Weather and Climate GW1

Question 1

What is the formula for relative humidity

Answer 1

Actual amount of water vapour in the air divided by the maximum amount of water vapour the air can hold

Question 2

How is the Northeast Monsoon formed?

Answer 2

1. Between December and February, the Northern hemisphere is experiencing winter while the Southern hemisphere is experiencing summer.
2. The Northern hemisphere thus has a higher air pressure compared to the Southern hemisphere.
3. Due to the difference in pressure between the northern and southern hemisphere, air moves from the Indian subcontinent and Central Asia to Australia as the northeast monsoon winds.
4. These winds are generally dry and cold as they blow across cold land.
5. As the wind cross the Equator, the coriolis effect deflect the winds to the left. These winds become the northwest monsoon winds and warms up as they head for Australia. The warm air picks up moisture as it travels over the Indian Ocean and bring heavy rain to Australia.

Question 3

Explain the process of convectional rain.

Answer 3

Convectional rain occurs when the earth’s surface is heated intensely.
As the sun’s energy heats up the earth’s surface, the warm surface heats the air around it. The air becomes unstable, causing it to expand and rise. As the air rises, its temperature begins to drop. When the rising air cools to dew point temperature, condensation occurs and clouds are formed. When the water droplets in the clouds become large and heavy enough, they fall to the ground as rain.

Question 4

Explain why temperature decreases with increasing altitude

Answer 4

The atmosphere is mostly heated by the earth’s surface. The sun’s solar energy enters the atmosphere and reaches the earth’s surface in the form of shortwave radiation. The warm surface then emits heat in the form of longwave radiation. The higher up you are, the further you are from the surface of the earth that is heated by the sun.

Therefore, temperature decreases with increasing altitude

Longwave radiation that is emitted by the earth is absorbed by greenhouse gases such as Co2 in the atmosphere, trapping the sun’s energy and warming the earth. Air nearer to the earth’s surface absorbs more heat from longwave radiation than air at higher altitudes.

This explains why temperature decreases with increasing altitude.

Air is less dense at higher altitudes. Dense air is able to absorb more heat from longwave radiation from the earths surface , resulting in higher temperatures. Less dense air has less ability to absorb heat, causing these lower temperatures.

Question 5

How did the Southwest Monsoon formed?

Answer 5

1. Between June and September, the Northern hemisphere is experiencing summer while the Southern hemisphere is experiencing winter.
2. The air over the Central Asia heats up, expands and rises, forming a region of low pressure over the area. During the same period, the southern hemisphere is experiencing winter. The low temperature causes the air to be cold and dense, exerting a greater force on the earth’s surface. This results in an area of high pressure over Australia.
3. Due to the difference in pressure between the northern and southern hemisphere, air moves from Australia to Indian subcontinent and Central Asia as the southeast monsoon winds.
4. The wind cross the Equator, the coriolis effect cause it to deflect right. These winds become the southwest monsoon winds and warm up as they head for Central Asia. The warm air picks up moisture as it travels over the Indian Ocean and bring heavy rain to Indian subcontinent.

Question 6

What are monsoon winds?

Answer 6

It is the regional wind patterns that reverse direction seasonally.

Question 7

How does monsoon rain affect rainfall?

Answer 7

It affect the seasonal changes in precipitation. Levels of precipitation can either decrease or increase, leading to wet of dry seasons.

Question 8

What is the Coriolis effect?

Answer 8

It is a force produced by the earth’s rotation.

Question 9

How does the Coriolis effect affect the movement of monsoon winds?

Answer 9

It causes the bending and deflection of winds.

Winds in the northern hemisphere will deflect right, while winds in the southern hemisphere will deflect left.

Question 10

Explain how land breeze is formed

Answer 10

• land breeze is a wind that blows from the land to the sea.
• it is formed by differences in air pressure due to the different rates at which land and sea bodies cool.
• the land loses heat and cools down faster than water bodies at night.
• sea has a higher temperature and lower air pressure than the land.
• as air moves from an area of high pressure to an area of low pressure, it forms a land breeze that blows from the land to the sea at night.

Question 11

What is an equatorial climate ?

Answer 11

1Equatorial climate is usually experienced at places located between 10 degree both and south of the equator, for example Singapore and Johor, Malaysia.

Equatorial climate is characterised by high temperatures because of the high solar angle. These places experience high mean annual temperatures of about 27 degrees throughout the year and a small annual temperature range of 2 degrees.

Another characteristic of the equatorial climate is the high relative humidity of over 80 per cent throughout the year. Due to the high temperatures, water evaporates quickly into the air, forming clouds.

Convectional rain often occurs in these places. The total annual rainfall for places with an equatorial climate is typically more than 2000mm. Rain generally falls throughout the year, with no distinct wet or dry seasons.

Question 12

Explain the formation of sea breeze.

Answer 12

1. In the day, the land heats up faster than the sea. This results in the land having a higher temperature than the sea.
2. The land thus has a lower air pressure compared to the sea.
3. As winds blow from an area of high pressure to low pressure, the winds blow from the sea to the land, forming sea breeze and lowering the temperature of the coastal area.

