Weather, climate and natural vegetation revision

Question 1

Weather

Answer 1

The current conditions of the atmosphere

Question 2

Climate

Answer 2

The average weather conditions

Question 3

Anemometer
(wind speed)

Answer 3

An anemometer is used to measure wind speed.
* When there is wind the cups rotate, The stronger the wind the faster the rotation.
* The number of rotations is recorded on a meter to give the speed in kmph.
* An anemometer should be placed well away from buildings or trees that may interfere with the free movement of air – buildings may channel air through narrow passages between two buildings or decrease the flow of air by blocking its path.
* Winds are shown by arrows on a weather map – the shaft of the arrow shows wind direction and the feathers on the arrow indicate wind speed.

Question 4

Wind vane
(wind direction)

Answer 4

• A wind vane is used to measure wind direction.
• A wind vane has the points of the compass (i.e. NESW) fixed and sited so that they point in the correct directions.
• Winds are shown by arrows on a weather map – the shaft of the arrow shows wind direction and the feathers on the arrow indicate wind speed.

Question 5

Barometer (air
pressure)

Answer 5

• Pressure is the amount of air pressing down on the earth’s surface.
• The unit of measurement for air pressure is millibars (MB)
• The mean average pressure at sea level is said to be 1013 mb, so pressures below these are usually said to be low and pressures above this high.
• Low air pressure is associated with unsettled conditions (as warm air is rising off the surface of the earth – which later cools and condenses forming clouds and potentially rain).
• High pressure is associated with settled/clear conditions as cool air is descending and warming up.
  Lines are drawn through points where pressure is the same – these lines are called isobars.

Question 6

Wet-dry
thermometer
/hygrometer
(relative
humidity)

Answer 6

Humidity is the amount of water vapour in a given volume of air.
* Water vapour is an invisible gas. The amount of water vapour that any air can hold depends on the temperature – warm air can hold more water vapour than cold air.

When air is cooled the amount of water vapour that it can hold reduces. If the air is cool sufficiently it reaches the maximum amount of moisture that is can hold – this is called dew point. Any further cooling will result in condensation – a process by which excess water vapour turns into water droplets or ice depending on the temperature of the air.

The relative humidity of the air is expressed as a percentage. When air is saturated the relative humidity is 100%.

If the air is not saturated water will evaporate from the muslin.
* Evaporation causes cooling of the bulb which causes the mercury to contract and register a lower temperature.
* The temperature of the wet bulb minus the temperature of the dry bulb temperature gives the depression of the wet bulb. The larger this is, the lower the relative humidity will be.

Question 7

Maximum-
minimum thermometer
(temperature)

Answer 7

Show the highest and lowest temperatures reached.
The instrument is read at eye level from the lower end of each index.
* It is reset by using a magnet to draw each index back to the mercury.
* Lines can be drawn on a map connecting areas of equal temperature – these lines are called isotherms.

Question 8

Rain gauge
(precipitation)

Answer 8

• Amounts of precipitation e.g. rain, snow, sleet or hail are measured using a range gauge.
  *The gauge is sunk into the ground so that the top of the funnel is about 30cm above ground level. This is to prevent water splashing on the ground and then entering the funnel.
• Rainfall collects in the jar and this is usually emptied every 24
  hours.

Question 9

Sunshine
recorder
(sunshine)

Answer 9

The number of hours and minutes of sunshine received at a place can be measured on a sunshine recorder.
* A strip of special card, divided into hours and minutes is placed below the sphere.
* When the sun shines, the sphere focuses the sun’s rays on the card.
* As the sun moves, the rays burn a trace on the card. At the end of the day the card is removed and replaced.
* The length of the trace represents the amount of sunshine the area received.

Question 10

The main clouds that you need to be aware of are:

Answer 10

Stratus: These are layered clouds that are low, grey and shapeless and usually are like a blanket of cloud over an area. They can bring some drizzle and rain.

Cumulus: These are clouds that move quite quickly. They are white and fluffy and look like cotton wool. They can bring rain showers – especially when the base is grey.

Cumulonimbus: These are much deeper clouds that climb high into the atmosphere. They often contain a lot of heavy rain and are associated with thunder and lightning storms.

Cirrus: These are very high clouds that are wispy and made up from ice crystals.

