Causes of wet and dry seasons in west africa

At december hot tropical summer comes to the republic of south africa. Climate, climate change, the dry and wet seasons in west. As a result of these interacting air masses, west africas precipitation regime is characterized by latitudinal belts of decreasing rainfall and wet season length. The tropical climate is characterized by a wet season and a dry season. An alternative subdivision recognizes savanna woodland, with trees and shrubs forming a light canopy. Between the tropics and the equator, locations may experience a short wet and a long wet season. Annual migration of tropical rain belt noaa climate. A monsoon is actually a seasonal shift in wind direction and pressure distribution that causes a change in precipitation.

Others have scorching hot summers and windy, wet winters. Aboriginal people of this region recognise more than just two seasons. In general what happens in the wilderness areas of africa is that with the dry season much of the. Average daytime temperature is in the range between 26 c 79 f in cape town and 28 c 82 f in pretoria and durban.

The rainfall varies and can even miss an area leading to drought. The first benefit is that the fertile nigerian land, which needs the rain in other to grow food and other agricultural produce. Oddly enough, it is actually a little cooler during this dry season. The rainy season occurs between april and october in the south while in the north, the start of the rainy season is delayed till june. Wet and dry seasons questacon the national science and. There is a rainy season in this case, the monsoon season, which lasts two to three months at latitude 16 n on the west coast, three to four months at 14 n, six to seven months at 10.

Nigeria, therefore, has two major seasons, the dry season and the wet season, the lengths of which vary from north to south. Moreover, wet and dry spells are assessed for various duration categories. Measles epidemics in niger fluctuate wildly from one season to another but the timing of the. Derived from mauism, the arabic word for season, a monsoon often refers to a rainy season but this only describes the weather a monsoon brings, not what a monsoon is. For tropical climates a to have a dry season, they need to have at least one month with less than 60mm of precipitation. Concurrently with the rainfall decline over eastern africa is a decrease in the surface pressure over arabia in may. The rainy season in west africa generally falls from the end of april july and again in septemberoctober. Savanna climate or tropical wet and dry climate or sudan climate this type of climate has alternate wet and dry seasons similar to monsoon climate but has considerably less annual rainfall. Factors contributing to urban malaria transmission in sub. Hot, dry continental air masses originating from the high pressure system above the sahara desert give rise to dusty harmattan winds over most of west africa from november to february. West africa has been identified as a climatechange hotspot, with climate. The southwest winter monsoon flows as a shallow humid layer of surface air less than 2,000 metres about 6,600 feet overlain by the primary northeast trade wind, which blows from the sahara and the sahel as a deep stream of. The monsoon circulation occurs in parts of africa, asia, northern australia and arguably in the north america desert southwest debatable because it lacks a true seasonal flow reversal.

The implication is that there is a prolonged rainy season in the far south of nigeria, while the far north undergoes long dry periods annually. The wet season sometimes called the rainy season is the time of year when most of a regions average annual rainfall occurs. Anomalously wet and dry rainy seasons in equatorial east. Semiarid climates bs often have a wet and dry season but it is not a defining factor. Most of africa experiences a wet season and a dry season each year. West africa generally, the dry season runs from november to april in west african countries like ghana and senegal. Dry season brings on measles in subsaharan africa date. The cause of this climate is directly related to large bodies of water such as the mediterranean sea and ocean. The wet season refers to the rains and many areas are closed to travel during the rains due to inaccessibility.

The most important consequence of this shifting is the annual alteration of wet and dry seasons in tropical africa. During the dry season, dry air flows out to sea and during the wet season, moist air flows inland from the sea, rises and produces rain. Although rainfed farming is a highrisk enterprise, it is also a way of life and people are committed to making the best of the scarce resources at their disposal. Tropical wet and dry climate is mainly found within the tropics. Where gorilla travel is concerned, keep in mind that bwindi national park is a rain forest at considerable elevation and can be wet and cool at any time of year. Sep 22, 2017 others have scorching hot summers and windy, wet winters. A monsoon is a seasonal change in the direction of the prevailing, or strongest, winds of a region. Objective seasons in the top end of the northern territory are generally known as the wet and the dry. Oct 26, 2016 floridas wet and dry seasons are very distinct. The a stands for a tropical climate, and the w for a dry season in the winter in the savanna climate there is a distinct dry season, which is in the winter. This indicates a strengthening of the arabian heat low. Jan 23, 2012 the local climate is coastalguinean with four seasons including a long dry season between november and march which is the hottest of the year with average monthly temperatures close to 28c.

