how does the location of the intertropical convergence zone (itcz) change over time?

Meteorological phenomenon

The ITCZ is visible as a band of clouds encircling Earth well-nigh the Equator.

The Intertropical Convergence Zone (ITCZ, pronounced "itch"^[1]), known by sailors equally the doldrums ^[2] or the calms because of its monotonous windless weather, is the surface area where the northeast and the southeast merchandise winds converge. It encircles Globe near the thermal equator though its specific position varies seasonally. When it lies near the geographic Equator, it is called the well-nigh-equatorial trough. Where the ITCZ is fatigued into and merges with a monsoonial apportionment, it is sometimes referred to as a monsoon trough, a usage that is more than common in Australia and parts of Asia.

Meteorology [edit]

The ITCZ was originally identified from the 1920s to the 1940s as the Intertropical Front (ITF), but after the recognition in the 1940s and the 1950s of the significance of wind field convergence in tropical weather production, the term Intertropical Convergence Zone (ITCZ) was and then applied.^[3]

The ITCZ appears as a band of clouds, normally thunderstorms, that encircle the globe near the Equator. In the Northern Hemisphere, the trade winds move in a southwestward management from the northeast, while in the Southern Hemisphere, they move northwestward from the southeast. When the ITCZ is positioned north or due south of the Equator, these directions change according to the Coriolis effect imparted by Earth's rotation. For instance, when the ITCZ is situated north of the Equator, the southeast merchandise wind changes to a southwest current of air as it crosses the Equator. The ITCZ is formed past vertical motion largely appearing equally convective activity of thunderstorms driven by solar heating, which effectively draw air in; these are the trade winds.^[4] The ITCZ is effectively a tracer of the ascending branch of the Hadley prison cell and is wet. The dry descending branch is the horse latitudes.

The location of the ITCZ gradually varies with the seasons, roughly respective with the location of the thermal equator. As the heat chapters of the oceans is greater than air over land, migration is more than prominent over land. Over the oceans, where the convergence zone is ameliorate defined, the seasonal cycle is more subtle, equally the convection is constrained past the distribution of ocean temperatures.^[5] Sometimes, a double ITCZ forms, with one located north and another s of the Equator, ane of which is usually stronger than the other. When this occurs, a narrow ridge of high pressure forms between the two convergence zones.

ITCZ over oceans vs. state [edit]

Seasonal variability of the Intertropical Convergence Zone (ITCZ), Congo air boundary (CAB), tropical rainbelt, and surface winds over Africa (adapted from Dezfuli 2022 with modification). This schematic shows that the ITCZ and the region of maximum rainfall can be decoupled over the continents.^[6]

The ITCZ is unremarkably divers as an equatorial zone where the trade winds converge. Rainfall seasonality is traditionally attributed to the north–s migration of the ITCZ, which follows the sunday. Although this is largely valid over the equatorial oceans, the ITCZ and the region of maximum rainfall can exist decoupled over the continents.^{[6] [7]} The equatorial atmospheric precipitation over land is not simply a response to just the surface convergence. Rather, it is modulated past a number of regional features such every bit local atmospheric jets and waves, proximity to the oceans, terrain-induced convective systems, moisture recycling, and spatiotemporal variability of land comprehend and albedo.^[vi]

South Pacific convergence zone [edit]

Vertical air velocity at 500 hPa, July boilerplate. Ascent (negative values) is concentrated close to the solar equator; descent (positive values) is more lengthened

The South Pacific convergence zone (SPCZ) is a reverse-oriented, or westward-northwest to east-southeast aligned, trough extending from the west Pacific warm pool southeastwards towards French Polynesia. It lies just south of the equator during the Southern Hemisphere warm season, only can be more extratropical in nature, specially eastward of the International Date Line. It is considered the largest and most important piece of the ITCZ, and has the least dependence upon heating from a nearby land mass during the summer than any other portion of the monsoon trough.^[8] The southern ITCZ in the southeast Pacific and southern Atlantic, known as the SITCZ, occurs during the Southern Hemisphere fall between 3° and x° south of the equator east of the 140th peak westward longitude during absurd or neutral El Niño–Southern Oscillation (ENSO) patterns. When ENSO reaches its warm phase, otherwise known as El Niño, the natural language of lowered sea surface temperatures due to upwelling off the South American continent disappears, which causes this convergence zone to vanish as well.^[9]

Effects on weather [edit]

The ITCZ moves further abroad from the equator during the Northern summer than the Southern one due to the N-heavy arrangement of the continents.

Variation in the location of the intertropical convergence zone drastically affects rainfall in many equatorial nations, resulting in the moisture and dry seasons of the tropics rather than the common cold and warm seasons of higher latitudes. Longer term changes in the intertropical convergence zone can result in severe droughts or flooding in nearby areas.

In some cases, the ITCZ may go narrow, especially when it moves away from the equator; the ITCZ tin can then be interpreted as a front along the leading edge of the equatorial air.^[10] At that place appears to exist a 15 to 25-twenty-four hours wheel in thunderstorm activity forth the ITCZ, which is roughly half the wavelength of the Madden–Julian oscillation (MJO).^[eleven]

Within the ITCZ the average winds are slight, unlike the zones north and southward of the equator where the merchandise winds feed. Equally trans-equator sea voyages became more than mutual, sailors in the eighteenth century named this belt of calm the doldrums because of the calm, stagnant, or inactive winds.

