[jsprunck]

Here is an analysis from a data-driven organization dedicated to listing, understanding and reducing biases in science records. They have covered the National Climate Data Center data (which apparently GISS uses).

http://berkeleyearth.org/understanding-adjustments-temperatu...

Edit: this discussion does focus on the U.S. network, where some of the articles you listed referred to data from Africa and South America, but assumedly the corrective techniques are similar.