In the savanna of west africa, there is a wet season and a dry season. There are actually two very different seasons in a savanna. Subsaharan africa suffers by far the greatest malaria burden worldwide and is currently undergoing a profound demographic change, with a growing proportion of its population moving to urban areas. There are two main seasons the rainy season and the dry season. Generally, the dry season runs from november to april in west african countries like ghana and senegal. The climate is known for warm to hot, dry summers and mild to cool, wet winters. Monsoons cause wet and dry seasons throughout much of the tropics. West africa has wet and dry seasons resulting from the interaction of two migrating air masses. Every year, the rainfilled monsoon winds cause the nearby bangali river to overflow its banks. In many countries, the rainy season also coincides with the best time of year to see young animals and migrant. Land in this area receives direct sunlight throughout most of the year.

Examples of such animals are zebras, elephants, and wildebeest. Near these latitudes, there is one wet season and one dry season annually. In the savanna climate there is a distinct dry season, which is in the winter. Which of the following is an important cash cropnative to central america and south america that was introduced to west africa during the colonial period. The ipcc expects central africa to see a decrease in the length of wet spells and a slight increase in heavy rainfall. Their seasonal calendar plays a very important role in traditional life. Urbanisation is generally expected to reduce malaria transmission. In july, when the sun is over the tropic of cancer, the itcz reaches its northernmost position at about 15n.

Average annual rainfall was 1,100 mm in 20072008 with less than 10% falling during the long dry season. At higher latitudes, precipitation decreases and is limited to a wet season of decreasing. Areas with wet seasons are dispersed across portions of the tropics and subtropics. Situated in the southern hemisphere, christmas in south africa is a sunny, beachbound affair. During the dry season, humidity is very low, causing some watering holes and rivers to dry up. Characteristics of wet and dry spells in the west african. Although humidity is high throughout the year especially on the coast, there are less mosquitoes during the dry season and unpaved roads are also in the best condition. Dry season determinants of malaria disease and net use in. Dry spells have been analyzed for durations of 23, 46, 715 and 1621 days similarly towhat was done by previous authors e. South floridas subtropical climate is characterized by warm, humid, rainy summers and mild, dry, pleasant winters with periodic incursions of cool air. Between december and february no rain will fall at all. This climate is caused by changing wind and ocean currents. The rainy season has several benefits to nigerians. The west of the country becomes rainy but showers occur after noon with sunny half of a day before.

Monsoons are most often associated with the indian ocean. In west africa, the northeast trades, in fact, blow offshore continent to sea from the sahara desert and reach the guinea coast as a dry, dustladen winds. The southwest winter monsoon flows as a shallow humid layer of surface air less than 2,000 metres about 6,600 feet overlain by the primary northeast trade wind, which blows from the sahara and the sahel as a deep stream of dry, often dusty air. During the dry seasons plant life and animal life suffers, but as the rainy season begins life flourishes in this area. Also, there is no distinct rainy season like in monsoon climate. In nigeria as well as in most part of africa there are only two seasons in a year. The term green season is also sometimes used as a euphemism by tourist authorities. We previously discovered a similar strengthening of the sahara heat low was linked with later wet seasons over west africa dunning et al. The climate observed is the result of the interactions between the ocean, the land and the atmosphere. Southern africa is particularly susceptible to climate variability and drought and is increasingly being threatened by desertification processes, degradation of land and water resources and loss of biodiversity.

