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42-460: The festival is always staged when the water level is high and during the rainy season to ensure that boats can float with the high wave of the water. Boats are decorated in beautiful colours with its occupants also dressed with native attire to showcase the aquatic culture of the people. The festival is celebrated by the riverine people in Niger delta region and is a time of showcasing aquatic culture of

84-565: A distinct rainy season. Also subtropical areas like Florida , South and Southeast Texas, and southern Louisiana in the United States have a rainy season. Monsoon regions include the Indian subcontinent , Southeast Asia (including Indonesia and Philippines ), northern sections of Australia , Polynesia , Central America , western and southern Mexico , the Desert Southwest of

126-497: A series of large ITCZ thunderstorms, and ice forming rapidly on airspeed sensors was the precipitating cause for a cascade of human errors which ultimately doomed the flight. Most aircraft flying these routes are able to avoid the larger convective cells without incident. Based on paleoclimate proxies , the position and intensity of the ITCZ varied in prehistoric times along with changes in global climate . During Heinrich events within

168-514: A southwest wind as it crosses the Equator. The ITCZ is formed by vertical motion largely appearing as convective activity of thunderstorms driven by solar heating, which effectively draw air in; these are the trade winds. The ITCZ is effectively a tracer of the ascending branch of the Hadley cell and is wet. The dry descending branch is the horse latitudes . The location of the ITCZ gradually varies with

210-615: A wet season in the winter months. Similarly, the wet season in the Negev Desert of Israel extends from October through May. At the boundary between the Mediterranean and monsoon climates lies the Sonoran Desert , which receives the two rainy seasons associated with each climate regime. The wet season is known by many different local names throughout the world. For example, in Mexico it

252-530: Is a reverse-oriented, or west-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, but can be more extratropical in nature, especially east of the International Date Line . It is considered the largest and most important piece of the ITCZ, and has

294-679: Is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the tropics and subtropics . Under the Köppen climate classification , for tropical climates , a wet season month is defined as a month where average precipitation is 60 millimetres (2.4 in) or more. In contrast to areas with savanna climates and monsoon regimes, Mediterranean climates have wet winters and dry summers. Dry and rainy months are characteristic of tropical seasonal forests : in contrast to tropical rainforests , which do not have dry or wet seasons, since their rainfall

336-603: Is equally distributed throughout the year. Some areas with pronounced rainy seasons will see a break in rainfall mid-season, when the Intertropical Convergence Zone or monsoon trough moves to higher latitudes in the middle of the warm season. When the wet season occurs during a warm season, or summer , precipitation falls mainly during the late afternoon and early evening. In the wet season, air quality improves, fresh water quality improves, and vegetation grows substantially, leading to crop yields late in

378-503: Is known as "storm season". Different names are given to the various short "seasons" of the year by the First Nations of Northern Australia : the wet season typically experienced there from December to March is called Gudjewg . The precise meaning of the word is disputed, although it is widely accepted to relate to the severe thunderstorms, flooding, and abundant vegetation growth commonly experienced at this time. In tropical areas, when

420-503: Is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal equator though its specific position varies seasonally. When it lies near the geographic Equator , it is called the near-equatorial trough . Where the ITCZ is drawn into and merges with a monsoonal circulation, it is sometimes referred to as a monsoon trough (a usage that is more common in Australia and parts of Asia). The ITCZ

462-627: The Atlantic meridional overturning circulation . The climate simulations run as part of Coupled Model Intercomparison Project Phase 5 (CMIP5) did not show a consistent global displacement of the ITCZ under anthropogenic climate change. In contrast, most of the same simulations show narrowing and intensification under the same prescribed conditions. However, simulations in Coupled Model Intercomparison Project Phase 6 (CMIP6) have shown greater agreement over some regional shifts of

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504-487: The Madden–Julian oscillation (MJO). Within the ITCZ the average winds are slight, unlike the zones north and south of the equator where the trade winds feed. As trans-equator sea voyages became more common, sailors in the eighteenth century named this belt of calm the doldrums because of the calm, stagnant, or inactive winds. Tropical cyclogenesis depends upon low-level vorticity as one of its six requirements, and

546-598: The Northern Hemisphere , the trade winds move in a southwestward direction from the northeast, while in the Southern Hemisphere , they move northwestward from the southeast. When the ITCZ is positioned north or 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 trade wind changes to

588-664: The Atlantic and Pacific underlying the ITCZ fringes and decreasing salinity underlying central belt of the ITCZ. The IPCC Sixth Assessment Report indicated "medium agreement" from studies regarding the strengthening and tightening of the ITCZ due to anthropogenic climate change. Less certain are the regional and global shifts in ITCZ position as a result of climate change, with paleoclimate data and model simulations highlighting contrasts stemming from asymmetries in forcing from aerosols, volcanic activity, and orbital variations , as well as uncertainties associated with changes in monsoons and

630-410: The Equator, one of which is usually stronger than the other. When this occurs, a narrow ridge of high pressure forms between the two convergence zones. The ITCZ is commonly defined as an equatorial zone where the trade winds converge. Rainfall seasonality is traditionally attributed to the north–south migration of the ITCZ, which follows the sun. Although this is largely valid over the equatorial oceans,

