Dry season

The dry season is a yearly period of low rainfall, especially in the tropics. The weather in the tropics is dominated by the tropical rain belt, which moves from the northern to the southern tropics and back over the course of the year. The tropical rain belt lies in the southern hemisphere roughly from October to March; during that time the northern tropics have a dry season with sparser precipitation, and days are typically sunny throughout. From April to September, the rain belt lies in the northern hemisphere, and the southern tropics have their dry season. Under the Köppen climate classification, for tropical climates, a dry season month is defined as a month when average precipitation is below 60 millimetres (2.4 in).[1]

During the dry season, humidity is very low, causing some watering holes and rivers dry up. This lack of water (and hence of food) may force many grazing animals to migrate to more fertile spots. Examples of such animals are zebras, elephants,[2] and wildebeest. Because of the lack of water in the plants, bushfires are common.[3]

Data shows that in Africa the start of the dry season coincides with a rise in the cases of measles—which researchers believe might be attributed to the higher concentration of people in the dry season, as agricultural operations are all but impossible without irrigation. During this time, some farmers move into cities, creating hubs of higher population density, and allowing the disease to spread more easily.[4]

The rain belt reaches roughly as far north as the Tropic of Cancer and as far south as the Tropic of Capricorn. Near these latitudes, there is one wet season and one dry season annually. 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. Between the tropics and the equator, locations may experience a short wet and a long wet season; and a short dry and a long dry season. Local geography may substantially modify these climate patterns, however.

New data shows that in the seasonal parts of the South American Amazon forest, foliage growth and coverage varies between the dry and wet seasons—with about 25% more leaves and faster growth in the dry season. Researchers believe that the Amazon itself has an effect in bringing the onset of the wet season: by growing more foliage, it evaporates more water.[5] However, this growth appears only in the undisturbed parts of the Amazon basin, where researchers believe roots can reach deeper and gather more rainwater.[6] It has also been shown that ozone levels are much higher in the dry than in the wet season in the Amazon basin.[7]

References

  1. ^ "Updated world Köppen-Geiger climate classification map" (PDF).
  2. ^ TONY RENNELL (June 29, 2007). "It's dry season and elephants are desperately seeking water - but poachers lie in wait". London: Daily Mail.
  3. ^ "Wet & Dry Seasons".
  4. ^ "Dry Season Brings On Measles In Sub-Saharan Africa". ScienceDaily. February 7, 2008.
  5. ^ "Amazon rainforest does have rainy and dry seasons". mongabay.com. March 12, 2007. Archived from the original on June 4, 2008.
  6. ^ "Amazon rainforest greens up in the dry season".
  7. ^ V. W. J. H. Kirchhoff, I. M. O. Da Silva, E. V. Browell (1990). "Ozone measurements in Amazonia: Dry season versus wet season". Journal of Geophysical Research. 95: 16913. Bibcode:1990JGR....9516913K. doi:10.1029/jd095id10p16913.CS1 maint: Multiple names: authors list (link)
Batticaloa Lagoon

Batticaloa Lagoon is a very large estuarine lagoon in Batticaloa District, eastern Sri Lanka. The city of Batticaloa is located on land between the lagoon and the Indian Ocean.Batticaloa district is flourished with three lagoons, such Batticaloa lagoon, Valaichchenai Lagoon and Vakari Lagoon. Among them, Batticaloa lagoon is the largest lagoon in Batticaloa District. Batticaloa lagoon is a long and narrow lagoon situated in the east coast of Sri Lanka with the total area of approximately 11,500 ha of water.

The lagoon is 56 km long. This lagoon extends from Eravur (Batticaloa district) in the north to Kalmunai (Ampara district) in the south. This lagoon opens into the sea at two points. One in the southern end of the lagoon at Kallar and the other is midway of the lagoon at Palameenmadu which is close to the Batticaloa town. Both are narrow and approximately 200 m wide. The width of the water flow at their openings varies with the seasons. During the dry season the width of the bar mouth of the lagoon decreases and gradually it get closed with the onset of the north east monsoon which piles up the sand bar by the end of dry season. Later with the rains and with the lagoon mouth closed.

