Weather forecasting

src: cdn.publishyourarticles.net

Weather forecasts are science and technology applications to predict atmospheric conditions for specific locations and times. Humans have tried to predict the weather informally for thousands of years and formally since the 19th century. Weather forecasts are made by collecting quantitative data about the current state of the atmosphere somewhere and using meteorology to project how the atmosphere will change.

After human efforts are based solely on changes in barometric pressure, current weather conditions, and sky or cloud cover conditions, weather forecasts now rely on computer-based models that take into account many atmospheric factors. Human input is still needed to select the best estimation model for the underlying prediction, which involves pattern recognition skills, teleconnections, knowledge of model performance, and knowledge of bias models. Forecasting inaccuracies is due to the chaotic nature of the atmosphere, the enormous computing power required to solve equations that describe the atmosphere, the errors involved in measuring the initial conditions, and the incomplete understanding of atmospheric processes. Therefore, the estimate becomes less accurate because the difference between the current time and the time for the forecast being made (estimated range ) increases. The use of the model ensemble and consensus helps narrow down the errors and choose the most likely outcome.

There are various end uses for weather forecasting. Weather warnings are important forecasts because they are used to protect life and property. Predictions based on temperature and precipitation are important for agriculture, and therefore for traders in commodity markets. Estimated temperatures are used by utility companies to forecast demand over the coming days. Everyday, people use weather forecasts to determine what to wear on a given day. Because outdoor activities are heavily constrained by heavy rain, snow and cold winds, estimates can be used to plan activities around these events, and to plan ahead and survive them. In 2014, the US spent $ 5.1 billion on weather forecasts.

Video Weather forecasting

History

Ancient forecasting

For thousands of years people have been trying to predict the weather. In 650 BC, the Babylonians predicted the weather from cloud and astrological patterns. Around 350 BC, Aristotle describes weather patterns in Meteorologica . Later, Theophrastus compiled a book about the weather forecast, called Book of Signs . The prediction of Chinese weather forecasts extends at least as far as 300 BC, which is also around the same time ancient Indian astronomers developed the weather-prediction method. In New Testament times, Christ himself refers to the decomposition and understanding of local weather patterns, saying, "When night comes, you say, 'This will be good weather, because the sky is red', and in the morning, 'Today into a storm, because the sky is red and overcast.'You know how to interpret the appearance of the sky, but you can not interpret the signs of the times. '

In 904 AD Ibn Wahshiyya Nabatean Agriculture discusses weather forecasting of atmospheric changes and signs of planetary astral changes; rain signs based on moon phase observation; and weather forecasts based on wind movement.

Ancient weather forecasting methods usually depend on the observed pattern of events, also called pattern recognition. For example, it can be observed that if the sun sets very red, the next day often brings a sunny day. This experience accumulated from generation to generation to produce weather knowledge. However, not all of these predictions proved to be reliable, and many of those who have been found can not stand the rigorous testing statistics.

Modern methods

It was not until the invention of the electrical telegraph in 1835 that the modern age of weather forecasts began. Prior to that, the fastest, fastest weather report was about 100 miles per day (160 km/day), but more typically 40-75 miles per day (60-120 km/day) (either by land or by sea). In the late 1840s, telegraphs allowed reports of weather conditions from large areas to be received almost instantaneously, allowing estimates made from knowledge of further weather conditions in the direction of the wind.

Two people who are regarded as the birth of forecasting as a science are Royal Navy officials Francis Beaufort and his protege Robert FitzRoy. Both were influential people in the naval and British government circles, and although laughed at the media at the time, their work gained scientific confidence, received by the Royal Navy, and formed the basis for all knowledge of today's weather forecast.

Beaufort developed the Code of Wind Strength and Weather Notation, which will be used in the journal for the rest of his life. He also promoted the development of reliable tide tables around the coast of England, and with his friend William Whewell, expanding record weather records at 200 Coast Guard stations.

