Wednesday, June 18, 2014

Another error in GHCN for May - from China CLIMAT form.

As I have noted in my usual posts for TempLS and GISS, Gavin Schmidt has tweeted that there is a problem with China data in the CLIMAT file, and the current GISS should be regarded as provisional.

When I looked into it I found that a large amount of the China May data was a copy of April's, and this was also in GHCN unadjusted. That explains why the TempLS map for May showed an intense cool spot over China, since TempLS uses that unadjusted data. It did not get into GHCN adjusted, and so GISS did not use China data.

How much does it matter? I did a repeat May calculation with TempLS using just the long term averages for China stations. That raised the global average anomaly from 0.47°C to 0.514°C. Oddly, it still left a cooler than average spot over China. Since the climatology I used does not allow for warming, it is likely that real China data will further raise the global average.


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