Mesonet


In meteorology, a mesonet, portmanteau of mesoscale network, is a network of automated weather and environmental monitoring stations designed to observe mesoscale meteorological phenomena. Dry lines, squall lines, and sea breezes 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. Mesonets usually record in situ surface weather observations but some involve other observation platforms, particularly vertical profiles of the planetary boundary layer.
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 utilize a spatial spacing of and report conditions every 1 to 15 minutes. Micronets, such as in metropolitan areas such as , , and , may be even denser in spatial resolution.

Purpose

s, squall lines, drylines, sea and land breezes, mountain breeze and valley breezes, mountain waves, mesolows and mesohighs, wake lows, mesoscale convective vortices, tropical cyclone and extratropical cyclone rainbands, macrobursts, gust fronts and outflow boundaries, heat bursts, urban heat islands, and other mesoscale phenomena can cause weather conditions in a localized area to be significantly different from that dictated by the ambient large-scale conditions. 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, however, are too sparse and report too infrequently for mesoscale research. ASOS and AWOS stations are typically spaced apart and report only hourly at many sites. The Cooperative Observer Program database consists of only daily reports. "Mesoscale" weather phenomena occur on spatial scales of tens to hundreds of kilometers and temporal scales of minutes to hours. Thus, an observing network with finer temporal and spatial scales is needed for mesoscale research. This need led to the development of the mesonet.
Mesonet data is directly used by humans for decision making, but also boosts the skill of numerical weather prediction and is especially beneficial for short-range mesoscale models. Mesonets, along with remote sensing solutions, allow for much greater temporal and spatial resolution in a forecast model. As the atmosphere is a chaotic nonlinear dynamical system, this increase in data increases understanding of initial conditions and boosts model performance. In addition to meteorology and climatology users, transportation departments, energy producers and distributors, other utility interests, and agricultural entities also have a need for fine scale weather information. These organizations operate dozens of mesonets within the US and globally. Environmental, emergency management and public safety, and insurance interests also are heavy users of mesonet information.
In many cases, mesonet stations may be located in positions where accurate measurements may be compromised; for instance, this is especially true of the stations built for WeatherBug's network, many of which were located on school buildings. The potential bias that these locations may cause must be accounted for when entering the data into a model, lest the phenomenon of "garbage in, garbage out" occur.

Operations

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 in Utah 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 and solar panels. An on-board computer takes readings from several instruments measuring temperature, humidity, wind speed & direction, and atmospheric pressure, as well as soil temperature and moisture, and other environmental variable deemed important to the mission of the mesonet, solar irradiance being a common non-meteorological parameter. The computer periodically saves these data to memory and transmits the observations to a base station via radio, telephone, or satellite transmission. Advancements in computer technology and wireless communications in recent decades 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 from 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:
Years of operationName of Network, PlaceSpacingNo. of Stations
Objectives
1939-41,, Tauche, Germany19-25research on convective hazard, squall lines and wind gusts, to aviation
1940Maebashi, Japan20research on convective hazard to aviation, examined structure of thunderstorms
1941Muskingum basin131rainfall and runoff research
1946The Thunderstorm Project, Florida50thunderstorm convection research
1947The Thunderstorm Project, Ohio58thunderstorm convection research
1960New Jersey23research on mesoscale pressure systems
1960Fort Huachuca, Arizona28Army operations research
1961Fort Huachuca, Arizona17research on influence of orography
1961–PresentDugway Proving Ground, Utah26air quality modeling and other desert area research
1961Flagstaff43cumulonimbus convection research
1961National Severe Storms Project 36research on structure of severe storms
1962National Severe Storms Project 210research on squall lines and pressure jumps
1972–PresentEnviro-Weather, Michigan Varies81agriculturally centered; archive, varies from 5-60 min observations
1981–PresentNebraska Mesonet, NebraskaVaries69
originally agriculturally centered now multipurpose; archive, near real-time observations
1983–PresentSouth Dakota Mesonet, South DakotaVaries27archive, real-time 5 min observations
1986–PresentKansas Mesonet, KansasVaries72archive, real-time observations
1986–PresentArizona Meteorological Network, ArizonaVaries27agriculturally centered; archive, real-time observations, 15 min - 1 hr
1988–PresentWashington AgWeatherNet, WashingtonVaries177agriculturally centered; archive, real-time observations, 15 min
1989–PresentOhio Agricultural Research and Development Center Weather System, OhioVaries17agriculturally centered; archive, hourly observations
1990–PresentNorth Dakota Agricultural Weather Network, North Dakota Varies91agriculturally centered; archive, real-time observations
1991–PresentOklahoma Mesonet, OklahomaVaries121comprehensive monitoring; archive, real-time observations
1991–PresentGeorgia Automated Weather Network, GeorgiaVaries82agriculture and hydrometeorology; archive, real-time observations, 15 min
1993–PresentMissouri Mesonet, MissouriVaries35agriculturally centered; archive, real-time observations at 21 stations
1994–Present**WeatherBug, across United StatesVaries>8,000real-time observations for schools and television stations
1997–PresentFlorida Automated Weather Network, FloridaVaries42agriculturally-centered; archive, real-time
1999–PresentWest Texas Mesonet, West TexasVaries63+archive, real-time observations
2001–PresentIowa Environmental Mesonet, IowaVaries469*archive, real-time observations
2002–PresentSolutions Mesonet, Eastern CanadaVaries600+*archive, real-time observations
2002–PresentWestern Turkey Mesonet, TurkeyVaries206+nowcasting, hydrometeorology
2003–PresentDelaware Environmental Observing System, DelawareVaries57archive, real-time observations
2004–PresentSouth Alabama Mesonet, AlabamaVaries26archive, real-time observations
2004-2010, southern Alberta average300research on spatial-temporal meteorological variation, and on weather and climate model performance, across adjoining mountain, foothills, and prairie topographies
2007–PresentKentucky Mesonet, KentuckyVaries68archive, real-time observations
2008–PresentQuantum Weather Mesonet, St. Louis metropolitan area, MissouriVaries 100utility and nowcasting; archive, real-time observations
PresentNorth Carolina ECONet, North CarolinaVaries99archive, real-time observations
2012–PresentBirmingham Urban Climate Laboratory Mesonet, Birmingham UK3 per km224urban heat island monitoring
2015–PresentNew York State Mesonet, New YorkVaries, averages 126real-time observations, improved forecasting
2016-PresentTexMesonet, TexasVaries64+ in network; 3,151 totalhydrometeorology and hydrology focused network operated by the Texas Water Development Board, plus network of networks; some real-time observations, archival
PresentNew Jersey Weather & Climate Network, New JerseyVaries66real-time observations
PresentKeystone Mesonet, PennsylvaniaVariesreal-time observations, archived; variety of uses, network of networks

*Not all stations owned by network.
**As these are private stations, although QA/QC measures are taken, these may not be scientific grade, and may lack proper siting, calibration, sensitivity, durability, and maintenance. The AWS/Weatherbug network is a collection of multiple mesonets, each typically centered around a host television station's media market.
Although not labeled a mesonet, the Japan Meteorological Agency also maintains a nationwide surface observation network with the density of a mesonet. JMA operates AMeDAS, consisting of approximately 1,300 stations at a spacing of. The network began operating in 1974.
Permanent mesonets are stationary networks consisting primarily of automated stations, however, some research projects utilize mobile mesonets. Prominent examples include the VORTEX projects.