Articles about the "Weather"

In 2020, the rainy season will start later than usual︎ The first day of the rainy season and the end of the rainy season
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In 2020, the rainy season will start later than usual︎ The first day of the rainy season and the end of the rainy season

Weather

The rainy season is plagued by rain. It's very embarrassing when you can't hang your laundry outside for days on end, isn't it? By the way, Japan is a small country compared to other countries, but did you know that the onset and end of the rainy season varies from region to region? In this article, we will look at the beginning and end of the rainy season across the country in 2020. I would be happy if you could use it as a reference.   What is the rainy season? Let's take a look at what the rainy season is all about in the first place. The rainy season is not found worldwide, but only in East Asia (southern China, coastal areas in the Yangtze River basin, Taiwan, Hokkaido, and Japan except for the Ogasawara Islands), and is a peculiar weather phenomenon with frequent cloudy and rainy weather. It occurs mainly from May to July. Incidentally, how did it come to be called the "rainy season"? There are various theories about the etymology of the word, such as that it comes from the time when the plum trees are ripe, or that it comes from the time when mold grows easily due to the high humidity, which is why it was called "moldy rain" and "ume".   The rainy season has entered 2020 Northeastern Japan's rainy season has begun The rainy season in the northern northeast will begin on June 15 in 2019, as usual, with the normal date being June 14. The start of last year's rainy season was nearly a week late in 2019, with June 12 in the southern Northeast and Hokuriku and June 7 in the normal. The onset of the rainy season in the southern northeast in 2020 is expected to be about a week later than last year, but as normal. The rainy season has entered the Kanto Koshin and Tokai regions The start of the rainy season in the Kanto Koshin and Tokai regions was almost normal in 2019, with the start of the rainy season on June 7 and the normal on June 8. In fiscal year 2020, the rainy season is expected to enter a week later than last year and later than normal. The rainy season has begun in western Japan The rainy season in Kinki is set to begin on June 27 for 2019, with a normal date of June 7. In China, 2019 is June 26 and the normal is June 7. Shikoku and northern Kyushu had a record-breakingly late start of the rainy season in 2019, with the exception of southern Kyushu, which entered the rainy season on May 31 as normal last year, on June 27 and June 7 as normal. The rainy season is expected to start about half a month earlier than last year in the 2020 fiscal year. The rainy season has begun in Amami and Okinawa The start of the Amami rainy season is May 14 in 2019, while the normal is May 11. In 2019, Okinawa is entering the rainy season on May 16, the earliest compared to other regions, with a normal date of May 9, but compared to a normal date, Amami was about 3 days behind and Okinawa was about a week behind. In 2020, the rainy season started earlier than last year, May 10 in Amami and May 11 in Okinawa, which is almost normal.   The end of the rainy season in 2020 The end of the rainy season in Tohoku The end of the rainy season in the northern northeast was July 31 in 2019, a few days later than normal at July 28, while the rest of the southern northeast and northland were at normal July 25 and July 24, respectively. In 2020, the rainy season is expected to start about a week earlier than last year, around the end of July or a little earlier than normal. The end of the rainy season in the Kanto, Koshin and Tokai regions Both Kanto Koshin and Tokai had a slightly later start to the rainy season in 2019, July 24, with the normal being July 21. The 2020 rainy season is expected to end in mid-July, a week earlier than last year, as it did in the northeast, which is normal or slightly earlier. The end of the rainy season in western Japan The rainy season in Kinki will end on July 24 in 2019, while the normal is July 21. The rainy season ended on July 25 in China, Shikoku, and northern Kyushu in 2019, but the normal was delayed by nearly a week to July 21, July 18, and July 19, respectively, while southern Kyushu was significantly delayed by July 24 and July 14 in 2019. The end of the rainy season in 2020 will be in the middle of July, which is roughly the same as the Kanto Koshin and Tokai regions. The end of the rainy season in Amami and Okinawa Amami's 2019 rainy season begins on July 13, with a normal date of June 29. Okinawa was significantly behind in 2019 with a July 10 date and a normal date of June 23. In 2020, however, the rainy season will end at the end of June, which is normal, much earlier than last year. Hokkaido weather in June and July In Hokkaido, we don't have a rainy season, so we don't have the beginning or end of the rainy season, but we do have some weather changes... June is a cyclical month, with sunny days in early July, but cloudy and rainy days in late July. The rain is expected to be torrential, rather than sporadic.   Overall rainy season precipitation in Japan by 2020 This summer's precipitation is expected to be normal throughout, but in western Japan, precipitation is expected to be above normal during the rainy season, so you need to be careful of heavy rainfall. From the end of the rainy season in mid-July, both western Japan and eastern Japan will see more sunny weather, but don't forget to bring an umbrella in case of a guerrilla downpour.   Recap How was it? The weather is such an important part of our lives that it's hard to keep track of it perfectly. Keep in mind that it's probably this time of year, and carry a folding umbrella in your bag. The more prepared you are, the better off you are.

