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Flashcards

Goegraphy: Weather & Climate

Ryan Kang English 44 cards

Goegraphy: Weather & Climate

Cards in this deck (44)

  1. 1Elements of Weather: Temperature It refers to the degree of hotness or coldnesss of a place. What determines temperature?It is determined by the energy from the sun which reaches the earth. Energy from the sun mostly travels through the atmosphere and is absorbed by the eath's atmosphere. This causes the earth's surface to warm up, which in turn heats the atmosphere.
  2. 2Elements of Weather: Temperature 2 Temperature is regularly measured and recorded around the world. Why?Recording temperatures is useful because it allows us to determine the weather patterns in a place.
  3. 3Elements of Weather: Temperature 2 Temperature is regularly measured and recorded around the world. How?Temperatures are measured using analogue or digital thermometers in degree Celsius. Maximum and minimum temperatures are measured with Six's Thermometer.
    Measuring maximum and minumum temperatures gives more accurate records as temperature varies throughout the day.
  4. 4Elements of Weather: Temperature 3 Latitude (Factors influencing the temperature of locations)It refers to the distance of any point on earth measured North or South from the Equator. Temperature differs between places at lower latitudes and higher latitudes because the sun's rays strike various parts of the world at different angles.
  5. 5Elements of Weather: Temperature 3 Latitude 2 (Factors influencing the temperature of locations)The erath tilts 23.5 degrees on its own axis. As a result, the sun's rays strike at various angles at different parts of the earth. When the angle of incidence at which the sun's rays reach the earth is higher, the sun's rays are more concentrated on a small area.
  6. 6Elements of Weather: Temperature 3 Latitude 3 (Factors influencing the temperature of locations)Temperature are lower at higher latitudes because the sun's rays strike at a lower angle and the solar energy is spread out over a wider area.
    As the sun's rays reach the earth at higher angle of incidence in the area between the Tropic of Cancer and the Equator (lower latitude), heat from the sun is concentrated on a small area.
  7. 7Elements of Weather: Temperature 4 Altitude (Factors influencing the temperature of locations)Altitude is the height of a place in relation to the sea level. Temperature approximately decreases by 6.5 degree Celsius with every 1,000 metres increase in altitude.
  8. 8Elements of Weather: Temperature 4 Altitude 2 (Factors influencing the temperature of locations)Temperature decreases with altitude because the atmosphere is mostly heated by the earth's surface. The sun's solar energy enters the atmosphere and reaches the earth's surface. About 45% of the heat is directly absorbed by the earth's surface, heating it up. The higher up the atmosphere, the further away from the surface of the earth which is heated by the sun.
  9. 9Elements of Weather: Temperature 4 Altitude 3 (Factors influencing the temperature of locations)Due to gravity, air is denser at lower altitudes. Dense air is able to absorb more heat from the earth's surface, resulting in higher temperatures near the surface. This means that the less dense air on top of a mountain has less ability to absorb the heat than the denser air at sea level, resulting in a lower temperature at the top of the mountain.
  10. 10Elements of Weather: Temperature 5 Distance from the sea (Factors influencing the temperature of locations)The sea heats up and cools down more slowly than the land. The difference in the rate of heating and cooling of the sea and land affects the temperature of coastal and inland areas.
  11. 11Elements of Weather: Temperature 5 Distance from the sea 2 (Factors influencing the temperature of locations)During warmer periods (day/summer), the air over the sea is cooler than air over the land as the land heats up quicker than the sea. The cooler air over the sea helps lower the temperature of coastal areas. Coastal areas are therefore cooler than inland areas.
  12. 12Elements of Weather: Temperature 5 Distance from the sea 3 (Factors influencing the temperature of locations)During cooler periods (night/winter), the air over the sea remains warmer than air over the land because the sea cools more slowly than the land. The warmer air over the sea increases the temperature of coastal areas. Hence, coastal areas will be warmer than inland areas.
  13. 13Elements of Weather: Temperature 5 Distance from the sea 4 (Factors influencing the temperature of locations)However, as inland areas are further away from the sea, the temperatures of these areas are not influenced by the sea.
    Hence, coastal areas would have a smaller temperature range than inland areas as the air over the sea helps to regulate the temperature of coastal areas but not inland areas.
  14. 14Elements of Weather: Temperature 6 Cloud cover (Factors influencing the temperature of locations)Cloud cover is the extent of the sky that is covered by clouds. The amount of cloud cover influences the temperature on the earth's surface in the day and at night. More cloud cover results in a smaller difference between day and night temperatures.
  15. 15Elements of Weather: Temperature 6 Cloud cover 2 (Factors influencing the temperature of locations)During the day, the presence of clouds reflect a larger portion of the sun's energy back to space, keeping the earth's surface cooler than compared to the absence of clouds
    During the night, the presence of clouds will absorb more of the heat that is radiated from the earth's surface and prevent it from escaping into space, keeping the air near the earth's surface warmer at night than compared to the absence of clouds
