Monday, December 21, 2009

Darwin and GHCN Adjustments


  1. GG's analysis is flawed. Consider a simple example with only 2 stations. Both stations have an unadjusted trend of 0 degrees/decade. Station A has an adjusted trend of 1 degree/decade and Station B has a adjusted trend of -1 degree/decade. Both stations records begin at year 1. Station A's record is 100 years and Station B's is 50. The distribution of the trend difference is symmetrical. Now average the temperature over the 100 year period for both records. The effect is obvious.

  2. The analysis isn't overall flawed. You're objecting to the use of the simple mean as a summary statistic. That's true - a better statistic would be the mean weighted by number of years in the record. But with a large sample, and not much dependence on record length, it doesn't make much difference. I did the calc - the mean trend adjustment over all stations increases from 0.0175 to 0.0179 C/decade if you weight by record length.

  3. You may find this interesting,

    Who is Willis Eschenbach?

    As of 2012 Mr. Eschenbach has been employed as a House Carpenter.

    He is not a “computer modeler”, he is not an “engineer” and he is certainly not a “scientist” (despite all ridiculous claims to the contrary).

    “A final question, one asked on Judith Curry’s blog a year ago by a real scientist, Willis Eschenbach…”