Robert FitzRoy was appointed in 1854 as head of the new department of the Trade Council to handle the collection of marine weather data as a service for seafarers. It is the pioneer of the modern Meteorological Office. All ship captains are tasked with collecting data on the weather and calculating it, using the tested instruments lent for this purpose.

The storm in 1859 that caused the loss of Royal Charter inspired FitzRoy to develop a chart to allow predictions to be made, which he called "weather forecast" , thus incorporating the term "weather forecast". Fifteen ground stations were established to use the telegraph to send him daily weather reports at specific times leading to the first wind service warning. The warning service for delivery began in February 1861, using telegraph communications. The first daily weather forecast was published at The Times in 1861. The following year, the system was introduced by lifting the storm warning cone at the main port when a storm wind was expected. The "Book Book" published by FitzRoy in 1863 was far ahead of the current scientific opinion.

As the electrical telegraph network extends, allowing for faster warning dissemination, a nationwide observational network is developed, which can then be used to provide synoptic analysis. Instruments for continuously recording variations of meteorological parameters using photography were supplied to the observation station of the Kew Observatory - this camera was invented by Francis Ronalds in 1845 and its previous barograf has been used by FitzRoy.

To convey accurate information, it soon becomes necessary to have a standardized vocabulary that describes the cloud; this was achieved by using a series of classifications first established by Luke Howard in 1802, and standardized in Atlas Cloud International in 1896.

Numerical predictions

It was not until the 20th century that advances in the understanding of atmospheric physics led to the foundations of modern numerical weather forecasts. In 1922, the British scientist Lewis Fry Richardson published "Weather Forecast With Numerical Processes", after discovering the records and derivations he worked on as an ambulance driver in World War I. He described in them how the small term in the dynamics of prognostic fluid dynamics governing atmospheric flow could neglected, and limited differencing schemes in space and time can be designed, to enable numerical prediction solutions to be found.

Richardson envisions a large auditorium of thousands of people doing calculations and giving them to others. However, the required number of calculations is too large to be completed without using a computer, and the grid size and time step lead to unrealistic results in the deepening system. It was later discovered, through numerical analysis, that this was due to numerical instability. The first computerized weather forecast was conducted by a team consisting of American meteorologist Jule Charney, Philip Thompson, Larry Gates, and Norwegian meteorologist Ragnar FjÃƒÆ'Ã‚Â¸rtoft, mathematician John von Neumann, and ENIAC programmer Klara Dan von Neumann. The practical use of numerical weather forecasts began in 1955, driven by the development of programmable electronic computers.

Broadcast

The first daily weather forecast was published in The Times on August 1, 1861, and the first weather map was produced in the same year. In 1911, the Met Office began issuing the first sea weather forecasts through radio transmissions. These include storm warnings and storms for areas around Great Britain. In the United States, the first public radio forecast was made in 1925 by Edward B. "E.B." Rideout, at WEEI, Edison Electric Illuminating station in Boston. The rideout came from the U.S. Weather Bureau, as did the weather forecaster WBZ G. Harold Noyes in 1931.

The world's first television weather forecast, including the use of weather maps, was experimentally broadcast by the BBC in 1936. It was practiced in 1949 after World War II. George Cowling gave the first weather forecast when broadcasted in front of the map in 1954. In America, experimental television forecasts were made by James C Fidler in Cincinnati in 1940 or 1947 on the DuMont Television Network. In the late 1970s and early 80s, John Coleman, the first weather expert on ABC-TV Good Morning America, pioneered the use of weather satellite information and computer graphics for television forecasts. Coleman was one of the founders of The Weather Channel (TWC) in 1982. TWC is now a 24-hour cable network. Some weather channels have started broadcasting on live programs like YouTube and Periscope to reach more viewers.

