Metman2012 wrote:

snip

No doubt there have been changes which may have been significant, but then
don't the climatologists make allowances for this. I know that even such
mundane things as SST measurement had to be adjusted by the method and
material of actually measuring the sea temp - the buckets used to get the
water had different characteristics and work was done to homogenize the
results.

Just my 2 pennyworth


As you imply, the sea surface temperature measurement can vary significantly
dependent on what method is used for the measurement. Unfortunately, the method
used is not usually recorded. For example, on the Ocean Weather Ships (at least
on the British ones) any one of the following could be used:

- canvas bucket (usually used only in relatively benign weather)
- rubber bucket (usually used only when under way)
- thermistor loctated somewhere in the engine-room sea water intake
- direct measurement of the engine-room sea water intake (turn on
a tap and stick a thermometer into the water)

The first 2 methods sampled the water at, or very close to the surface. The
other 2 sampled the water a few metres below the surface. It was up to the
individual observer to decide which method was used at each observation. I
don't know if any comparative tests were ever made. I can't recall any during
my time on the Weather Ships.


--
Norman Lynagh
Tideswell, Derbyshire
303m a.s.l.
http://peakdistrictweather.org