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Mesonet

Mesonet

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In meteorology
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

, a mesonet is a network of automated weather station
Weather station
A weather station is a facility, either on land or sea, with instruments and equipment for observing atmospheric conditions to provide information for weather forecasts and to study the weather and climate. The measurements taken include temperature, barometric pressure, humidity, wind speed, wind...

s designed to observe mesoscale meteorological
Mesoscale meteorology
Mesoscale meteorology is the study of weather systems smaller than synoptic scale systems but larger than microscale and storm-scale cumulus systems. Horizontal dimensions generally range from around 5 kilometers to several hundred kilometers...

 phenomena. Dry line
Dry line
A dry line separates moist air from the Gulf of Mexico and dry desert air from the south-western states . The dry line is an important factor in severe weather frequency in the Great Plains of North America...

s, squall lines
Squall
A squall is a sudden, sharp increase in wind speed which is usually associated with active weather, such as rain showers, thunderstorms, or heavy snow. Squalls refer to an increase in the sustained winds over a short time interval, as there may be higher gusts during a squall event...

, and sea breeze
Sea breeze
A sea-breeze is a wind from the sea that develops over land near coasts. It is formed by increasing temperature differences between the land and water; these create a pressure minimum over the land due to its relative warmth, and forces higher pressure, cooler air from the sea to move inland...

s are examples of phenomena that can be observed by mesonets. Due to the space and time scales associated with mesoscale phenomena, weather stations comprising a mesonet will be spaced closer together and report more frequently than synoptic scale observing networks, such as ASOS. The term mesonet refers to the collective group of these weather stations, and are typically owned and operated by a common entity.

The distinguishing features that classify a network of weather stations as a mesonet are station density and temporal resolution. Depending upon the phenomena meant to be observed, mesonet stations will have a spatial spacing of 2 to 40 km and report conditions every 1 to 15 minutes.

Why mesonets?


Thunderstorms, squall lines
Squall
A squall is a sudden, sharp increase in wind speed which is usually associated with active weather, such as rain showers, thunderstorms, or heavy snow. Squalls refer to an increase in the sustained winds over a short time interval, as there may be higher gusts during a squall event...

, dry line
Dry line
A dry line separates moist air from the Gulf of Mexico and dry desert air from the south-western states . The dry line is an important factor in severe weather frequency in the Great Plains of North America...

s, and other mesoscale phenomena can cause weather conditions in a localized area to be significantly different from that dictated by the ambient large-scale condition. As such, meteorologists need to understand these phenomena in order to improve forecast skill. Observations are critical to understanding the processes by which these phenomena form, evolve, and dissipate.

The long-term observing networks (ASOS, AWOS,COOP), however, are too sparse and report too infrequently for mesoscale research. ASOS and AWOS stations are typically spaced 50 to 100 km apart and report only hourly on most occasions. The Cooperative Observer Program (COOP) database consists of only daily reports. "Mesoscale" weather phenomena occur on spatial scales of tens to hundreds of kilometers and temporal (time) scales of hours. Thus, an observing network with finer temporal and spatial scales is neede for mesoscale research. This need led to the development of the mesonet.

How do mesonets work?


Mesonets were born out of the need to conduct mesoscale research. The nature of this research is such that mesonets, like the phenomena they are meant to observe, are short-lived. Long term research projects and non-research groups, however, have been able to maintain a mesonet for many years. For example, the U.S. Army Dugway Proving Ground
Dugway Proving Ground
Dugway Proving Ground is a US Army facility located approximately 85 miles southwest of Salt Lake City, Utah in southern Tooele County and just north of Juab County...

 in Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...

 has maintained a mesonet for many decades. The research-based origin of mesonets has led to the characteristic that mesonet stations tend to be modular and portable, able to be moved from one field program to another.

Whether the mesonet is temporary or semi-permanent, each weather station is typically independent, drawing power from a battery
Battery (electricity)
An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy. Since the invention of the first battery in 1800 by Alessandro Volta and especially since the technically improved Daniell cell in 1836, batteries have become a common power...

 and solar panel
Photovoltaic module
A solar panel is a packaged, connected assembly of solar cells, also known as photovoltaic cells...

s. An on-board computer takes readings from several instruments measuring temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...

, humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...

, wind, soil temperature, and atmospheric pressure
Atmospheric pressure
Atmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...

 (or any other environmental variable deemed important to the mission of the mesonet). The computer periodically saves these data to memory and transmits the observations to a base station via radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

, telephone
Telephone
The telephone , colloquially referred to as a phone, is a telecommunications device that transmits and receives sounds, usually the human voice. Telephones are a point-to-point communication system whose most basic function is to allow two people separated by large distances to talk to each other...

, or satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

 transmission. Advancements in computer technology and wireless communications in recent decades has made possible the collection of mesonet data in real-time. The availability of mesonet data in real-time can be extremely valuable to operational forecasters as they can monitor weather conditions from many points in their forecast area.

History



Early mesonets operated differently than modern mesonets. Each constituent instrument of the weather station was purely mechanical and fairly independent of the other sensors. Data were recorded continuously by an inked stylus that pivoted about a point onto a rotating drum covered by a sheath of graphed paper called a trace chart, much like a traditional seismograph station. Data analysis could occur only after the trace charts from the various instruments were collected.

One of the earliest mesonets operated in the summer of 1946 and 1947 and was part of a field campaign called The Thunderstorm Project. As the name implies, the objective of this program was to better understand thunderstorm convection.

Examples


The following table is an incomplete list of mesonets that have operated in the past and present.
Last Year Operated Name of Network, Place Spacing (miles) No. of Stations Objectives
1946 The Thunderstorm Project, Florida 1 50 thunderstorm convection
1947 The Thunderstorm Project, Ohio 2 58 thunderstorm convection
Present Dugway Proving Ground, Utah 9 26 air quality modeling
Present Weatherbug
WeatherBug
WeatherBug is a brand owned by Earth Networks, Ask.com and IAC/InterActiveCorp based in Germantown, Maryland, that provides live weather data and maintains continuously monitored weather stations throughout the United States, mainly located at public and private schools, educational institutions...

 (AWS), across United States
Varies 7,809 real-time observation
Present Oklahoma Mesonet
Oklahoma Mesonet
The Oklahoma Mesonet is a network of environmental monitoring stations designed to measure the environment at the size and duration of mesoscale weather events. The phrase "mesonet" is a portmanteau of the words mesoscale and network. In meteorology, “mesoscale” refers to weather events that...

, Oklahoma
Varies 121 real-time observation
Present Iowa Environmental Mesonet, Iowa Varies 469* archive, real-time observation
Present Kentucky Mesonet, Kentucky Varies 45 archive, real-time observation
Present QuantumWeather Mesonet, Missouri 15km 100 archive, real time observation
Present North Carolina ECONet, North Carolina Varies 37 archive, real-time observation

*Not all stations owned by network.

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