Captain Nemo wrote on Nov 29
th, 2018 at 10:20am:
The data is not too sparse.
At your proposed 50 stations it is. What be be the level o uncertainty inolved for a mere 50 stations?
Captain Nemo wrote on Nov 29
th, 2018 at 10:20am:
The other three have grid boxes measuring five by five degrees. They also differ in how many land stations they have around the world, too. HadCRUT4 has about 5,500, GISTEMP takes middle place with about 6,300, but MLOST has the most of all, with about 7,000 land stations.
All the way back to 1880?
The earth's circumference is about 40,000 Km. To find the arc distance 5/360*40000. About 550km. So if we assume a box 5ºx5º it would be 302,500 sq km. And you are going to assume that the same conditions apply uniformly in that area.
hese 5x5 grids? What happens when there is no landmass? The ocean is vast, especially in the Southern Hemisphere.
So what didn't you understand about the sparseness of the data in the SH?
"Tom,
The issue Ray alludes to is that in addition to the issue
of many more drifters providing measurements over the last
5-10 years, the measurements are coming in from places where
we didn't have much ship data in the past. For much of the SH
between 40 and 60S the normals are mostly made up as there is
very little ship data there."
https://web.archive.org/web/20131101144134/http://di2.nu/foia/foia2011/mail/2729...
That email was in 2009. So how good was the "made up" data prior to that?
Or this-
"
From John McLean's PHD thesis on HADCRUT4 data -
"For two years the entire Southern Hemisphere temperature was estimated from one sole land-based site in Indonesia and some ship data. We didn’t get 50% global coverage until 1906. We didn’t consistently get 50% Southern Hemisphere coverage until about 1950."
So just how much of this "global data" just made up?
You keep going back to 1880 as if the "data" actually existed.