Surface weather observation

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Weather station at Mildura Airport, Victoria, Australia. Mildura Airport Weatherstation.jpg
Weather station at Mildura Airport, Victoria, Australia.

Surface weather observations are the fundamental data used for safety as well as climatological reasons to forecast weather and issue warnings worldwide. [1] They can be taken manually, by a weather observer, by computer through the use of automated weather stations, or in a hybrid scheme using weather observers to augment the otherwise automated weather station. The ICAO defines the International Standard Atmosphere (ISA), which is the model of the standard variation of pressure, temperature, density, and viscosity with altitude in the Earth's atmosphere, and is used to reduce a station pressure to sea level pressure. Airport observations can be transmitted worldwide through the use of the METAR observing code. Personal weather stations taking automated observations can transmit their data to the United States mesonet through the Citizen Weather Observer Program (CWOP), the UK Met Office through their Weather Observations Website (WOW), [2] or internationally through the Weather Underground Internet site. [3] A thirty-year average of a location's weather observations is traditionally used to determine the station's climate. [4] In the US a network of Cooperative Observers make a daily record of summary weather and sometimes water level information.

Contents

History

Reverend John Campanius Holm is credited with taking the first systematic weather observations in Colonial America. He was a chaplain in the Swedes Fort colony near the mouth of the Delaware River. Holm recorded daily observations without instruments during 1644 and 1645. While numerous other accounts of weather events on the East Coast were documented during the 17th Century. President George Washington kept a detailed weather diary during the late 1700s at Mount Vernon, Virginia. The number of routine weather observers increased significantly during the 1800s. In 1807, Dr. B. S. Barton of the University of Pennsylvania requested members throughout the Union of the Linnaean Society of Philadelphia to maintain instrumented weather observing sites to establish a climatological history.During the early 1900s, numerous observer stations moved from farms to residential districts of towns, where service was available to mail the observation forms. By 1926, more than 5000 observing locations were located throughout the U.S., West Indies, and the Caribbean.In 1939, the Bureau of Aeronautics in the U. S. Navy began to actively develop automated weather stations. [5]

Airports

ASOS sensors, located at Salinas, California Asos SNS sunset.jpg
ASOS sensors, located at Salinas, California

Surface weather observations have traditionally been taken at airports due to safety concerns during takeoffs and landings. The ICAO defines the International Standard Atmosphere (also known as ICAO Standard Atmosphere), which is the model of the standard variation of pressure, temperature, density, and viscosity with elevation/altitude in the Earth's atmosphere. This is useful in calibrating instruments and designing aircraft, [6] and is used to reduce a station's pressure to sea level pressure (SLP) where it can then be used on weather maps. [7]

In the United States, the FAA mandates the taking of weather observations at larger airports for safety reasons. To help facilitate the purchase of an automated airport weather station, such as ASOS, the FAA allows federal dollars to be used for the installation of certified weather stations at airports. [8] The airport observations are then transmitted worldwide using the METAR observing code. METAR reports typically come from airports or permanent weather observation stations. Reports are generated once an hour; however, if conditions change significantly, they may be updated in special reports called SPECIs. [9] [10] [11] [12]

Data reported

Surface weather observations can include the following elements:

Example of a METAR surface weather observation

METAR LBBG 041600Z 12003MPS 090V150 1400 R04/P1500N R22/P1500U +SN BKN022 OVC050 M04/M07 Q1020 NOSIG 9949//91= [26]

Personal weather stations, maintained by citizens rather than government officials, do not use METAR code. Software allows information to be transmitted to various sites, such as the Weather Underground globally, [3] or the CWOP within the United States, [27] which can then be used by the appropriate meteorological organizations either to diagnose real-time conditions, or be used within weather forecast models.

Use of weather maps

Station model used on surface weather maps Station model.gif
Station model used on surface weather maps

Data collected by land locations coding in METAR are conveyed worldwide via phone lines or wireless technology. Within many nations' meteorological organizations, this data is then plotted onto a weather map using the station model. A station model is a symbolic illustration showing the weather occurring at a given reporting station. [28] Meteorologists created the station model to plot a number of weather elements in a small space on weather maps. [29] Maps filled with dense station-model plots can be difficult to read, but they allow meteorologists, pilots, and mariners to see important weather patterns.