What is high tide?
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What is high tide?

Weather

Waves are also one of the most important factors in surfing, as the words "high tide" and "low tide" refer to. It is important to know how the tide is coming and going, especially if you want to ride a good wave and improve quickly. Here, let's look at the high tide. What is high tide? If you look at it casually, you won't notice much, but the sea level goes up and down almost twice a dayevery day. The height of the sea level is always changing slightly. If the tides rise and fall twice a day, it takes about six to seven hours for the water level (tide level) to fall from the highest to the lowest, and then it takes another six to seven hours for the water level to rise from the lowest to the highest. In addition, it is also possible to make use of the new technology to improve the quality of your life. It is there. On the other hand, when the water level is at its lowest point, it is called "low tide".   How the high tide works Many people know that the tide goes in and out, but how does it go in and out again? Here's how the high tide works. The relationship with the moon plays a big part in the ebb and flow of the tide. The Moon revolves around the Earth in an orbit of about 27.3 days. As can be seen by the law of universal gravitation, all objects in this universe have a gravitational pull. This is also true of the moon, which also has a gravitational pull. The seawater in the ocean is liquid, so it can move freely and change its shape. Therefore, on the side of the sea facing the moon, the pull of the moon lifts the surface of the sea, and the tide is high. This attraction works not only on the sea surface facing the moon, but also on the sea surface facing and opposing the moon. For this reason, it is high tide, both on the side facing the moon and on the other side of it. Then, the middle part between the side facing the moon at high tide and the other side of the moon is at low tide.   How much is the difference between high and low tide? For those of you who enjoy surfing and other sea activities, the difference between high and low tide may be a concern. The actual difference between high and low tide varies greatly from place to place as well. In Japan, the difference between high tide and low tide in the Sea of Japan is about 40cm, so the sea level does not change that much. On the other hand, on the Pacific side, the difference between high and low tide is about 1.5 meters, which is an extra 1 meter compared to the Japan Sea side. Outside of Japan, the difference in tide can be as much as 10 meters in Incheon, South Korea, and 15 meters in Mont Saint-Michel, France. And the world's highest tide difference between high and low tide is in the Bay of Fundy in eastern Canada. In the Bay of Fundy, there is a tide difference of up to 16m. The tide has eroded the cliffs and exposed fossils, so it's a great spot for surfers and your family and friends to enjoy.   Don't judge a surfing newbie by the tide alone! Looking at the difference in tide level, some people may think that the Japan Sea side is gentler than the Pacific side, so be careful. When surfing or playing in the sea, it is important to take into account not only the tide level but also the influence of the wind. On the Japan Sea side, the sea tends to be rough from late August to April due to the north wind, so even if the tide is low, it is not recommended for beginner surfers. On the other hand, from May until around Obon, the winds blow from the south, so the Sea of Japan side is relatively calm. The Pacific Ocean side is the opposite of the Sea of Japan side, with calm seas from late August to April, and rough seas from May to around Obon. Therefore, if you are a surfing beginner, it is recommended to practice from spring to Obon on the Sea of Japan side, from Obon to winter on the Pacific side.   High tide is not good for surfing If you are a beginner or not familiar with the waves, you may think that the sea level is higher at high tide, which is a good time to surf. However, high tide is not a good time to surf. When surfing conditions are dangerously high, you don't want to have dangerously high waves, but you don't want to have any waves at all or have no waves at all. The waves are good for surfing when the tide is moderately high, called the low (ebb) or high (pot) tide. Ebb tide is literally the state of the sea level as it drops from high tide to low tide, while ebb tide is when the sea level rises from low tide to high tide. At this time, the amount of seawater gradually changes over a long period of time, which is difficult for us humans to notice, and the sea level moves along with it. In fact, without this kind of sea level movement, there would be no waves. Therefore, it is not suitable for surfing at high or low tide when the sea level does not change. In addition, beginners are more comfortable and easy to practice in the calm sea, but it is also not suitable for surfing if there is no change in the sea level, such as no wind. It is necessary to check the high and low tide time the day before you go surfing, but if the high and low tide come up during surfing or the wind is gone, it is a good idea to take a break until the sea level changes.  

