Senior one geography problem

Very simple, please look at the world ocean current map.

When the North Atlantic Warm Current flows to the Norwegian Sea, due to the continuous cooling all the way, the water temperature of this warm current is already very low, for example, it has dropped to more than 0 and less than 10 degrees Celsius, but it is still higher than the temperature of the surrounding seawater, so it is still a warm current.

Let's look at another ocean current, the California cold current, which starts to flow southward from the mid-latitude area (the sea area slightly north of the US-Canada border). As it goes south step by step, when it reaches the coast of Mexico, the temperature of the ocean current has risen to more than 10 degrees Celsius, but it is still lower than the temperature of the surrounding seawater (the temperature of the surrounding tropical waters exceeds 20 degrees), so it is still a cold current.

Look at these two examples of ocean currents and you will understand.