The most important consequence of this shifting is the annual alteration of. It is located between 5 and 25 degrees latitude, in central. Jul, 2019 walker also found that asian monsoon seasons were often linked to drought in australia, indonesia, india, and parts of africa. Monsoonal climate seasons in the top end of the northern territory are generally known as the wet and the dry. In the dry season only an average of about 4 inches of rain falls. If it were not for the change in wind direction when the southeast trades have crossed the equator, the monsoon system of west africa could not be distinguished from the weather system, caused by the seasonal shift in the latitude of the intertropical convergence, as experienced over most of central africa. Differences between anomalously wet and dry rainy seasons over the period 19612001 in equatorial east africa kenya, northern tanzania are studied at local scale using a 53 raingauge network and analysing six intraseasonal characteristics iscs. What is the reason for alternating wet and dry seasons in savanna type climate.

The a stands for a tropical climate, and the w for a dry season in the winter. At the equator there are two wet and two dry seasons, as the rain belt passes over twice a year, once moving north and once moving south. But even then, its nowhere as low as winter temperatures in europe. Later wet seasons with more intense rainfall over africa. Winter temperatures are usually between 30 and 65 degrees. African safari guide africa rainy season safari seasons. The climate of nigeria, in west africa on the gulf of guinea, is tropical,and it tends to be hot all yearround.

Villagers pass a submerged rice paddy during a monsoon in nischintapur, bangladesh. Changing wet and dry seasons may 30, 2017 extremes, precipitation ed hawkins the fickle nature of weather patterns is ultimately responsible for the where and when of tropical rainfall extremes which wreak damage on agriculture, infrastructure and people. African savanna climate the savanna biome has a wetdry climate. This lack of water and hence of food may force many grazing animals to migrate to more fertile spots. It is located between 5 and 25 degrees latitude, in central and south america, africa, australia and asia. The characteristic four seasons of the continental united states give way in southernmost florida to only two seasons. Climate types for kids tropical wet and dry climate. At the gulf of guinea, precipitation is abundant yearround without a marked dry season. A delay in the wet season over west africa and the sahel of over 510 days on average, and later onset of the wet season over southern africa, is identified and associated with increasing strength of the saharan heat low in late boreal summer and a northward shift in the position of the tropical rain belt over augustdecember. Its highlands receive more rainfall than the lowlands, while the saharan regions receive the. Uganda has a springlike climate year round and has a less obvious wet and dry season. The tropical wet and dry climate is part of the climate classification system that groups climates based on vegetation. The climate of nigeria, in west africa on the gulf of guinea, is tropical, and it tends to be hot all yearround.

Characteristics of wet and dry spells in west africa 127 rainy season is observed from june to september to thenorth. During the wet season, a lot of rain falls, causing rivers to fill up or even flood. Climate, climate change, the dry and wet seasons in west africa 2 on february 27, 20 12. However, depending on your destination, the dry season has its own drawbacks, ranging from intense heat to severe drought. Jacob bjerknes, a norwegian meteorologist, would later recognize that the circulation of winds, rain, and weather was part of a pacificwide air circulation pattern he called walker circulation. Drought impact mitigation and prevention in the limpopo. Rainfall decline over eastern africa linked to shorter wet. When they do, the dry season occurs mostly during winter. In summer, moist equatorial air masses originating over the atlantic ocean bring annual monsoon rains nicholson, 20. Its highlands receive more rainfall than the lowlands, while the. Vegetation, wildlife and human life are quite different from monsoon.

Jan 10, 2016 so rainfall decreases from east to west here. The first, is the hot, dry tropical continental air mass of the northern high pressure system, which gives rise to the dry, dusty, harmattan winds which blow from the sahara over most of west africa from november to february. The country is quite dry, with rainfall averages at around 464mm or less. Miami, for example, receives only about 26 percent of its average annual rain in a sixmonth period from november through april. The southern parts have one wet season and one dry season whereas east africa will have the dry season but also have two wet seasons. Often, the rainy season is the most scenic time to visit africas wild places, as it causes flowers to bloom and parched brush to turn green again. Over land, the line is distorted because of the interaction between the tropical rain belt and monsoon circulations. The tropical rain belt migrates north and south of the equator as the seasons change, leading to pronounced wet and dry seasons in many tropical countries. The main characteristics of the west african seasons have been known to the scientific community for more than two centuries.