The lagoon is fed by a number of small rivers. It is linked to the sea by a two narrow channels, one at Batticaloa and the other at Periyakallar. During the dry season these channels are blocked by sand bars.

The lagoon is surrounded by a densely populated region used for cultivating rice, coconut and other crops. The surrounding land is used for shrimp farming and rice cultivation.

The lagoon has extensive mangrove swamps and some sea grass beds. The lagoon attracts a wide variety of water birds.

Cedrela

Cedrela is a genus of several species in the mahogany family, Meliaceae. They are evergreen or dry-season deciduous trees with pinnate leaves, native to the tropical and subtropical New World, from southern Mexico south to northern Argentina.

Charpa Falls

Charpa Falls is a waterfall located in Athirappilly panchayath in Thrissur district of Kerala. Located on the west-flowing Chalakudy River, this waterfall lies in between the more famous Athirappilly Falls and Vazhachal Falls. It is a popular stopover for tourists who are visiting the Athirappilly and Vazhachal Falls. It is located close to the road, and during monsoon months (June to August), the water splashes onto the road. During the dry season, the water stops flowing.

Climate of Brazil

The climate in Brazil varies considerably mostly from tropical north (the equator traverses the mouth of the Amazon) to temperate zones south of the Tropic of Capricorn (23°26' S latitude). Temperatures below the equator are high, averaging above 25 °C (77 °F), but not reaching the summer extremes of up to 40 °C (104 °F) in the temperate zones. There is little seasonal variation near the equator, although at times it can get cool enough to need to wear a jacket, especially in the rain. Average temperatures below the Tropic of Capricorn are mild, ranging from 13 °C (55 °F) to 22 °C (72 °F).

At the country's other extreme, there are frosts south of the Tropic of Capricorn and during the winter (June–September). Snow falls on the high plateau and mountainous of the mountains of the states of Rio Grande do Sul, Santa Catarina, and Paraná and it is possible, but very rare, in the states of São Paulo, Rio de Janeiro, Minas Gerais, and Mato Grosso do Sul. The cities of Belo Horizonte and Brasília have moderate temperatures, usually between 15 and 30 °C (59 and 86 °F), because of their elevation of approximately 1,000 metres (3,281 ft). Rio de Janeiro, Recife, and Salvador on the coast have warm climates, with average temperatures of each month ranging from 23 to 27 °C (73 to 81 °F), but enjoy constant trade winds. The cities of São Paulo, Curitiba, Florianópolis and Porto Alegre have a subtropical climate similar to that of southern United States, and temperatures can fall below freezing in winter.Precipitation levels vary widely. Most of Brazil has moderate rainfall of between 1,000 and 1,500 mm (39 and 59 in) a year, with most of the rain falling in the summer (between December and April) south of the Equator. The Amazon region is notoriously humid, with rainfall generally more than 2,000 mm (79 in) per year and reaching as high as 3,000 mm (118 in) in parts of the western Amazon and near Belém. It is less widely known that, despite high annual precipitation, the Amazon forest has a three- to five-month dry season, the timing of which varies according to location north or south of the equator.

High and relatively regular levels of precipitation in the Amazon contrast sharply with the dryness of the semiarid Northeast, where rainfall is highly erratic and there are severe droughts in cycles averaging seven years. The Northeast is the driest part of the country. The region also constitutes the hottest part of Brazil, where during the dry season between May and November, temperatures of more than 38 °C (100 °F) have been recorded. However, the sertão, a region of semidesert vegetation used primarily for low-density ranching, turns green when there is rain. Most of the Center-West has 1,500 to 2,000 mm (59 to 79 in) of rain per year, with a pronounced dry season in the middle of the year, while the South and most of the East is without a distinct dry season.