Weather maps are used to display information quickly showing the analysis of various meteorological quantities at various levels of the atmosphere, in this case the surface layer. [30] Maps containing station models aid in the drawing of isotherms, which more readily identifies temperature gradients, [31] and can help in the location of weather fronts. Two-dimensional streamlines based on wind speeds show areas of convergence and divergence in the wind field, which are helpful in determining the location of features within the wind pattern. A popular type of surface weather map is the surface weather analysis, which plots isobars to depict areas of high pressure and low pressure.

Ship and buoy reports

Different shapes and sizes of buoys Buoys.svg
Different shapes and sizes of buoys

For over a century, reports from the world's oceans have been received real-time for safety reasons and to help with general weather forecasting. The reports are coded using the synoptic code, and relayed via radio or satellite to weather organizations worldwide. [32] Buoy reports are automated, and maintained by the country that moored the buoy in that location. Larger moored buoys are used near shore, while smaller drifting buoys are used farther out at sea. [33]

Due to the importance of reports from the surface of the ocean, the voluntary observing ship program, known as VOS, was set up to train crews how to take weather observations while at sea and also to calibrate weather sensors used aboard ships when they arrive in port, such as barometers and thermometers. [34] The Beaufort scale is still generally used to determine wind speed from manual observers out at sea. Ships with anemometers have issues with determining wind speeds at higher wind speeds due to blockage of the instruments by increasing high seas.

Use in establishing climate of a location

Climate, (from Ancient Greek klima) is commonly defined as the weather averaged over a long period of time. [35] The standard averaging period is 30 years for an individual location, [4] but other periods may be used. Climate includes statistics other than the average, such as the magnitudes of day-to-day or year-to-year variations. The Intergovernmental Panel on Climate Change (IPCC) glossary definition is:

Climate in a narrow sense is usually defined as the "average weather", or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period is 30 years, as defined by the World Meteorological Organization (WMO). These quantities are most often surface variables such as temperature, precipitation, and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. [36]

The main difference between climate and everyday weather is best summarized by the popular phrase "Climate is what you expect, weather is what you get." [37] Over historic time spans there are a number of static variables that determine climate, including: latitude, altitude, proportion of land to water, and proximity to oceans and mountains. Degree of vegetation coverage affects solar heat absorption, water retention, and rainfall on a regional level.

See also

Related Research Articles

<span class="mw-page-title-main">Climate</span> Statistics of weather conditions in a given region over long periods

Climate is the long-term weather pattern in a region, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind, and precipitation. In a broader sense, climate is the state of the components of the climate system, including the atmosphere, hydrosphere, cryosphere, lithosphere and biosphere and the interactions between them. The climate of a location is affected by its latitude, longitude, terrain, altitude, land use and nearby water bodies and their currents.

<span class="mw-page-title-main">Surface weather analysis</span> Type of weather map

Surface weather analysis is a special type of weather map that provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations.

<span class="mw-page-title-main">Weather station</span> Facility for atmospheric research and prediction

A weather station is a facility, either on land or sea, with instruments and equipment for measuring atmospheric conditions to provide information for weather forecasts and to study the weather and climate. The measurements taken include temperature, atmospheric pressure, humidity, wind speed, wind direction, and precipitation amounts. Wind measurements are taken with as few other obstructions as possible, while temperature and humidity measurements are kept free from direct solar radiation, or insolation. Manual observations are taken at least once daily, while automated measurements are taken at least once an hour. Weather conditions out at sea are taken by ships and buoys, which measure slightly different meteorological quantities such as sea surface temperature (SST), wave height, and wave period. Drifting weather buoys outnumber their moored versions by a significant amount.

<span class="mw-page-title-main">Precipitation</span> Product of the condensation of atmospheric water vapor that falls under gravity

In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor, so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation but colloids, because the water vapor does not condense sufficiently to precipitate. Two processes, possibly acting together, can lead to air becoming saturated: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers.

METAR is a format for reporting weather information. A METAR weather report is predominantly used by aircraft pilots, and by meteorologists, who use aggregated METAR information to assist in weather forecasting. Today, according to the advancement of technology in civil aviation, the METAR is sent as IWXXM model.

