Friday, December 8, 2017

November global surface temperature down 0.04°C

TempLS mesh anomaly (1961-90 base) was down from 0.724°C in October to 0.683°C in November. This compares with the larger reduction of 0.12°C in the NCEP/NCAR index, and a much greater fall (0.27) in the UAH LT satellite index. The TEmpLS average for 2017 so far is 0.720°C, which would put it behind 2016, and just behind 2015 (0.729°C). It's unlikely that December will be warm enough to change that order, or cool enough to lose third place (0.594°C in 2014).

Update 10 Dec: As Olof noted in comments, although I had tested and enabled use of ERSST 5 (instead of 4) earlier this year, it wasn't actually implemented (failure to correctly set a switch). It doesn't make much difference on a month to month basis. The fall in November was 0.064°C instead of 0.04°C, and the spatial pattern is very similar. But as he astutely noted, it does make a difference to 2017 versus 2015. The means for the last three years are 0.729, 0.835, and 0.758. That puts 2017 0.029°C clear of 2015, which means 2017 will be in second place if December exceeds 0.41°C, which seems likely.

The anomaly pattern showed two marked warm spots in W Siberia and N of Bering Strait, and less pronounced in SW US. Cool in Canada and E Siberia, fairly warm near the poles. Theer was a weak La Nina pattern; much less than with the NCEP/NCAR index.

Here is the temperature map:


This post is part of a series that has now run for six years. The TempLS mesh data is reported here, and the recent history of monthly readings is here. Unadjusted GHCN is normally used, but if you click the TempLS button there, it will show data with adjusted, and also with different integration methods. There is an interactive graph using 1981-2010 base period here which you can use to show different periods, or compare with other indices. There is a general guide to TempLS here.

The reporting cycle starts with a report of the daily reanalysis index on about the 4th of the month. The next post is this, the TempLS report, usually about the 8th. Then when the GISS result comes out, usually about the 15th, I discuss it and compare with TempLS. The TempLS graph uses a spherical harmonics to the TempLS mesh residuals; the residuals are displayed more directly using a triangular grid in a better resolved WebGL plot here.



8 comments:

  1. Nick, the rank of years may change if TempLS switch to ERSST5.
    In the Gistemp map version, 2017 goes up 0.02 C vs 2015 if one changes the source from ERSST4 to ERSST5. (I have checked with annual 2015 and first three quarters of 2017).

    ReplyDelete
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    1. Olof,
      Thanks for noting that. I had set up to switch to v5, and I thought I had done so, but indeed TempLS is still using V4. I don't think it will make much difference month to month, but I'll recalc using V5 and report.

      Delete
    2. Thanks Nick,
      The effect of ERSST5 was somewhat larger than I thought. TempLS will likely agree even better with Gistemp loti now. ERSST5 must be a significant improvement in the recent decade since it includes Argo data, giving improved coverage in the southern oceans, for instance.

      Delete
  2. Is there La Niña this year or not? BOM calls La Niña, but MEI index drops back by a half.

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    Replies
    1. 2nd warmest La Niña in the instrument record.

      Delete
  3. Too soon to leap, but it is looking like December could come in with a higher anomaly than November, which is not what people expected from a La Niña. So here in the twilight of 2017, most likely the 2nd warmest year in the instrument record, it's time to start thinking about 2018. After back-to-back La Niña events, which have increased the 30-year trend, it looks possible the 2018 could finish 2nd, maybe even warmest evah! Why? Because the Eastern Pacific drives this thing, and it's showing no signs of intensified trade winds, which means anthropogenic global warming friendliness in all phases of ENSO. This situation could last another year, or it could last for more than a decade. Nobody knows.

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    Replies
    1. Return of Weddell Sea polynya also favors warmth.

      https://news.upenn.edu/news/penn-how-openings-antarctic-sea-ice-affect-worldwide-climate

      Chubbs

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  4. Berkeley earth land/ocean for November is out, and it is actually up a little from October, +0.006 C.

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