Weather

Storm near Gazrajau (Madeira).

The weather or meteorological is the state of the atmosphere at a given time and place defined by various meteorological variables such as temperature, pressure, wind, solar radiation, humidity, and precipitation. Most weather events occur in the troposphere, the layer below the Stratosphere, being the bottom layer of the atmosphere that is in contact with the surface. It is important to differentiate weather from climate, since the latter refers to the average atmospheric conditions that characterize a place. These averages are usually made over periods of several decades.

Weather is driven by air pressure, temperature, and humidity differences from one place to another. These differences can occur due to the angle of the sun at any particular site, which varies by latitude from the tropics. The sharp temperature contrast between polar and tropical air gives rise to the largest-scale atmospheric circulations: the Hadley Cell, Ferrel cell, polar cell, and jet stream. Mid-latitude weather systems, like extratropical cyclones, are caused by jet stream flow instabilities. Because the Earth's axis is tilted relative to its orbital plane, sunlight hits it at different angles in different months of the year. On Earth's surface, temperatures typically vary by ±40 °C annually. Over thousands of years, changes in Earth's orbit can affect the amount and distribution of solar energy received by Earth, thus influencing the long-term climate and global climate change.

Surface temperature differences in turn cause pressure differences. Higher altitudes are cooler than lower altitudes due to differences in compression heating. Weather forecasting is the application of science and technology to forecast the state of the atmosphere for a future time and location. The system is a chaotic; Changes so small to one part of the system can grow to have large effects on the entire system. Throughout history, there have been human attempts to control the weather, and there is evidence that human activities such as agriculture and industry have modified weather patterns.

The study of how time works on other planets have been useful in understanding how time works on Earth. A famous place in the solar system, Jupiter's Great Red Spot, is an anticyclonic storm that has existed for at least 300 years. However, time is not limited to planetary bodies. A star's corona is constantly drifting off into space, creating what is essentially a very thin atmosphere across the solar system. The transport of mass ejected from the Sun is known as the solar wind.

Origin and flow of atmospheric energy

A NASA satellite image of the Amazon launch shows us some of the energy flows in the atmosphere: the solar rays heat the Earth's surface, the lands in the first place (more quickly) and the waters later (more slowly). The warming of the lands warms the surface air, which rises, cooling and condemning the atmospheric humidity that becomes liquid water that forms the clouds. Meanwhile, the water of the large Amazonian rivers is absorbing solar radiation more slowly so there is no evaporation of its waters and therefore there is no warming of the air in those areas, there is no convection or condensation in them.

Sunstroke

Almost all of the solar energy that generates all atmospheric changes comes from solar radiation, that is, from insolation. But the solar rays do not directly heat the atmospheric air due to the property of air as a whole of diathermancy, which explains that the atmosphere is allowed to pass through the solar rays without practically heating up. Thus, the heating of the atmosphere by solar radiation is indirect: the solar rays first heat the lithosphere (quickly) and the hydrosphere (slower than the lithosphere). When both the lithosphere and the hydrosphere have warmed, they release that heat to the atmosphere, the first quickly and the second more slowly, all in accordance with what was explained about the warming of the lithosphere and the hydrosphere in the aforementioned article (diathermancy). The image of the Amazon river delta presented here was taken during the morning. If we were to compare it with a similar image during the evening of that same day (this is possible, not in an image of the visible spectrum, but in an infrared image) we would see that the situation is reversed, appearing more condensation on the rivers than on the land.

2015 – 5th Hottest Global Year in Registration (from 1880) to 2021 – Colors indicate temperature anomalies (NASA/NOAA; 20 January 2016).

Because Earth's axis is tilted relative to its orbital plane, sunlight hits it at different angles at different times of the year. In June, the Northern Hemisphere is tilted toward the sun, so at any latitude in the Northern Hemisphere, sunlight falls more directly on that location than it does in December. This effect causes seasons. Over thousands to hundreds of thousands of years, changes in Earth's orbital parameters affect the amount and distribution of solar energy received by Earth and influence long-term climate. (See Milankovitch cycles.)

