Ok, admittedly I'm not educated in these matters, but I was following the presented data up to the last paragraph. The last paragraph makes it sound like this published article was about, another publication. Why did this article end with reference about another publication? I assume it is to let us know that there is another respected publication in this field.
Now, since I don't know anything about what the article is talking about, I only say this with question...
"The analysis used records from 36,866 stations"
Well, are all 36,866 stations using the same formulae? If so, wouldn't the variations of the results basically be a simple matter of opening a map and reading latitude and longitude, maybe throwing in a barometer? Obviously, I'm clueless, but I don't see how you can expect too much variation. Maybe that is the point.