Flashcards in Unit9.1(weather&Climate) What Is The Earth's Radiation Budget? Deck (36)
What is solar radiation?
Solar radiation is the energy emitted by the sun in form of short wave radiation by means of electromagnetic waves.
What is insolation?
Insulation is the portion of solar radiation that reaches the earth
What are the ways of radiation transfer?
•absorption (earth’s surface/atmosphere)
•scattered (all direction)
What factors affect the insolation received on the earth’s surface ?
-Angle of the sun:
•time of day
-duration of daylight
What is albedo ?
Albedo is the reflectivity of the earth surface.
How does the factor of albedo affect the insolation received on the earth’s surface ?
•the reflectivity of the earth surface (known as albedo) affects the amount of insolation being received
•the lighter the colour of the earth surface, the higher the albedo, the smaller amount of insolation absorbed by the earth’s surface
What is overhead sun ? Where does it take place ?
•When the sun is directly heated over headed, or when the angle of the sun is 90*, it is known as overhead sun.
•between 23.5*N and 23.5*S
How does the angle of the sun affects the insolation received ?
-high angle of the sun:
•If the angle of the sun is higher (larger), solar radiation is more concentrated in a smaller area .
•The amount of insolation received by the earth's surface is more intense.
•Temperature is higher. *
-low angle of the sun:
•If the angle of the sun is lower (smaller), solar radiation is less concentrated. Energy is dispersed over a larger area.
•The amount of insolation received by the earth's surface is less intense.
•Temperature is lower.
How does the angle of the sun varies with latitude ?
•In low-latitude regions, the angle of the sun is larger (higher) The same amount of solar radiation received (i.e. insolation) is concentrated on a smaller area in these regions. Therefore, the insolation is more intense As a result, the air temperature is higher.
In high-latitude regions, the angle of the sun is smaller (lower) The same amount of solar radiation received (i.e. insolation) is dispersed over a larger area in these regions. Therefore, the insolation is less intense. As a result, the air temperature is lower
How does the amount of insolation received affect the air temperature in low-latitude regions and high-latitude regions?
High-latitude regions receive less insolation because the angle of the sun is smaller there. These regions have lower air temperatures.
What is the relationship between the angle of the sun and the time of a day?
The angle of the sun increases from sunrise, reaches maximum at n oon, and then decreases to the lowest at sunset
What season when it is on
How does the angle of the sun varies with season in the northern Hemisphere ?
-on spring Equinox :
~the overhead sun is located at the Equator(0*)
-on summer solstice:
~ the overhead sun is located at the 23.5*N
~the angle of the sun is larger in Northern Hemisphere,but it is smaller in the Southern Hemisphere
-on autumn Equinox:
~the overhead sun is located at the Equator(0*)
-on Winter Solstice:
~ the overhead sun is located at the 23.5*s
~the angle of the sun is larger in Southern Hemisphere,but it is smaller in the Northern Hemisphere
Explain why the angle of the sun varies with seasons.
•The earth revolves around the sun.
•The earth's axis is tilted at an angle of 23.5°
•This results in different angles of the sun at a particular place during different seasons.
How does the angle of the sun in different seasons affect the amount of insolation received in the North Pole?
•Because of its location, the angle of the sun is always small at the North Pole. Only little insolation is received.
•However,when the angle of the sun is the largest at 23°N on the summer solstice, the North Pole receives the largest amount of insolation in a year. There are 24 hours of sunlight a day. The air temperature is higher in summer
•when the angle of the sun is the largest at 23°S during the winter solstice,the North Pole receives the least amount of insolation in a year.There are 24 hours of darkness.No insolation is received at all for the whole day.The air temperature is very low in winter
how duration of daylight affects the insolation received.
•the longer the duration of daylight, the more insolation received.
•The revolution of the earth around the sun causes seasonal differences in the duration of daylight.
•in low-latitude regions such as the places located along the Equator,the duration of daylight is almost 12 hours daily throughout the year.
•In high-latitude regions, e.g. the polar regions, the duration of daylight differs at different times:
~Duration of daylight is longer in summer. Daylight can last for as long as 24 hours in polar regions
~Duration of daylight is shorter in winter. Daylight may last for as littl as 0 hour in polar regions.
—> annual variations of insolation increases with latitude
how the atmosphere affects the insolation received.
•Gas molecules, clouds and dust particles in the atmosphere absorb reflect and scatter insolation.
•The longer the distance that sun's rays have to travel through the atmosphere, the less insolation received by the earth's surface.
Name 3 ways of energy transfer (from ground to atmosphere)
What would you conclude about the radiation budget of the earth system ?
The earth system maintains a balanced radiation budget
Place received more radiation then is lost to space has a ___________ in radiation budget.
Where are the places that have energy surplus?
Low-latitude regions/that is in the tropies
Where are the places that have energy deficit?
High-latitude regions /that is in near the poles
The difference in radiation budget between regions does not make some places get hotter nor some places get colder. Do you know why?
This is because wind and ocean currents help transfer heat energy from region with a surplus of energy to regions that have a deficit in energy
Describe the distribution of insolation over the earth’s surface at equatorial region
-it received the large amount of insolation. However, the largest amount of insolation is not found there
-due to high angle of the sun, equatorial region receives large amount of insolation. However, the amount is reduced by the cloud cover so it results in stronger reflection and scattered of insolation
Describe the distribution of insolation over the earth’s surface around 23.5*N and S
Drier climate in the region results in less cloud cover. The earth’s surface receives more insolation
What should be write when the question ask you to describe “temp. pattern” ?
•annual range of temp
•annual mean of temp
What are the factors affecting temperature pattern ?
•land and sea
Explain the diferences with reference to the way of heat transfer over the land and over the sea
•Heat can be transferred quickly through the land by conduction.
•Land absorbs and loses heat Quickly
•As a result, the land is hotter in summer and colder in winter than the sea.
•The water in the sea is heated by convection.
•As it takes longer time for seawater to transfer the heat, the sea absorbs and loses heat Slowly//Sea water has a higher specific heat capacity
•as a result, sea is cooler in summer, and warmer in winter than the land.
Identify the two types of wind and their effects on the air temperature of Hong Kong.
-onshore wind (Summer):
•The wind is cool. It helps reduce the summer temperature of Hong Kong •Why? : As sea absorbs heat slower than land in summer so it has lower temperature in summer.
-offshore wind (winter):
•The wind is cold. It helps reduce the winter temperature of Hong Kong
•Why? As land loses heat faster than sea winter so it has lower temperature winter.