Wet season | Wikipedia audio article

Wet season | Wikipedia audio article


The wet season (sometimes called the rainy
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.==Character of the rainfall==In areas where the heavy rainfall is associated
with a wind shift, the wet season is known as the monsoon. Many tropical and subtropical climates experience
monsoon rainfall patterns. Rainfall in 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 savannah and monsoon
regions. Further, 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 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 affected==
Areas with a savanna climate in Sub-Saharan Africa, such as Ghana, Burkina Faso, Darfur,
Eritrea, Ethiopia, and Botswana have a distinct rainy season. Also subtropical areas like Florida, South
and Southeast Texas, and southern Louisiana have a rainy season. Monsoon regions include the Indian subcontinent,
Southeast Asia (including Indonesia and Philippines), northern sections of Australia’s North, Polynesia,
Central America, western and southern Mexico, the Desert Southwest of the United States,
southern Guyana, portions of 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 and the Mediterranean coastline of Italy, Greece, and Turkey experience
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 is known as “storm
season”. Different names are given to the various short
“seasons” of the year by the Aboriginal tribes 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.==Effects==In tropical areas, when 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 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 the heavy rainfall runoff.===Floods===
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 the internet.==Life adaptations=====Humans===
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.===Animals===
Cows calve, or give birth, at 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 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.==See also==
Akhet East Asian rainy season
Dry season

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