<span class="mw-page-title-main">Low-pressure area</span> Area with air pressures lower than adjacent areas

In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather, while high-pressure areas are associated with lighter winds and clear skies. Winds circle anti-clockwise around lows in the northern hemisphere, and clockwise in the southern hemisphere, due to opposing Coriolis forces. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the atmosphere (aloft). The formation process of a low-pressure area is known as cyclogenesis. In meteorology, atmospheric divergence aloft occurs in two kinds of places:

<span class="mw-page-title-main">Synoptic scale meteorology</span> 1000-km-order method of measuring weather systems

In meteorology, the synoptic scale is a horizontal length scale of the order of 1,000 km (620 mi) or more. This corresponds to a horizontal scale typical of mid-latitude depressions. Most high- and low-pressure areas seen on weather maps are synoptic-scale systems, driven by the location of Rossby waves in their respective hemisphere. Low-pressure areas and their related frontal zones occur on the leading edge of a trough within the Rossby wave pattern, while high-pressure areas form on the back edge of the trough. Most precipitation areas occur near frontal zones. The word synoptic is derived from the Ancient Greek word συνοπτικός (sunoptikós), meaning "seen together".

<span class="mw-page-title-main">Prevailing winds</span> Strongest direction of wind on a region of Earths surface

In meteorology, prevailing wind in a region of the Earth's surface is a surface wind that blows predominantly from a particular direction. The dominant winds are the trends in direction of wind with the highest speed over a particular point on the Earth's surface at any given time. A region's prevailing and dominant winds are the result of global patterns of movement in the Earth's atmosphere. In general, winds are predominantly easterly at low latitudes globally. In the mid-latitudes, westerly winds are dominant, and their strength is largely determined by the polar cyclone. In areas where winds tend to be light, the sea breeze/land breeze cycle is the most important cause of the prevailing wind; in areas which have variable terrain, mountain and valley breezes dominate the wind pattern. Highly elevated surfaces can induce a thermal low, which then augments the environmental wind flow.

<span class="mw-page-title-main">Atmospheric physics</span> The application of physics to the study of the atmosphere

Within the atmospheric sciences, atmospheric physics is the application of physics to the study of the atmosphere. Atmospheric physicists attempt to model Earth's atmosphere and the atmospheres of the other planets using fluid flow equations, radiation budget, and energy transfer processes in the atmosphere. In order to model weather systems, atmospheric physicists employ elements of scattering theory, wave propagation models, cloud physics, statistical mechanics and spatial statistics which are highly mathematical and related to physics. It has close links to meteorology and climatology and also covers the design and construction of instruments for studying the atmosphere and the interpretation of the data they provide, including remote sensing instruments. At the dawn of the space age and the introduction of sounding rockets, aeronomy became a subdiscipline concerning the upper layers of the atmosphere, where dissociation and ionization are important.

SYNOP is a numerical code used for reporting weather observations made by staffed and automated weather stations. SYNOP reports are typically sent every six hours by Deutscher Wetterdienst on shortwave and low frequency using RTTY. A report consists of groups of numbers describing general weather information, such as the temperature, barometric pressure and visibility at a weather station. It can be decoded by open-source software such as seaTTY, metaf2xml or Fldigi.

The World Ocean Circulation Experiment (WOCE) was a component of the international World Climate Research Program, and aimed to establish the role of the World Ocean in the Earth's climate system. WOCE's field phase ran between 1990 and 1998, and was followed by an analysis and modeling phase that ran until 2002. When the WOCE was conceived, there were three main motivations for its creation. The first of these is the inadequate coverage of the World Ocean, specifically in the Southern Hemisphere. Data was also much more sparse during the winter months than the summer months, and there was—and still is to some extent—a critical need for data covering all seasons. Secondly, the data that did exist was not initially collected for studying ocean circulation and was not well suited for model comparison. Lastly, there were concerns involving the accuracy and reliability of some measurements. The WOCE was meant to address these problems by providing new data collected in ways designed to "meet the needs of global circulation models for climate prediction."

