Last month I added code to vischeck.py so that it could more easily display the seasonal averages computed by ccc-gistemp and GISTEMP. We can display temperature change for a particular season.
It is customary for meteorologists to define seasons in 4 blocks of 3 months. June, July, and August form the Southern Hemisphere cool season and the Northern Hemisphere warm season.
Here’s the latest comparison with GISTEMP for the June, July, August season:
tool/vischeck.py --download > jja.png --legend ccc-gistemp\|GISS --extract JJA result/mixedGLB.Ts.ERSST.GHCN.CL.PA.txt http://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts+dSST.txt
For 2014 both ccc-gistemp and GISTEMP report an anomaly of 0.62 °C for the June, July, August season (using a base period of 1951 to 1980). And normally we’re an exact match, occasionally the rounding shifts one way or the other and we can be 0.01 °C out. For 2013 we’re a whopping 0.03 °C different. Does anyone want to investigate?