Role in tropical whirlwind formation [edit]

Hurricanes Celia and Darby in the eastern Pacific and the forerunner to Hurricane Alex in the Intertropical Convergence Zone. (2010)

Tropical cyclogenesis depends upon depression-level vorticity as one of its half-dozen requirements, and the ITCZ fills this role as it is a zone of air current change and speed, otherwise known as horizontal wind shear. Equally the ITCZ migrates to tropical and subtropical latitudes and even across during the respective hemisphere'south summer season, increasing Coriolis force makes the formation of tropical cyclones within this zone more possible. Surges of college pressure level from high latitudes can raise tropical disturbances forth its axis.^[12] In the northward Atlantic and the northeastern Pacific oceans, tropical waves motion along the axis of the ITCZ causing an increase in thunderstorm activity, and clusters of thunderstorms can develop nether weak vertical wind shear.^{[ citation needed ]}

Hazards [edit]

Thunderstorms forth the Intertropical Convergence Zone played a part in the loss of Air French republic Flight 447, which left Rio de Janeiro–Galeão International Airport on Sun, 31 May 2009, at about 7:00 p.m. local time (6:00 p.thou. EDT or 10:00 p.m. UTC) and had been expected to state at Charles de Gaulle Airdrome almost Paris on Monday, 1 June 2009, at 11:15 a.m. (5:xv a.m. EDT or ix:15 a.grand. UTC).^[13] The aircraft crashed with no survivors while flight through a serial of large ITCZ thunderstorms, and ice forming rapidly on airspeed sensors was the precipitating crusade for a cascade of homo errors which ultimately doomed the flying. Nigh aircraft flying these routes are able to avoid the larger convective cells without incident.

In the Age of Sail, to discover oneself becalmed in this region in a hot and muggy climate could hateful death when wind was the only effective way to propel ships across the ocean. Calm periods within the doldrums could strand ships for days or weeks.^[14] Even today, leisure and competitive sailors attempt to cross the zone as rapidly as possible equally the erratic weather and wind patterns may cause unexpected delays.

In literature [edit]

The doldrums are notably described in Samuel Taylor Coleridge's verse form The Rime of the Ancient Mariner (1798) and too provide a metaphor for the initial state of colorlessness and indifference of Milo, the child hero of Norton Juster'south archetype children's novel The Phantom Tollbooth. Information technology is also cited in the book Wind, Sand and Stars.

See too [edit]

• Asymmetry of the Intertropical Convergence Zone
• Monsoon trough
• Chemical equator
• Roaring Forties
• Horse latitudes
• Polar front

Notes [edit]

1. ^ ITCZ
2. ^ Chisholm, Hugh, ed. (1911). "Doldrums". Encyclopædia Britannica. Vol. viii (11th ed.). Cambridge Academy Press. p. 386.
3. ^ Barry, Roger Graham; Chorley, Richard J. (1992). Atmosphere, weather, and climate . London: Routledge. ISBN978-0-415-07760-half dozen. OCLC 249331900. Temper, weather, and climate.
4. ^ "Inter-Tropical Convergence Zone". JetStream - Online School for Atmospheric condition. NOAA. 2007-10-24. Retrieved 2009-06-04 .
5. ^ "Inter Tropical Convergence Zone (ITCZ) - SKYbrary Aviation Condom". www.skybrary.aero . Retrieved 2018-04-12 .
6. ^ ^{a b c} Dezfuli, Amin (2017-03-29). "Climate of Western and Fundamental Equatorial Africa". Oxford Research Encyclopedia of Climate Science. doi:ten.1093/acrefore/9780190228620.013.511. ISBN9780190228620.
7. ^ Nicholson, Sharon E. (February 2022). "The ITCZ and the Seasonal Wheel over Equatorial Africa". Message of the American Meteorological Society. 99 (2): 337–348. Bibcode:2018BAMS...99..337N. doi:10.1175/bams-d-16-0287.1. ISSN 0003-0007.
8. ^ E. Linacre and B. Geerts. Movement of the South Pacific convergence zone Retrieved on 2006-eleven-26.
9. ^ Semyon A. Grodsky; James A. Carton (2003-02-fifteen). "The Intertropical Convergence Zone in the South Atlantic and the Equatorial Cold Tongue" (PDF). University of Maryland, College Park. Retrieved 2009-06-05 .
10. ^ Djurić, D: Weather Assay. Prentice Hall, 1994. ISBN 0-xiii-501149-3.
11. ^ Patrick A. Harr. Tropical Cyclone Germination/Structure/Motion Studies. Role of Naval Research Retrieved on 2006-11-26. Archived November 29, 2007, at the Wayback Machine
12. ^ C.-P. Chang, J.E. Erickson, and 1000.M. Lau. Northeasterly Cold Surges and Near-Equatorial Disturbances over the Winter MONEX Area during December 1974. Part I: Synoptic Aspects. Retrieved on 2007-04-26.
13. ^ "Q & A Turbulences" 1.June.2009 The Guardian
14. ^ [1] NOAA. What are the doldrums? National Body of water Service website, https://oceanservice.noaa.gov/facts/doldrums.html, 01/07/20

External links [edit]

Look up doldrums in Wiktionary, the costless dictionary.

• The ITCZ in Africa via the University of South Carolina
• A Shifting Band of Pelting from March 2022 Scientific American
• Duane E. Waliser and Catherine Gautier, 1993: A Satellite-derived Climatology of the ITCZ. J. Climate, six, 2162–2174.

Source: https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone

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