Gulf Stream

This is a temperature map of the world's oceans. It is obtained by satellite, by looking at a small notch in the infrared and microwave bands. That is how we get our land surface temperatures as well. Warm air radiates a certain frequency, and it doesn't matter if that air is about land or water. Physics ensures us that the surface of both land and water are in equilibrium (the same temperature) as the air.

The maps are constantly getting better, but as we go back in time, the data gets worse. We have almost no information from before 1980, except sporadic weather stations. Since the Little Ice Age, we have had some very strong northern currents. The North Pacific current was very important for North America, and the famous Gulf Stream determined the weather of the UK and Europe.

The Gulf Stream can be measured by both the current and the surface temperature. It is difficult to define it by current, since, once in the Atlantic it goes into 3-dimensional braids. It's generally best to define it by the temperature effect, and it appears as a narrow, winding river of warmer water.

Nobody is keeping an eye on these currents and how they shift over time. Before 2016, I noticed them as very strong. The Gulf Stream could actually direct the line of tropical plumes, and a hurricane once followed the channel of warm water out to sea. Then, both currents were gone.