672-466: The ITCZ and the region of maximum rainfall can be decoupled over the continents. The equatorial precipitation over land is not simply a response to just the surface convergence. Rather, it is modulated by a number of regional features such as local atmospheric jets and waves, proximity to the oceans, terrain-induced convective systems, moisture recycling, and spatiotemporal variability of land cover and albedo. The South Pacific convergence zone (SPCZ)

714-440: The ITCZ fills this role as it is a zone of wind change and speed, otherwise known as horizontal wind shear . As the ITCZ migrates to tropical and subtropical latitudes and even beyond during the respective hemisphere's summer season, increasing Coriolis force makes the formation of tropical cyclones within this zone more possible. Surges of higher pressure from high latitudes can enhance tropical disturbances along its axis. In

756-586: The ITCZ in response to anthropogenic climate change, including a northward displacement over the Indian Ocean and eastern Africa and a southward displacement over the eastern Pacific and Atlantic oceans. The doldrums are notably described in Samuel Taylor Coleridge 's poem The Rime of the Ancient Mariner (1798) and also provide a metaphor for the initial state of boredom and indifference of Milo,

798-457: The ITCZ may have led to drought in the Sahel in the 1980s. Atmospheric convection may become stronger and more concentrated at the center of the ITCZ in response to a globally warming climate, resulting in sharpened contrasts in precipitation between the ITCZ core (where precipitation would be amplified) and its edges (where precipitation would be suppressed). Atmospheric reanalyses suggest that

840-471: The ITCZ over the Pacific has narrowed and intensified since at least 1979, in agreement with data collected by satellites and in-situ precipitation measurements. The drier ITCZ fringes are also associated with an increase in outgoing longwave radiation outward of those areas, particularly over land within the mid-latitudes and the subtropics . This change in the ITCZ is also reflected by increasing salinity within

882-787: The United States, southern Guyana , and northeast Brazil . Northern Guyana has two wet seasons: one in early spring and the other in early winter. In western Africa, there are two rainy seasons across southern sections, but only one across the north. Within the Mediterranean climate regime, the west coast of the United States, the southwest coast of Australia and South Africa, the Mediterranean coastline of Italy, Spain, Greece, Lebanon, Syria, Algeria, Morocco, Tunisia, and Turkey, as well as areas further inland in Western Asia which include Jordan, Northern Iraq and most parts of Iran, experience

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924-403: The beginning of the wet season. The onset of the rainy season signals the departure of the monarch butterfly from Mexico. Tropical species of butterflies show larger dot markings on their wings to fend off possible predators and are more active during the wet season than the dry season . Within the tropics and warmer areas of the subtropics, decreased salinity of near shore wetlands due to

966-554: The charging of local aquifers during the wet season. Water also softens, as the concentration of dissolved materials reduces during the rainy season. Erosion is also increased during rainy periods. Arroyos that are dry at other times of the year fill with runoff, in some cases with water as deep as 10 feet (3.0 m). Leaching of soils during periods of heavy rainfall depletes nutrients. The higher runoff from land masses affects nearby ocean areas, which are more stratified , or less mixed, due to stronger surface currents forced by

1008-494: The communities. These participants appear in beautifully adorned native wears and used to showcase the communities defence mechanism before colonization, ceremonies and their religion. Besides dressing in beautiful local wrappers and outfits, other aspects of the festival includes shooting of canons on boats and masquerade performances to thrill the crowd at the event. Recently in Rivers State, Governor Nyesom Wike declared that

1050-591: The doldrums could strand ships for days or weeks. Even today, leisure and competitive sailors attempt to cross the zone as quickly as possible as the erratic weather and wind patterns may cause unexpected delays. In 2009, thunderstorms along the Intertropical Convergence Zone played a role in the loss of Air France Flight 447 , which crashed while flying from Rio de Janeiro–Galeão International Airport to Charles de Gaulle Airport near Paris . The aircraft crashed with no survivors while flying through

1092-446: The festival should be celebrated annually on May 27 to mark the creation of Rivers state and also to showcase the culture and traditions of the people of Rivers state. Henley Royal Regatta Wet season The wet season (sometimes called the rainy season or monsoon season ) is the time of year when most of a region's average annual rainfall occurs. Generally, the season lasts at least one month. The term green season

1134-740: The heavy rainfall runoff. High rainfall can cause widespread flooding, which can lead to landslides and mudflows in mountainous areas. Such floods cause rivers to burst their banks and submerge homes. The Ghaggar-Hakra River , which only flows during India's monsoon season, can flood and severely damage local crops. Floods can be exacerbated by fires that occurred during the previous dry season, which cause soils which are sandy or composed of loam to become hydrophobic, or water repellent. In various ways governments may help people deal with wet season floods. Flood plain mapping identifies which areas are more prone to flooding. Instructions on controlling erosion through outreach are also provided by telephone or

