Friday, February 3, 2017

NCEP/NCAR January warmest month since April 2016.

The Moyhu NCEP/NCAR index at 0.486°C was warmer than any month since April 2016. But it was a wild ride. It started very warm, dropped to temperatures lower than seen for over a year, rose again, and the last two weeks were very warm, and it still is. The big dip coincided with the cold snap in E North America, and in Central and East Europe, extending through Russia. Then N America warmed a little, although some of Europe stayed cold, and there was the famous snow in the Sahara. Overall, Arctic and Canada (despite cold snaps) were warm, as was most of Asia. Europe and the Sahara were indeed cold.

I'll note just how warm it still is, historically. I don't make too much of long term records in the reanalysis data, since it can't really be made homogeneous. But January was not only warmest since April, but warmer (by a lot) than any month prior to October 2015.

UAH satellite, which dropped severely in December, rose a little, from 0.24°C to 0.30°C. Arctic sea ice, which had been very low, recovered a bit to be occasionally not the lowest recorded for the time of year. Antarctic ice is still very low, and may well reach a notable minimum.

With the Arctic still warm, I would expect a substantial rise for GISS and TempLS mesh, with maybe less for HADCRUT and NOAA.


  1. Nick, a minor nitpick... GMST for January is typically over 3C lower than July, so there is no way January could be the warmest month since last April. However, I understand what you mean to say, and that is the January GMSTA was the highest for any month since April.

    And yes, it was a wild ride, especially in the higher latitudes of the northern hemisphere. I suspect the earth has been getting rid of some of the excess heat built up from the 2015-2016 El Nino. As excess heat surges into the winter pole it makes for big extremes with both large warm and cold anomalies, causing large oscillations in the anomalies over time. This happens every winter, but seems to have been a bit more extreme than usual in both the SH winter of 2016 and the NH winters both 2015-2016 and 2016-2017. The GFS is indicating the beginning of another dip in daily GMSTA during the next week, although it remains to be seen if it will drop as much as in January. I suspect not, but time will tell.

    1. We who are familiar with Nick's blog know well his well justified hostility to claims of "warmest ever", so, yes this is about anomalies. What really strikes me is that January 2017 has the largest anomaly of any month outside an el Nino.

  2. Nick - " Arctic sea ice, which had been very low, recovered a bit ...."

    I realize you're speaking to the fact extent now only fluctuates between the lowest and 2nd or 3rd lowest for the date, but "recovery" seems a bit strong :)

    Volume should be increasing slowly as this year's new ice simply can't form much thickness and existing ice won't add much either. The magnitude of reduction in new ice thickness, as reflected in the Freezing Degree Days anomaly, is unprecedented.

    DMI N80 Freezing Degree Days thru Feb 2, 2017
    (Climatology = 1958 to 2002)

    Accumulated FDDs
    Climatology: 3095.9
    2016-7: 1833.0
    Anomaly: -1262.9

    Implied new ice thickness to date:
    Per Lebedev:
    Climo: 1.755 m
    2016-7: 1.288 m

    Per Bilello:
    Climo: 1.408 m
    2016-7: 1.039 m

    Graphs at,1611.msg101637.html#msg101637

  3. OK, NCEP/NCAR is down by 0.18 C from previous January. If this also applies to Gistemp loti it would become 0.99 in Jan ( 1.17 Jan-16).
    However, the SST can be tricky and behave differently. I think it is a safer prediction to say that Gistemp dTs will be 1.19 in Jan (1.37 in 2016)

  4. PIOMAS is in for January and indeed we've seen slow ice growth just as the Freezing Degree Days indicated.

    Zach labe has a graph:;topic=1611.0;attach=41318;image

    And of course the PIOMAS site does as well:

    Pretty spectacular really.

  5. Are you sure your link to the UAH6.LT data in you "Latest Ice and Temperature data" is valid? The last update was the November 2016 data.

    1. Erik,
      Apparently we are now up to beta6, so the filename changes I'll update the listing. But that file still doesn't have January.

  6. The Copernicus Era-interim report for January is here

    January 2017 is the second warmest January on record, 0.17 C below Jan 2016

  7. So I have a question about RSS TLT and TTT. How do they differ and which is better for comparisons with surface temps? Thanks.

    1. RSS 4.0 TTT is basically the successor to 3.3 TLT. They have done rather similarly to UAH6, which uses a weighting that peaks at 4km rather than 2. That lets them do a better job of separating the stratosphere, and also radiation from the ground. But it is total trop rather than (trying to be) lower. Should be more reliable (although I'm not sure about UAH V6).

      I think people overdo comparison of satellite and surface. They really are different, and there is no way around that. TTT is a mix of all levels (as TLT was).

    2. Nick, your reply agrees with my own interpretation of the UAH pre-published 'paper' (on Roy Spencer's web site still - he cites the actual publication as in-press now, but I still haven't seen it published on line anywhere), i.e. that the change in the altitude weighting function means that it can't really be considered to be a TLT dataset any more. But the really interesting thing is that this brings it close to the RSS TTT weighting function (aomething I've pointed out on several occasions to Werner Brozek on WUWT who seems to insist on a near religious faith in RSS 3.3 TLT despite the issues with that dataset that Mears et al. pointed out in their published paper).

      So here's the real question: Which dataset is right?

      RSS 4.0 TTT and UAH 6.0 TLT are probably the best direct comparison between two alternative state of the art methods for compensating for the main issues with Satellite datasets (e.g. diurnal drift, orbital decay, surface reflection effects etc.). They show quite different trends and can't both be right.

      UAH 6.0 remains very strongly correlated with RSS 3.3, which Mears et al. says contains a known cooling bias.

  8. Probably not the right place for this comment, but... is it my imagination, or does John Bates not understand how to read a binary file format?

    "This is confirmed by parsing the file name actually used on the FTP site for the K15 dataset [link]; NOTE: placing a non-machine readable copy of a dataset on an FTP site does not constitute archiving a dataset)."

    There's a readme.txt file on the ftp site with descriptions of the file formats of the various files. I haven't actually tried to write the code to extract the file, but... it certainly looks like they are just regular binary files, which would totally count as archiving a dataset, right?


    1. MMM,
      I think it's the opposite complaint. The files are in ascii. It's possible there is a recommendation somewhere to use NetCDF or some such, although for many people that reduces readability. So most NOAA data publicly released is ascii, usually gzipped if long. The format they stored their ISTI/GHCN and ERSST data is exactly the public release format. And there is the further odd objection to it being a ftp server. I have no idea what that is about. All the NOAA data that I access, I think, is on ftp. Again, bates may be pushing NOMADS or some such. People have vested interests.

    2. Ah, thanks, that's helpful... though Bates and his complaints continue to baffle me.