Compilations of New Zealand land historical temperature trends 1864-2005 by various groups over the years 1986-2006, an overview and comparison.

In 1991 when I first looked at how the Jones et al 1986 team compiled New Zealand T data I saw they used all the main cities and few rural or small town stations but came up with what I thought was a reasonable trend. My 1993-1994 studies of NZ station data showed many long term sites with warm periods in the late 19C or early 20C, as in SE Australia. Data in graphic from the KNMI ClimateExplorer, see my Blog. CRUT2 is they latest iteration of the Jones et al data that has been the yardstick of IPCC global warming for near 20 years now. CRUT2 is not updated beyond 2005 and I predict will be eventually pulled from public access.

NIWA has published various trends for NZ over the years but they always found more warming the Jones et al 1986 and its final iteration, CRUT2
NIWA's latest effort is at  http://www.niwascience.co.nz/ncc/clivar/pastclimate

On the NIWA website now  if you scroll way down the page you can find this graphic with its stunning trend from 1900 which exceeds global warming. A comparison of NIWA trends from this graphic with CRUT2 and CRUT3 can be found at my Blog post; http://www.warwickhughes.com/blog/?p=113#comments By whatever choice of grid cells you measure NZ trends, NIWA and CRUT3 (see below) have vastly more warming than Jones et al CRUT2. Figure 6: Mean annual temperature over New Zealand, from 1855 to 2005 inclusive. The blue and red bars show annual differences from the 1971 - 2000 average, the solid black line is a smoothed time series, and the dotted line is the linear trend over 1900 to 2005.

In 1993  I purchased all NZ T station data from NIWA  and explored what long term stations I could find. The preliminary results from non city data are in the two graphics linked below, never before promulgated on the internet. These are works in progress, meaning they will be updated and further work done after I can access NIWA data without paying for it.  Click on links for full  sized graphic

North Island

You see some long term stations with warm periods in the late 19C and early 20C

South Island

As in the North Island you see some long term stations with warm periods in the late 19C and early 20C

Clearly the Jones et al  CRUTem2 trend at the page top incorporated more of the early warm data, in contrast to the NIWA trend which must have adjusted out much of these early warm NZ data.
Finally we come to the 2006 publication of the Hadley Centre CRUTem3 trend

The outliers near 1860 are a puzzle but blind Freddie can see that  Hadley Centre people have "touched the forelock" to NIWA and have adjusted  much warm early NZ data to be cooler.  For actual trend numbers calculated in Excel, see my Blog. http://www.warwickhughes.com/blog/?p=113#comments Who was it said, "the future is known, it is the past that changes". It is high time that the Hadley Centre renamed CRUTem3 to  say HadTem3 to reflect the reality that their people are the lead authors and Jones is the "tail end Charlie" author at number 5.

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Post quickly on 31 May 2007 to assist  discussion on Blogs.