What are the health consequences of low pressure?
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What are the health consequences of low pressure?

Weather

Sickness Affected by Weather 'I thought my head hurt and then it rained the next day,' or 'I'm not feeling well during the rainy season and can't do anything about it,' Many of you may have had the experience of getting sick on a rainy day or before the weather breaks, such as "when it rains, my old wounds hurt. You may be thinking, "Maybe it's just a coincidence that I'm getting tired," or "Maybe it's just my imagination," but did you know that it's not your imagination? Poor physical condition caused by such weather changes is called "weather disease" or "weather pain". People who suffer from this weather disease or weather pain are more likely to be women in their 20s and 40s who are more susceptible to female hormones It is said that. Low pressure in the shadow of poor performance But here's a little something that stuck with me. It's called a "weather disease," and while some people get headaches or get sick before the weather breaks, you don't often hear of people getting sick before the weather recovers. In addition, some people who get sick because of the weather have a headache or get sick if it's raining normally, but when it's before a guerrilla downpour or a typhoon, they can't help but take their medication. Some people have severe headaches and can't stay awake. The reason why such a mysterious phenomenon occurs is that human health and low pressure have a big influence on it.   The workings of the autonomic nervous system and dysregulation Normally, if you're in good health, you won't get sick when the temperature and weather change. This is because we have the ability to maintain a constant state of the body even when the environment surrounding us, such as temperature and weather, changes. It is thanks to the "autonomic nerves" that the body is able to keep itself in a constant state. The autonomic nerve is a nerve that is in charge of life support activities such as the circulatory, digestive and respiratory systems in the human body, and it works 24 hours a day even when we are unconscious, such as while sleeping. When the autonomic nervous system is out of balance, the body becomes sluggish, headaches, shortness of breath, diarrhea, constipation, and various other ailments appear. If this condition becomes severe, it becomes a disease called "autonomic dysautonomia".   Low pressure + autonomic disturbance causes poor physical condition

What is a low pressure and what is a high pressure? About the change in weather
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What is a low pressure and what is a high pressure? About the change in weather

