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I have been a little surprised at how some local bloggers have been getting all emotional about the “climategate” scandal in the UK, and particularly New Zealand climate change information coming from our National Institute of Water and Air, NIWA.

Well, not really too surprised. The ideological orientation of these bloggers suggest they would take up the line they do. They are usually quite unsympathetic with science and scientists. No, mainly my surprise is about the way they restrict their information to only a few sources (confirmation bias) and are prepared to attack the integrity of our scientists without searching for and reading what they have to say.

The basic description of the issue was explained in Climate change deniers live in glass buildings). However, I urge readers who wish to keep informed to keep their eyes on the NIWA news pages and Gareth Renowden’s Hot Topic blog, which is also syndicated at SciBlogs NZ. Gareth is the author of the book “Hot Topic: Global Warming and the Future of New Zealand“, which was shortlisted for the Royal Society of NZ’s 2008 Science Book Prize, so is well informed on the subject and keeps in touch with current research.

Have a look at Gareth’s recent post (NZ temps: warming real, record robust, sceptics wrong) and the latest press release from NIWA (NZ temperature rise clear).

In this press release NIWA rejects criticisms of its New Zealand temperature series made by the local denier organisations the Climate Science Coalition and Climate Conversation Group. Here are some extracts.

Rejecting the unscientific combination of data from several different stations by the deniers:

“We again reiterate that for the longer ’seven station’ time series, adjustments to account for significant site changes are necessary in order to provide a meaningful estimate of New Zealand temperature trends.

For example, in Wellington, early temperature measurements were made in Thorndon at three metres above sea level, but in 1928 the measurement site was moved to Kelburn at 125 metres above sea level. The Kelburn site is on average 0.8ºC cooler than Thorndon because of the extra height above sea level. So, the raw data need to be adjusted to ensure we are comparing apples with apples.

By the same token, if the climate station had been moved the other way — from Kelburn down to Thorndon — the raw data would then give too warm a reading and would also need to be adjusted.

NIWA’s analysis of measured temperatures uses internationally-accepted techniques to make adjustments for changes such as movement of measurements sites.”

Showing that the NZ Climate Science Coalition is disingenuous in there presentation of data:

For more than two years, New Zealand Climate Science Coalition members have known of the need to adjust the ’seven station’ data. They have had access to:

  • the raw data
  • the adjusted data (anomalies)
  • information needed to identify the adjustments made by Dr Salinger
  • information needed to develop their own adjustments.

However the NZ Climate Science Coalition paper collated by Richard Treadgold (25 November 2009), and the media release issued by the Coalition on 26 November, were based on analysing the ’seven station’ data without any adjustments at all for site changes. This is why NIWA Chief Climate Scientist Dr David Wratt expressed his disappointment with the coalition statements, in NIWA’s media release of 26 November.

(a) Coalition told in 2006 of need to take account of site changes

NIWA advised NZ Climate Science Coalition member Dr Vincent Gray of the need to calculate appropriate adjustments to account for significant site changes in an email to him dated 19 July 2006, pointing out problems with graphs he had produced without any such adjustments. We advised him that over the period covered by his analysis the Hokitika site moved from the town centre, to the edge of town, then the airport. We also advised him there had been several site changes in Auckland and Dunedin, and told him about the 120 metre change in the height of the Wellington measurements.

(b) Methodology for adjusting data publicly available

The methodology for adjusting for site changes in the NZ temperature record was published in the peer-reviewed International Journal of Climatology in 1993. NIWA referred Dr Vincent Gray of the NZ Climate Science Coalition to this paper on 19 July 2006.

Reference:

Rhoades, D.A. and Salinger, M.J., 1993: Adjustment of temperature and rainfall measurements for site changes. International Journal of Climatology 13, 899 — 913.

(c) Unadjusted (raw) data publicly available

NIWA’s unadjusted climate data is available to anyone at no charge, through web access to the NIWA climate database. This has been the case since 1 July 2007.

(d) Adjusted series provided in 2006

NIWA provided Dr Salinger’s adjusted temperature series (anomalies compared with 1961—1990 averages) for each of the seven stations, to NZ Climate Science Coalition member Warwick Hughes on 19 July 2006. Information about changes to the seven station sites is documented in a publicly-available report published by the NZ Meteorological Service in 1992, and much of this information is also available from the metadata in the climate database.

Reference:

Rhoades, D.A. and Salinger, M.J., 1993: Adjustment of temperature and rainfall measurements for site changes. International Journal of Climatology 13, 899 — 913.

(c) Unadjusted (raw) data publicly available

NIWA’s unadjusted climate data is available to anyone at no charge, through web access to the NIWA climate database. This has been the case since 1 July 2007.

(d) Adjusted series provided in 2006

NIWA provided Dr Salinger’s adjusted temperature series (anomalies compared with 1961—1990 averages) for each of the seven stations, to NZ Climate Science Coalition member Warwick Hughes on 19 July 2006. Information about changes to the seven station sites is documented in a publicly-available report published by the NZ Meteorological Service in 1992, and much of this information is also available from the metadata in the climate database.

Reference:

Fouhy, E., Coutts, L., McGann, R., Collen, B., Salinger, M.J., 1992: South Pacific Historical Climate Network Climate Station Histories. Part 2, New Zealand and Offshore Islands. NZ Meteorological Service, Wellington. ISBN 0-477-01583-2.

Unfortunately, the local climate change deniers and their camp followers in the blogosphere are reacting in a predictable way. They have gone into denial!

Denial that they had been informed of the need for adjustment. Denial that the information and data were available. Many of these bloggers have made it quite clear they are unprepared to either look for the information or consult the NIWA press releases and the National Climate Database.

The deniers are in denial!

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