1176-560: The internet. The wet season is the main period of vegetation growth within the Savanna climate regime. However, this also means that wet season is a time for food shortages before crops reach their full maturity. This causes seasonal weight changes for people in developing countries, with a drop occurring during the wet season until the time of the first harvest, when weights rebound. Malaria incidence increases during periods of high temperature and heavy rainfall. Cows calve, or give birth, at

1218-404: The intertropical convergence zone can result in severe droughts or flooding in nearby areas. In some cases, the ITCZ may become narrow, especially when it moves away from the equator; the ITCZ can then be interpreted as a front along the leading edge of the equatorial air. There appears to be a 15 to 25-day cycle in thunderstorm activity along the ITCZ, which is roughly half the wavelength of

1260-558: The last 100 ka, a southward shift of the ITCZ coincided with the intensification of the Northern Hemisphere Hadley cell coincident with weakening of the Southern Hemisphere Hadley cell. The ITCZ shifted north during the mid-Holocene but migrated south following changes in insolation during the late-Holocene towards its current position. The ITCZ has also undergone periods of contraction and expansion within

1302-594: The last millennium. A southward shift of the ITCZ commencing after the 1950s and continuing into the 1980s may have been associated with cooling induced by aerosols in the Northern Hemisphere based on results from climate models ; a northward rebound began subsequently following forced changes in the gradient in temperature between the Northern and Southern hemispheres. These fluctuations in ITCZ positioning had robust effects on climate; for instance, displacement of

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1344-525: The least dependence upon heating from a nearby land mass during the summer than any other portion of the monsoon trough . The southern ITCZ in the southeast Pacific and southern Atlantic, known as the SITCZ, occurs during the Southern Hemisphere fall between 3° and 10° south of the equator east of the 140th meridian west longitude during cool or neutral El Niño–Southern Oscillation (ENSO) patterns. When ENSO reaches its warm phase, otherwise known as El Niño,

1386-421: The monsoon arrives, high daytime high temperatures drop and overnight low temperatures increase, thus reducing diurnal temperature variation . During the wet season, a combination of heavy rainfall and, in some places such as Hong Kong , an onshore wind, improve air quality . In Brazil, the wet season is correlated with weaker trade winds off the ocean. The pH level of water becomes more balanced due to

1428-469: The north Atlantic and the northeastern Pacific oceans, tropical waves move along the axis of the ITCZ causing an increase in thunderstorm activity, and clusters of thunderstorms can develop under weak vertical wind shear. In the Age of Sail , to find oneself becalmed in this region in a hot and muggy climate could mean death when wind was the only effective way to propel ships across the ocean. Calm periods within

1470-432: The rains causes an increase in crocodile nesting. Other species, such as the arroyo toad , spawn within the couple of months after the seasonal rains. Armadillos and rattlesnakes seek higher ground. Intertropical Convergence Zone The Intertropical Convergence Zone ( ITCZ / ɪ tʃ / ITCH , or ICZ ), known by sailors as the doldrums or the calms because of its monotonous windless weather,

1512-412: The season. Rivers overflow their banks, and some animals retreat to higher ground. Soil nutrients diminish and erosion increases. The incidence of malaria and dengue increases in areas where the rainy season coincides with high temperatures, particularly in tropical areas. Some animals have adaptation and survival strategies for the wet season. Often, the previous dry season leads to food shortages in

1554-434: The seasons, roughly corresponding with the location of the thermal equator. As the heat capacity of the oceans is greater than air over land, migration is more prominent over land. Over the oceans, where the convergence zone is better defined, the seasonal cycle is more subtle, as the convection is constrained by the distribution of ocean temperatures. Sometimes, a double ITCZ forms, with one located north and another south of

1596-480: The tongue of lowered sea surface temperatures due to upwelling off the South American continent disappears, which causes this convergence zone to vanish as well. Variation in the location of the intertropical convergence zone drastically affects rainfall in many equatorial nations, resulting in the wet and dry seasons of the tropics rather than the cold and warm seasons of higher latitudes. Longer term changes in

1638-472: The tropics can have two wet seasons, because the monsoon trough, or Intertropical Convergence Zone , can pass over locations in the tropics twice per year. However, since rain forests have rainfall spread evenly through the year, they do not have a wet season. Areas with a savanna climate in Sub-Saharan Africa , such as Ghana , Burkina Faso , Darfur , Eritrea , Ethiopia , and Botswana have

1680-414: The wet season is mainly due to daytime heating, which leads to diurnal thunderstorm activity within a pre-existing moist airmass , so the rain mainly falls in late afternoon and early evening in savanna and monsoon regions. Much of the total rainfall each day occurs in the first minutes of the downpour, before the storms mature into their stratiform stage. Most places have only one wet season, but areas of

1722-474: The wet season, as the crops have yet to mature. Crops which can be successfully planted during the wet or rainy season are cassava , maize , groundnut , millet , rice and yam . The temperate counterpart to the tropical wet season is spring or autumn . In areas where the heavy rainfall is associated with a wind shift, the wet season is known as the monsoon season. Many tropical and subtropical climates experience monsoon rainfall patterns. Rainfall in

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1764-465: 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 then applied. The ITCZ appears as a band of clouds, usually thunderstorms, that encircle the globe near the Equator. In

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