of the record warmest year for various datasets. This year, I'll show an update for the three main surface sets. The jump from 2014 to 2015 is among the largest record jumps in at least a century. Here is GISS:

And below the fold, NOAA and HADCRUT:

Thursday, January 21, 2016

GISS and TempLS compared, in December and in 2015.

In my previous post, I noted the record levels reached in both the NOAA and GISS indices in December, and for 2015. In the NOAA report they note that December 2015 exceeded any earlier December by 0.29°C.

In this post, I'll present my usual map comparison between GISS and TempLS mesh in December. But I'll also expand on the continued close association between GISS and TempLS mesh, on one hand, and NOAA and TempLS grid on the other. The plot below shows those timeseries for 2015:

There is a deviation in the first three months, where both GISS and NOAA drifted away. I wonder if it is a concidence that these were the last months before introduction of ERSST4. But otherwise, the pairing, and close tracking of the pairs is very evident.

GISS up by 0.07°C in December, NOAA by 0.14, many records set.

As widely discussed here, 2015 was record hot, and getting hotter at the end. NOAA and GISS made a joint release - NOAA's report is here. For 2015 the annual average anomaly for 2015 was 0.9 °C, which beat the 2014 record level by 0.16°C. GISS put it at 0.87°C, relative to their 1951-80 base; for 2014 it was 0.74.

For December, GISS reported 1.12°C. This was a rise of 0.07°C from November. As usual, this was very close to the change in TempLS mesh, which now stands at 0.076°C. The rise in NOAA (0.14) was also, as usual, very similar to TempLS grid (0.16°C).

According to the NCEP/NCAR index, January is even hotter again, by a long way. The last two days have been cooler. I'll post more on the historical significance of these huge monthly and annual readings shortly, along with the usual GISS/TempLS comparison.

Sunday, January 17, 2016

An old WUWT SST blooper back to life.

In recent days, someone who comments as Kristian, but blogs as okulaer, has been active. He commented here to draw attention to his extensive recent posts, and has been plastering the material at WUWT. The ratio of sense to graphs is small. But there is one I want to treat here, since it relates to a 2010/2 blooper by Bob Tisdale at WUWT, and on his own blog .

Kristian posted a WUWT comment here, saying that GISS land mask had failed, and showing (from here) this plot:

It shows trends (despite y-axis label) of land-masked GISS vs OIv2 SST, which GISS used at the time. The divergence near the poles is attributed to GISS "deleting data". Now I should say that this plot does not seem to have been cross-posted at WUWT. But it expresses Bob's complaint at WUWT about deleting data, and is referred to most months at WUWT (see pingback list) in Bob's updates, most recently Nov 2015 here. The boiler-plate complaint is
Unlike the UK Met Office and NCEI products, GISS masks sea surface temperature data at the poles, anywhere seasonal sea ice has existed, and they extend land surface temperature data out over the oceans in those locations, regardless of whether or not sea surface temperature observations for the polar oceans are available that month. Refer to the discussions here and here.