muso wrote on Jan 23^rd, 2014 at 6:13pm:



Sorry, My paraphrasing. try a search for "estimate".

noun: estimate; plural noun: estimates
ˈestəmit/

    1. an approximate calculation or judgment of the value, number, quantity, or extent of something.
    "at a rough estimate, our staff is recycling a quarter of the paper used"
    synonyms:      rough calculation, approximation, estimation, rough guess;

The published documentation [3] explains the numbering system used by the Bureau of Meteorology and the methods used to manage the changes of stations at each site ([15], section 2.4 and 3.4). During each transition period, one of the sites, generally the old one, is kept as a comparison site for a minimum period of five years of parallel observations. These modifications of the network structure are related to factors such as the urbanisation of the original site, in particular, the construction of new buildings affecting the observations, and the systematic transfer of bureau-staffed sites from city centres to airports. For example, the Darwin ACORN-SAT site is sourced from three successive deployment phases (1910-1942, 1941-2007 and 2001-now) [11]. The first phase corresponds to the observations done at the Darwin Post Office (PO) from 1910 to 1942. The BoM code for this station is 014016. The second and third phases correspond to two separate sites at the Darwin Airport (AP), located one kilometre away from each other. One common BoM code (014015) is used for the observations made at these two sites. During and after the overlap period, the decommissioned site is renamed and referred to as the Darwin Airport Comparison station (014040). ACORN-SAT utilises improved analysis techniques which exploit pair-wise comparison between one station and up to 10 comparable stations used as references. The algorithm applies differential adjustments to different parts of the daily temperature frequency distribution to better estimate the deltas with reference stations before and after an inhomogeneity. The ACORN-SAT method uses all the available background information or metadata about station moves, changes in technology and in observational procedures to identify and locate the breakpoints and to evaluate and validate the adjustments.

generally the old one, is kept as a comparison site for a minimum period of five years of parallel observations.

The first phase corresponds to the observations done at the Darwin Post Office (PO) from 1910 to 1942.

Well, you tell me. You're the one making the claims without even having any knowledge of the methodology.
Posted by: lee  Mark & Quote Quote      

In 1981 as part of my PhD work, I produced a seven-station New Zealand temperature series, known as 7SS, to monitor historic temperature trends and variations from Auckland to as far south as Dunedin in southern New Zealand.

A decade later, in 1991-92 while at the NZ Meteorological Service, I revised the 7SS using a new homogenisation approach to make New Zealand’s temperature records more accurate, such as adjusting for when temperature gauges were moved to new sites.

For example, in 1928 Wellington’s temperature gauge was relocated from an inner suburb near sea level up into the hills at Kelburn, where - due to its higher, cooler location - it recorded much cooler temperatures for the city than before.

With statistical analysis, we could work out how much Wellington’s temperature has really gone up or down since the city’s temperature records began back in 1862, and how much of that change was simply due to the gauge being moved uphill. (You can read more about re-examining NZ temperatures here.)