  16. 16Elements of Weather: Relative Humidity It refers to the ratio between the actual amount of water vapour present in a mass of air and the maximum amount of water vapour the air could hold at a given temperature. How is it measured?It is measured using a hygrometer, which consists of a wet bulb thermometer and a dry bulb thermometer
  17. 17Elements of Weather: Relative Humidity 2 What is its relation to temperature?Relative humidity varies with temperature. Warm air can hold more water vapour than cool air. When the temperature increases, the amount of water vapour in the air stays the same, bu the rise in temperatire makes air more able to hold water vapour. Thus, relative humidity decreases as temperature increases.
  18. 18Elements of Weather: Relative Humidity 3 SaturationWhen the air holds the maximum amount of water vapour it can hold, it is said to be saturated. Saturation occurs when relative humidity is at 100%.
  19. 19Elements of Weather: Relative Humidity 4 Dew Point TemperatureThe temperature at which saturation occurs is known as the dew point temperature. Condensation first starts to occur at dew point temperature. Condensation is a process in which water vapour changes to a liquid form by cooling.
  20. 20Elements of Weather: Relative Humidity 4 HygrometerThe dry bulb thermometer measures the temperature of the surrounding air. The wet bulb thermometer has its bulb wrapped with a muslin which is kept moist by a wick dipped in distilled water.
  21. 21Elements of Weather: Relative Humidity 4 Hygrometer 2If the air is not saturated, evaporation from the wet muslin occurs. As latent heat is used up during evaporation, cooling occurs which causes the wet bulb thermometer to register a lower reading.
  22. 22Elements of Weather: Relative Humidity 4 Hygrometer 3If the wet bulb depression is large, the RH is low
    If the wet bulb depression is narrow, the RH is high    Elements of Weather: Relative Humidity 4 Hygrometer 3
  23. 23Elements of Weather: Precipitation It refers to water in any form that falls from the atmosphere to the surface of the earth. It includes hail, snow, sleet and rain. What are the conditions for it to occur?Air should be saturated, RH at 100%
    Particles of soot, dust, ash, ice etc are present in the air
    Air temperature is below dew point temperature
  24. 24Elements of Weather: Precipitation 2 How is air cooled?Air comes into contact with a cold surface Warm air blows over a cold cold current or land mass, giving rise to mist and fog.
    OR
    Air may be forced to rise, causing 3 types of uplift - convectional, relief & frontal.
  25. 25Elements of Weather: Precipitation 3 Formation of Rain1. Air that has been lifted cools
    2. Saturation takes place at dew point temperature
    3. Air is cooled further as it continues to rise
    4. Water vapour condenses into water droplets around atmospheric particles
    5. Water droplets coalesce to form clouds
    6. Rain falls when water droplets in the air become too heavy to suspend
  26. 26Elements of Weather: Precipitation 4 Convectional RainAir near the ground/sea surface is heated up by conduction because of intense isolation. Warm air expands and becomes unstable and rises (convectional uplift). Rising air cools to its dew point at its level of condensation. Warm moist air is saturated at dew point temperature. Relative humidity reaches 100%. Condensation takes place upon further cooling to form cumulonimbus clouds. When water vapour in the air becomes too heavy, convectional rain falls.
  27. 27Elements of Weather: Precipitation 4 Convectional Rain 2Associated with tropical depressions (typhoons) and thunderstorms, sometimes with lightning.
    Almost a daily occurence in tropical areas.
    Intense, but short-lived showers and is localised, usually in the afternoon.
    Rain drops are usually large; heavy downpour.
  28. 28Elements of Weather: Precipitation 4 Convectional Rain 3Elements of Weather: Precipitation 4 Convectional Rain 3
  29. 29Elements of Weather: Precipitation 5 Relief RainMoist air passes over the sea and arrives at the coast. As it moves forward and reaches large obstacles such as hills and mountains, the air is forced to rise over the top. The air rising up the windward side of the mountain is forced to cool. When the temperature of the air reaches dew point temperature, condensation occurs and clouds form. When the water droplets become large and heavy enough, they fall as rain on the windward side of the mountain where air has risen up. By the time the air moves to the leeward side, it is usually dry because most of the moisture would have fallen on the windward side.
  30. 30Elements of Weather: Precipitation 5 Frontal RainIt is caused by cyclonic activity when 2 huge air masses of different temperature, humidity and density come together from different directions, air may be uplifted and cooled. Their differences depend on where they have developed, whether it is a warm or cold surface. A zone called the front separates the 2 air masses.
  31. 31Elements of Weather: Precipitation 5 Frontal Rain 2At the warm front, the lighter warm air rises gently over the heavier cold air which remains close to the ground. As warm air rises, it expands, cools and condenses to form clouds. The light rain falls steadily over a wide area for several hours.Elements of Weather: Precipitation 5 Frontal Rain 2
  32. 32Elements of Weather: Precipitation 5 Frontal Rain 3At the cold front, heavy cold air slips under lighter warm air and forces it up aggressively, causing it to rise quickly and condense, forming cumulonimbus clouds. The heavy rain that falls over a small area is of a short duration.Elements of Weather: Precipitation 5 Frontal Rain 3