Because the South Atlantic basin is generally not a favorable environment for their development, Brazil has only rarely experienced tropical cyclones. The country's coastal population centers are therefore not as burdened with the need to prepare for cyclones, as are cities at similar latitudes in the United States and Asia.

Climate of Zambia

The climate of Zambia in Central and Southern Africa is definitely tropical modified by altitude (elevation). In the Köppen climate classification, most of the country is classified as humid subtropical or tropical wet and dry, with small patches of semi-arid steppe climate in the south-west.

Climate and specifically rainfall amount is the chief determinant of type and distribution of the ecoregions of Zambia.

So technically Zambia is a very arid country with a humid and subtropical year with small patches of semi arid steppe.

Climate of the Philippines

The Philippines has five types of climates: tropical rainforest, tropical monsoon, tropical savanna, humid subtropical, and oceanic (both are in higher-altitude areas) characterized by relatively high temperature, oppressive humidity and plenty of rainfall. There are two seasons in the country, the wet season and the dry season, based upon the amount of rainfall. This is also dependent on location in the country as some areas experience rain all throughout the year (see Climate types). Based on temperature, the warmest months of the year are March through October; the winter monsoon brings hotter air from November to February. May is the warmest month, and January, the coolest.Weather in the Philippines is monitored and managed by Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

Elbow Falls

Elbow Falls is a small set of waterfalls along the Elbow River, west of the hamlet of Bragg Creek within Kananaskis Improvement District, Alberta. They are located along Highway 66, 20 km (12 mi) west of the Bragg Creek turnoff on Highway 22.

In the dry season, the falls reach a height of 6 meters (20 ft), while in June, during high discharges, the river fills up and the waterfall is only 3 m (9.8 ft) high.A day use area (i.e. picnics) is maintained at the falls site, and also serves as the start/finish of a short 1 km (0.62 mi) long hiking trail. Overnight camping is available at several nearby campgrounds.After the 2013 Alberta floods, the day use area was destroyed. The Elbow River overflowed its banks and destroyed all of the picnicking area and most of the paved trails. The riverbed itself also suffered major destruction, now being replaced by mounds of rock, rather than soil and trees.

Evergreen

In botany, an evergreen is a plant that has leaves throughout the year that are always green. This is true even if the plant retains its foliage only in warm climates, and contrasts with deciduous plants, which completely lose their foliage during the winter or dry season. There are many different kinds of evergreen plants, both trees and shrubs. Evergreens include:

most species of conifers (e.g., pine, hemlock, blue spruce, and red cedar), but not all (e.g., larch)

live oak, holly, and "ancient" gymnosperms such as cycads

most angiosperms from frost-free climates, such as eucalypts and rainforest trees

clubmosses and relativesThe Latin binomial term sempervirens, meaning "always green", refers to the evergreen nature of the plant, for instance

Cupressus sempervirens (a cypress)

Lonicera sempervirens (a honeysuckle)

Sequoia sempervirens (a sequoia)Leaf persistence in evergreen plants varies from a few months to several decades (over thirty years in the Great Basin Bristlecone Pine).

Geography of Nigeria

Nigeria is a country in West Africa. Nigeria shares land borders with the Republic of Benin in the west, Chad and Cameroon in the east, and Niger in the north. Its coast lies on the Gulf of Guinea in the south and it borders Lake Chad to the northeast. Noted geographical features in Nigeria include the Adamawa highlands, Mambilla Plateau, Jos Plateau, Obudu Plateau, the Niger River, River Benue and Niger Delta.

Nigeria is found in the Tropics, where the climate is seasonally damp and very humid.

Nigeria is affected by four climate types; these climate types are distinguishable, as one moves from the southern part of Nigeria to the northern part of Nigeria through Nigeria's middle belt.

