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New Zealand Temperature Trends

October 30, 2014

By Paul Homewood

  

Hokitika Aero

 

The only long running rural temperature station in New Zealand, listed by GHCN, is Hokitika Aero, located on the South Island 94 miles from Christchurch.

What can Hokitika tell us about long term trends?

 

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http://data.giss.nasa.gov/cgi-bin/gistemp/show_station.cgi?id=507936150000&dt=1&ds=1

 

 

Between 1909 and 2009, mean temperatures rose at a rate of just 0.3C/century. This, of course, is in line with the results of the study be de Freitas et al, which found a similar trend for New Zealand as a whole.

 

It is also worth looking at the trend since 1979, which has been flat. Note also the cold years of 1983 and 1992, which were associated with the El Chichon and Pinatubo eruptions.

 

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18 Comments
  1. October 30, 2014 4:07 pm

    Hokita,
    ! know that one, located it some time ago.

    -42.712876° 170.984271°

    Something vaguely rings a bell about historic station moves, implies it has been discussed and someone pointed this out.

  2. October 30, 2014 4:54 pm

    I am getting both Christchurch and Auckland running a bit opposite the global (cooling) wave, like CET, warming at ca. 0.13K/decade, from 2000.
    Otherwise, since 1980 my results for NZ are also flat, if you take Auckland and Christchurch on average.

    Click to access henryspooltableNEWc.pdf


    Like I said before, any uptrend noted over the past 88 years (= 1 Gleissberg cycle) could well be just due to improved observing and measuring techniques.

  3. robinedwards36 permalink
    October 30, 2014 8:28 pm

    Have you noticed that in Aug 1911 the prevailing temperature suddenly dropped by very close to 1.0 deg C? Then, in 1970 it rose suddenly by 0.8 deg C? This is made clear by plotting the cusum of the data, or, better, by forming the monthly anomalies (I call them monthly differences) and computing their cusum series. If you have never tried this approach you will probably be amazed at the insight it gives into noisy climate data.

  4. velcro permalink
    October 30, 2014 10:02 pm

    Know it well. Was the busiest airport in NZ, for 5 minutes a day in the 1980’s, when the NAC Fokker Friendship doing the Christchurch-Hokitika-Westport-Wellington circuit landed within 5 minutes of the Friendship doing the circuit the opposite way round. They both pulled up directly in front of the air terminal shed you can see, and left their engines running during the stopover – the noise was unbelievable!
    The airfield is on a flat elevation about 30m above the town, which is on the coast at sea level. I doubt there would be much change in temperature from one site to the other.

  5. David permalink
    October 31, 2014 11:03 am

    The BEST group also considered Hokitika Aero: http://berkeleyearth.lbl.gov/stations/172949

    The raw BEST data from 1909-2009 agrees on a rate of +0.3C/century. After quality control and breakpoint alignment this rises to +0.6 C/century; slightly higher than the NASA adjustment, which found +0.5.

    There was a +1.0C warm bias up to about 1917 (by eye): http://berkeleyearth.lbl.gov/auto/Stations/TAVG/Figures/172949-TAVG-Alignment.pdf Interestingly, if you just count the prolonged period with no station moves or breaks (1920-2000) the rate in the raw data also warms at a rate of +0.6C/century.

    BEST found the regional expectation for NZ to be +0.7C/dec.

    • David permalink
      October 31, 2014 11:13 am

      Regional rate for ‘that part’ of NZ, I should have said. BEST found the rate in NZ as a whole from 1910 to have been +0.87C/century (and +2.41 C/century since 1990!): http://berkeleyearth.lbl.gov/regions/new-zealand

      • October 31, 2014 11:27 am

        I still don’t know anybody who treats BEST seriously!

      • David permalink
        October 31, 2014 11:33 am

        Yes, it’s funny how it was suddenly dropped like a hot stone by some of its former most ardent admirers once it started publishing!

      • October 31, 2014 11:35 am

        I’m not aware of any “former admirers”.

      • October 31, 2014 11:33 am

        It is also a fact that there has been no increase at all since 1979 at Hokitiki, in fact a slight fall.

      • October 31, 2014 12:45 pm

        Funny how the long running rural station comes out with a lower trend!

      • David permalink
        October 31, 2014 3:07 pm

        I get a warming trend of +0.22C/century from 1979-2011 from the raw data via your link under the chart, Paul; though I had to filter out 2008 due to lack of monthly observations.

        The BEST record indicates there were 5 station moves since 2000 at Hokitika Aero, at least 4 of which are biased cool and would require upward adjustment: http://berkeleyearth.lbl.gov/auto/Stations/TAVG/Figures/172949-TAVG-Alignment.pdf

        In the adjusted data from 1979-2011 the GISS trend is +0.60C/century and in BEST it’s 0.63.

      • October 31, 2014 5:27 pm

        I took it up to 2009, as per the de Freitas paper, and get -0.01/century.

        Neither NIWA nor NOAA have any record of station moves since 2000

      • David permalink
        October 31, 2014 6:11 pm

        Maybe it’s because I was using the MetANN data. Using Jan-Dec I get -0.1/century to 2009 and +0.1/century to 2011 (since 1979).

        You may be right about the BEST data! For some reason it shows 4 station moves since 2000 but I can’t find any confirmation of this either.

      • October 31, 2014 6:21 pm

        Yes, I used MetANN as well. It’s easier using this as GISS list it.

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