Maps Weather forecasting

How models make estimates

The basic idea of â€‹â€‹numerical weather forecasts is to sample the fluid state at any given time and use fluid dynamics and thermodynamic equations to estimate the fluid state at some future time. The main inputs from country-based weather services are surface observation of automatic weather stations at ground level and from ocean weather buoys. The World Meteorological Organization acts to standardize instrumentation, observing these observational practices and timing around the world. Both stations report every hour in the METAR report, or every six hours in the SYNOP report. The site launches radiosondes, which rise through the depths of the troposphere and also into the stratosphere. Data from weather satellites are used in areas where traditional data sources are not available. Compared with similar data from radiosondes, satellite data has a global coverage advantage, but with lower accuracy and resolution. Meteorological radar provides information about the location and intensity of precipitation, which can be used to estimate accumulated deposition over time. In addition, if Doppler weather radar is used then wind speed and direction can be determined.

Trades provide pilot reports along the plane route, and ship reports along the cruise route. Flight research uses reconnaissance planes flying in and around attractive weather systems such as tropical cyclones. Surveillance aircraft are also flown over open seas during winter into the system causing significant uncertainty in forecasting guidance, or are expected to impact a 4- to 7-day high into the future over the downstream continent.

Model is initialized using this observed data. Irregular spatial observations are processed by data assimilation and objective analysis methods, which perform quality control and obtain values â€‹â€‹at locations that can be used by mathematical modeling algorithms (usually the same distance grid). The data is then used in the model as the starting point for the forecast. Generally, the set of equations used to predict what is known as physics and atmospheric dynamics is called primitive equations. This equation is initialized from the analysis data and the rate of change is determined. The rate of change predicts the state of the atmosphere in the shortest time into the future. This equation is then applied to this new atmospheric state to find new levels of change, and this new rate of change predicts the atmosphere for a longer time in the future. The time stepping procedure is repeated until the solution reaches the desired approximate time. The length of the time step is related to the distance between the points on the computing lattice.

The length of time step selected in this model is related to the distance between the points on the computing lattice, and is selected to maintain numerical stability. The time step for the global model is in the order of tens of minutes, while the time step for the regional model is between one and four minutes. Global models run at varying times in the future. The Unified Met Office model runs the next six days, the European Center for Medium-Range Weather Forecasts model runs out for the next 10 days, while the Global Forecast System model run by the Environmental Modeling Center runs 16 days into the future. The visual output generated by the model solution is known as a prognostic graph, or prog . The raw output is often modified before it is presented as a forecast. This can be a statistical technique to remove known biases in the model, or adjustments to consider account consensus among other numerical weather forecasts. MOS or model output statistics are techniques used to interpret numerical model outputs and produce location-specific guidance. This guide is presented in numerically coded form, and can be obtained for virtually all National Weather Service reporting stations in the United States. As Edward Lorenz puts it in 1963, long-term estimates, made in the range of two weeks or more, are impossible to definitively predict the state of the atmosphere, due to the chaotic nature of the fluid dynamics equations involved. In the numerical model, a very small error in the initial value doubles about every five days for variables such as temperature and wind speed.

Basically, a model is a computer program that generates meteorological information for the future at a particular location and altitude. In every modern model is a set of equations, known as primitive equations, used to predict the state of the future atmosphere. This equation - along with the ideal gas law - is used to develop the potential temperature scalar density, pressure, and field scalar and atmospheric velocity velocity fields over time. Additional transport equations for other pollutants and aerosols are included in some mesoscale models with primitive equations as well. The equations used are nonlinear partial differential equations, which can not be solved precisely through analytical methods, with the exception of some idealized cases. Therefore, numerical methods obtain approximate solutions. Different models use different solution methods: some global models use spectral methods for horizontal dimensions and different methods up to vertical dimensions, whereas regional models and other global models typically use different methods up to in three dimensions.

