Hadley Centre inserts more warming into New Zealand climate history

I have two graphics here comparing the “old” CRUTem2 data of Jones, with the new Hadley Centre CRUT3. Looking at 140 years of New Zealand land based data and we now see huge extra warming in the Hadley Centre CRUT3 gridded data.

Both graphics tell a very similar story, the first uses data from a square of gridcells, 35-45 South, 170-180 East, which excludes Dunedin. Trends as follows.

1864-2005 -0.086 0.64 0.86
1900-2005 0.32 1.06 1.06

The second uses data from three gridcells, 35-50 South, 170-175 East, which includes all main NZ cities but not the eastern North Island. Trends as follows.

1864-2005 0.15 0.83 0.86
1900-2005 0.4 0.96 1.07

I expect the Hadley Centre will do a similar adjustment to their Australian data.Data are from the KNMI ClimateExplorer climexp.knmi.nl/ (under “Select a Field, Take “Monthly Observations”)

See my post from January www.warwickhughes.com/blog/?p=82. There are now huge variations now between the 3 main global T datasets, where I said Jones was trending out of the picture in favour of the Hadley Centre.
Added 1 June: New web page setting out a perspective of compilations of the NZ land based T history from the 1986 work of Jones et al up to the Hadley Centre’s CRUT3.

6 thoughts on “Hadley Centre inserts more warming into New Zealand climate history”

  1. Dear Warwick,

    I am a close follower of climate audit as well as your site and am extremely interested in your post on NZ temps. Could you give me an overview of what these changes mean to NZ’s temperature history and what is the response of NIWA to these changes?

  2. The main implication I see is that it now lets NIWA claim closer agreement with IPCC data when they promulgate trends on the NIWA website claiming a high rate of warming since 1900. Facts are that much long term NZ station data shows warm periods in the 19C and early 20C. NIWA’s Dr Jim Salinger has for years published trends that adjust out these early warm periods. But for whatever reason Jones always stuck with his own version of NZ data (see CRUT2 on my graphics), which left much of the early warmth intact. Now the Hadley Centre CRUT3 has gone much closer to NIWA.
    If you look at my January Blog post linked above,www.warwickhughes.com/blog/?p=82
    you will see I claim that in the N Hem the Hadley Centre has had to step back from some of Jones CRUT2 far north high warming grid cells that were hard to justify. So to keep overall global trends little changed they are no doubt happy to recover a bit more warming from anywhere.
    I am not aware NIWA has said anything, they are seeing a giant UK group agree more closely with what they have pushed for years, no need for NIWA to say anything. I am the one drawing attention to this.
    You could try asking NIWA and I would be fascinated to read any reply.

  3. Dear Warwick,

    Have recieved a reply to my latest email. With respect to the writer I would prefer at this stage to send you the email personally rather than post on site here. Could you oblige with an address please and will copy to you.

  4. Truth be known, it’s the grid cells that are warming.

    Problem is these grid cells have no physical basis in reality, since the are 2 dimensional planes and thus zero thickness and as a consequence zero mass, so the warming is essentially a mathematical artefact.

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