Gombe State

Gombe, usually referred to as Gombe State to distinguish it from the city of Gombe, is located in the northeastern part of Nigeria, is one of the country's 36 states; its capital is Gombe. The boundaries of the state roughly correspond to those of the Tangale-Waja Chiefdom and Gombe Emirate, a traditional state.

The State, nicknamed the Jewel of Excellence, was formed in October 1996 from part of the old Bauchi State by the Abacha military government. Its location in the north eastern zone, right within the expansive savannah, allows the state to share common borders with the states of Borno, Yobe, Taraba, Adamawa and Bauchi. The state has an area of 20,265 km² and a population of around 2,365,000 people as of 2006. Gombe has two distinct climates, the dry season (November–March) and the rainy season (April–October) with an average rainfall of 850mm. The State is headed by the Executive Governor Ibrahim Hassan Dankwambo and also has 24 State House Assembly members. Gombe has 11 Local Government Areas and 14 Emirates /chiefdoms. It has 3 Senators and 6 Members in the National Assembly.

Guelta

A guelta (Arabic: قلتة‎, also transliterated qalta or galta; Berber: agelmam) is a pocket of water that forms in drainage canals or wadis in the Sahara. The size and duration will depend on the location and conditions. It may last year-round through the dry season if fed by a source such as a spring. When a river (wadi) dries up, there may be pockets of water remaining along its course (c.f. oxbow lake). In Western Sahara, gueltas correspond with oases.Some examples include Guelta d'Archei in Chad and Timia in Niger.

Harmattan

The Harmattan is a season in the West African subcontinent, which occurs between the end of November and the middle of March. It is characterized by the dry and dusty northeasterly trade wind, of the same name, which blows from the Sahara Desert over West Africa into the Gulf of Guinea. The name is related to the word haramata in the Twi language. The temperature is cold in most places, but can also be hot in certain places, depending on local circumstances.The Harmattan blows during the dry season, which occurs during the lowest-sun months. In this season the subtropical ridge of high pressure stays over the central Sahara Desert and the low-pressure Intertropical Convergence Zone (ITCZ) stays over the Gulf of Guinea. On its passage over the Sahara, the harmattan picks up fine dust and sand particles (between 0.5 and 10 microns).

Meliaceae

Meliaceae, the mahogany family, is a flowering plant family of mostly trees and shrubs (and a few herbaceous plants, mangroves) in the order Sapindales.

They are characterised by alternate, usually pinnate leaves without stipules, and by syncarpous, apparently bisexual (but actually mostly cryptically unisexual) flowers borne in panicles, cymes, spikes, or clusters. Most species are evergreen, but some are deciduous, either in the dry season or in winter.

The family includes about 53 genera and about 600 known species, with a pantropical distribution; one genus (Toona) extends north into temperate China and south into southeast Australia, another (Synoum) into southeast Australia, and another (Melia) nearly as far north.

Season

A season is a division of the year marked by changes in weather, ecology, and amount of daylight. On Earth, seasons result from Earth's orbit around the Sun and Earth's axial tilt relative to the ecliptic plane. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations.

During May, June, and July, the Northern Hemisphere is exposed to more direct sunlight because the hemisphere faces the Sun. The same is true of the Southern Hemisphere in November, December, and January. It is Earth's axial tilt that causes the Sun to be higher in the sky during the summer months, which increases the solar flux. However, due to seasonal lag, June, July, and August are the warmest months in the Northern Hemisphere while December, January, and February are the warmest months in the Southern Hemisphere.

In temperate and subpolar regions, four seasons based on the Gregorian calendar are generally recognized: spring, summer, autumn or fall, and winter. The definition of seasons is also cultural. In India from the ancient times, six seasons or Ritu based on south Asian religious or cultural calendars are recognised and identified even today for the purposes such as agriculture and trade. Ecologists often use a six-season model for temperate climate regions which are not tied to any fixed calendar dates: prevernal, vernal, estival, serotinal, autumnal, and hibernal. Many tropical regions have two seasons: the rainy, wet, or monsoon season and the dry season. Some have a third cool, mild, or harmattan season. Seasons often held special significance for agrarian societies, whose lives revolved around planting and harvest times, and the change of seasons was often attended by ritual.