Uneven solar heating (the formation of zones of temperature and moisture gradients, or frontogenesis) can also be due to climate itself in the form of cloudiness and precipitation. Higher altitudes are typically cooler than lower altitudes, which is the result of a higher surface temperature and radiant heating, which produces the adiabatic decay rate. In some situations, the temperature increases with altitude. This phenomenon is known as inversion, and it can make the tops of mountains warmer than the valleys below. Inversions can lead to fog formation and often act as a boundary that suppresses thunderstorm development. At local scales, temperature differences can occur because different surfaces (such as oceans, forests, ice sheets, or man-made objects) have different physical characteristics such as reflectivity, roughness, or moisture content.

Other sources of atmospheric energy

Eruption of the Mayon Volcano on the island of Luzon, Philippines, in 1984. You can see on the left a cloud formed by very hot water vapor from the eruption by cooling with ambient temperature.

Submarine hydrothermal source, whose energy produces the environment that allows the existence of abyssal fauna in its surroundings despite the enormous pressure that exists by the great depth of the ocean floor.

In addition to solar radiation, there are three minor sources of thermal energy that can heat the atmosphere:

• The geothermal energy of hot points in the ocean floor. This energy passes to the oceanic water that heats or even boils, evading with what absorbs heat that, when condensed, passes to the atmospheric air (for example, the last submarine eruption on the island of El Hierro in the Canary Islands).
• Volcanic eruptions can also warm the atmosphere directly, without solar radiation intervening.
• Breathing of plants and animals as well as breathing of living beings. This last source of heat is very important, as shown by the infrared photographs of the vegetation areas present on the Earth's surface. However, these three heat sources are insignificant when compared to the solar energy received on the Earth's surface. If noted here is to clarify the initial idea of this subject that almost all of the energy stored in the atmosphere comes from solar radiation. And of the three heating sources other than solar radiation, the one formed by the breath of vegetation is the most important for its stability in time and for using CO₂ as a raw material, besides the release of free oxygen, without which the life of the animals would become impossible.

Meteorological phenomena

Hurricane Luis in 1995.

The weather changes driven by the differences in solar energy perceived in each differentiated area according to a time scale that goes from less than a day (radiation differences between day and night) to seasonal periods throughout the year. anus. Weather stations measure different local weather variables such as temperature, atmospheric pressure, humidity, cloudiness, wind, and the amount of rain or rainfall. Once these direct variables are known, other derivatives can be found, such as the condensation vapor pressure, the sensation temperature or the muggy temperature.

Using networks of local weather stations, stations on ships, and weather satellites, meteorology tries to find out the weather variables at the vertices of a three-dimensional mesh of the smallest possible size. Starting from these initial conditions and applying the laws of physics, an attempt is made to predict the evolution of time. For this, powerful computers must be used that are in charge of carrying out the calculations using a predictive model of an empirical type.

Weather forecast

The realization of meteorological forecasts at a regional scale and, especially, at a local scale, constitutes today an extremely important and widespread activity in almost the entire world and in numerous activities. The organization of civil aviation (schedules, forecasts, flight alternatives, etc.) depends to a great extent, and increasingly, on very detailed weather forecasts. The same happens with other types of activities (agriculture, transport, commerce, services of all kinds, etc.). This activity is based on the data provided by strategically located and intercommunicated weather stations and on the information obtained in real time from a multitude of weather satellites, mainly geostationary satellites, drones (unmanned flights) and other means of data collection. atmospheric.

An example of the data obtained almost in real time and with sequence images of the western hemisphere and its sectors (which allow to see the movement of the cloud masses, displacement and energy transported by the clouds, etc.) are those that Provides the NASA Goes Geostationary Satellite Web site (http://www.goes.noaa.gov/). An animated view of the Caribbean and Atlantic image sequence north of the equator, updated every 30 minutes, can be seen at: [1].

Effect on humans

Climate, viewed from an anthropological perspective, is something that all humans in the world constantly experience through their senses, at least while outside. There is socially and scientifically constructed knowledge about what weather is, what makes it change, the effect it has on humans in different situations, etc. Therefore, weather is something that people often communicate about. Countries have a National Weather Service that typically produces an annual report of deaths, injuries, and total damage costs that include crops and property. For example in the United States as of 2019, tornadoes have had the greatest impact on humans with 42 deaths and cost crops and property damage of more than $3 billion.

