Saturday, November 3, 2018

October NCEP/NCAR global surface anomaly up 0.1°'C from September

In the Moyhu NCEP/NCAR index, the monthly reanalysis anomaly average was 0.298°C in October, up from 0.196°C in September, 2018. In the lower troposphere, UAH rose by 0.08°C. The Surface temperature had been drifting down since April, and October started on that trend, but a big rise in the second half made it the warmest month since April.

In fact, N America (especially Canada), China and W Europe were rather cool. The Arctic was warm, and E Europe; the Antarctic was patchy but mostly cool.

On El Niño from the BoM:

"The ENSO Outlook is set at El Niño ALERT. This means the chance of El Niño forming in 2018 is around 70%; triple the normal likelihood.

The tropical Pacific Ocean has warmed in recent weeks and is now just touching upon the El Niño threshold. Latest observations and model outlooks suggest further warming is likely, with most models indicating a transition to El Niño in November remains likely."

This post is part of a series that has now run for some years. The NCEP/NCAR integrated average is posted daily here, along with monthly averages, including current month, and graph. When the last day of the month has data (usually about the 3rd) I write this post.
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.

A list of earlier monthly reports of each series in date order is here:

  1. NCEP/NCAR Reanalysis report
  2. TempLS report
  3. GISS report and comparison with TempLS


  1. TempLSmesh for October is up and running now. It is up 0.175 C from Sept, but it should be taken with a pinch of salt since less than half of the land area have reported.
    However, the change doesn't seem unreasonable. NCEP/NCAR land only is up 0.39 C from Sept and ERSST5 is up 0.07 C.
    So Gistemp loti for October may leap above 0.90 C. If GHCN v4 become introduced in the dataset everything will change. GHCN v4 is operational now and no longer beta.
    My qualified guess/prediction is that GHCN 4 will increase recent Arctic trends, increase global trends slightly, and make a lot of skeptics upset..

    1. Yes. It seems to be a big rise in SST, for which all the numbers are in. TempLS also sees about 0.075. I hope the land situation will be clearer in about four hours.

    2. Today there is more data (still a lot missing) and the temperature is even higher. The rise in TempLS grid is lower than mesh, so I checked with the spherical harmonics quadrature, which I don't normally run this early. It gives a similar rise to TempLS mesh (0.205). Using grid with proper infilling gave a smaller rise, at 0.144°C.

    3. Copernicus ERA-interim for October is in, up 0.145 C from September.
      I have looked at the temperature change from Sept to Oct in different atmospheric layers in NCEP/NCAR over at ESRL/WRIT. The troposphere at 700 mbar and above has actually cooled a little bit.

      Difference degrees C Oct - Sept (1981-2010 base)
      700 mbar -0.035
      850 mbar +0.049
      925 mbar +0.100
      2 m +0.151
      SST/skin +0.206

      So there is more warming closer to the surface. If we make proper blend, 71% sea-masked SST/skin (+0.117) and 29% land-masked 2 m air (+0.390), the blend will be +0.196. This is maybe the best comparison/indicator for the blended observational datasets.

      Nick, you daily NCEP/NCAR data source is "sig 995" (i I remember right), which refers to the level with 99.5% of the surface pressure. I think that equals the temperature at about 50 m above the surface. The change from Sept that you report, +0.102, is between that of 2 m and 925 mbar, which makes sense. Maybe different baselines have some effect also also, or that 925 mbar data for land above that level is missing from the retrieved global average?

    4. Interesting. Warming causes expansion, so the height of the 700mb should have increased in direct proportion to the increase in temperature, would be worth a check. I find that the the height of the 300mb layer is a good rough proxy for satellite TLT.


  2. Looks like "The Blob" is back. Cue endless discussion about that.

    It does look like Nino3.4 SSTs will reach levels consistent with being reported as an El Nino, but one major issue is that I can't see any real sign as yet of the East-West gradient which defines it, and it's getting very late in the year. In terms of average equatorial West Pacific ocean temperatures down to 300m we're currently at record highs when we would expect negative anomalies if an El Nino is developing.

    It seems like temperatures are just generally warm in the tropical Pacific right now.

    1. Nothing in ENSO from the 30-day MA of SOI indicates an El Nino.
      ENSO/SOI, PDO, AMO, MJO, NAO, AO, QBO are likely all common-mode mechanisms but phased differently.

    2. Impressive warmth subsurface in the Pacific. Usually a leading indicator of enso and global temperatures.