Monday, October 3, 2016

Reanalysis index up 0.047°C in September

The Moyhu NCEP/NCAR index rose in September to 0.475°C, up from 0.428 in August. This brings it back to about the level of May. There was then a drop to June, followed by a gradual increase to now. This seems to be associated with ENSO-neutral conditions. And as usual recently, it was the hottest month of its kind in the record. Next month will test this trend of records, since Oct 2015 was very warm.

On other matters, I apologise for the absence of blogroll, search etc. Apparently Google Blogger has recalled them for repair. I'm told they should reappear soon.


  1. Thanks for the update on your blogroll, I find it very useful for keeping up with blogs of interest!

  2. Preliminary UM CCI CFSV2 was down by 0.01C from August to September and preliminary WxBell CFSV2 was down 0.04C. The preliminary to final estimates from both sources sometimes change by plus or minus 0.02C or more, so we may have to wait for final values. Regardless, the uncertainty of the monthly global temperature estimates could be as much as 0.3C or more, so we may not really be able to resolve a difference when changes are so small. Both September CFSV2 estimates are more than 0.3C lower than the peak in February, so I have better confidence that there has been a downward trend since then. The UM CCI September preliminary global temperature estimate of 15.92C ties the UM CCI 2003 CFSR estimate as highest for September in the record going back to 1979, although considering uncertainty other years are involved in the tie as well.

  3. There was then a drop to June, followed by a gradual increase to now. This seems to be associated with ENSO-neutral conditions.

    Not sure about that. ENSO indicators seem to be dropping steadily, pretty much in-line with previous events and this would tend to produce a steady drop in global average temperature. I think non-ENSO variability primarily caused the apparent rapid downtick, and now uptick. I would expect October through December to persistently drop from here.

    That said, indicators of decadal Pacific variability do seem to be persisting high, so that may offset the ENSO-related drop over the coming year. For example, Gulf of Alaska SSTs rocketed upwards according to the NCEP reanalysis: expect to see "Return of the Blob" stories over the next month.

    1. Paul S - the PDO index keeps dropping, but the North Pacific SST appears to keep getting warmer. Is there an obvious reason for that?

      Does the PDO index give disproportionate weight to upwelling off the west coast of North America?

      I announced the emergence of double blob weeks ago. Compared with double blob, single blob, as blobs go, was a piker.

    2. JCH - Can't say I completely understand how the PDO index decides up and down, but seems to be primarily related to East -> West difference. E.g. April had a textbook PDO pattern - cold in the West, warm in the East. August was more fuzzy.

      Using the JISAO PDO numbers and averaging each month over the past 20, 30 and 40 years there is a clear and substantial annual cycle which peaks in March-April, troughs in September-November - peak to trough difference about 0.7. So, wouldn't be surprised to see a further drop for September's figure. However, the annual average for 2016 is going to remain high and the 3yr average will almost certainly be highest since the mid-80s.

    3. Interesting. You can see it by comparing months, this is May versus October.

  4. Ever seen a blog post as misguided as this one claiming that Lorenz's theory is validated?

    These deniers such as Curry and Pielke should just keep digging deeper and deeper. Like Trump, they should never stop digging themselves into a deep hole.