Monday, October 12, 2015

GISS September steady at 0.81°C

The GISS global anomaly is out. The timing is odd - it appeared on a Sunday, but seems to have been prepared on Friday 9 Oct, which is very early. It was 0.81°C, same as August. I have been writing about the somewhat disparate estimates - NCEP/NCAR was up 0.06, TempLS grid was steady, and TempLS mesh down 0.05°C. I thought differing estimates of Antarctica played a role.

This September was not (for once) the highest ever in the GISS record; it came second behind 2014 at 0.90°C. That was one of the warmest in 2014. Sep 2015 was still well about the record annual average (2014) of 0.75°C, keeping 2015 on track to be hottest ever.

I'll show this time first the GISS polar projections:

Antarctica is indeed cold, though not as uniformly as TempLS had it. But there is also a substantial grey area in the coldest part. That will be assigned the global mean value in averaging. Here I think that is a warm bias; TempLS mesh is probably more accurate there. Below the jump I'll show the usual lat/lon plot and comparison with TempLS.

Update - I see that with earlier comparison plots with TempLS ver 3 (since June) I have been inappropriately subtracting the mean, so the anomaly base was not 1951-80 as stated. Now fixed.

As with the TempLS spherical harmonics map below, it shows cold in Antarctica, W Siberia, N Atlantic, and watmth in US/E Canada, E Europe, E Pacific (ENSO) and Brazil.


  1. That grey part is precisely the one GFS and NCEP is giving a warm anomaly... Stay tuned for Byrd station.

  2. GISS has separate NH and SH anomalies. Sep 2015 SH was 0.50 compared to Sep 2014 SH 0.94 (which was SH record), much colder there. On the other hand the NH anomalies are going through the roof.

  3. I think Giss is a little bit premature, several countries in Africa are still missing, especially in Sahel, plus Peru, Bolivia, Spain, Sweden, etc. So there could be potential for an uptick of a few hundreths.
    Based on ERSST v4 and NCEP/NCAR land, the globally weighted anomaly should be up 0.04 from August.

    Next global index in the pipeline is JMA, which delivered the warmest monthly anomaly ever (of all months) in August, 0.46 above 1981-2010 average. With TempLSgrid as indicator, September could reach similar temperatures...

    1. JMA for september is out now. It's skyrocketing with 0.50 C, beating the newly set record in August by 0.04, and the old september record from 2014 by 0.15
      It is a preliminary value with similar deficiencies as GISS. The value may rise slightly when all reports are in.
      As a gridded dataset it is not very much affected by the cold Antarctica.