15 May '11, 9am

[email protected] This might help to explain it:

.@chriskkenny This might help to explain it:

There is an “early measurement effect” because all the first year’s monthly temperature measurements will all be both maximum and minimum records. Subsequent months will modify the records so that it will take a few years for the annual counts to settle down. Since the effect influences both maximum and minimum records, Figure 2 is, on the average, free of this effect. In Figure 2, the early decades show perhaps a 20 -year period of cooling. After 1920, a mid-century warming commences, and this looks like natural variation (a half-sine wave) up to about 1940. Then a period of stasis ensues (for 12 years) until the excess of maximum over minimum records starts again with an accelerating increase up to 2010. Figure 2 resembles charts of the temperature anomaly – but it has a different origin than subtracting the temperature observation from a chosen baseline. It is more “gra...

Full article: http://www.skepticalscience.com/Maximum-and-minimum-month...

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