Anthony Watts igen tilbagevist - denne gang (delvist) af ham selv.......

Given the now extensive documentation by surfacestations.org (Watts [2009]) that the exposure characteristics of many USHCN stations are far from ideal, it is reasonable to question the role that poor exposure may have played in biasing CONUS temperature trends.

The 1997 Conference on the World Climate Research Programme to the Third Conference of the Parties of the United Nations Framework Convention on Climate Change concluded that the ability to monitor the global climate was inadequate and deteriorating. As a result, the National Research Council (NRC) undertook an assessment of the U.S. climate observing capacity. The NRC recommended that a system of performance measures be developed and monitored on a regular basis because it would be unwise to wait for a major environmental assessment or data archeology effort to discover that problems that occurred 10 or 20 years earlier had already inflicted considerable damage to the climate record. The NRC also recommended that an institutional infrastructure be developed to assess the quality of data sets and correct problems as they occur.

Vastly improved documentation of all changes in equipment, operations, and site factors in operational observing systems are required to build confidence in the time series of decadal-to-centennial climate change.

Noting the conclusions of the report that, inter alia, in many instances global and regional coverage is inadequate,

Without action to reverse this decline and develop the Global Climate Observation System, the ability to characterize climate change and variations over the next 25 years will be even less than during the past quarter century.

..er også en misforståelse: Det kommer an på, hvad man mener med "pålideligt".

De faglige organisationer, rapporter og Menne et al. stiller selv spørgsmålstegnet ved (bl.a.) netop pålideligheden af data for trend udregning

WMO målestationer... det ved jeg tilfældigvis noget om.

Hvis ikke kravene til målestationens placering ikke opfylder de specifikationer der er gældende, så sker der fejlmålinger.

F.eks. hvis græsset og vegatatioen omkring målestationen er omkring 1.5 meter højt, så stiger den aflæste temperatur med omkring 1 C over gennemsnittet på årsplan.

Min målestation her i Kangerlussuaq opfylder alle krav og er repræsantativ for området. Det betyder ikke at DMI 100% accepterer de indkomne data fra stationen, de bliver sommetider justeret op eller ned.... jeg aner faktisk ikke hvorfor.

Din insisteren på at affeje spørgsmålet rent a priori forstår jeg ikke.

What then is the benefit then of this effort [Surfacestations.org, CBH]? As stated above, more information is always useful, but knowing what to do about potentially problematic sitings is tricky. One would really like to know when a problem first arose for instance – something that isn't clear from a photograph from today. If the station is moved now, there will be another potential artifact in the record. An argument could certainly be made that continuity of a series is more important for long term monitoring. A more convincing comparison though will be of the existing network with the (since 2001) Climate Reference Network from NCDC. However, that probably isn't as much fun as driving around the country taking snapshots.

Dertil minder jeg om at det ikke kun er på nationalt plan netværket benyttes. Område/stats modeller kalibreres vel også efter målingerne i et eller andet omfang?
Selvom vi måske kun vil tale decimalfejl i en længerevarende trend kan det såmænd også være en ikke uvæsentlig korrektion i diverse modeller.

[T]he climate models used in the IPCC forecasts are not statistical, but are physical in nature. They are self-consistent descriptions of the whole system whose inputs are only the boundary conditions and the changes in external forces (such as the solar constant, the orbit, or greenhouse gases). They do not assimilate the surface data, nor are they initiallised from it.

It has been estimated that the mean anomaly in the Northern hemisphere at the monthly scale only has around 60 degrees of freedom – that is, 60 well-place stations would be sufficient to give a reasonable estimate of the large scale month to month changes. Currently, although they are not necessarily ideally placed, there are thousands of stations – many times more than would be theoretically necessary. The second error is obvious from the fact that the recent warming is seen in the oceans, the atmosphere, in Arctic sea ice retreat, in glacier recession, earlier springs, reduced snow cover etc., so even if all met stations were contaminated (which they aren't), global warming would still be "unequivocal". Since many of the participants in the latest effort appear to really want this assumption to be true[that finding enough problems will make global warming go away, CBH], pointing out that it doesn't really follow might be a disincentive, but hopefully they won't let that detail damp their enthusiasm...

...de kan såmænd ende med at fjerne et grundlag for tvivlere...... Tænk hvis vi havde fået opsat de 200+ målestationer NRC selv var ude at sige for ca. 15 år siden der var behov for (alene i USA) – så havde vi slet ikke behøvet diskutere alt det her halløj...Hvad Watts mener om det ene og andet emne og hvordan han formulerer sig er for mig ligegyldigt.

Hans Henrik Hansen skrev:

blabla.....faglige organisationer........rapporter......stiller spørgsmålstegn........nye ligegyldige linklalala.....jeg-tilknytter-lige-et-irrelevant billede.........tralalajegkanikkehøredig osv. osv.