Question 11

Stevenson screen adaptation

Answer 11

Made of wood. It is a bad conductor of heat.
Painted white. To reflect sun rays.
Has slates/louvres. To allow free circulation of air.
Has a double roof. For insulation.
Placed 1.21m above the ground too avoid flooding
The door of the screen faces South in the Southern hemisphere and North in the Northern hemisphere.
In a fenced area to avoid human contact
On grass so that the ground absorbs heat

Question 12

Cloud cover

Answer 12

Cloud cover is observed (not measured) in units called oktas. Each okta represents one-eighth of the sky covered by clouds.

Question 13

Synoptic chart

Answer 13

A map that summarises atmospheric conditions

Question 14

Factors influencing climate

Answer 14

Latitude
Prevailing wind
Distance from sea
Relief
Ocean currents

Question 15

Presenting climate data

Answer 15

Bars: Rainfall
Line: Temperature

Question 16

Relief rainfall

Answer 16

• Relief rainfall occurs when air has been blown over the sea and is then forced up over an area
  of high land.
• This causes the air to cool and the moisture in the air condenses and rain falls.

Question 17

Frontal rainfall

Answer 17

• Frontal rainfall occurs when warm air is forced to rise over cold air.
• The moisture in the warm air condenses as it cools which causes clouds and rain.

Question 18

Convectional rainforests

Answer 18

• Occurs mostly in tropics where it is hot.
• When air is hot is rises and cools and condenses forming rain.
• If the air is hot enough, it rises very quickly and can cause thunderstorms.

Question 19

Tropical rainforest: Location:

Answer 19

• Along the equator and between the tropics
• Main areas are northern South America (e.g. Amazon), Central Africa (e.g. Congo) and South
  East Asia.

Question 20

Tropical rainforest climate:

Answer 20

• Consistently high temperatures throughout the year – an average of about 25°C
• Annual temperature range: less than 5°C
  Rainfall – amount exceeds 2000mm
• Rainfall– seasonal distribution: fairly evenly distributed throughout the year
• Wind: low
  Cloud: heavy
  Humidity: high
• Pressure: low
• Little seasonal variation

Question 21

Rainforests typically receive convectional rainfall:

Answer 21

Stage 1.
The sun heats the ground, and warm air rises.
Stage 2.
As the air rises, it cools, and water vapour condenses to form clouds.
Stage 3.
When the condensation point is reached, large cumulonimbus clouds are formed.
Stage 4.
Heavy rainstorms occur. These usually include thunder and lightning due to the electrical charge created by unstable conditions.

Convectional rainfall is widespread in areas where the ground is heated by the hot sun,
such as the Tropics. This is why areas, such as the Amazon Rainforest, experience heavy
rainfall most afternoons.

Question 22

Layers of rainforest

Answer 22

Emergent trees
Canopy
Under canopy
Shrub layer/ Forest floor

Question 23

Nutrients cycle

Answer 23

Nutrients are the goodness that plants need to grow.

Most nutrients in rainforests are not held in the soil, but instead in the biomass.

When plants and animals die they decompose on the forest floor.

The mixing of dead organic material and weathered rock in the soil leads to the development of nutrients.

Nutrients are then taken up by shallow plant roots, providing plants with the goodness they need to grow.

Question 24

Plant adaptations of rainforest

Answer 24

*Lianas - these are woody vines that have roots in the ground but climb up the trees to reach the sunlight. Their leaves and flowers grow in the canopy.

*Tree trunks - these are tall and thin to allow trees to reach the sunlight. The bark on these trees is smooth to allow water to flow down to the roots easily.

*Drip tips - plants have leaves with pointy tips. This allows water to run off the leaves quickly without damaging or breaking them.

*Buttress roots - large roots have ridges which create a large surface area that help to support large trees.

*Epiphytes - these are plants which live on the branches of trees high up in the canopy. They get their nutrients from the air and water, not from the soil.

Question 25

Animal adaptations of rainforest

Answer 25

The sloth uses camouflage and moves very slowly to make it difficult for predators to spot.
The spider monkey has long, strong limbs to help it to climb through the rainforest trees.
The flying frog has fully webbed hands and feet, and a flap of loose skin that stretches between its limbs, which allows it to glide from plant to plant.
The toucan has a long, large bill to allow it to reach and cut fruit from branches that are too weak to support its weight.