Weather forecast icons stock illustration. Illustration of ...

src: thumbs.dreamstime.com

Technique

Perseverance

The simplest method of forecasting weather, perseverance, depends on today's conditions to predict the conditions of tomorrow. This can be a valid way to predict the weather when it is in a steady state, such as during the summer in the tropics. This forecasting method is highly dependent on the presence of stagnant weather patterns. Therefore, when in a fluctuating weather pattern, this forecasting method becomes inaccurate. This can be useful in both close-range and distance estimates.

Use of the barometer

Barometric pressure measurements and pressure tendencies (pressure changes over time) have been used in forecasting since the late 19th century. The greater the pressure changes, especially if more than 3.5 hPa (2.6 mmHg), the greater the weather change can be expected. If the pressure drops rapidly, the low pressure system approaches, and there is a greater possibility of rain. The increase in fast pressure is associated with an increase in weather conditions, such as clear skies.

Skyline

Along with the trend of pressure, sky conditions are one of the more important parameters used to forecast weather in mountainous areas. Cloud thickening cloud cover or higher cloud invasion is an indication of rain in the near future. High thin cirrostratus clouds can create a circle of light around the sun or moon, which shows a warm front and rain-related approach. The morning fog signified a fair condition, because the precipitation was preceded by wind or clouds that prevented the formation of fog. The approach of the storm line may indicate a cold front approach. Cloud-free sky is an indication of good weather for the near future. A bar may indicate a tropical storm to come. The use of sky cover in weather prediction has led to various weather knowledge for centuries.

Nowcasting

Weather forecasting in the next six hours is often referred to as nowcasting . In this time span it is possible to forecast smaller features such as individual showers and lightning storms with reasonable accuracy, as well as other features that are too small to be completed by computer models. A human being given the latest radar, satellite, and observation data will be able to make a better analysis of existing small-scale features and thus will be able to make more accurate forecasts for the next few hours. However, there is now an expert system that uses the data and mesoscale numerical models to make better extrapolations, including the evolution of such features on time.

Use of approximate model

In the past, human forecasters were responsible for generating all weather forecasts based on available observations. Currently, human input is generally limited to model selection based on various parameters, such as bias and model performance. Using consensus model estimates, as well as ensemble members of various models, can help reduce estimation errors. However, regardless of how small an average error occurs on each individual system, major errors in a particular section of the guide are still possible on each given model. Humans are asked to interpret model data into weather forecasts that can be understood by the end user. Humans can use knowledge about local effects that may be too small to complete by model to add information to estimates. While improving the approximate model accuracy implies that humans may no longer be required in the forecast process at some point in the future, there is currently still a need for human intervention.

Analog technique

Analogue techniques are a complicated way to make forecasts, requiring forecasters to remember previous weather events that are expected to be replicated by upcoming events. What makes it a difficult technique to use is that there is rarely a perfect analogue for an event in the future. Some people call this type of pattern recognition recognition. This remains a useful method for observing rainfall over empty data such as oceans, as well as estimates of the amount of rainfall and distribution in the future. The same technique is used in medium-distance forecasting, known as teleconnections, when systems in other locations are used to help determine the location of other systems in the surrounding regime. An example of teleconnections is to use the associated phenomenon El NiÃƒÆ'Ã‚ Ã‚ o-Southern Oscillation (ENSO).

src: weather360dotnet.files.wordpress.com

Communicate public estimates

Most of the estimated end users are members of the general public. Lightning can create strong winds and dangerous lightning strikes that can cause death, power cuts, and widespread hail damage. Heavy snow or rain showers can transport and trade into immobile conditions, and cause flooding in lowland areas. Excessive heat or cold waves can cause illness or kill them with inadequate utility, and drought may affect water use and destroy vegetation.

Some countries use government agencies to provide forecasts and hours/warnings/advice to the public to protect lives and property and retain commercial interests. Knowledge of what the end user needs of the weather forecast should be taken into account to present the information in a useful and understandable way. Examples include the National Oceanic and Atmospheric Administration's National Weather Service (NWS) and Canada Environmental Meteorology Service (MSC). Traditionally, newspapers, television, and radio have become the main channels for presenting weather forecast information to the public. In addition, some cities have weather flare. Increasingly, the internet is in use because of the large amount of specific information that can be found. In all cases, these outlets update their estimates regularly.