<span class="mw-page-title-main">Weather buoy</span> Floating instrument package that collects weather and ocean data

Weather buoys are instruments which collect weather and ocean data within the world's oceans, as well as aid during emergency response to chemical spills, legal proceedings, and engineering design. Moored buoys have been in use since 1951, while drifting buoys have been used since 1979. Moored buoys are connected with the ocean bottom using either chains, nylon, or buoyant polypropylene. With the decline of the weather ship, they have taken a more primary role in measuring conditions over the open seas since the 1970s. During the 1980s and 1990s, a network of buoys in the central and eastern tropical Pacific Ocean helped study the El Niño-Southern Oscillation. Moored weather buoys range from 1.5–12 metres (5–40 ft) in diameter, while drifting buoys are smaller, with diameters of 30–40 centimetres (12–16 in). Drifting buoys are the dominant form of weather buoy in sheer number, with 1250 located worldwide. Wind data from buoys has smaller error than that from ships. There are differences in the values of sea surface temperature measurements between the two platforms as well, relating to the depth of the measurement and whether or not the water is heated by the ship which measures the quantity.

<span class="mw-page-title-main">Station model</span> Type of meteorological illustration

In meteorology, station models are symbolic illustrations showing the weather occurring at a given reporting station. Meteorologists created the station model to fit a number of weather elements into a small space on weather maps. This allows map users to analyze patterns in atmospheric pressure, temperature, wind speed and direction, cloud cover, precipitation, and other parameters. The most common station plots depict surface weather observations although upper air plots at various mandatory levels are also frequently depicted.

<span class="mw-page-title-main">Meteorological instrumentation</span> Measuring device used in meteorology

Meteorological instruments, including meteorological sensors, are the equipment used to find the state of the atmosphere at a given time. Each science has its own unique sets of laboratory equipment. Meteorology, however, is a science which does not use much laboratory equipment but relies more on on-site observation and remote sensing equipment. In science, an observation, or observable, is an abstract idea that can be measured and for which data can be taken. Rain was one of the first quantities to be measured historically. Two other accurately measured weather-related variables are wind and humidity. Many attempts had been made prior to the 15th century to construct adequate equipment to measure atmospheric variables.

<span class="mw-page-title-main">Automated airport weather station</span> Automated sensor suites

Airport weather stations are automated sensor suites which are designed to serve aviation and meteorological operations, weather forecasting and climatology. Automated airport weather stations have become part of the backbone of weather observing in the United States and Canada and are becoming increasingly more prevalent worldwide due to their efficiency and cost-savings.

The following are considered ocean essential climate variables (ECVs) by the Ocean Observations Panel for Climate (OOPC) that are currently feasible with current observational systems.

CLIMAT is a code for reporting monthly climatological data assembled at land-based meteorological surface observation sites to data centres. CLIMAT-coded messages contain information on several meteorological variables that are important to monitor characteristics, changes, and variability of climate. Usually these messages are sent and exchanged via the Global Telecommunication System (GTS) of the World Meteorological Organisation (WMO). Modifications of the CLIMAT code are the CLIMAT SHIP and CLIMAT TEMP / CLIMAT TEMP SHIP codes which serve to report monthly climatological data assembled at ocean-based meteorological surface observation sites and at land-/ocean-based meteorological upper-air observation sites, respectively. The monthly values included usually are obtained by averaging observational values of one or several daily observations over the respective month.

<span class="mw-page-title-main">Marine weather forecasting</span> Forecasts of weather conditions at sea

Marine weather forecasting is the process by which mariners and meteorological organizations attempt to forecast future weather conditions over the Earth's oceans. Mariners have had rules of thumb regarding the navigation around tropical cyclones for many years, dividing a storm into halves and sailing through the normally weaker and more navigable half of their circulation. Marine weather forecasts by various weather organizations can be traced back to the sinking of the Royal Charter in 1859 and the RMS Titanic in 1912.

<span class="mw-page-title-main">Observer (meteorological)</span>

A meteorological observer, or weather observer, is a person authorized by a weather authority to make or record meteorological observations. They are technicians who are responsible for the accurate observation, rapid measurement, timely collection, recording, and timely submission of meteorological parameters and information and various atmospheric phenomena to the Meteorological Center. Surface, upper air, radar, and satellite are all forms of weather observations.

