Thursday, December 8, 2016

Global TempLS unchanged in November; sea ice is low.

The November TempLS mesh index was virtually unchanged, at 0.687°C in November from 0.692°C in October. The TempLS grid index declined, from 0.626°C to 0.56°C. The disparity between mesh and grid is unusually large, and is caused by the polar warmth, which LS mesh is more sensitive to. Other indices generally rose in November; NCEP/NCAR index by 0.06°C, and also UAH lower troposphere (0.04°C).

The main map features are a cool band across Siberia, and big warmth in North America. Antarctic was warm, also Arctic.

I mention sea ice again, because it is starting to get more general attention. Arctic ice remains at record low, although it didn't really get worse during the month, despite an actual melting episode mid-month. But Antarctic ice has been exceptionally low since mid October, and is now entering the fast melt times.. Here is a section of the radial plot:


  1. With the release of the Nov. PIOMAS volume data northern hemisphere sea ice is now at record lows for this time of year in all major metrics; area, extent, and volume.

  2. What will the GISS Nov 16 anomaly be? If I use GFS+NCEP only I would say 0.94, but from TempLS+RSS regression I get 0.87 only. If I combine all datasets will already Nov 16 temperature I get 0.91 to 0.92.

    Meanwhile Dec seems to cool down according to Karstens site. This is interesting, because my regression model predicted this since about May at significant level.

  3. Uli - I noted that Held recently said he knows of no way to put natural decadal or multidecadal variability into a GCM. I noticed this paper in my nightly searches of Google Scholar. Predictability and prediction of persistent cool states of the Tropical Pacific Ocean "...Our results suggest that the Pacific will undergo a shift to a warmer mean state after the 2015–2016 El Niño. ..." This is exactly what I was expecting. The last half of the 1930s saw a sharp upward turn in the PDO, and a rapid warming. BOM shows ENSO ONI taking an upward track starting in January-February 2017. NOAA PDO took a sharp upward turn in November despite cool North Pacific. Looks like 2017 could be very warm.

    1. "I noted that Held recently said he knows of no way to put natural decadal or multidecadal variability into a GCM."
      Yes, I think that is true, and relates to something often misunderstood. GCMs solve a whole lot of discretised equations relating adjacent elements. It's not easy to put in any kind of global condition on the unknowns. You can do it with material properties like gas mix. But otherwise, you need tuning-type methods. Take some existing parameter that has a fair range of uncertainty, and vary it until by trial you satisfy the global constraint (eg TOA balance).

      The thing is, there are only so many parameters that qualify. And the trial process is a lot of computing. One issue is apparent if you think of ordinary simultaneous equations. If you have the same number of equations as unknowns (as GCMs usually do), then if you add another equation, something's gotta give. The other problem is that the solution methods generally rely on the variables in each equation being local. Global constraints are a numerical pain.

    2. I've read so many demands that the AMO should be included in GCM's. It's a RELIEF to know it can't be done... just kidding, but the result would be a 60-year fairy tale

  4. Why arctic anomalies are so low?

  5. @pdjakow: See the discussion here
    I think most of the temperature indices does not reconstruct the anomaly over the sea correctly, if it was sea ice in the past but is open water now.

  6. GISS November is out, 0.95 C, up 0.07 from Oct. Slightly warmer than expected I suppose..
    More astonishing is maybe the dTs index, which still has warmer monthly anomalies than 2015, ie the running 12 month average is still rising..