Bad weather warnings and advisors

The main part of modern weather forecasts is a bad weather warning and advisers that national weather service problems if bad or dangerous weather is expected. This is done to protect life and property. Some of the best known of bad weather advisers are thunderstorms and tornado warnings, as well as severe thunderstorms and tornadoes. Other forms of this adviser include winter weather, strong winds, floods, tropical cyclones, and fog. Warning and severe weather warnings are broadcast through the media, including radio, using emergency systems as Emergency Standby Systems, which break into regular programs.

Low temperature forecast

The low temperature forecast for today is calculated using the lowest temperature found between 7 Ãƒ, pm that night up to 7 Ãƒ, the next morning. So, in short, today is thought to be low likely low temperatures tomorrow.

Abstract Word Cloud For Weather Forecasting With Related Tags ...

src: previews.123rf.com

Forecasting specialists

There are a number of sectors with their own specific needs for weather forecasts and specialist services provided to these users.

Air traffic

Because the aviation industry is very sensitive to weather, accurate weather forecasting is essential. A very low fog or ceiling can prevent many planes from landing and taking off. Turbulence and icing are also significant aviation hazards. Lightning is a problem for all aircraft because of the severe turbulence due to rising and exiting currents, ice cover due to heavy rain, as well as large hail, strong winds, and lightning, all of which can cause severe damage to aircraft.. Volcanic ash is also a significant problem for aviation, because aircraft can lose engine power in ash clouds. On daily planes are geared to take advantage of streamwash jet streams to improve fuel efficiency. Aircrews were briefed before taking off on expected conditions on the way and at the destination. In addition, airports often change the foundation used to take advantage of the headwind. This reduces the distance required for takeoff, and eliminates the potential of crosswinds.

Marine

Commercial use and recreation of waterways can be significantly limited by wind direction and speed, wave and height periodicity, tidal, and rainfall. These factors can each affect the safety of marine transits. As a result, various codes have been established to efficiently send detailed marine weather forecasts to ship pilots via radio, eg MAFOR (ocean estimates). Typical weather forecasts are acceptable at sea through the use of RTTY, Navtex and Radiofax.

Agriculture

Farmers rely on weather forecasts to decide what work to do on a particular day. For example, drying of straw is only feasible in dry weather. Prolonged drought can damage cotton, wheat, and corn crops. While corn crops can be damaged by drought, their dry debris can be used instead of animal feed in the form of silage. Dew froze and froze with good plants during spring and autumn. For example, full blooming peach trees can have their potential peach plants destroyed by freezing springs. The clump of oranges can suffer significant damage during the winter and freeze, regardless of the time.

Forestry

Wind forecasts, precipitation and moisture are essential for preventing and controlling forest fires. Different indices, such as the Forest Fire weather index and Haines Index , have been developed to predict areas at risk of experiencing fire from natural or human causes. Conditions for the development of harmful insects can be predicted by estimating the evolution of the weather as well.

Utility company

Electric and gas companies rely on weather forecasts to anticipate demand, which can be heavily weather-induced. They use a quantity called degrees day to determine how strong the usage would be for warming (day degree heating) or cooling (day degrees of cooling). This quantity is based on the daily average temperature of 65Ãƒ, Ã‚ Â° F (18Ãƒ, Ã‚ Â° C). Cold temperatures force day warming degrees (one per degree Fahrenheit), while warmer temperatures force day degrees of cooling. In winter, severe cold weather can cause a spike in demand when people turn on their heater. Similarly, in the summer the surge in demand can be attributed to the increased use of air conditioning systems in hot weather. In anticipation of a surge in demand, utility companies may purchase additional power or natural gas supplies before prices rise, or in some circumstances, supply is limited through the use of power outages and blackouts.