Weather

When you're planning a weekend of surfing or a family trip to the beach, you're probably concerned about the weather forecast. If you watch the weather forecast on TV, you may hear the weatherman say "low pressure will develop over the weekend" or "high pressure will develop". There are vague images of "low pressure = bad weather" and "high pressure = better weather". However, I think there are not many people who know about low pressure and high pressure in detail, so I will introduce low pressure and high pressure here. What is a low pressure? The "barometric pressure" of a low or high pressure is the pressure of a gas and generally refers to the pressure of the atmosphere. When the pressure is low, it is called a low pressure, but there is no standard for a low pressure below 0 hPa. Low pressure is relative, when it is low compared to the surrounding pressure It is called a low pressure. The air is thinner than its surroundings in the "low" part of the region where the pressure is lower than its surroundings. The air is denser in the higher pressure areas around the low compared to the low. Therefore, the air in the high pressure area, where the air is dense, will move towards the low pressure area, where the air is thin. This causes the wind to blow towards the low pressure. That way, after the air that flowed in collided with each other, the only place to escape was up and down and down. The upward wind (updraft) is generated because of the ground. In the air, there is originally a lot of water vapor, and this water vapor goes up into the sky on the updraft. Since there is cold air in the sky above, the water vapor on the updrafts is cooled down to form water droplets and ice, and the grains of these water droplets are called clouds. These water droplets and grains of ice collide with each other and become large and heavy, so they cannot float in the air and fall as rain or snow. This is why, when there is a low pressure on the weather map, it becomes cloudy at the center of it, or rain or snow falls and causes the weather to break down.     What is a high pressure? The high pressure causes the exact opposite of the low pressure. The air is denser in the "hyperbaric" areas where the pressure is lower than the surrounding area. The low air pressure areas around high pressure are thin compared to high pressure. Therefore, air is blown out to take air from the high pressure area to the low pressure area. When that happens, there is no air in the high pressure area, so air comes down from above to take in air. Therefore, when there is a high pressure, even if there are clouds in the sky above, they will be scattered into the air by the downward wind. Therefore, when a high pressure system arrives, the clouds above will disappear and the weather will clear up and improve.   Why does the low pressure occur? Low pressure is a place where the air is thinner than the surrounding area, which may raise the question of why such a place is created. During the day, when the sun is out, its light hits the ground. However, in doing so, for some reason The sun's rays don't hit the ground evenly, and only one area of the ground may be heated and have heat. This is when the low pressure occurs. This is because when the ground warms up, the air above it also warms up. Warmed air rises because it has the propensity to go up. That way, the area where the air has risen will have less air, so air will move in from around it, creating a low pressure.   Front related to rainfall At first glance, it looks like a low pressure = bad weather = low temperature, but a low pressure is a collection of warm air. This boundary between warm and thin air and normal air is called the front. If there is a low pressure in the middle, it will be in the form of a front on the right and a front on the left, but these two fronts are very different in nature. The front on the right in the figure below is called a "warm front" because when it passes through this front, it is taken into the warm air of a low pressure and the air temperature rises. On the other hand, if a front on the left passes through while in a warm low pressure, it will be thrown out into the normal air and the temperature will drop, so it is called a cold front. In the case of a warm front, warm air flows into the cold air, but the warm air is so warm that it slides over the cold air as it rises. On the contrary, cold fronts allow cold air to flow into warm air. The cold, chilly air is heavy compared to the warm air, so it slides down. In fact, this difference can make a big difference in the weather. In the case of a warm front, the air moves gently and water vapor evaporates along the air, forming clouds. On the other hand, a cold front is characterized by the fact that the boundary between cold and warm air is steep and clouds tend to gather in one place. Depending on these characteristics, there are different types of clouds. Clouds formed in a warm front tend to form stratospheric clouds, while those in a cold front tend to form cumulonimbus clouds. As a result, there will be strong showers and cooler temperatures under a cold front. On the other hand, when a warm front passes through, there is a long period of moderate rain and the temperature rises. So, before you go out to surf or go to the beach, make sure that a cold front does not pass through.  

Typhoon measures and basic knowledge to hold down
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Typhoon measures and basic knowledge to hold down

