Mesoscale meteorology
Encyclopedia
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. Examples of mesoscale weather systems are sea breeze
s, squall line
s, and mesoscale convective complex
es.
Vertical velocity often equals or exceeds horizontal velocities in mesoscale meteorological systems due to nonhydrostatic processes such as buoyant acceleration of a rising thermal or acceleration through a narrow mountain pass.
, literature about mesoscale analysis uses cold, warm, and occluded fronts on the mesoscale to help describe phenomena. On weather maps mesoscale fronts are depicted as smaller and with twice as many bumps or spikes as the synoptic variety. In the United States
, opposition to the use of the mesoscale versions of fronts on weather analyses, has led to the use of an overarching symbol (a trough symbol) with a label of outflow boundary as the frontal notation.
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...
systems smaller than synoptic scale systems but larger than microscale
Microscale meteorology
Microscale meteorology is the study of short-lived atmospheric phenomena smaller than mesoscale, about 1 km or less. These two branches of meteorology are sometimes grouped together as "mesoscale and microscale meteorology" and together study all phenomena smaller than synoptic scale; that is they...
and storm-scale
Storm-scale
Storm-scale is a scale of sizes of weather systems on the order of individual thunderstorms.-See also:* Synoptic scale meteorology* Mesoscale meteorology* Microscale meteorology* Misoscale meteorology...
cumulus systems. Horizontal dimensions generally range from around 5 kilometers to several hundred kilometers. Examples of mesoscale weather systems are 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, squall line
Squall line
A squall line is a line of severe thunderstorms that can form along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front. It contains heavy precipitation, hail, frequent lightning, strong straight-line winds, and possibly tornadoes and waterspouts....
s, and mesoscale convective complex
Mesoscale Convective Complex
A mesoscale convective complex is a unique kind of mesoscale convective system which is defined by characteristics observed in infrared satellite imagery. They are long-lived, nocturnal in formation and commonly contain heavy rainfall, wind, hail, lightning and possibly tornadoes.-Size:A...
es.
Vertical velocity often equals or exceeds horizontal velocities in mesoscale meteorological systems due to nonhydrostatic processes such as buoyant acceleration of a rising thermal or acceleration through a narrow mountain pass.
Subclasses
Mesoscale Meteorology is divided into these subclasses (Orlanski, 1975):- Meso-gamma 2-20 km, deals with phenomena like thunderstorm convection, complex terrain flows (at the edge to microscaleMicroscale meteorologyMicroscale meteorology is the study of short-lived atmospheric phenomena smaller than mesoscale, about 1 km or less. These two branches of meteorology are sometimes grouped together as "mesoscale and microscale meteorology" and together study all phenomena smaller than synoptic scale; that is they...
, also known as storm-scaleStorm-scaleStorm-scale is a scale of sizes of weather systems on the order of individual thunderstorms.-See also:* Synoptic scale meteorology* Mesoscale meteorology* Microscale meteorology* Misoscale meteorology...
)
- Meso-beta 20-200 km deals with phenomena like sea breezes, lake effect snow storms
- Meso-alpha 200-2000 km fronts, deals with phenomena like squall lines, mesoscale convective systems (MCS), tropical cyclones at the edge of synoptic scale
Mesoscale boundaries
As in synoptic frontal analysisSurface weather analysis
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...
, literature about mesoscale analysis uses cold, warm, and occluded fronts on the mesoscale to help describe phenomena. On weather maps mesoscale fronts are depicted as smaller and with twice as many bumps or spikes as the synoptic variety. In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, opposition to the use of the mesoscale versions of fronts on weather analyses, has led to the use of an overarching symbol (a trough symbol) with a label of outflow boundary as the frontal notation.
See also
- Microscale meteorologyMicroscale meteorologyMicroscale meteorology is the study of short-lived atmospheric phenomena smaller than mesoscale, about 1 km or less. These two branches of meteorology are sometimes grouped together as "mesoscale and microscale meteorology" and together study all phenomena smaller than synoptic scale; that is they...
- Misoscale meteorology
- POLYGON experimentPOLYGON experimentThe POLYGON experiment was a pioneer experiment in oceanography conducted in middle of the Atlantic Ocean during the 1970s. The experiment, led by Leonid Brekhovskikh, was the first to establish the existence of so-called "mesoscale eddies", eddies at the 100-km and 100-day scale, which triggered...
- Storm scaleStorm-scaleStorm-scale is a scale of sizes of weather systems on the order of individual thunderstorms.-See also:* Synoptic scale meteorology* Mesoscale meteorology* Microscale meteorology* Misoscale meteorology...
- Surface weather analysisSurface weather analysisSurface 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...
- Synoptic scale meteorologySynoptic scale meteorologyThe synoptic scale in meteorology is a horizontal length scale of the order of 1000 kilometres or more. This corresponds to a horizontal scale typical of mid-latitude depressions...
Further reading
- Orlanski, I., 1975: A rational subdivision of scales for atmospheric processes. Bulletin of the American Meteorological Society, 56(5), 527-530.
- Fujita, T. T.Ted Fujitawas a prominent severe storms researcher. His research at the University of Chicago on severe thunderstorms, tornadoes, hurricanes and typhoons revolutionized knowledge of each.- Biography :Fujita was born in Kitakyūshū, Fukuoka Prefecture, Japan...
, 1986. Mesoscale classifications: their history and their application to forecasting, in Ray, P. S., ed., Mesoscale Meteorology and Forecasting: American Meteorological Society, Boston, p. 18-35. [presented 1984; published 1986]