【高校地理】3-4. 海流と気候（海岸砂漠、エルニーニョ現象など） | 3. 世界の気候

#Geography #Climate #OceanCurrents #GeographyB #HighSchoolGeography #ElNiñoPhenomenon Hello everyone! This is the fourth installment of our high school geography lesson video, "The World's Climate," and it's "Ocean Currents and Climate." "What is the relationship between ocean currents and climate?" This video is divided into four main parts. 1. How Ocean Currents Work 2. Ocean Currents and Climate (1) West Coast Climate and East Coast Climate (2) Coastal Desert (3) Ice-Free Ports 3. El Niño and La Niña Phenomenon 4. Supplementary Information: Deep Currents (Thermohaline Circulation) First, in 1. How Ocean Currents Work, you'll learn to visualize the direction and nature of ocean currents. Then, in 2. Ocean Currents and Climate, I'll explain three examples of how ocean currents affect climate: west coast climate and east coast climate, coastal desert, and ice-free ports. 3. The El Niño and La Niña phenomena are phenomena in which abnormalities occur in ocean currents. Finally, as a supplement, I'll introduce something called deep-sea currents (thermohaline circulation). 1. How Ocean Currents Work Let's take a look at how ocean currents work. The important points about ocean currents are the direction of flow and the distinction between cold and warm currents, but there's no need to memorize each and every one of the many ocean currents. There's only one thing to remember: "Ocean currents are driven by the wind." Just like you can see the flow of miso soup when you blow on the surface, ocean water flows as if it's being blown by the wind—specifically, the trade winds and westerlies. Let's think about it using a simple diagram. There are two continents with an ocean in the middle. Imagine that this ocean is actually the Pacific or Atlantic Ocean. Here, trade winds blow from the east near the equator, and westerlies blow from the west at high latitudes. Drifted by these winds, ocean currents flow from east to west near the equator, splitting into north and south when they hit a continent, and as the latitude increases, they are blown east by the westerly winds. When they hit a continent to the east, they return to lower latitudes, making a full circle. In this way, ocean currents circulate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. To this, let's add the distinction between warm and cold currents. A "warm current" is a current that moves from warm to cold areas, in other words, an ocean current that flows from low to high latitudes. The ocean currents shaded red on the left are warm currents. Warm currents have the effect of warming the atmosphere, similar to room heating. In contrast to "cold currents," ocean currents flow from high to low latitudes, and have the effect of cooling the atmosphere, similar to air conditioning. The ocean currents shaded blue on the right are cold currents. "Warm" and "cold" currents do not have a specific temperature above which they are warm or cold; they simply refer to their relative warmth or coldness compared to the surrounding ocean. Therefore, there is no need to be particularly concerned with which cross-flowing ocean currents are warm and which are cold. Of course, in reality, more complex forces are at work, but this circular model is sufficient to understand the basic flow. Let's take a look at actual ocean currents around the world. First, the Pacific Ocean. Near the equator, the North Equatorial Current and South Equatorial Current flow from east to west, driven by the trade winds. When they collide around Indonesia, they split into north and south warm currents. The warm current that reaches Japan in this way is called the Kuroshio Current or Japan Current. It is then blown by the westerly winds and flows east as the North Pacific Current, before colliding with the western side of the North American continent and moving south as a cold current. This cold current is called the California Current. This completes the full circle, but in the Pacific Ocean, another small circulation also occurs to the north, forming a figure-eight like this. The cold current that reaches Japan at the top of this figure-eight is called the Oyashio Current, or Kuril Current. In the Southern Hemisphere, it's simpler: after a warm current passes east of Australia, it joins with a current near Antarctica called the Westerly Current and flows north across South America as a cold current. This cold current is called the Peru Current or Humboldt Current. In addition, between the North Equatorial Current and the South Equatorial Current, there is also a current flowing in the opposite direction, from west to east, called the Equatorial Countercurrent. This is one of the ocean currents known as "slope currents." This current is created when the trade winds and equatorial current cause sea levels to rise higher on the west side than on the east side near the equator, causing water to slide from higher to lower areas, like a slide....