weather and climate Flashcards
what is weather
The day to day condition of the atmosphere including temperature, rainfall, sunshine and wind.
what is climate
The average weather conditions in an area over a prolonged period of time, around 30 years.
what are the elements of weather (7)
Sun Temperature Pressure Wind direction and wind speed Humidity Cloud type and cloud cover Precipitation
what is a stevensons screen (5)
Stevenson’s Screen: contains the thermometers
Painted white to reflect sun with double lid for insulation
Slatted sides to let the air circulate, but slanted downwards to prevent light getting in
Legs 1m long to prevent heating from ground
On short grass for same amount of reflection
how to measure sunshine
sunshine recorder
The number of hours and minutes of sunshine received at a place can be measured and recorded by a sunshine recorder.
This is a glass sphere partly surrounded by a metal frame. A strip of special card, divided up into hours and minutes, is placed below the sphere.
When the sun shines, the sphere burns the ray’s trace on the card and at the end of the day the length of the trace represents the amount of sunshine the location received
how to measure temperature
thermometer
Measures temperature degrees Celsius or Fahrenheit
Consists of a glass tube filled with mercury (or ink)
When the thermometer is warmed, the mercury expands pushing itself up the glass tube
When it is cool, it contracts moving back down towards the reservoir
The thermometers can be placed in a Stevenson Screen to make sure that the temperature is taken in a shady environment. This is a wooden box with slatted sides, a sloping roof and legs to keep the screen off the ground. It is painted white to reflect the sun.
how to measure air pressure
- barometer
Used to measure air pressure – the amount of pressure that is being subjected on the earth’s surface by the atmosphere above
Measures in millibars (mb)
Works by measuring how much a series of corrugated metal strips expand or contract
how to measure windspeed
anemometer
Measures wind velocity
Wind spins the cups on a shaft and a reading is given in meters per second
Usually used continuously to give an average wind speed
how to measure wind direction
wind vane
Measures the direction the wind is blowing in
Wind catches the thick end of the vane and spins the arrow towards the direction the wind is blowing
Needs to be situated in open ground, above the height of buildings/vegetation nearby
how to measure humidity
wet and dry bulb thermometers
Measure the humidity in the air
Consist of a regular thermometer (dry) and a wet thermometer
Dry air will absorb moisture from the muslin and cool the wet thermometer, moist air will not.
how to measure cloud type/cover
visual assessment
The ten main types of clouds can be separated into three broad categories according to the height of their base above ground
Cloud cover is measured in Oltas (eights) and is measured by a visual assessment of how much of the sky is covered in clouds
how to measure precipitation
rain gauge
Measures the amount of precipitation that has fallen in a give area
Must be placed in an open space to avoid runoff from vegetation/buildings
The funnel should be sunk into the ground to prevent evaporation from the sun
what are the climate zones
Polar Temperate Arid Tropical Mediterranean Mountains
what are the factors affecting climate
latitude pressure systems winds distance from the sea altitude ocean currents
how does latitude affect climate
Highest temperatures are recorded between the tropics (Cancer and Capricorn) 23.5 degrees north and south of the equator
As you move away from the equator, temperatures decrease
The Sun’s energy is more concentrated on or near the equator and becomes more dispersed as you move further north or south
The tilt of the earth and orbit throughout the year expand the warmest regions
how does pressure systems affect climate
Rising air at the equator causes a warm, wet climate
Descending air at the tropics causes dry, arid conditions
Temperate regions experience cold air descending from the poles and warm air from the tropics
The meeting of warm and cool air brings mild temperature and increased precipitation
how do winds affect climate
The prevailing wind is the most frequent wind direction a location experiences. In Britain the prevailing wind is from the South West, which brings warm, moist air from the Atlantic Ocean. This contributes to the frequent rainfall. When prevailing winds blow over land areas it can contribute to creating desert climates.
how does the distance from the sea affect climate
Land heats up and cools down quicker than the sea
Water takes longer to heat up than the land so in summer months, areas by the coast are cooled by the water
In winter, the opposite occurs – coastal areas are kept warmer as the sea loses temperature slower
Inland areas are more likely to experience extremes of temperature and increased temperature range
how does the altitude affect climate
Air temperature decreases as altitude increases
Air at sea level is under greater pressure and therefore denser. Denser air is able to hold more warmth
As you increased in altitude, air pressure drops and the air becomes thinner and cooler
For every 100m increase in altitude you can expect a drop in temperature by 1⁰C
how do ocean currents affect the climate
Warm ocean currents from lower latitudes warm cooler regions
Cold currents from polar regions can cool temperatures
Cold currents can increase aridity in certain areas
what is the latitude of equatorial regions and how does this affect the climate
- Close to the equator/on tropics
- closer to the equator = higher temperature
what is the wind amount of equatorial regions and how does this affect the climate
- low
- more humid and warm
what is the cloud amount of equatorial regions and how does this affect the climate
- heavy
- more rain and more humid
what is the humidity of equatorial regions and how does this affect the climate
-high
what is the pressure of equatorial regions and how does this affect the climate
- low
- strong convection