Question 26

Effects of deforestation/ resource extraction in the tropical rainforest:

Answer 26

Tropical rainforests are fragile environments as they are easily disturbed by human activity. Areas like the Amazon basin in Brazil are under pressure because they not only have valuable timber resources but also minerals such as
gold, iron ore, oil and gas.
In the Oriente region of the Amazon in Ecuador Oil has discharged 4.3 million barrels of toxic waste into the environment each day.
Toxic contaminants in drinking water have reached 1,000 times the safe standard Increases in gastrointestinal problems, skin rashes, birth defects and cancers (stomach cancer 5x more in areas with oil extraction).
Miscarriage is high amongst indigenous
people such as Huaorani.
Plants such as periwinkle (used to cure childhood leukaemia) are now endangered.
The oil has only benefitted a few- many have become poorer- social inequalities. Only 20 years of oil left in the Amazon.
The reason it happens is because of the need for development in this LEDC area (the benefits outweigh the costs) and the needs for resources from this area

Question 27

The climate of the tropical rainforest Amazon rainforest (e.g. Ecuador)

Answer 27

The Equatorial Climate is characterised by hot average temperature all year round and high monthly precipitation, typically no less than 60 mm a month with annual precipitation tending to be over 2000mm.

The Hadley cell means that at the equator, air is heated by the sun and forced to rise causing low
pressure.
As the heated air rises, it cools, condenses and forms huge storm clouds and rains causing rainforests.

High levels of soil moisture and interception of rainfall from the dense vegetation leads to transpiration (evaporation of water held in the leaves of plants).

This leads to a repetitive climate pattern of hot humid air, dry but misty mornings and late afternoon downpours and conventional storms.

Question 28

Case Study of the Napo region in Ecuador, an ecotourism area within the Yasuni National Park

Answer 28

● The Rio Napo region is situated at the western extreme of Amazonia where it has extraordinarily rich tropical forests.
● There has been a lot of oil exploration and deforestation in the past
● This was destroying the traditional lifestyles of the locals (Quichua people).
● The NGO Action Aid helped to develop an eco-tourism project to stop this from continuing and to provide a sustainable income for the Quichua people.
● The Napo Wildlife Centre is a 100% community-owned lodge which is located inside the Yasuni
National Park deep in the Ecuadorian Amazon.
● All money goes to the local community so all Quicha people benefit with education and healthcare.
● 85-93% of locals make up workforce, so a lot of employment has been made by eco-tourism
scheme.
● The lodge has an environmentally sustainable sewage system and all waste water is treated to the highest standard in order to keep the swamps clean.
● Rubbish is kept to a minimum and they compost what they can, burn and bury what is safe to burn, and pack the remainder to designated landfills.
● Solar panels and diesel generations provide power.

Question 29

Hot Desert Climate:

Answer 29

Location: between 5° and 30° north and south of the equator
Mean temperature of the hottest month: 30°C
Mean temperature of the coldest month: no less than 18°C
NOTE: during the day it can get to 50°C but during the night it gets to about 0°C so the average is lower.
Rainfall – amount: less than 250mm in a year
Rainfall – seasonal distribution: irregular rainfall
Wind: strong
Cloud: virtually cloudless skies
Humidity: low
Pressure: high

Question 30

Contributing factors: to desert climate

Answer 30

• distance from oceans;
• winds blow over large areas of land;
• winds blow offshore/do not blow from sea hence no source of moisture/water sources;
• low humidity;
• lack of evaporation;
• sparse vegetation;
• lack of transpiration;
• high air pressure;
• descending air;
• rain shadow effect;
• cold offshore currents

Question 31

What is a desert?

Answer 31

A dry area with less than 250mm of rainfall.

Question 32

Describe where deserts are found

Answer 32

Hot deserts are typically located 15- 30 degrees north and south of the equator in tropical and sub-tropical regions,

for example the Sahara Desert in northern Africa and the Arabian Desert in the Middle East.

Some deserts are found at a higher latitude, these are cold deserts such as the Gobi Desert in Asia.

Many deserts are found on the western edges of continents e.g., the Atacama in South America.

Question 33

Why are deserts found in certain locations?

Answer 33

Most hot deserts are found between 15-30° north and south of the equator. This is because of atmospheric circulation within the Hadley cell.

Warm air rises at the equator and cools producing clouds and rainfall over the equator.

However, some of this cooled air spreads out towards the tropics and sinks back down.

This creates high-pressure areas, characterized by cloudless skies and an absence of rainfall.

It is these sub-tropical regions where deserts are located.

Question 34

Rain shadow deserts

Answer 34

Some deserts form in the rain shadow of mountains.
Air is forced to rise over mountains, air cools and condensation occurs, rain falls over the mountains, then dry air sinks down the other side of the mountain, creating a rain shadow (area where little rainfall occurs).

