Weather KQ1 Flashcards
Describe how lattitude affects the temperature at a location.
The sun’s rays strike the earth’s curved surface at different angles which results in an unequal distribution of solar energy over the earth. Places near the equator receive more direct sunlight and experience greater heating hence have higher temperatures. The energy received by places nearer the poles is spread over a larger area and experience less heating hence lower temperatures. Hence, there is a drop in mean annual temperature with increasing latitude.
Describe how altitude affects the temperature at a location.
The Earth’s surface is heated by the sun and transfers heat to the air. There are more air molecules closer to sea level due to gravity. The greater the number of air molecules present, the greater the amount of heat transferred. As altitude increases, the amount of air molecules decreases and air pressure decreases, therefore the transfer of heat is not as effective. Thus, mean air temperatures are warmer near sea level than on mountaintops. Hence, temperature decreases with increasing altitude. (6.5C /1000m)
Describe how the distance from sea affects temperature at a location.
The sea heats up and cools down slower than the land. In temperate regions during winter, the sea is warmer than the land. Thus air temperature over the sea is also warmer than over the land. Cold winter temperatures in coastal areas are moderated by the warm air over the sea. Places further inland do not experience this warming effect. Therefore coastal areas experience warmer winters than areas inland. In summer, the sea is cooler than the land. Thus air temperature over the sea is also cooler than over the land. Warm summer temperatures in coastal areas are moderated by the cool air over the sea. Places further inland do not experience this cooling effect. Therefore, coastal areas experience cooler summers than areas inland.
Describe how cloud cover affects temperature at a location.
Places with higher cloud cover experience lower daily temperature ranges than places with low cloud cover (cooler in the day and warmer at night). Higher amount of cloud cover reflects a large portion of solar radiation. This reduces the amount of solar radiation reaching the ground. Therefore temperatures are lower in places with high cloud cover than in places with low cloud cover. At night, cloud cover prevents heat from escaping back into space. It absorbs and re-radiates the heat back towards earth. Therefore nighttime temperatures are warmer in places with higher cloud cover and lower in places with low cloud cover.
Describe and explain Relative Humidity (RH)
RH is the ratio between the actual amount of water vapour present in the air to the maximum amount of water vapour the air can hold at a given temperature. RH varies with temperature. Warmer air can hold more water vapour than cooler air. If the amount of water vapour remains constant, an increase in temperature will cause a decrease in RH (RH decreases as temperature increases)*. Saturation occurs when the RH is equal to 100% (actual amount of water vapour in the air is equal to the maximum amount that the mass of air can hold at a certain temperature). Dew Point temperature is the temperature at which 100% RH occurs.
Describe convectional rain.
On hot days, air near the earth’s surface get heated up. The air expands, becomes less dense and rise upwards. As air rises, its temperature cools and the amount of water vapour it can hold decreases. When the temperature reaches dew point, it becomes saturated. After the dew point is reached, condensation occurs and clouds form. The cloud droplets combine to form heavier droplets and fall as rain. This is known as convectional rain.
Describe relief rain.
Parcels of moist air coming in from the sea may encounter coastal mountain ranges. The air parcel is forced to rise up the side of the range. As air rises, its temperature cools and the amount of water vapour it can hold decreases. When the temperature reaches dew point, it becomes saturated. After the dew point is reached, condensation occurs and clouds form. The cloud droplets combine to form heavier droplets and fall as rain. The clouds and rain normally form on the side facing the incoming wind. This is known as the windward side of the mountain. By the time the winds pass over the mountain range, it has lost most of its moisture. It descends down the leeward side of the mountain as a dry wind with little/no rain.
Describe sea breeze.
During the day the land heats up faster than the sea. This causes the air over the land to heat up faster than air over the sea. The warm air rises, forming an area of low pressure over the land. Cool air over the sea sinks forming an area of higher pressure. Air moves from an area of higher pressure to lower pressure. Air moves from the sea to the land as a sea breeze.
Describe land breeze.
At night, the land cools down faster than the sea. This causes the air over the land to cool down faster than air over the sea. The warm air rises, forming an area of low pressure over the sea. Cool air over the land sinks forming an area of higher pressure. Air moves from an area of higher pressure to lower pressure. Air moves from the land to the sea as a land breeze.
Describe the Monsoon Winds during the middle of the year.
During the middle of the year (June), land in central Asia is heated up. The air is warm and rises, forming an area of low pressure over Asia at sea level.
In Australia, it is winter and the cold, dense air sinks, forming an area of high pressure over Australia at sea level. Air moves from an area of high pressure to an area of low pressure. Therefore, air moves from Australia to Asia. As the wind crosses the equator it is deflected to the right due to the Coriolis Effect and becomes the south-west monsoon in Asia.
Describe the Monsoon Winds during the beginning and end of the year.
Land in central Asia is cold and dense. The air sinks forming an area of high pressure over Asia at sea level. In Australia, it is summer, and the warm air rises, forming an area of low pressure over Australia at sea level. Air moves from an area of high pressure to an area of low pressure. Therefore air moves from Asia to Australia. As the wind blows out from Asia it is deflected to the right due to the Coriolis Effect and hence becomes the north-east monsoon in Asia.
State the distribution of Equatorial Climates.
The tropical equatorial climate is found distributed between latitudes 10°north and south of the Equator. Major regions include the Amazon lowlands of South America, the northern Congo Basin of equatorial Africa and the Southeast Asian region (Malaysia, Singapore and Indonesia).
Describe and explain the temperature of Equatorial Climates.
Temperatures are high and constant throughout the year. Mean annual temperatures above 27°C and small annual temperature range of 2°C to 3°C. The Sun’s rays strike places at or near the Equator at high angles of incidence. Thus solar energy is concentrated over a smaller area, resulting in high average annual temperatures. However high humidity leads to an extensive cloud cover that prevents temperatures from becoming too high.
Describe and explain the rainfall of Equatorial Climates.
There is no distinct wet and dry season and a total annual rainfall of more than 2000 mm. The large amount of rain is due to high temperatures that cause rapid evaporation from water bodies. These clouds produce large amounts of rainfall evenly distributed throughout the year.
State the distribution of Monsoon Climates.
Found between latitudes 10° to 25° north and south of the equator. It includes mainly Asian countries like India, Bangladesh, southern China, Myanmar, parts of Philippines and Thailand, as well as parts of northern Australia.
