Can anyone explain to me how the average temperature of planet Earth is derived? And I don't want the opinion of this scientist or that scientist. I want the systems, networks and data points. I ask because as of this point I'm appalled by that what is commonly referred to. I'm particularly interested in how current data is compared to past data.
There's two wildly different data gathering methods.. Actually three if you count devining data from 10,000 yr old trees, ice cores and mud bug shells...
But for MODERN temp. records you have the satellite record and landbased thermometers..
The satellite record has been around since 1979... There are 2 independent "data processors" for the satellite fleet Univ Alabama at Huntsville and RSS... They use entirely different algorithms for data prep but have always agreed extraordinarly well.. The satellite record can't really be messed with.. Like trying to correct land-based measurements from the 1930s every month of the current year.. They are VERY precisely obtained on the satellite paths every time at the exact same times of day.. And they measure MORE of the atmospheric "lower troposphere" than a thermometer on an 8 ft pole..
The land based recordings are from about 15,000 thermometers and sea buoys.. NOAA attempts to merge these with balloon data, sea captain reports (seriously an 18th century method) and other available assets.. There's very spotty coverage STILL on the entire African continent, tundra country anThe satellite d the extreme lattitudes and the seas.....
There are probably a dozen govts that are lead data processors of this info... And the land based records USED TO AGREE brilliantly with the satellite record until about 1998 and the 2000s when GW "took a nap"... for about a decade.. This led to a LOT of hanky panky in how the land based data is massaged and manipulated.. And as I said, these agencies have NO problem with cooling the 30s and warming the 2000s every day of the year... There's a stash of historical temperature charts from GISS and NOAA (the US agencies) showing how the data has changed over the years.. And in reality, prior to 1920 or so there just wasn't even FAIR coverage of the globe or accuracy to measure the entire planet to the 1/100th of degree required.. Coverage got a bit better since then, but there's a lack of faith in the newer tools to "REANALYZE" the simple ass thermometers using modeling that ignore the raw data and PROJECT what model thinks the temperature is in sparse coverage areas....
More if ya want it.... LOL....