References

  1. ↑ Office of the Federal Coordinator of Meteorology. Surface Weather Observation Program. Archived 2009-05-06 at the Wayback Machine Retrieved on 2008-01-12.
  2. ↑ "WOW - A new weather website for everyone". Met Office. 2011-02-11. Archived from the original on 2014-08-15.
  3. 1 2 Weather Underground. Personal Weather Station. Retrieved on 2008-03-09.
  4. 1 2 MetOffice. Climate Averages. Archived 2009-07-06 at the Wayback Machine Retrieved on 2008-03-09.
  5. ↑ Fiebrich, Christopher A. (2009-04-01). "History of surface weather observations in the United States". Earth-Science Reviews. 93 (3): 77–84. Bibcode:2009ESRv...93...77F. doi:10.1016/j.earscirev.2009.01.001. ISSN   0012-8252.
  6. ↑ ICAO, Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet)) , Doc 7488-CD, Third Edition, 1993, ISBN   92-9194-004-6
  7. ↑ Patricia M. Pauley. An Example of Uncertainty in Sea Level Pressure Reduction. Retrieved on 2008-03-29.
  8. ↑ Allweatherinc. Why buy an AWOS? Archived 2007-02-14 at the Wayback Machine Retrieved on 2008-01-12.
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  10. ↑ Canada, Environment and Climate Change (2021-12-02). "Manual of Surface Weather Observation Standards (MANOBS) 8th Edition, Amendment 1". www.canada.ca. Retrieved 2023-02-04.
  11. ↑ Training Guide in Surface Weather Observations (PDF). U.S. DEPARTMENT OF COMMERCE NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION National Weather Service Office of Systems Operations Systems Integration Division Observing Systems Branch. May 1998.
  12. ↑ U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION ORDER JO 7900.5E. U.S. DEPARTMENT OF TRANSPORTATION FEDERAL AVIATION ADMINISTRATION. 15 January 2020.{{cite book}}: CS1 maint: date and year (link)
  13. ↑ Texas A&M University. Coding the Type of Report, Station Identifier, Date/Time, and Report Modifier groups. Archived 2008-04-09 at the Wayback Machine Retrieved on 2008-04-06.
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  16. ↑ Glossary of Meteorology. Air Temperature. Archived 2008-06-22 at the Wayback Machine Retrieved on 2008-04-06.
  17. ↑ Glossary of Meteorology. Dewpoint. Archived 2011-06-06 at the Wayback Machine Retrieved on 2008-04-06.
  18. ↑ Glossary of Meteorology. Dewpoint Formula. Archived 2007-08-16 at the Wayback Machine Retrieved on 2008-04-06.
  19. 1 2 Office of the Federal Coordinator for Meteorology. Federal Meteorological Handbook No. 1 - Surface Weather Observations and Reports September 2005 Appendix A: Glossary. Retrieved on 2008-04-06.
  20. ↑ Hurricane Research Division. Frequently Asked Questions Subject D4) What does "maximum sustained wind" mean? How does it relate to gusts in tropical cyclones? Retrieved on 2008-04-06.
  21. ↑ Patricia M. Pauley. An Example of Uncertainty in Sea Level Pressure Reduction. Retrieved on 2008-04-14.
  22. ↑ USA Today. Understanding Air Pressure. Retrieved on 2008-04-14.
  23. ↑ Texas A&M University. Present Weather Group w'w'(ww). Archived 1997-07-11 at the Wayback Machine Retrieved on 2008-04-14.
  24. ↑ Ben C. Bernstein, Thomas P. Ratvasky, Dean R. Miller, and Frank McDonough. Freezing Rain as in In-Flight Icing Hazard. Archived 2009-03-21 at the Wayback Machine Retrieved on 2008-04-14.
  25. ↑ NOAA Meteorological Assimilation Data Ingest System. How to Take Snow Measurements. Archived 2008-07-23 at the Wayback Machine Retrieved on 2008-04-14.
  26. ↑ National Climatic Data Center. Key to METAR Surface Weather Observations. Retrieved on 2008-03-09.
  27. ↑ Russ Chadwick. Citizen Weather Observer Program. Retrieved on 2008-03-09.
  28. ↑ Steve Ackerman and Tom Whittaker.Station Model. Retrieved on 2008-03-27.
  29. ↑ Illinois Central College. LAB J: Weather Maps and Humidity. Retrieved on 2008-03-27.
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  36. ↑ Intergovernmental Panel on Climate Change. Appendix I: Glossary. Retrieved on 2007-06-01.
  37. ↑ National Weather Service Office Tucson, Arizona. Main page. Retrieved on 2007-06-01.

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