Zonal and meridional
The terms zonal and meridional are used to describe directions on a globe
A globe is a three-dimensional scale model of Earth or other spheroid celestial body such as a planet, star, or moon...

. Zonal means "along a latitude circle
Circle of latitude
A circle of latitude, on the Earth, is an imaginary east-west circle connecting all locations that share a given latitude...

" or "in the west–east direction"; while meridional means "along a meridian
Meridian (geography)
A meridian is an imaginary line on the Earth's surface from the North Pole to the South Pole that connects all locations along it with a given longitude. The position of a point along the meridian is given by its latitude. Each meridian is perpendicular to all circles of latitude...

" or "in the north–south direction".

These terms are often used in the atmospheric
Atmospheric sciences
Atmospheric sciences is an umbrella term for the study of the atmosphere, its processes, the effects other systems have on the atmosphere, and the effects of the atmosphere on these other systems. Meteorology includes atmospheric chemistry and atmospheric physics with a major focus on weather...

 and earth science
Earth science
Earth science is an all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet. There are both reductionist and holistic approaches to Earth sciences...

s to describe global phenomena, such as "meridional wind flow", or "zonal temperature". (Strictly speaking, zonal means more than simply a direction as it also implies a degree of localization in the meridional direction, so that the phenomenon in question is localized to a zone
-Places:France* Any of several divisions during the German occupation of France during World War IIGermany* The Zone , a derogatory term for the German Democratic RepublicGreece...

 of the planet.)

"Meridional" is also used to describe the axis close to the chain orientation in a polymer fiber, while the term "equatorial" is used to describe the direction normal to the fiber axis.

For vector field
Vector field
In vector calculus, a vector field is an assignmentof a vector to each point in a subset of Euclidean space. A vector field in the plane for instance can be visualized as an arrow, with a given magnitude and direction, attached to each point in the plane...

s (such as wind velocity), the zonal component (or x-coordinate) is denoted as u, while the meridional component (or y-coordinate) is denoted as v.

The term meridional, sometimes abbreviated to "Mer.", was used in historical astronomy to indicate the southern direction on the celestial globe, together with septentrional
Septentrional is a word that means "of the north", rarely used in English but commonly used in Latin and in the Romance languages. Early maps of North America, mostly those before 1700, often refer to the northern- or northwestern-most unexplored areas of the continent at "Septentrional" or...

 ("Sep.") for northern, oriental ("Ori.") for eastern and occidental ("Occ.") for western.

See also

  • Meridional flow
    Meridional flow
    Meridional flow is a meteorological term meaning that the general flow pattern is north to south, or south to north, along the Earth's longitude lines . Extratropical cyclones in this environment tend to be stronger and move slower...

  • Zonal flow
    Zonal flow
    Zonal flow is a meteorological term meaning that the general flow pattern is west to east, or east to west, along the Earth's latitude lines . Extratropical cyclones in this environment tend to be weaker, moving faster and producing relatively little impact on local weather.-References:**...

  • Zonal and poloidal
    Zonal and poloidal
    In magnetic confinement fusion the zonal direction primarily connotes the poloidal direction , the corresponding coordinate being denoted by y in the slab approximation or θ in magnetic coordinates...

  • Zonal flow (plasma)
    Zonal flow (plasma)
    In toroidally confined fusion plasma experiments the term zonal flow means a plasma flow within a magnetic surface primarily in the poloidal direction...

  • Meridione
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.