In chaos theory, the butterfly effect is the sensitive dependence on initial conditions in which a small change in one state of a deterministic nonlinear system can result in large differences in a later state.
Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw modest progress in the field after weather observation networks were formed across broad regions. Prior attempts at prediction of weather depended on historical data. It was not until after the elucidation of the laws of physics and more particularly, the development of the computer, allowing for the automated solution of a great many equations that model the weather, in the latter half of the 20th century that significant breakthroughs in weather forecasting were achieved. An important domain of weather forecasting is marine weather forecasting as it relates to maritime and coastal safety, in which weather effects also include atmospheric interactions with large bodies of water.
Atmospheric pressure, sometimes also called barometric pressure, is the pressure within the atmosphere of Earth. The standard atmosphere is a unit of pressure defined as 1013.25 mbar (101325 Pa), equivalent to 760 mmHg (torr), 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth, that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.
Weather forecasting is the application of science and technology to predict the conditions of the atmosphere for a given location and time. People have attempted to predict the weather informally for millennia and formally since the 19th century. Weather forecasts are made by collecting quantitative data about the current state of the atmosphere at a given place and using meteorology to project how the atmosphere will change.
Henry Cavendish FRS was an English natural philosopher, scientist, and an important experimental and theoretical chemist and physicist. He is noted for his discovery of hydrogen, which he termed "inflammable air". He described the density of inflammable air, which formed water on combustion, in a 1766 paper, On Factitious Airs. Antoine Lavoisier later reproduced Cavendish's experiment and gave the element its name.
Charles Thomson Rees Wilson, CH, FRS was a Scottish physicist and meteorologist who won the Nobel Prize in Physics for his invention of the cloud chamber.
Atmospheric electricity is the study of electrical charges in the Earth's atmosphere. The movement of charge between the Earth's surface, the atmosphere, and the ionosphere is known as the global atmospheric electrical circuit. Atmospheric electricity is an interdisciplinary topic with a long history, involving concepts from electrostatics, atmospheric physics, meteorology and Earth science.
Ensemble forecasting is a method used in numerical weather prediction. Instead of making a single forecast of the most likely weather, a set of forecasts is produced. This set of forecasts aims to give an indication of the range of possible future states of the atmosphere. Ensemble forecasting is a form of Monte Carlo analysis. The multiple simulations are conducted to account for the two usual sources of uncertainty in forecast models: (1) the errors introduced by the use of imperfect initial conditions, amplified by the chaotic nature of the evolution equations of the atmosphere, which is often referred to as sensitive dependence on initial conditions; and (2) errors introduced because of imperfections in the model formulation, such as the approximate mathematical methods to solve the equations. Ideally, the verified future atmospheric state should fall within the predicted ensemble spread, and the amount of spread should be related to the uncertainty (error) of the forecast. In general, this approach can be used to make probabilistic forecasts of any dynamical system, and not just for weather prediction.
Francis Hauksbee the Elder FRS (1660–1713), also known as Francis Hawksbee, was an 18th-century English scientist best known for his work on electricity and electrostatic repulsion.
Probabilistic forecasting summarizes what is known about, or opinions about, future events. In contrast to single-valued forecasts, probabilistic forecasts assign a probability to each of a number of different outcomes, and the complete set of probabilities represents a probability forecast. Thus, probabilistic forecasting is a type of probabilistic classification.
An atmospheric model is a mathematical model constructed around the full set of primitive dynamical equations which govern atmospheric motions. It can supplement these equations with parameterizations for turbulent diffusion, radiation, moist processes, heat exchange, soil, vegetation, surface water, the kinematic effects of terrain, and convection. Most atmospheric models are numerical, i.e. they discretize equations of motion. They can predict microscale phenomena such as tornadoes and boundary layer eddies, sub-microscale turbulent flow over buildings, as well as synoptic and global flows. The horizontal domain of a model is either global, covering the entire Earth, or regional (limited-area), covering only part of the Earth. The different types of models run are thermotropic, barotropic, hydrostatic, and nonhydrostatic. Some of the model types make assumptions about the atmosphere which lengthens the time steps used and increases computational speed.
Sir Francis Ronalds FRS was an English scientist and inventor, and arguably the first electrical engineer. He was knighted for creating the first electric telegraph over a substantial distance. In 1816 he laid eight miles of iron wire between wooden frames in his garden and sent pulses using electrostatic generators. Others like Francisco Salva Campillo in 1804 or Samuel Thomas von Sömmerring in 1809 already built telegraphs but with lengths of only 0.4 - 2.2 miles.
Atmospheric convection is the result of a parcel-environment instability, or temperature difference layer in the atmosphere. Different lapse rates within dry and moist air masses lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to increased winds, cumulus cloud development, and decreased surface dew points. Moist convection leads to thunderstorm development, which is often responsible for severe weather throughout the world. Special threats from thunderstorms include hail, downbursts, and tornadoes.
The King's Observatory is a Grade I listed building in Richmond, London. Now a private dwelling, it formerly housed an astronomical and terrestrial magnetic observatory founded by King George III. The architect was Sir William Chambers; his design of the King's Observatory influenced the architecture of two Irish observatories – Armagh Observatory and Dunsink Observatory near Dublin.
The history of numerical weather prediction considers how current weather conditions as input into mathematical models of the atmosphere and oceans to predict the weather and future sea state has changed over the years. Though first attempted manually in the 1920s, it was not until the advent of the computer and computer simulation that computation time was reduced to less than the forecast period itself. ENIAC was used to create the first forecasts via computer in 1950, and over the years more powerful computers have been used to increase the size of initial datasets as well as include more complicated versions of the equations of motion. The development of global forecasting models led to the first climate models. The development of limited area (regional) models facilitated advances in forecasting the tracks of tropical cyclone as well as air quality in the 1970s and 1980s.
Professor Percival Albert "Peter" Sheppard CBE FRS was a Meteorologist at Imperial College, London from 1952 to 1974 and thereafter emeritus professor.
David John Beerling is the Director of the Leverhulme Centre for Climate change mitigation and Sorby Professor of Natural Sciences in the Department of Animal and Plant Sciences (APS) at the University of Sheffield, UK.
Professor John Alan Chalmers was a British atmospheric physicist based at Durham University. He is well known for his contributions to atmospheric electricity, particularly an internationally-respected textbook, and, outside his scientific work, for his involvement with Scouting. This led to him being widely known to his colleagues by the nickname, "Skip", a commonly used term for the leader of a Scout troop.
Roy Michael Harrison is the Queen Elizabeth II Birmingham Centenary Professor of Environmental health at the University of Birmingham in the UK and a Distinguished Adjunct Professor at King Abdulaziz University in Jeddah, Saudi Arabia.
