Comments on: Why the difference?

By: StuartOH

StuartOH — Sun, 14 Jun 2009 22:34:55 +0000

Maybe its not why the difference but what’s the difference

… who’s gonna miss us in year or so, so whats the difference if we go.

The problem I have, amongst many others, is the idea of a global temperature.

Where ever there are accurate temperature measurements, these should be observed and lets assume that the temperature record in the US shows a dramatic increse in temperature which correlates with a dramatic increase in Europe then I suppose one could say there is an increase in global temperatures.

The use of anomalies is lovely when the data is complex however if one looks at the graph of temperature/against time for central united kingdom since 1650 then what’s the difference?

Steve if off post please delete.

By: John F. Hultquist

John F. Hultquist — Fri, 12 Jun 2009 00:36:11 +0000

In #4 (Motl) the comment “ . . . difference by 2-5 deg C seems just way too much . . . ”

caused me to look at the graph again. Y-axis is in tenths below the zero and in full digits above. Odd.

By: Thor

Thor — Thu, 11 Jun 2009 22:05:10 +0000

Re: UC (#39),

Seems the filename is wrong, this one works though:
http://hadobs.metoffice.com/crutem3/HadCRUT3_accepted.pdf

By: UC

UC — Thu, 11 Jun 2009 21:22:14 +0000

http://hadobs.metoffice.com/crutem3/diagnostics/time-series.html

More details are given in the paper introducing the dataset.

links to http://hadobs.metoffice.com/crutem3/CRUTEM3_accepted.pdf ,

Error 404: page not found .

I guess they mean Brohan et al. , a paper that IMO has some problems with bias-like errors. But reported bias uncertainties seem to be quite wide for the series in question.

By: steven mosher

steven mosher — Thu, 11 Jun 2009 20:43:59 +0000

RE 36. You can head over to http://hadobs.metoffice.com/crutem3/data/download.html

and have a look

By: Bill Yarber

Bill Yarber — Thu, 11 Jun 2009 16:51:01 +0000

I think that the first 25 years of the red line were inadvertantly inverted. Oh wait, I forgot, that processing algorithym is only allowed for bristlecones and select Anartic surface stations!

Bill

By: Gary Strand

Gary Strand — Thu, 11 Jun 2009 16:39:34 +0000

What are the counts of the number of grid boxes with valid data for all three bands, over time?

By: Vincent

Vincent — Thu, 11 Jun 2009 14:56:19 +0000

My guess is that the difference in land mass between the Nothern and Southern hemisphere, combined with the much later move of western science into the Southern hemisphere has in some way skewewd the data. I doubt that there were many weather station inland in Southern Africa before about 1900.

The data for South Afirca before 1900 would largely be biased towards the 30S zone. I suspect the same would apply to Australia.

Just a guess.

By: Steve McIntyre

Steve McIntyre — Thu, 11 Jun 2009 11:46:22 +0000

Re: Willis Eschenbach (#32), I downloaded the gridded data and did zonal averages,

By: Geoff Sherrington

Geoff Sherrington — Thu, 11 Jun 2009 11:37:23 +0000

The problem of the early days of land temperatures arises from modern rejection and adjustment of data.

According to Australian Bureau of Meteorology records, these stations started operating in these years:

1855 Melbourne Central
1857 Armidale NSW, Goulburn NSW
1858 Casino, Bathurst, Sydney Observatory, Deniliquin, Beechworth, Murrurundi
1859 Echuca, Gabo Island, Port Augusta, Mount Gambier, Robe?, Longerernong

Of these, Casino at 29 deg 51S is the most northerly and only one included in the band being discussed. But others closer to the Equator followed. Darwin in 1869 at 12 deg 27S, Alice Springs in 1873 at 23 degS, etc.

Some of these are still in use today as rural sutes (like Gabo Island). Others have been overcome by UHI (like Melbourne and Sydney).

In recent years, the BOM has been reluctant to use station data later than about 1910. Some years ago it was decided that a change to Stevenson screens was mostly complete by 1910, so data before then were rejected in bulk, e.g. in Della-Marta et al, 2004. (This is a general statement and there could be instances of other treatment).

When the BOM sends its data to GISS or CRU (in those days) for compilation into a global average, it is already homogenised in ways taking man-years to reconstruct. What GISS or CRU do in terms of further rejection or further sdjustment is something of a mystery.

Hence part of the reason for the graph above. My guess is that it’s mainly poor housekeeping of data.

Again, I caution against getting too sophisticated with mathematical/statistical treatment of data that has been hacked around to an unknown extent. These early stations were mainly set up to help farmers and travellers and it is a bit much to expect the extraction of tiny trends from them today, no matter how good the maths package is.

If GISS or CRU have a paucity of stations from pre-1900, maybe they would be the people to ask why so many were rejected and on which criteria. I’ve just found 17 old stations in Australia in a few minutes. There are plenty more. If the global gurus claim the existence of only a few early stations, then it’s their shortcoming through not looking hard enough. Don’t believe their counts of available stations.

It’s not rocket science. It 1, 2, 3, 4, 5, 6,……