The oceans contain 90% of the heat energy on the surface of the Earth, which makes it “kinda important”. There are claims that the missing heat went into ocean temperatures, which are allegedly warming by five thousandths of a degree per year (which is still a lot less than the models predicted). The ARGO array of 3,000 ocean buoys deployed from mid-2003 is a vast improvement on the occasional sampling from ships that preceded it, but each single thermometer measures a vast 200,000 cubic kilometers of ocean.
The original Argo Science Report had an expected temperature sensor uncertainty of 0.005C. But it’s just not possible to measure the ocean temperature that accurately. Each thermometer may be accurate in a laboratory to 0.005C, but thermal noise in the ocean is an impossible beast. The four-kilometer-deep swirling mass of eddies varies from 0C – 30C. It is not a well mixed swimming pool at one temperature, being measured 3,000 times simultaneously — the statistics are entirely dissimilar.
I went looking for papers on error estimates and found Hadfield 2007.
The Hadfield study compared the new ARGO robotic buoys to other ways of measuring ocean temperatures in a slice across the North Atlantic. [...]