Weather

If you want to enjoy marine sports such as surfing, it is important to keep yourself safe. Especially in the case of typhoons, strong winds and high waves have a great impact on the sea, so it is important to think about how to prepare for typhoons. The importance of countermeasures for each type of typhoon damage Unlike natural disasters such as earthquakes that strike without warning, typhoons are natural disasters that can be predicted to a certain extent in advance, so it is necessary to take precautions in advance. If you live in Japan, you have been experiencing typhoons many times since you were a child. It is important to take appropriate measures for the type of damage. The damage from the typhoon was mainly ・gale ・Rain and heavy rain ・Landslides ・Storm surge There are four types of products. Of these, let's consider typhoon countermeasures for common storms and torrential rains and typhoon countermeasures near the sea.   Storm Control Of the four, the one that has the most widespread impact is the storm. In the case of wind typhoons, etc. Storms and gusts of wind can cause massive damage in an instant. Especially in the case of wind storms, flying debris picked up by the wind can cause damage such as hitting window glass or flying roofing materials, and injuries from flying debris can be considered. Eliminate flying objects. Therefore, as a countermeasure for storms before a typhoon, it is possible to remove anything that may be scattered from around the building, such as the home. Plant pots, clothes poles, bicycles, etc. that are outdoors should be taken into the building. If you can't take it indoors, secure it with a string to prevent it from flying away. Protect your windows One of the most common types of damage during a typhoon is when objects scattered in the storm hit the window glass and break it. The most effective way to prevent such damage is to tighten the shutters and shutters on the windows. If you don't have a storm door or shutters, hold a board or cardboard against the window glass and secure it with curing tape. This way, not only does the board or cardboard act as a cushioning material and make it harder to break, but it also prevents the glass from flying off in the event of a break. What's more, a broken window can not only cause rain to shake in, but it can also cause the roof to be lifted and blown away by the storm winds blowing in through the broken window. This kind of damage can also be prevented by reinforcing it with boards or cardboard. Especially in areas near the sea, the wind from the sea tends to be strong, so it is important to take appropriate measures.   Rain Protection There is a type of typhoon called a rain typhoon. The biggest problem in a rainy typhoon is that roads and buildings are flooded. As a countermeasure, remove leaves and debris clogging gutters and gutters that serve as rain flow paths. It's easy to forget, but if a heavy downpour falls in a short period of time, the sewer system can't handle it all It can back up and run down the drain into the room. If you hear a rumbling sound, especially in the toilet, bathroom or washroom, you need to be careful. If you're worried about flooding in a heavy rainstorm, cover the drains with a plastic bag filled with water, for example.   Keep an eye on the path of the typhoon If you've had a typhoon in the far south of Japan, but plan to go to the beach soon, you'll want to be sure to keep your eyes open. It's important to know the path of the typhoon. Even in areas away from the typhoon, the wind and waves could have an impact, depending on the path and direction of the typhoon There is. However, if the predicted path to the area where you are or will be going, you may not even know if a typhoon is coming or not. If this is the case, you should prepare yourself to some extent before you go out to sea by anticipating your route. ◆Typical paths by time of year Typhoons occurring in the southern part of Japan have a different path depending on the time of year and the main path that we know from the statistics so far. Typhoons that occur between July and October, when the most typhoons enter Japan, tend to curve to the east. The other months of June and November/December tend to move westward and away from Japan. In particular, from July to August, the route from Kyushu northward to the Sea of Japan, from the Kii Peninsula and Tokai to Kanto in September, and from east to west over the southern ocean without approaching the Japanese Islands in October There is a lot of progress to be made. ◆ Check the position of the high pressure One of the characteristics of a typhoon is that it follows the high pressure and goes around. When a typhoon arrives near the Japanese Islands, if there is a high pressure on the weather map near Japan, it will move from west to east with westerly winds following the high pressure in most cases.   If this happens, don't go anywhere near the ocean One of the most common questions asked during the typhoon season at dive shops offering ocean activities is, "There is a typhoon approaching, is it going to be canceled? I can only say that the answer to this depends on the type of activity and the circumstances. Diving, kayaking, and glass boating will be cancelled as early as the waves start to come out, as small children may be involved. On the other hand, surfers may find it more fun to have a few waves. However, there is no point in getting injured or losing your life. Depending on your experience and skill, there is a difference in when you should stop surfing. However, if a surfing competition is cancelled or a surfing spot is closed out, stay away from the ocean as the danger is just around the corner. In addition, beginners and those who are not good at swimming should not enter the sea if the waves are higher than the waist, if the typhoon is approaching, because it will be dangerous.  

What is a typhoon?
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What is a typhoon?

