|
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.〔''Air Apparent: How Meteorologists Learned to Map, Predict, and Dramatize Weather.'' University of Chicago PressChicago: 1999.〕 Weather maps are created by plotting or tracing the values of relevant quantities such as sea level pressure, temperature, and cloud cover onto a geographical map to help find synoptic scale features such as weather fronts. The first weather maps in the 19th century were drawn well after the fact to help devise a theory on storm systems.〔Eric R. Miller. (American Pioneers in Meteorology. ) Retrieved on 2007-04-18.〕 After the advent of the telegraph, simultaneous surface weather observations became possible for the first time, and beginning in the late 1840s, the Smithsonian Institution became the first organization to draw real-time surface analyses. Use of surface analyses began first in the United States, spreading worldwide during the 1870s. Use of the Norwegian cyclone model for frontal analysis began in the late 1910s across Europe, with its use finally spreading to the United States during World War II. Surface weather analyses have special symbols that show frontal systems, cloud cover, precipitation, or other important information. For example, an ''H'' may represent high pressure, implying good and fair weather. An ''L'' on the other hand may represent low pressure, which frequently accompanies precipitation. Various symbols are used not just for frontal zones and other surface boundaries on weather maps, but also to depict the present weather at various locations on the weather map. Areas of precipitation help determine the frontal type and location. == History of surface analysis == The use of weather charts in a modern sense began in the middle portion of the 19th century in order to devise a theory on storm systems.〔Human Intelligence.(Francis Galton. ) Retrieved on 2007-04-18.〕 The development of a telegraph network by 1845 made it possible to gather weather information from multiple distant locations quickly enough to preserve its value for real-time applications. The Smithsonian Institution developed its network of observers over much of the central and eastern United States between the 1840s and 1860s once Joseph Henry took the helm.〔Frank Rives Millikan. Smithsonian Institution. (Joseph Henry: Father of the Weather Service. ) Retrieved on 2006-10-22. 〕 The U.S. Army Signal Corps inherited this network between 1870 and 1874 by an act of Congress, and expanded it to the west coast soon afterwards. At first, all the data on the map was not taken from these analyses because of a lack of time standardization. The first attempts at time standardization took hold in Great Britain by 1855. The entire United States did not finally come under the influence of time zones until 1905, when Detroit finally established standard time.〔WebExhibits. (Daylight Saving Time ). Retrieved on 2007-06-24.〕 Other countries followed the lead of the United States in taking simultaneous weather observations, starting in 1873.〔NOAA. (An Expanding Presence. ) Retrieved on 2007-05-05.〕 Other countries then began preparing surface analyses. The use of frontal zones on weather maps did not appear until the introduction of the Norwegian cyclone model in the late 1910s, despite Loomis' earlier attempt at a similar notion in 1841.〔David M. Schultz. ''(Perspectives on Fred Sanders's Research on Cold Fronts )'', 2003, revised, 2004, 2006, p. 5. Retrieved on 2006-07-14.〕 Since the leading edge of air mass changes bore resemblance to the military fronts of World War I, the term "front" came into use to represent these lines.〔Bureau of Meteorology. (Air Masses and Weather Maps. ) Retrieved on 2006-10-22.〕 Despite the introduction of the Norwegian cyclone model just after World War I, the United States did not formally analyze fronts on surface analyses until late 1942, when the WBAN Analysis Center opened in downtown Washington, D.C..〔Hydrometeorological Prediction Center. (A Brief History of the Hydrometeorological Prediction Center. ) Retrieved on 2007-05-05.〕 The effort to automate map plotting began in the United States in 1969,〔ESSA. (Prospectus for an NMC Digital Facsimile Incoder Mapping Program. ) Retrieved on 2007-05-05.〕 with the process complete in the 1970s. Hong Kong completed their process of automated surface plotting by 1987.〔Hong Kong Observatory. (The Hong Kong Observatory Computer System and Its Applications. ) Retrieved on 2007-05-05.〕 By 1999, computer systems and software had finally become sophisticated enough to allow for the ability to underlay on the same workstation satellite imagery, radar imagery, and model-derived fields such as atmospheric thickness and frontogenesis in combination with surface observations to make for the best possible surface analysis. In the United States, this development was achieved when Intergraph workstations were replaced by n-AWIPS workstations.〔Hydrometeorological Prediction Center. (Hydrometeorological Prediction Center 1999 Accomplishment Report. ) Retrieved on 2007-05-05.〕 By 2001, the various surface analyses done within the National Weather Service were combined into the Unified Surface Analysis, which is issued every six hours and combines the analyses of four different centers.〔David Roth. Hydrometeorological Prediction Center. (Unified Surface Analysis Manual. ) Retrieved on 2006-10-22.〕 Recent advances in both the fields of meteorology and geographic information systems have made it possible to devise finely tailored products that take us from the traditional weather map into an entirely new realm. Weather information can quickly be matched to relevant geographical detail. For instance, icing conditions can be mapped onto the road network. This will likely continue to lead to changes in the way surface analyses are created and displayed over the next several years.〔Saseendran S. A., Harenduprakash L., Rathore L. S. and Singh S. V. (A GIS application for weather analysis and forecasting. ) Retrieved on 2007-05-05.〕 The pressureNET project is an ongoing attempt to gather surface pressure data using smartphones. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Surface weather analysis」の詳細全文を読む スポンサード リンク
|