Over the last day I have received some questions about the satellite data and why I consider it more accurate.
First I should define what station data is. Station data is temperature records that are made at any approved location that reports temperatures. The local news temperatures are likely sources that go into the station data. They are perfectly accurate and there are generally not problems with stations being inaccurate. There are some problems that can occur, but those are not relevant as to why I think satellite data is better.
The limitation in the station data is location. Primarily they exist only where people exist. Vast areas of the planet do not have people. Here is an example of the typical station coverage.
For this map each station represents an area that is very, very large. Then they fill in the blanks with some average between the stations. That is really the biggest reason why I consider the station data to be inferior. Note the large areas of Africa, Asia, Arctic and Antarctic regions that have little to no coverage. The typical solution is to fill in the blank areas by increasing the area that each station projects from 250 km to 1200 km. The result looks like this.
These maps were created from the GISS project of NASA. Even with the larger projection the coverage of the Earth is not complete. I fully agree that most stations provide very accurate measurements, but they simply do not cover most of the Earth. You might notice that the oceans have good coverage. Ships report temperature data while they sail, but there are also many areas of the world that have special buoys that record water and air temperature. Their coverage is not everywhere as the ocean is very big, but they do provide data for the Atlantic and Pacific oceans. Overall here is the distribution of stations worldwide used to collect the temperature data.
The United States, Europe, Australia and Japan all show good coverage, but outside of those places there are areas with a dozen stations covering a million square miles. That is not enough. It is especially disconcerting that the Arctic and Antarctic regions are the areas that have the least coverage, especially since those are the areas that would be the best indicators of global warming. A dozen stations to cover an entire polar area is not sufficient.
So all of these different sources of data are merged together as anomaly data and the result of that is what I call the station data. There are more than the two I chose for my work, but those are two of the main three. All sets of station data suffer from this highly limited source of locations.
The satellite data is a very different beast. Each satellite does not cover the whole Earth each day, but they get very accurate coverage of most of the Earth every day. Here is a comparison map of the daily satellite coverage.
This is very good daily coverage. This isn’t anomaly data though which is why the range of temperatures is so great. Satellite measurement of temperature is complicated, but according to NASA they are accurate to within 0.03 °C. Combined with the superior coverage the satellite’s provide, there is no question that satellite data is better. The only limitation is that the data only goes back to 1979. If there was 1,000 years of satellite coverage there would be no debate about what was going on with the Earth’s climate today because there would be a much better understanding.
Here is a sample of final satellite coverage.
I would be perfectly happy to only use the satellite data, but then my data would only go back to 1979 or not use the more accurate data that satellite provides. This conundrum is what has driven me to get a feel for combining the two sets of data so I can always use a continuous set of data that combines the best of both sets. By making it open to everyone I still hope that others will support this idea.