Other commercial companies

More and more private companies pay forecasts tailored to their needs so that they can increase their profits or avoid major losses. For example, supermarket chains can change the stock on their shelves to anticipate different consumer shopping habits in different weather conditions. Weather forecasts can be used to invest in commodity markets, such as futures in oranges, corn, soybeans, and oil.

Military applications

British Armed Forces

Royal Navy

The Royal Navy, working with the UK Met Office, has its own weather and weather forecast branch, as part of the Hydrographic and Meteorology specialization (HM), which monitors and estimates operational conditions worldwide, to provide timely and accurate information. weather and oceanographic information to Fleet Air Arm submarines, ships and aircraft.

Royal Air Force

A mobile unit at the RAF, which works with the UK Met Office, predicts the weather for the region in which the soldiers and English women called for are deployed. A group headquartered at Camp Bastion provides forecasts for the British armed forces in Afghanistan.

United States Armed Forces

US Navy

Similar to the private sector, military weather forecasters present weather conditions to combatant combatants. Military weather forecasters provide prior and in-flight weather previews to pilots and provide real-time resource protection services for military installations. The naval seaman covers the waters and sends weather forecasts. The United States Navy provides special services to them and the federal government by issuing estimates for tropical cyclones in the Pacific and Indian Oceans through their Common Typhoon Warning Center.

US Air Force

In the United States, Air Force Weather provides weather forecasts for the Air Force and the Army. Air Force Forecasters include air operations in both wartime and peacetime operations and provide Army support; Coast Guard oceanographic technicians from the United States provide ship forecasts for ice breakers and other operations within their territory; and maritime forecasters provide support for US-based Marine Corps operations based on land and air. The four military branches took their initial meteorological early technical training at Keesler Air Force Base. Military and civilian forecasters actively work together in analyzing, creating and critiquing the weather forecast.

src: www.noaanews.noaa.gov

References

src: blogs.henrico.k12.va.us

External links

Meteorological bodies

This is an academic or government meteorological organization. Most provide at least limited estimates for areas of interest on their website.

The World Meteorological Organization
European Center for Medium Range Weather Forecast (ECMWF)
European Meteorological Satellite EUMETSAT
The Australian Meteorological Bureau
The Royal Meteorology Institute of Belgium
Canadian Weather Office Environment
The Finnish Meteorological Institute
French National Meteorological Service
The Indian Meteorological Department (IMD)
National Center for Medium Range Weather Forecast (NCMRWF)
Indian Tropical Meteorology Institute (IITM)
National Atmospheric Research Laboratory (NARL)
Department of Meteorology of Pakistan
National Hellenic Meteorological Service (Greece)
Hong Kong Observatory
Meet ÃƒÆ'Ã¢ â‚¬ ireann (Ireland)
Italian Air Force Service (Aeronautica Militare)
Korean Meteorological Administration
MetService New Zealand
South African Weather Service
Meteo Suisse (Swiss Weather Agency) (in English)
Met Office from the UK
yr.no (joint online weather service from the Norwegian Meteorological Institute (met.no) and Norwegian Broadcasting Corporation (NRK))
Unidad de MeteorologÃƒÆ'a - IVIC (Meteorology Unit - Venezuelan Research Institute) (in Spanish)
Instituto Nacional de HidrometeorologÃƒÆ'a (in Spanish)
The Slovenian National Meteorological Service based on the Academa and WebMet Application servers
Centro de PrevisÃƒÆ' Ã‚ Â£ o de Tempo e Estudos ClimÃƒÆ'Ã‚Â¡ticos in INPE (Brazil)
United States National Weather Service
National Meteorological Center (China)
The Israeli Meteorological Service (IMS)

Weather forecasting

Rabu, 20 Juni 2018

Weather forecasting

Video Weather forecasting