fatslob-:O said:
I find it questionable that you even can measure the global average temperature ... A temperature is only a point in a 3D scalar field so how do you imagine that we can even take an average in space ? |
But you don't measure the global average temperature. That makes no sense. You can't measure an average. Averages are calculated from many averages. We take measurements from both stations around the world, and satelites that continuously scan a small chaning part of earth's surface, and calculate the average. The measurements will be a finite number of measurements from a finite number of places. You then take the average for each individual place (to make sure places that have more measurements don't count more than places with fewer measurements), and then again take the average of those values to find the global average temperature. You can extrapolate the calculations to get an average for time periods as well. Honestly, the calculation is the simple part. Getting a huge dataset is the difficult part, but thanks to our advanced infrastructure and years of hard work and scientific progress, we have equipment many places in the globa that can measure temperature very accurately, giving us such a good dataset.