Question 35

Western edge deserts

Answer 35

Some deserts are found on the western edges of continents.
They are caused by cold ocean currents, which run along the coast.
They cool the air and make it harder for the air to hold moisture.
Most moisture falls as rain before it reaches the land, e.g. the Namib Desert in Africa.

Question 36

Desert soil

Answer 36

*Desert soils are thin, sandy, rocky and generally grey in colour.
*Desert soils are very dry.
*When it does rain they soak up the water very quickly.
*The surface of the soil may appear crusty. This is due to the lack of rainfall. As it is so hot water is drawn up to the surface of the soil by evaporation. As the water evaporates, salts
are left behind on the surface of the soil.

Question 37

Typical plant adaptations in deserts

Answer 37

*Small leaves - these ensure that less water is lost from the plant by transpiration because the leaf has a smaller surface area.

*Tap roots - these are long roots (7-10 metres long) that reach deep under the ground to access water supplies. The tap roots are much longer and bigger than the plant which is
visible at the surface.

*Spines - some plants have spines instead of leaves, eg cactuses. Spines lose less water than
leaves so are very efficient in a hot climate. Spines also prevent animals from eating the
plant.

*Waxy skin - some leaves have a thick, waxy skin on their surface. This reduces water loss by
transpiration.

*Water storage - some plants, known as succulents, store water in their stems, leaves, roots or even fruits. Plants which store water in their leaves and stems also have a thick waxy
skin so that they lose less water by transpiration.

Question 38

Animal adaptations in desert

Answer 38

• Nocturnal desert animals keep cool by being active at night
• Other desert animals get away from the sun’s heat by digging underground burrows
• Some animals have big ears to help keep them cool
• Some animals have light-coloured coats to reflect rather than absorb sunlight and to protect them from
  intense heat
• Some creatures get the moisture they need from their food, so they don’t need to drink much water

Question 39

Sonoran desert

Answer 39

Located in the southwest of the United States and the north-west of Mexico. It is mostly in the state of Arizona, however, it also stretches into southern California.
* The Sonoran Desert has a subtropical climate and receives 75 to 380 mm of rain per
year.
* Most of it falls during the monsoon season (July–September), when strong, brief thunderstorms bring heavy rain.
* Lighter winter rainfall occurs in December and January.
* Frosts are rare.
* The hottest and driest part of the desert is near the lower Colorado River, where summer temperatures can reach up to 50°C and rainfall is less than 80mm.

Question 40

Plant adaptations in the Sonoran Desert:

Answer 40

Saguaro Cactus:
* The Saguaro does not need a lot of water to survive.
* When it rains the Saguaro, soaks up water and holds it in its ribs. Since it does not rain a lot in the desert, the cactus uses the water that it stores when it doesn’t rain. The Saguaro Cactus can absorb a lot of water because the ribs on the plant can expand.
* Saguaro has one taproot that is about 3 feet long to reach water underground and it also has a network of radial routes to soak up water.
* Cacti, like the Saguaro are succulents; they store water in their tissues (roots, stems, leaves or fruit).
* Spikes instead of leaves for a small surface area to minimize transpiration (water loss through
evaporation).
* Cacti’s spikes deter consumer species. Downward pointing spines make it easier to direct rainwater into the depressions of the cactus. The spines help to cool the outer skin. The spines also help redirect the wind and insulate the plant.
* Desert cacti bloom suddenly after rainfall to complete their life cycle quickly.

Prickly Pear:
* They have reduced their leaves to spines to reduce water loss and to protect the cactus.
* The roots of the prickly pear are also made for a very dry environment to help adapt to the desert’s hot weather.
* The pads of the cactus store water so that they can survive without water for longer.

Palo Verde * The bark has chlorophyll so that photosynthesis can carry on when the tree has shed its leaves during dry, hot periods
* The tree has a very deep root system to access any underground water supply
* It is drought deciduous and drops its leaves during dry hot periods so that water loss is prevented.

Question 41

Animal adaptations in the Sonoran desert

Answer 41

Gila woodpecker:
* Gila woodpeckers have strong beaks so that they can hollow out a hole in the Saguaro Cactus.
* They build their nests inside the hollow as it provides a safe, cool place for the woodpeckers to raise their young. The spines of the cactus also provide protection from predators.

Kangaroo rat:
* Kangaroo rats are nocturnal, meaning they are active at night. This is to avoid the hot desert heat during the day.
* Some desert animals are able to get all the water they need from the food they eat. Kangaroo rats are the kings of water conservation! They don’t have to drink water or eat juicy plants. Instead, the kangaroo rat’s special digestive system is able to get enough water from the seeds they eat for them
to survive.