How strong is the hurricane?
In essence, a hurricane is actually a tropical cyclone, but this rotating storm system can be hundreds of miles long. In the classification of hurricane grades, category 5 hurricane has no upper limit and the lowest wind speed reaches 25 1 km per hour. Theoretically, hurricanes are powerful enough to blow away some water from seawater, which is why hurricanes have only two components: heat and water. With global warming, our oceans may also get warmer. In order to make the hurricane gain strength, the fuel of warm water can determine how fast the wind speed can reach, which is also the theoretical basis for scientists to predict that the future storms will be stronger than before. Although in our physics, scientists have given that the maximum potential limit of hurricane prediction is 305 kilometers per hour according to the current marine and atmospheric conditions of the earth, this so-called upper limit does not mean that it is absolutely effective.
With global warming, the potential maximum intensity of hurricanes may increase. Scientists use a set of figures to show the influence of climate on hurricanes. When the temperature of our tropical ocean rises 1 degree Celsius, the maximum wind speed of the hurricane will also increase by about 5%. Perhaps, some people will wonder why some hurricanes can reach a higher wind speed than category 5, but they are not named category 6 or even higher. Scientists say that once the wind speed of a hurricane reaches category 5, the damage it will bring will be enormous, and a larger number of classifications are meaningless. Perhaps many people don't know that water is more destructive than wind in terms of property loss and life loss. Moreover, the significance of hurricane classification is to measure the degree of damage that the wind may cause. When the wind speed exceeds 25 1 km per hour, the damage is almost the same. Therefore, we need to pay more attention to its impact.
How hurricanes work.
First of all, we can start with the formation conditions of hurricanes, such as the water temperature reaching at least 26.6 degrees Celsius, continuous evaporation and condensation cycles, and the pressure difference between the surface and the upper air. In fact, tropical cyclones can be formed all over the world, but they are given different names because of their different locations. Hurricanes generally form in the eastern Pacific or Atlantic Ocean, typhoons in the western North Pacific, and cyclones in the Indian Ocean and the South Pacific. Hurricanes often start from thunderstorms in tropical ocean waters, and then gradually form hurricane state through hours to days of organization. The hurricane season in the Atlantic Ocean is from June to 165438+ 10, while the hurricane season in the eastern Pacific Ocean is relatively long, which can last from mid-May to 165438+ 10. The center of the hurricane is a low-pressure area called the eye of the wind. The rain belt spirals outward from the eye of the wind, and the sea water swept by the hurricane will produce dangerous storm surges. Hurricanes can transform warm ocean air energy into powerful winds and waves, just like a huge heat engine, and the air around them is far less warm than its center.
Of course, from storms to hurricanes, there will be some major stages. The first stage is called tropical disturbance, which is mainly manifested as a series of strong thunderstorms and showers; Its second stage is to become a tropical depression, a more organized form, with a wind speed of 40 to 60 kilometers per hour; When classified as a tropical storm, the wind speed has reached 63 to117km/h; Finally, when the wind speed reaches 1 19 kilometers per hour, it will be officially classified as a hurricane, and then its level will be defined according to the safire-Simpson scale. In short, the formation of hurricanes is inseparable from the "fuel" of warm seawater and the wind mode near the surface. As the air rotates inward, the warm air in the center of the storm rises, creating an eye in the central area with low pressure characteristics. The width of the relatively calm eye is generally about 32 to 48 kilometers. The smaller the eyes, the greater the destructive power, and the air inhaled into the surface will increase with the decrease of the central air pressure.
Structure and types of hurricanes
Among the structural components of hurricanes, the most well-known part is called the eye of the wind, but there are actually two other parts, namely the rain belt and the eye wall. Clockwise in the southern hemisphere or counterclockwise in the northern hemisphere, air spirals toward the center, while in the opposite direction, it spins outward from the top. The eye wall around the eyes is a circle of towering thunderstorms, while the curved thunderstorms and clouds are far away from the eye wall in a spiral way. These rain belts will produce a lot of precipitation and strong winds, and their destructive power can cover a range of 242 kilometers. In fact, wind is not the only hazard of this tropical cyclone. The surge of wind will push the sea water to the shore, and the rise of water level will lead to floods. From the past historical data, most of the deaths caused by tropical cyclones are catastrophic damage caused by floods.
In the classification of hurricanes by scientists, category 5 is the most destructive hurricane, which can cause power outages for weeks or even months, and most of the houses with frame structures will be destroyed, making them uninhabitable areas; 1 This category is the least harmful hurricane, and only some minor problems such as broken branches, collapsed trees and leaking roofs will occur; Category 2 hurricane is of medium type, and trees may be uprooted, which may cause damage to the roof and side panels; The damage caused by category 3 and category 4 hurricanes is catastrophic. The power outage in this area will be prolonged, and the roofs and external walls of houses will be damaged, which may make them uninhabitable for weeks or even months. Although some scientists object to using wind speed as an indicator to measure the severity and potential damage of hurricanes, it is not a simple matter to actually measure indicators such as storm surges. For example, local differences in Haiti's topography will affect the height of storm surges.