Effects on populations

New Orleans, Louisiana, after being hit by Hurricane Katrina. Katrina was a Category 3 hurricane when it hit land, although it was a Category 5 hurricane while moving across the Gulf of Mexico.

Climate has played an important and sometimes direct role in human history. Apart from climatic changes that have caused the gradual drift of populations (for example, the desertification of the Middle East and the formation of land bridges during ice ages), extreme weather events have caused population movements on a smaller scale and have directly involved in historical events. One such event is Japan's salvation from the invasion of Kublai Khan's Mongol fleet by Kamikaze winds in 1281. French claims to Florida came to an end in 1565 when a hurricane destroyed the French fleet, allowing Spain conquer Fort Caroline. Most recently, Hurricane Katrina redistributed more than a million people from the Central Gulf Coast to other parts of the United States, making it the largest diaspora in United States history.

The Little Ice Age led to crop failure and famine in Europe. During the period known as the Grindelwald Fluctuation (1560–1630), events resulting from volcanic activities appear to have produced extreme weather events. These included unseasonable droughts, storms, and blizzards, as well as causing the expansion of the Swiss Grindelwald Glacier. The 1690s saw the worst famine in France since the Middle Ages. Finland suffered a severe famine in 1696-1697, during which about a third of the Finnish population died.

Modification

The aspiration to control the weather is evident throughout human history: from ancient rituals to bring rain for crops to the US Army's Operation Popeye, an attempt to disrupt power lines. supply by stretching out the North Vietnamese monsoon. The most successful attempts to influence the weather involve cloud seeding; they include fog dispersal techniques and low stratus clouds employed by major airports, techniques used to increase winter precipitation over mountains, and techniques to suppress hail. A recent example of weather control was China's preparation for the Games. 2008 Summer Olympics. China fired 1,104 rain-dispersing rockets from 21 sites in the city of Beijing in an effort to keep rain off the opening ceremony of the games on August 8, 2008. Guo Hu, head of the Beijing Municipal Meteorological Bureau (BMB) confirmed the success of the operation with 100mm falling on Baoding City in southwestern Hebei Province and Beijing's Fangshan District recording 25mm rainfall.

While there is no conclusive evidence of the effectiveness of these techniques, there is ample evidence that human activity, such as agriculture and industry, leads to unintended climate change:

• Acid rain, caused by the industrial emission of sulphur dioxide and nitrogen oxides to the atmosphere, negatively affects lakes, vegetation and freshwater structures.
• anthropogenic pollutants reduce air quality and visibility.
• Climate change caused by human activities that emit greenhouse gases into the air is expected to affect the frequency of extreme weather events such as droughts, extreme temperatures, floods, strong winds and severe storms.
• It has been shown that heat, generated by the large metropolitan areas, affects the near climate thoroughly, even at distances of up to 1,600 kilometers.

The effects of unnoticed climate change can pose serious threats to many aspects of civilization, including ecosystems, natural resources, food and fiber production, economic development, and human health.

Alien weather in the Solar System

The Great Jupiter Red Spot in February 1979, photographed by the unmanned ship of the NASA Voyager 1.

Studying how weather works on other planets has been helpful in understanding how it works on Earth. Weather on other planets follows many of the same physical principles as weather on Earth, but it occurs on different scales and at different times. atmospheres that have different chemical composition. The Cassini-Huygens mission to Titan discovered clouds formed from methane or ethane that deposit rain composed of liquid methane and other organic compounds. Earth's atmosphere includes six latitudinal circulation zones, three in each hemisphere. In contrast Jupiter's striped appearance indicates the presence of numerous zones, Titan has a single jet stream near the 50th parallel north latitude, and Venus has a single jet stream near the equator.

One of the most famous landmarks in the Solar System, Jupiter's Great Red Spot, is an anticyclonic storm known to have existed for at least 300 years. In other gas giants, the lack of surface area allows wind to reach enormous speeds: gusts of up to 2,100 km/h have been measured on the planet Neptune. This has created a puzzle for planetary scientists. Ultimately, weather is created by solar energy and the amount of energy received by Neptune is only about ¹⁄₉₀₀ that received by Earth, however, the intensity of weather events on Neptune is much greater than on Earth. The strongest planetary winds discovered so far are on the extrasolar planet HD 189733 b, which is believed to be it has easterly winds moving at more than 9,600 km/h.