In the previous chapter, we have seen that the Mediterranean behaves like an ocean, a small ocean. I have a lot of properties that can be studied in the Mediterranean, can be applied to the ocean. This is more true in terms that it's a model or a reduced model. Now, here we are going to do the jump from the Mediterranean to the Atlantic. The exit door from the Mediterranean is the Strait of Gibraltar. This is a very nice picture from the mid 19th century, showing what is the nearly a strait. You can see here, this is the Gibraltar mountain and this other the Jebel Musa is the mountain in the African coast. But it is really very difficult from one going from sea to sea that between these two mountains there is a gap flowing and opening to a vast ocean, and as we are now just have been in Barcelona World Race has finished in few days. We'll see more or less we can go, and try to do the same traction. This is tracking from the Barcelona race, the first race. Just to note that in the Mediterranean, a typical distance for example this one is about 300 miles. This is exaggerating the scale, it is an arbitrary number, but it is exaggerating 1,200 times or 1,000, 2,000 percent. If we go next step from the Gibraltar, we will open to the Atlantic sea, and there's a very big blue part here, and you see that the typical distance here it's not 300 miles is about 900 miles following the coast, but you can see that it's more widely open. So finally, if we go back and we'll use six times the scale, we'll see these are the typical distances from the oceans that is 6,000 miles which is 20 times what was the initial distance we use at the Mediterranean shore. When we open to the ocean, the distances are much more wider. But there are more things that are different. So this is the Mediterranean, and another important thing is that the band of latitude that the Mediterranean is comprised in a very relatively narrow of latitude between 48 and 30 degrees North. So it is the Northern hemisphere, and even far from the tropical areas and also far from polars areas. So it's in the central part of temperate latitudes. While the Atlantic is from the North pole, look at this is open and will not see this because the images is built from the North, but you'll see it's spreading until 75 degrees South which corresponds to the Weddell Sea in the Antarctica. So it's a very wide latitude. At least you have two hemispheres at all latitude almost and only one interior zone in one of the hemispheres. So the first thing we can see is that the cycle, is the cycle a natural annual cycle and in March is called Spring, is becoming more uniformly, the temperature is growing but more uniformly. In September is fully developed. The situation of warm water especially in the southern eastern part, but also here. Know that water coming from the Atlantic, this is out of theme. Finally, we go back to the Autumn and see that it is becoming again colder and starting to be more cold by more continental part which is the Black Sea, but also in the Northern of Atlantic, and go back to the other annual cycle. Well, this is the Atlantic, and at the Atlantic, you'll see that this region is almost during all the year it's hot, but perhaps moving from one side to the other. So in March, the temperature is in the equator, but also in the Southern part of the equator, while in September is reverse because here is the summer in the hemisphere and here is double in the Southern hemisphere. You also see that here in the winter of the Northern hemisphere, all this part is very cold, and now is less cold. It is more difficult to see in the Southern part because here is more as we got some things like this one, we'll see that that shows that at the end of autumn and winter in the Southern hemisphere cold water arrives to the La Plata sphere here in the South American coastal, while in Spring and Summer is less. So this is spreading in the two hemispheres, and this is also seen in the deep distribution. In this distribution, you can see that the temperatures of the waters on the bottom are nearly near zero degrees because they are flowing down the Antarctic here, and the central part is very high. You can see that the zone here corresponds to the zone Antarctica example and here is the contribution of the Mediterranean. There is an experiment that we will see showing the mixture of different water masses from different conditions with low and high density is very clear to see that. Then more things, the distribution of the water from the Mediterranean to the Atlantic, water from the Mediterranean exits Gibraltar and is spreading at about 1000 meters then it is spreading across the Atlantic. This is temperature, it is temperature at this position is mixing with local waters. But you see the fog of this water and salinity is much more clear is spreading here. This is the situation of the central part of the Atlantic. So at the surface of the water is included in this area, and you can see here a little bit. This is in TS diagram, you'll see essentially this is the North Atlantic central water, which is all the area occupying all the water column down to about 1,000 meters. This is the intrusion of the Mediterranean overflow water from 800 to 1,100 meters more or less that gives this highest solubility and also relatively higher temperature, and here this is a transition zone with a Labrador sea water which has a similar density or will be higher density, but much lower temperature and not so much more lower salinity. Because it is water that has the important influence from the ice cover in the Labrador sea, and here is the Gibraltar sea, is a section and see that the water is forced to go down while the Atlantic water is going up, and I'll show another picture of the distribution of salinity from different temperatures. This scheme I showed you. This is the center water, the external waters, the interior waters, and this is the Antarctic Gibraltar water which is in the bottom, the very dense water from the Antarctic itself that is spreading across the whole ocean. The profile of salinity is very nice because it is showing these maximum of salinity at about 1,000 meters, and these more or less the path of this water, one spreading towards the Portugal coast, and then to the North Atlantic, and the other is moving going to the South up to the West towards the Caribbean sea. I think that's more or less that is all.