Weather

What is a typhoon? For those who enjoy marine sports such as surfing, wakeboarding, and diving, the weather is as important as the information on the waves. Among them, it is especially important to pay attention to typhoons. Typhoons come to Japan from the end of summer to autumn and have become a seasonal phenomenon, but the question "What is a typhoon? Let's take a look at typhoons, because many people don't understand the meaning of the word "typhoon". According to the JMA's definition, a tropical depression that occurs over the ocean in the tropics and is located in the Northwest Pacific or South China Sea and has an average maximum wind speed of 17 m/s for 10 minutes and a wind speed of 8 (tree branches are broken or it is difficult to stand) is called a "typhoon.   How do typhoons come into being? In autumn, typhoons suddenly appear on the weather map one day, but there is a mechanism by which they form. As the seawater temperature rises, the seawater evaporates as water vapor. In doing so, water vapor is lighter than air, so it creates an updraft. When an updraft is created, the air pressure drops and it becomes a state called a low pressure. A normal low pressure can be formed in the Japanese Islands, but a tropical depression, which becomes the base of a typhoon, is formed in the tropics. The water vapor evaporated from the sea surface is cooled in the sky above and becomes a cumulonimbus cloud. These cumulonimbus clouds form a vortex under the influence of the forces exerted by the Earth's rotation. When the wind speed exceeds 17 meters per second near the center of this vortex, it changes from a tropical cyclone to a typhoon.   Typhoons vary in name and time of occurrence by location Many people enjoy surfing and other marine sports not only in Japan but also overseas. When checking the local weather forecast, it is important to note that typhoons are called differently depending on the location. Tropical cyclones, which can be considered the source of typhoons, occur not only in the Northwest Pacific and South China Sea, but also in warm oceans around the world. After the occurrence of a typhoon, it is swept away by the wind to various places, and its name changes depending on where it goes. It's called a cyclone when it's in the eastern part of Africa near the Indian Ocean and the South Pacific, where Fiji and Tonga are popular travel destinations for marine sports enthusiasts. A hurricane is also called a hurricane if it is located in the Pacific Ocean in the northern hemisphere, east of 180°E across the eastern edge of Russia, or in the Atlantic Ocean between Europe and Africa and the Americas. If it is in the Pacific Ocean around East Asia, which is west of 180°E in the Northern Hemisphere, including Japan, it is called a typhoon (Typhoon). The timing of occurrence is also very different between typhoons and hurricanes and cyclones. Typhoons and hurricanes primarily occur between June and November, whereas cyclones occur between April and December. If you enjoy marine sports such as surfing, be aware of typhoons, cyclones and hurricanes, depending on where you are going and when.   Typhoon size When looking at typhoon information, you may hear expressions like "large typhoon" or "super large typhoon". These "large" and "very large" expressions are classifications that indicate the size of the typhoon. In addition, it can be used as an alternative to the traditional Japanese typhoon. or not. In the case of large typhoons, the wind speed of 15 m/s or more is defined as a radius of 500 km to less than 800 km. It's a great way to get to know your neighbors and friends. It is the size that can fully fit into the In addition, super-sized typhoons are defined as having a wind speed of 15 m/s or more and a wind range of 800 km or more. A radius of more than 800 km exceeds the size of the city of Tomakomai in Hokkaido in the east from Tokyo and Ube in Yamaguchi Prefecture in the west.   How many typhoons are coming to Japan? Every year, a large number of typhoons occur over the ocean to the south and west of Japan, with an average of 25 occurrences per year for the 30 years from 1981 to 2010. Of these, only 11 are approaching Japan, with five to six coming within 300 km of a meteorological station from Hokkaido to Kyushu, and seven to eight in the Amami region of Okinawa Prefecture.   Typhoon types Typhoons can be broadly divided into two types of typhoons, depending on the damage they cause. One of the two types is a "rain typhoon" and the other is a "wind typhoon". A rain typhoon is literally a typhoon that is strongly affected by rain, while a wind typhoon is a typhoon that is strongly affected by wind. In both cases, you need to be careful of heavy rains and storms, but it is the wind typhoons that have the greatest impact on the sea. In the ocean, waves are caused by the wind blowing on the seawater. The size of the waves changes daily depending on the strength of the wind and the time of day it blows. This is the reason why the waves are higher when the wind blowing into the sea due to the typhoon and when the typhoon occurs. Before heading out to sea, pay attention to the wind direction and time of day, such as high tide.  Beware of dangerous half-circles; Beware the dangerous half-circle Many of you have heard that areas to the right of the typhoon are more likely to be affected by the wind I think it's because of this. Even among sailors, the right side of a typhoon is known as the "danger half-circle" because it is dangerous to navigate. In the northern hemisphere, where Japan is located, typhoons generally move from west to east. At that time, a counterclockwise wind current was formed on the ground toward the center of the typhoon. Because the direction of the wind that blows in and moves the typhoon is the same as the direction of the wind that moves the typhoon, the synergistic effect makes the wind stronger. It is an ironclad rule to stay away from the sea when a typhoon is approaching, but be especially careful in the coastal areas to the right of the eye of the typhoon, where the waves tend to be high due to strong winds.  

What is the difference between a tropical cyclone and a typhoon?
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What is the difference between a tropical cyclone and a typhoon?

