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« Marc my words... | Main | NIWA’s minister told to put up or shut up »

Comments

Dave

But the warming does appear to have occurred between when Kelburn starts and when Airport starts.

As Wishart noted, Thorndon started and ended at about the same temperature, as did Airport.

So this shows a temperature increase between 1928 and 1960 in Wellington but not after 1960.

Dave

It's just not legitimate to make adjustments to the input data that are on the same order of magnitude as the effect you are trying to measure. It's a shame that the stations were moved, but the only answer is not to use the data from them. When you make adjustments this large, all you are measuring are your own inputs. The result you end up with is completely specious.

bill

AJ,

Then why normalize? Offsets do not affect trends.

bill

Dave

I meant "iwishart" instead of "Wishart."

Dave

To the other Dave:
NIWA has convinced me that temperatures at Kelburn and Airport roughly parallel each other, offset by 0.79 degrees. I make no comments as to whether NIWA's other adjustments are valid -- just this one particular adjustment that they've given data for.

Huub Bakker

I have to say that I am disappointed in the Climate Science Coalition on this one. It is an example of sensationalist journalism. They made it look like a smoking gun when NIWA had admitted to making adjustments for movements of weather stations etc. This has simply given NIWA and pro-warming groups the chance to criticise the science of the report, and rightly so.

If it was an attempt to get NIWA to provide the raw data then it has had some success but surely they could have gone about it a little differently.

Still, the data is suggestive of poor methodology and begs for all the data to be looked at more closely. While those of us who are non-climatologists are presently ignorant of how adjustments like these are made, many of us are intelligent researchers in our own right and quite capable of judging whether the methodology makes sense once it is explained to us.

Keep up the good work Ian.

George Turner

The egregious mistake (invalid scientific justification) for their adjustment was that the station was moved to a location that's 400 feet higher than the original. So they applied the formula for the decrease in temperature with altitude in a standard atmosphere (used by aviators).

That might be justified if they moved their thermometer by hoisting it up a radio tower, but that's not what they did. They moved it inland.

By their logic, since land is almost always higher than sea level, inland areas are always colder than the beach. I'm sure this will come as a surprise to anyone living in Los Angeles, the Australian outback, East Africa, etc.

They must not get out much.

John Boy

"While those of us who are non-climatologists are presently ignorant of how adjustments like these are made,..."

That's the trouble here. The adjustments appear as simple as just writing in the number you want and hoping no one with common sense asks a question.

bill

I guess my question on thermometer accuracy still stands since these data are represented against an absolute temperature scale. Error bars would be nice.

Stuart

I suppose that any possible explanation for the increase in the remaining stations can only likewise be an increase in altitude of the sites, or moving from urban to rural, although I can't see the latter being that significant in my layman opinion. There do seem to be some step changes on some graphs, but it seems there is more going on in them too. I think this would probably demand an Anthony Watts kind of scrutiny of the history of the sites involved.

Kevin O'Brien

The data has been politicised.
They cannot even claim common sense as a justification because the small differences require a greater degree of precision consistently to detect.

To show a result one prefers is called bias. To create bias is dishonesty. To use bias is fraud.

Take away their computers.

Huub Bakker

I suspect the real answer is that adjustments this far back in time can only made as a 'best guess' (and best practice may well be 'best guess') and that they are only shown to be inadequate when looking for small, long-term trends.

Certainly they are open to interpretation and debate.

ZenTiger

Where exactly at Wellington airport is the temperature monitor? Near the tarmac, or up on the top of the hill with the communications array, which is probably about the same level above sea as the Kelburn monitor...

Rimu

this is the explanation: http://hot-topic.co.nz/nz-sceptics-lie-about-temp-records-try-to-smear-top-scientist/

Ian Wishart

Sorry Rimu, not so. The idea that NZ can have an AGW impact higher than the global average, when NIWA is already on record saying impact of AGW is lower here because we are surrounded by ocean, should be ringing alarm bells in your head.

And, more to the point, the release of all data by NIWA on these magic little adjustments might help other scientists assess whether their methodology is faulty.

If NIWA don't release the data, speculation will grow that they have made mistakes

Falafulu Fisi

Good work there Ian. Keep up that excellent investigative work of yours.

David Wratt is just another cult warmist.

George Turner

It's about as crazy as all the ad-hoc adjustments NASA's James Hanson makes to old data sets. If present trends continue, by the year 2150 the 1930's will be in the grip of an ice age!

jjw

I love all the conjecture on top of speculation on top of assumptions in these comments. That is just awesome.

Best of all, it's all based on the reporting of a man who believes that the Bible is literal truth.

David Wratt

Ian

Some points for your readers:

First, regarding data - NIWA climate data are available to anyone who registers, through the Web. Also, we provided the homogenised NZ temperature time series for the 7 sites used in forming the NZ time series to a member of the NZ Climate Science Coalition in July 2006. This is presumably the data used in the paper collated by Richard Treadgold and released by the Climate Science Coalition earlier this week.

Second, regarding information - We have written and published papers on data homogenization. We have written and published papers on NZ temperature trends. We have responded to internet blogs (Climate Audit), and newspaper letters, and to NZ Climate Science Coalition members at various times in the past regarding data homogenization, and in particular the Wellington temperatures.

Then three years after we provided the data but one week before the Copenhagen climate meeting: Allegations are spread around the internet and through press releases that NIWA scientists are fudging data. These allegations are based on an unrefereed article which ignores all of the best-practice guidance in the literature and the common knowledge about the need to account for site changes (including Wellington), That (to put things mildly) really annoys me. So do inferences that NIWA has restricted data access. But the claims of the Treadgold paper appear to be unquestionably accepted by yourself and most of your correspondents.

Regards – David Wratt

Andrew

Dave

> from NIWA's graph in their explanation, the measurements
> from Kelburn and Airport appear to track each other well
> with a 0.79°C offset during the period of overlap.

So what? The relationship between Airport and Kelburn is irrelevant.

Airport is being used to scale Kelburn to match Thorndon.
This assumes the present Airport average is equal to what the present Thorndon average would be if the station still existed).

This is invalid for 2 reasons:

1) The climate may have been hotter 100 years ago.
2) The airport might be hotter today due to UHI

If either if these points is true - then the offset used to stitch the series together will create a false warming trend.

As another poster mentioned, the trends they're claiming to have identified are far smaller than the potential offset errors they're using to stitch different series together.

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