  33. 33Elements of Weather: Pressure & Winds Air Pressure It is the force exerted on a unit area of the earth's surface by the weight of a column of air above it. How is it measured? How is it related to altitude?Air pressure is measured in millibars (mb) using a barometer. Isobars are imaginary lines joining places of equal air pressure, represented in a synoptic chart.
    Air pressure decreases as altitude increase. Air is less dense at higher altitudes because gravity pulls air molecules toward the surface of the earth. Hence, air pressure is higher at sea level and lower at higher altitudes.
  34. 34Elements of Weather: Pressure & Winds Winds It refers to the movement of air from an area of high pressure to an area of low pressure. What is wind speed? What affects it?Wind speed is the rate at which air is moving and is measured in kilometres per hour using an anemometer.
    Pressure gradient is the difference in the air pressure between 2 locations. The greater the difference in air pressure (steeper pressure gradient), the faster the wind speed.
  35. 35Elements of Weather: Pressure & Winds Winds 2 What is wind direction? What is wind frequencyWind direction refers to the direction from which the wind blows. A wind vane is used to determine the wind direction. The wind vane points to the direction the wind is blowing from.
    Wind frequency refers to the percentage of time the wind blows from a particular direction. Winds that blow most frequently from a specific diredction are called prevailing winds. Wind direction and frequency can be recorded using wind roses.
  36. 36Elements of Weather: Pressure & Winds Wind Systems What are land and sea breezes? How do they affect the temperature of an area?Land and sea breezes are local winds that occur in coastal areas.
    These winds lower the temperature of coastal areas during the day and regulate the temperature at night, leading to a smaller diurnal temperature range in these areas
  37. 37Elements of Weather: Pressure & Winds Wind Systems: Land BreezeA land breeze is a wind that blows from the land to the sea. It is formed by the differences in air pressure due to the different rates at which the land and water bodies cool. The land cools down faster than water bodies at night. As a result, the sea has a higher temperature and lower air pressure than the land. As air moves from an area of high pressure to low pressure, it forms a land breeze that blows from the land to the sea at night.
  38. 38Elements of Weather: Pressure & Winds Wind Systems: Sea BreezeA sea breeze is a wind that blows from the sea to the land. It is formed by the difference in air pressure due to the different rates at which land and water bodies heat up. During the day, the land heats up faster than its nearby water bodies. As a result, air pressure over the land is lower than the sea. Therefore, wnd blows from the sea (high pressure) to the land (low pressure) during the day to form a sea breeze.
  39. 39Elements of Weather: Pressure & Winds Wind Systems: Monsoon Winds They are regional wind patterns that reverse direction seasonally.This brings seasonal changes in precipitation. The levels of precipitation can either increase or decrease with the occurence of monsoons, leading to wet or dry seasons.
  40. 40Elements of Weather: Pressure & Winds Wind Systems: Monsoon Winds 2 What is the Coriolis effect? How does it affect winds?Coriolis effect is a force produced by te earth's rotation. As the earth rotates, the Coriolis effect changes the course of moving objects on the earth's surface.
    The Coriolis effect causes the deflection of winds. The Coriolis effect is strongest near the poles, weak in the tropics and not felt at the Equator. In the northern hemisphere, the Coriolis effect deflects winds to the right. In the southern hemisphere, winds are deflected to the left.
  41. 41Elements of Weather: Pressure & Winds Wind Systems: Monsoon Winds 3 Southwest MonsoonIt takes place between June and September, when it is summer in the northern hemisphere. The air over 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.
  42. 42Elements of Weather: Pressure & Winds Wind Systems: Monsoon Winds 3 Southwest Monsoon 2Due to the difference in pressure between Central Asia and Australia, air from Australia moves to the Indian sub-continent and Central Asia as the southeast monsoon winds. As the winds cross the Equator, the Coriolis effect deflect the winds to the 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 brings heavy rain to the Indian sub-continent.
  43. 43Elements of Weather: Pressure & Winds Wind Systems: Monsoon Winds 4 Northeast MonsoonIt takes place between October and February, when it is summer in the southern hemisphere. The air over Australia heats up, expands and rises, forming a region of low pressure over the area. During the same period, the northern 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 the Indian sub-continent and Central Asia.
  44. 44Elements of Weather: Pressure & Winds Wind Systems: Monsoon Winds 4 Northeast Monsoon 2Due to the difference in pressure between Australia and Central Asia, air from the Indian sub-continent and Central Asia moves to Australia as the northeast monsoon winds. As the winds cross the Equator, the Coriolis effect deflect the winds to the left. These winds become the northwest monsoon winds and warm up as they head for Australia. The warm air picks up moisture as it travels over the Indian Ocean and brings heavy rain to Australia.

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Flashcards on Goegraphy: Weather & Climate, created by Ryan Kang on 12/02/2015.
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Ryan Kang
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