Question 13

What are land and sea breezes and how do they affect temperature?

Answer 13

They are the local winds that occur in coastal areas. The wind lower the temperature of coastal areas during the day and regulate the temperature during the night.

Question 14

How do you calculate the diurnal temperature range?

Answer 14

Maximum daily temperature - Minimum daily temperature

Question 15

How to calculate the annual temperature range?

Answer 15

Maximum mean monthly temperature - minimum mean monthly temperature

Question 16

Definition of weather

Answer 16

Weather is the condition of the atmosphere at a particular place and time. The atmosphere is a layer of air surrounding the earth. The weather affects how we live from day today

Question 17

Definition of climate

Answer 17

cClimate is the average condition of the atmosphere of a specific place over a long period of time, usually over 30 years

Question 18

How do relief rain occurs?

Answer 18

1. Warm, moist air from the sea is forced to rise due to the mountains.
2. Air cools as it rises. When dew point temperature is reached, condensation occurs and cloud form. When the water droplets are large and heavy enough, rain falls on the windward side.
3. By the time air moves to leeward side, the air is dry and there is no rain fall.

Question 19

What is the difference between weather and climate?

Answer 19

Weather is the condition of the atmosphere at a particular place and time, from day to day. While climate is the average condition of the atmosphere of a specific place over a long period of time, usually over 30 years.

Question 20

Explain how latitude affects temperature.

Answer 20

Latitude is the distance of any point on the earth measured north or south from the equator.

At lower latitudes, the sun’s rays hit the earth’s surface at a higher angle of incidence, causing the heat to be concentrated on a small area, resulting in higher temperatures.

At higher latitudes, the sun’s rays hit the earth’s surface at a lower angle of incidence, causing the heat to be spread out over a larger area, resulting in lower temperatures.

Question 21

Explain the maritime effect.

Answer 21

Maritime effect is the effect that large ocean bodies have on the climate of coastal areas, resulting in a lower annual temperature range.

During summer, the air over the sea is cooler than the air over the land, as the land heats up faster than the sea. The cooler air over the sea helps to lower the temperature of the area, resulting in cooler summers.

During winter, the air over the sea is higher than the air over the land, as the land cools down faster than the sea. The warmer air over the sea helps increase the temperature of the area, resulting in warmer winters.

Question 22

Explain why inland areas have a higher annual temperature range.

Answer 22

Inland areas have a higher annual temperature range due to the continental effect.

During summer, the land heats up quickly, while during winter, the land cools down quickly. As a result, inland areas experience hotter summers and colder winters, leading to a higher annual temperature range.

Question 23

Explain why there is a larger daily temperature range in the desert.

Answer 23

Deserts lack cloud cover.

In the day, all of the sun’s energy is thus able to reach the earth’s surface, heating it up quickly and causing the temperature to increase.

At night, most of the heat radiated from the earth’s surface escapes into the atmosphere, causing temperatures to drop.

Question 24

Explain why places with cloud cover have a lower daily temperature range.

Answer 24

In the day, the clouds reflect a large portion of the sun’s energy back to space, keeping the earth’s surface cool. At the same time, the clouds absorbs some of the heat radiated from the earth’s surface, lowering the temperature.

At night, the clouds absorbs some of the heat radiated from the earth’s surface, preventing them from escaping into space, keeping the earth warmer.

Question 25

Explain the factors affecting relative humidity.

Answer 25

1. Temperature.

Higher temperatures can hold more water vapour. Given the same amount of water vapour, places with higher temperature will therefore have a lower relative humidity compared to a place with lower temperature.

Higher temperatures result in more evaporation -> more water vapour -> higher relative humidity.

2. Amount of water vapour

Coastal areas or places near water bodies have higher chances of evaporation -> more water vapour -> higher relative humidity.

More trees -> more transpiration -> higher relative humidity.

Question 26

Explain how clouds form.

Answer 26

1. Evaporation from water bodies and transpiration from trees , lead to water vapour in the atmosphere.
   2, When the water vapour cools at dew point temperature, condensation takes place to form water droplets.
2. The water droplets merge and become larger to form clouds.

Question 27

Define ‘air pressure’.

Answer 27

Air pressure is the force on an unit area of the earth’s surface by the weight of a column of air above it.

Question 28

Explain how wind is formed.

Answer 28

When there is a difference in temperature and thus a difference in air pressure, the air moves from an area of high pressure to an area of low pressure, forming wind.

Question 29

Describe the characteristics of the monsoon climate.

Answer 29

1. Located between 5 -25 degrees north and south of the equator.
2. High mean annual temperatures of about 28 degrees.
3. Small annual temperature range of around 3 - 4 degrees.
4. High total annual rainfall of around 2000mm.
5. Distinct wet and dry season depending on the monsoon winds.

Question 30

Describe the characteristics of the cool temperate climate.

Answer 30

1. Located at coastal areas between 40 - 60 degrees north and south of the equator.
2. Low to moderate mean annual temperature ranging from -3 to 18 degrees.
3. Large annual temperature range of around 21 degrees.
4. Low total annual rainfall of 300 - 900mm.
5. No distinct wet and dry season.