The GISTEMP result differs because GISTEMP covers the polar regions missing from the other datasets.
As the figure caption says, the ccc -
gistemp result in the figure was produced using «software revision 700 ``.
But the WUWT blog seems to like it and it reminded me of
the GISTEMP results.
Not exact matches
The NASA
results, calculated by Goddard Institute for Space Studies are published monthly on the NASA / GISS website (
GISTEMP).
# 10 Paul «One thing that seems potentially new and interesting from their
results (and that I haven't seen many comments on) is the fact that their global record goes back about 50 more years than CRU and 80 more years than
GISTEMP by starting with the year 1800.
So I don't think it is unreasonable to use HadCRUT for analyzing global temperatures and not bother comparing the
results to
GISTEMP.
One thing that seems potentially new and interesting from their
results (and that I haven't seen many comments on) is the fact that their global record goes back about 50 more years than CRU and 80 more years than
GISTEMP by starting with the year 1800.
We also checked that using different observational datasets (NOAA, Berkeley,
GISTEMP) gave similar
results (
results shown in Extended Data).
And if you don't trust NOAA, compare their
results to those of
GISTEMP and HADCRUT, not to mention the Japanese Met Office.
We also used
GISTEMP global annual surface temperature anomalies, and a 4 - month lag between MEI and
GISTEMP, consistent with the
results in Foster & Rahmstorf (2011).
And the differences in this one small region were big enough to explain about two thirds of the difference in trend between our
results and
GISTEMP.
Result: two years later
GISTEMP, HadCRUT, and NCDC stopped showing this fake warming and aligned their data with satellites.
The
GISTEMP analysis was not affected by this error, i.e. none of the
results, tables, maps, graphs about global or regional means changed.
Although in the early history of ccc -
gistemp we were very particular to match exactly the precise details of every step of GISTEMP, so that we could understand and reproduce them, subsequent development has allowed many independent variations and experiments, and the fundamental results have been very robust under such var
gistemp we were very particular to match exactly the precise details of every step of
GISTEMP, so that we could understand and reproduce them, subsequent development has allowed many independent variations and experiments, and the fundamental results have been very robust under such var
GISTEMP, so that we could understand and reproduce them, subsequent development has allowed many independent variations and experiments, and the fundamental
results have been very robust under such variation.
Remember he stated he was «surprised» that the BEST
results matched
GISTEMP and HadCRUT.
The
result is that if you reduce the coverage of
GISTEMP to match HadCRUT3, the bulk of the difference between the two datasets disappears.
A summary finds about 1/2 C of added'til t» to the temperature data (
resulting ONLY from the
GIStemp processing through STEP1):
Note that when the
GISTEMP data is masked to reduce the coverage to match one of the other datasets, the
resulting temperature trend is a good match for the trend in the incomplete dataset.
ccc -
gistemp is just one analysis, and while it mimics NASA GISTEMP very closely, rounding and other sources of computational ambiguity sometimes result in a slightly different
gistemp is just one analysis, and while it mimics NASA
GISTEMP very closely, rounding and other sources of computational ambiguity sometimes result in a slightly different
GISTEMP very closely, rounding and other sources of computational ambiguity sometimes
result in a slightly different
result.
You can use WinBUGS to fit change - point models with auto - correlated errors (applying to
GISTEMP data produces
results that look v. similar to Fig. 4 in the RealClimate post).