intertropical convergence zone

(redirected from Doldrum)
Also found in: Dictionary.

intertropical convergence zone

[¦in·tər′träp·ə·kəl kən′vər·jəns ‚zōn]
(meteorology)
The axis, or a portion thereof, of the broad trade-wind current of the tropics; this axis is the dividing line between the southeast trades and the northeast trades (of the Southern and Northern hemispheres, respectively). Also known as equatorial convergence zone; meteorological equator.

Intertropical Convergence Zone

 

an intermediate zone, several hundred kilometers wide, between the trade winds of the northern and southern hemispheres. For most of the year, the intertropical convergence zone is located north of the equator; during the northern hemisphere’s winter it nears the equator (and can sometimes penetrate into the southern hemisphere), and during the summer it recedes from it. Over the Atlantic and Pacific oceans, seasonal displacements of the intertropical convergence zone are not great; they are greater over Africa and South America, but they are particularly significant in the basin of the Indian Ocean, where trade-wind circulation over extensive areas is replaced by monsoon circulation. Considerable shifts in the intertropical convergence zone are frequently observed even from one day to the next.

In general, the intertropical convergence zone coincides with the equatorial depression—that is, with a low-pressure belt situated between the subtropical high-pressure zones of the northern and southern hemispheres. In this zone, in addition to light, variable winds, squalls and winds with a pronounced general easterly or westerly direction are observed. The nature of the weather in the intertropical convergence zone differs sharply from the weather in the trade-wind zones. Convection here is accelerated by the confluence of lines of flow; there is increased cloudiness, the clouds reach great heights, and abundant precipitation falls from them.

The intertropical convergence zone, as a rule, is not uniform in its breadth and properties; wave and vortex perturbations arise in it, leading to the formation of separate cloud clusters. The overwhelming majority of tropical cyclones with storm winds and catastrophic consequences form in this zone.

REFERENCE

Riehl, H. Tropicheskaia meteorologiia. Moscow, 1963. (Translated from English.)

S. P. KHROMOV

intertropical convergence zone (ITCZ)

The boundary zone between the tradewinds of the Northern and the Southern Hemispheres. It is characterized in maritime climates by overcast skies, showers, and precipitation, with cumulus clouds sometimes extending to great heights.
References in periodicals archive ?
For Roach and his clients, dog-day doldrums are not a myth.
Review of Doldrum Bay by Hilary Fannin, translated by Francois Letourneau, directed by Philippe Soldevila.
Nevertheless it survived with a much more modest presence; communists and Quakers were reckoned to be the organisations which kept it alive during those doldrum years--the Scottish secretary of the movement was a Party member.
The legions of the poor have been re-forming in the United States and around the world in the persisting doldrum that followed the great economic dislocations of 2008.
Can-do" perseverance for commercial agencies during this economic doldrum comes in the form of working smarter, learning to live on less, and clearly demonstrating a service standard second to none.
Currently forestry industry is being in the doldrum that many units of heavy equipment lie idle.
What we think happens is that during an El Nino, which can produce doldrum conditions in the Great Barrier Reef (GBR), sometimes for a couple of weeks at a time, this process shuts down,' Jones told Mongabay.
Described by jury chairman Gordon Fergus-Thompson as having "risen like a phoenix" after a doldrum period in the 1990s, the event concluded on Sunday in Dudley's acoustically benign Concert Hall (Town Hall in old money) with three finalists tackling three very different works.
I have tried to set up to be one of the more western boats so that it can be a faster Doldrum crossing for me.
But despite the doldrum years of 1996 to 2004, in 2007 the blue-collar vote for Labor (at 55 per cent) was closer to the level of the late 1980s (64 per cent in 1987) than it had been for some time.
Despite falling in the doldrum period between the festivals of Cheltenham and Aintree, there was still equine talent on show.
Ulster Bank Head of Mortgages Derek Wilson explained: "This time of year tends to be a doldrum period for house prices but this is the first time we have seen any report of dropping prices.