In some parts of the world, some other "seasons" capture the timing of important ecological events such as hurricane season, tornado season, and wildfire season. The most historically important of these are the three seasons—flood, growth, and low water—which were previously defined by the former annual flooding of the Nile in Egypt.

Seasonal tropical forest

Seasonal tropical forest: also known as moist deciduous, semi-evergreen seasonal, tropical mixed or monsoon forests, typically contain a range of tree species: only some of which drop some or all of their leaves during the dry season. This tropical forest is classified under the Walter system as (ii) tropical climate with high overall rainfall (typically in the 1000–2500 mm range; 39–98 inches) concentrated in the summer wet season and cooler “winter” dry season: representing a range of habitats influenced by monsoon (Am) or tropical wet savannah (Aw) climates (as in the Köppen climate classification). Drier forests in the Aw climate zone are typically deciduous and placed in the Tropical dry forest biome: with further transitional zones (ecotones) of savannah woodland then tropical and subtropical grasslands, savannas, and shrublands.

Semi-deciduous

Semi-deciduous or semi-evergreen is a botanical term which refers to plants that lose their foliage for a very short period, when old leaves fall off and new foliage growth is starting. This phenomenon occurs in tropical and sub-tropical woody species, for example in Mimosa bimucronata. Semi-deciduous or semi-evergreen may also describe some trees, bushes or plants that normally only lose part of their foliage in autumn/winter or during the dry season, but might lose all their leaves in a manner similar to deciduous trees in an especially cold autumn/winter or severe dry season (drought).The term is also used to indicate a forest that consists of a mixture of deciduous and evergreen woody plants in the tropics and semi-tropics. It differs in its use from a mixed forest, a term usually applied to woods that contain both conifers and broad-leaved trees.

Such forests receive less than 150 cm rainfall. Saagwan, Saal, Bamboo etc. are found in these forests.

Tropical climate

A tropical climate in the Köppen climate classification is a non-arid climate in which all twelve months have mean temperatures of warmer than 18 °C (64 °F). In tropical climates there are often only two seasons: a wet season and a dry season. Tropical climates are frost-free, and changes in the solar angle are small. In tropical climates temperature remains relatively constant (hot) throughout the year. Sunlight is intense.

Tropical savanna climate

Tropical savanna climate or tropical wet and dry climate is a type of climate that corresponds to the Köppen climate classification categories "Aw" and "As".

Tropical savanna climates have monthly mean temperatures above 18 °C (64 °F) in every month of the year and typically a pronounced dry season, with the driest month having less than 60 mm (2.36 inches) of precipitation and also less than 100 – [total annual precipitation {mm}/25] of precipitation. This latter fact is in direct contrast to a tropical monsoon climate, whose driest month sees less than 60 mm of precipitation but has more than 100 – [total annual precipitation {mm}/25] of precipitation. In essence, a tropical savanna climate tends to either see less rainfall than a tropical monsoon climate or have more pronounced dry season(s).

In tropical savanna climates, the dry season can become severe, and often drought conditions prevail during the course of the year. Tropical savanna climates often feature tree-studded grasslands, rather than thick jungle. It is this widespread occurrence of tall, coarse grass (called savanna) which has led to Aw and As climates often being referred to as tropical savanna. However, there is some doubt whether tropical grasslands are climatically induced. Additionally, pure savannas, without trees, are the exception rather than the rule.

Wet season

The monsoon season is the time of year when most of a region's average annual rainfall occurs. Generally the season lasts at least a month. The term "green season" 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 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 the season. Rivers overflow their banks, and some animals retreat to higher ground. Soil nutrients diminish and erosion increases. The incidence of malaria 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 the wet season, as the crops have yet to mature.

Temperate seasons
Tropical seasons
Specific

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.