Weather

Often, the weather forecast says, "A typhoon has turned into a tropical depression. Do you know the difference between a typhoon and a tropical cyclone? Before explaining the difference between a "tropical depression" and a "typhoon", I would like to first explain how a "tropical depression" is generated. First of all, what is a "tropical depression" is a low pressure whose maximum wind speed is 17.2m/s or less over the tropics or subarctic zone. A low pressure is a phenomenon in which a lot of water vapor evaporated from the sea rises and the air swirls around. By the way, all the "depressions" mentioned in the news in Japan are "tropical depressions". The reason why tropical cyclones occur in high-temperature oceans such as the tropics is that they need a lot of water vapor to occur, so they must be in high-temperature oceans. This is why they are often found in tropical and sub-arctic regions where the ocean temperature is high. And typhoon No. 19, which recently ravaged Japan, developed rapidly in this place. The speed at which it developed was the fastest in the world, and the level of danger was so high that some experts in the U.S. said it was so powerful that it was the highest non-existent level 6 in the Kagodeli ranking of typhoon strength. What is the difference between a "temperate depression" and a "tropical depression"? "Temperate" and "tropical" depressions are the same depression, but they are completely different. A tropical cyclone is made up of only warm air, but a temperate cyclone is made up of both warm air and cold air, so the type of air that is made up is different. A "temperate depression" is composed of warm and cold air, which causes a front to develop, whereas a tropical depression does not. How do typhoons occur? Types rarely appear out of the blue as typhoons, but basically they occur as "tropical cyclones". A basic typhoon forms in the southern sky and moves toward the northern sky, so it is called a "typhoon" only when it gains strength and its maximum wind speed exceeds 17.2 m/s. When the force drops and the maximum wind speed becomes less than 17.2 m/s, it is called "tropical depression" again. Briefly, a summary of how typhoons can be made (1) A "tropical cyclone" is generated. (The maximum wind speed at this time is less than 17.2 m/s.) If the maximum wind speed exceeds 17.2 m/s, it becomes a "typhoon". (3) After becoming a typhoon, it returns to a tropical cyclone when its power drops and its maximum wind speed drops to less than 17.2 m/s. (iv) Natural annihilation..... Just like that, typhoons are created and disappear. Incidentally, typhoons are most likely to occur from summer to autumn. The reason for this is that seawater, which is the fuel for typhoons, tends to evaporate due to high seawater temperatures. Next, I would like to explain what the storm and strong wind areas are, which indicate the size of a typhoon. Basically, the size of the typhoon is estimated by the size of the strong wind area. A high wind area is a range of places where winds are blowing or are likely to blow above 15 m/s. In weather forecasts, it is often represented by yellow or other colors. And the extent of the area where stronger winds are likely to blow is called the storm area. By even stronger winds here, I mean winds of 25 m/s or more. In weather forecasting, it is often represented by a red circle.   Where does the "tropical depression" that will come to be called a "typhoon" occur? In fact, no matter where it occurs in the sky, it is not called a "typhoon" if it comes over Japan. To be called a "typhoon," a "tropical depression" in the western North Atlantic Ocean (South China Sea, Philippine Sea, Sea of Japan, etc.) must have a maximum wind speed of 17.2 m/s or higher. If it occurs in the northern and southern Indian Ocean or the southern Pacific Ocean, and the central pressure is 17.2 m/s or more, it is called a cyclone; if it occurs in the northern and southern Atlantic Ocean or the northeastern and north-central Pacific Ocean, and the maximum wind speed is greater than 32.7 m/s, it is called a hurricane. Surprisingly, there is a difference in the direction of the swirl depending on where the tropical depression has developed. The northern hemisphere is counterclockwise and the southern hemisphere is clockwise. When the maximum wind speed is 32.7 m/s or higher, it is called a "strong typhoon"; when the maximum wind speed is 43.7 m/s to 54.0 m/s, it is called a "very strong typhoon"; and when the maximum wind speed is 54.0 m/s or higher, it is called a "fierce typhoon". Recap At the end of the day, the difference between a typhoon and a tropical cyclone is the difference in the size of the maximum wind speed. (Maximum wind speed of 17.2 m/s or more is a typhoon) In other words, there is no difference between a typhoon and a tropical cyclone except for the size of the maximum wind speed.