Transcript 3A06

The Geography project
To study how climatic conditions
affecting the types of vegetation in the
arid and humid regions
The name lists
Ho Kin Tao (Chris) (3)
Leung Pak Hei (Marco) (5)
Kwan Pak Yan (Zoe) (25)
Tang Cheuk Yiu (Yoyo) (28)
Yuen Sau Yan (Eliza) (35)
Climate condition of arid region
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An arid climate also called desert climate and in which precipitation
is too low to sustain any vegetation at all, or at most a very scanty
scrub.
Severe lack of rainwater and moisture
less than 250 mm (10 inches) per year of precipitation
in some years may experience no precipitation at all.
an area may experience more than 250 mm of precipitation annually,
but is considered an arid climate because the region loses more
water via evapotranspiration than falls as precipitation
Desert climate (arid climate) can be divided into hot desert climate
and cold desert climate
Hot desert climates are typically found under the subtropical ridge
where there is largely unbroken sunshine for the whole year due to
the stable descending air and high pressure. Such areas include the
Sahara Desert, Northern Mexico, and much of Australia. These
areas are located between 30 degrees south and 30 north latitude Hot
desert climates are globally hot, sunny and dry year-round.
Climate condition of arid region
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Hot desert climates feature hot and dry. In many locations featuring
a hot desert climate, maximum temperatures of 40 °C (104 °F) to 45
°C (113 °F) are common in summer. During colder periods of the
year, night-time temperatures can drop to freezing or below due to
the exceptional radiation loss under the clear skies.
Cold desert climates can feature hot , dry summers, and cold winter
, sometimes brutally cold, dry winters with temperatures far below
the freezing point. Cold deserts are typically found at higher
altitudes than hot desert climates, and are usually drier than hot
desert climates.
A cold desert climate is typically found in temperate zones, almost
always in the rain shadow of high mountains which restrict
precipitation from the westerly winds, or in the case of Central Asia,
from the monsoon. e.g the Gobi desert.
Location of Arid region
Climate condition of humid region
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Humid climate are characterized by a warm and wet climate.
Rainfall is heavy in all months. The total annual rainfall is often
more than 250 cm. (100 in.). There are seasonal differences in
monthly rainfall but temperatures of 27°C (80°F) mostly stay the
same. Humidity is between 77 and 88%.
High surface heat and humidity cause cumulus clouds to form early
in the afternoons almost every day.
The climate on eastern sides of continents are influenced by
maritime tropical air masses. These air masses flow out from the
moist western sides of oceanic high-pressure cells, and bring lots of
summer rainfall. The summers are warm and very humid. It also
rains a lot in the winter
 Average temperature: 18 °C (°F)
 Annual Precipitation: 262 cm. (103 in.)
 Latitude Range: 10° S to 25 ° N
 Humidity is between 77 and 88%.
 Global Position: Amazon Basin; Congo Basin of equatorial
Africa; East Indies, from Sumatra to New Guinea.
Location of humid region
Major characteristics of vegetation in arid region
Arid Region
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Trunk and stem: thick
Leave : most of them have small and with needle-shaped
(Cactus)
Some plants develop a waxy resin
Root : long and in the deep part of the soil,
widespread.
e.g. Echinocactus grusonii (Golden Ball Cactus), Opuntia
tuna, Haworthia bolusii.
Dry Plant
Dry Plant
Major characteristics of vegetation in humid region
Humid Region
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Evergreen
Trunk : thick, some of them have tall trunk.
Leave : board and with drip-tip, some of them have wax on
their surface.
Root : some of them have shallow and buttress root.
e.g. Dieffenbachia picta (Dieffenbachia), Asparagus falcatus,
Codiaeum variegatum (Garden Croton) .
Humid Plant
Humid Plant
How the characteristics of vegetation are related to the
climatic condition in arid region?
Climate condition of the arid region
Major characteristics of vegetation in
arid region
Extremely dry (annual rainfall less than
250mm)
Due to lack of water and high evaporation
rate:
Some plants have shallow roots, they
spread over a wide area. The roots of
plants which have a tap root system can go
as deep as 30 meters under the surface of
the earth to draw water.
High evaporation rate
Some plants adapt their leaves in such a
way that they become needle-shaped,
which reduces the surface area of leaves
exposed to the sun so as to curb
evaporation.
Some plants develop a waxy resin which
help in minimizing water evaporation.
Thick truck and stem (e.g. cactus) used for
storing water.
How the characteristics of vegetation are related to the climate
condition in humid region?
Climate condition of the humid region
Major characteristics of vegetation in
humid region
Hot and wet throughout the year
Evergreen
High annual amount of rainfall
Plants grow luxuriantly and continuously
under the continuous hot and wet climate
Rich diversity of plant species (hot and
humid climate results in rich diversity of
plant species
Trees have shallow roots (able to nutrients
up from the topsoil)
Trees have buttress roots (provide strong
support for the tall trees)
Broad , waxy leaves with drip tips help
shed excess water from leaves.
Visit to the Foregate Conservatory of the Hong
Kong Park (Dry Plant House)
Visit to the Foregate Conservatory of the Hong
Kong Park (Humid Plant House)
~The End~