Chapter 2 Gateway 1: Weather and climate Flashcards
What is weather?
Weather is the immediate condition of the atmosphere at a particular place and time
What are the elements of weather?
- Wind
- Clouds
- Air pressure
- Temperature
- Relative humidity
- Rainfall
What is climate?
Climate is the average condition of the atmosphere of an area over a long period of time
What is temperature? What is considered high and low? How to measure it?
The degree of hotness or coldness of a place
High temp > 20
Low temp < 10
Analogue
Digital thermometer
Mean daily temperature
Sum of hourly temperatures / 24
Diurnal temperature range
Max daily temp - min daily temp
Mean monthly temperature
Sum of mean daily temperatures in the month / number of days in the month
Mean annual temperature
Sum of mean monthly temperatures in the year / 12
Annual temperature range
Max mean monthly temp - min mean monthly temp
Factors affecting temperature
Cloud cover
Latitude
Altitude
Distance from sea
What is latitude and description
The distance of any point of the earth measured north or south from the equator
Most important factor affecting temperature
The temperature differs between places at lower latitudes and higher latitudes because the sun’s rays strike various parts of the world at different angles
Singapore is located at 1 degree north and experiences a mean annual temperature of 27 degrees celcius
Russia is located at 60 degrees north and experiences a mean annual temperature of 6 degrees celcius
What is altitude and description
The height of a place in relation to the sea level
Temperature decrease by 6.5 degree celcius when altitude increase by 1000m (generally)
Air pressure decreases as altitude increased
Peak of mount everest at 8848m above sea level: -20 degrees celcius to -35 degrees celcius
Foot of mount everest at 1400m above sea level: 16 degrees celcius
What is longwave and shortwave radiation?
Longwave
Land to sun
Shortwave
Sun to land
What is the maritime effect? Summer + Winter
The effect that large ocean bodies have on the climate of coastal areas
SUMMER
Land: Air heats up quickly
Sea: Air gains heat slowly
WINTER
Land: Air loses heat quickly
Sea: Air loses heat slowly
Anchorage, Alaska, USA: annual temperature ranges from -9 degree celcius to 14 degree celcius
What is the continental effect? Summer + Winter
The effect that continental surfaces have on the climate of inland areas
SUMMER
Land: Air heats up quickly
WINTER
Land: Air loses heat quickly
Fairbanks, Alaska, USA: annual temperature ranges from -24 degree celcius to 17 degree celcius
What is cloud cover?
The extent of the sky that is covered by clouds
The amount of cloud cover influences the temperature on the earths surface in the day and in the night
More cloud cover results in a smaller difference between day and night temperatures, leading to a smaller diurnal temperature range
What is relative humidity? + Formula, relationship and saturation
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
FORMULA
Actual amount of water vapour in the air (g/m^3) /
Maximum amount of water vapour the air could hold (g/m^3) X 100%
RELATIONSHIP
Relative humidity decreases as temperature increases
SATURATION
Occurs when relative humidity is at 100 per cent, also known as dew point temperature
What is a cloud, condensation nuclei, coalescence, wet bulb temperature and relationship
A visible mass of water droplets or ice crystals that are suspended in the atmosphere from the condensation of water vapour
Tiny particles
The process where water droplets in the air will merge and become larger
The difference between the dry and the wet
Lower the humidity —> lower the web bulb temperature
What is rainfall((definition,air instability,high,low,precipitation)(def,exp,measure))
The result of air instability
The tendency of a parcel of air that rise rather than remain in its original position
> 1500mm
<250mm
Water in any form that falls from the atmosphere to the surface of the earth
Hail, snow, sleet, rain
Rain gauge (mm)
What is convection rain?(definition,process)
Occurs when the earth’s surface is heated intensely
- The sun’s energy reaches the earth’s surface
- The earth’s surface is heated up the sun’s energy. This in turn heats up the surrounding air
- Air expands and rises
- As the air rises, it cools. Air reaches dew point temperature and condensation occurs
- Cumulonimbus clouds are often formed
- When water droplets become large and heavy enough, they fall to the ground as rain
What is relief rain?(definition,process)
Occurs when the warm, moist air is forced to rise over landforms such as a mountain range
- Warm, moist air from the sea is forced to rise
- As air cools, it rises. When dew point temperature is reached, condensation occurs and clouds form. When the water droplets are large and heavy enough, rain falls
- By the time the air moves to the leeward side, the air is dry and no rain falls
What is air pressure?(definition,measurement,high/low,isobars)
The forces exerted on an unit area of the earth’s surface by the weight of a column of air above it
Barometer (millibars)
High > Above sea level value
Low < Below sea level value
Lines joining places of equal air pressure
What is wind?(definition,area,pressure gradient,describe)
The movement of air
Air moves from an area of high pressure to an area of low pressure
The different between the air pressure between the two locations
Higher pressure - lower pressure
Speed, direction and frequncy
What is wind speed?(definition,measurement)
The rate at which the air is moving
Anemometer (km/h)
What is wind direction?(definition,measurement)
Direction from which the wind blows
Wind rose
What is wind frequency?
The percentage of time the wind blows from a particular direction
What is prevailing winds?
Winds that blow most frequently from a specific direction
Wind systems
- Land and sea breezes
- Monsoon winds
Land and sea breezes
Local winds that occur in coastal areas
Lower the temperature of coastal areas during the day and regulate the temperature during the night, leading to a smaller diurnal temperature range in these areas
LAND BREEZE
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 water bodies cool
formation..
1: Air expands and rises, lowering air pressure over the sea
2. Air cools and sinks
3. Air moves from an area of high pressure to an area of low pressure as a land breeze
SEA BREEZE
Wind that blows from the sea to the land
It is formed by differences in air pressure due to the different rates at which land and water bodies heat up
formation..
1. Air over the land surface heats up. Warm air expands and rises, lowering air pressure over the land
2. Air cools and sinks
3. Air moves from an area of high pressure to an area of low pressure as a sea breeze
Monsoon winds
Regional wind patterns that reverse direction seasonally
This brings seasonal changes in precipitation
Monsoon winds and other winds are affected by the Coriolis effect, which is a force produced by the earths rotation
The Coriolis effect causes the bending or deflection of winds
Strongest in poles, weak in tropics, no effect on equator
Northern hemisphere, wind deflects to the right
Southern hemisphere, wind deflects to the left
Climate types
- Equatorial climate
- Monsoon climate
- Cool temperate climate
Equatorial climate
Located between 10 degrees north and south of the equator
Singapore
Characterised by high temperatures because of the high solar angle
High mean annual temperatures of 27 degrees and small annual temperature range of 2 degrees
Monsoon climate
Located between 5 degrees and 25 degrees north and south of the equator
Mumbai, India
Characterised by high mean annual temperatures but lower than equatorial climate
Mean monthly temperature:
Before rainy seasons 28 degrees
During rainy seasons 26 degrees
Small annual temperature range of 3 to 4 degrees
Cool temperate climate
Located near coastal areas found between 40 degrees and 60 degrees north and south of the equator
London
Characterised by four distinct seasons, spring, summer, autumn and winter due to the tilt of the earth and its revolution around the sun
Large annual temperature range of 21 degrees ranging between -3 degrees and 18 degrees
Northeast monsoon and southwest monsoon
NORTHEAST MONSOON
NEOF
october to february
SOUTHWEST MONSOON
SWJS
june to september
