Weather And Climate Flashcards
(20 cards)
Weather
Day to day state of the atmosphere
Wind speed and direction
Precipitation
Temperature
Humidity
Sunshine/ cloud cover
Cirrus
High feathery looking
Cumulus
Lower, cotton wool like
Cumulonimbus
Cumulus may grow and become very thick
Give heavy thunderstorms
Nimbostratus
Low, dark grey clouds
Prolonged rain associated with fronts
For condensation to take place
Dew point must be reached as cold air cannot hold as much water vapor, so as warm air rises and cools, it eventually becomes saturated. The temp that this takes place is the dew point
Must be hygroscopic nuclei present as condensation can only occur onto stolid surfaces such as dust and smoke
Relief rainfall
Warm moist air picks up water from the sea
Air is forced to rise due to relief
Rising air cools and condenses forming rain
Sinking air warms and clouds evaporate, causing dry climates on the other side of mountain
Frontal rainfall
Warm moist air from tropics meet cold dry air from polar regions
Warm air forced to rise over cold air
Air cools and condenses forming clouds
Rains along the front (boundary between warm and cool air)
Convectional rainfall
Sun heats the land and the air above
Warm air rises and cools, condenses to form clouds
Clouds grow and form cumulonimbus clouds which give heavy afternoon rainfall
Most common in equatorial regions where sun is at high angle
Tropical storms
Areas of intense low pressure hundreds of kilometers across
Develop between 5 and 20 degree north and south of the equator when sea temperatures are high
Form rapidly when rising air draws water vapor with it in a spiral movement
Rising air cools and condensation releases large quantities of heat energy
Heat powers the storm and only dies when it hits land and the source offices energy (moist rising air) is removed
Life span 7-10 days
High winds up to 250kph
Heavy rainfall and storm surges
Climate
Average weather conditions for a place over the last 30 years
Distance from sea
sea retains heat for longer once warmed and takes longer to cool down in winter (maritime effect) which removes any extremes of temperatures in coastal areas. Areas nearer to coast have higher rainfall bc of warm moist air
Latitude
warmer nearer to the equator due to curvature of the earth and the high angle of the sun overhead concentrates suns enrgy onto a smaller area
Prevailing winds
warm weather if passing over warm surfaces and cold weather when passing over cold ones. Prevailing winds coming from oceans will bring more rainfall
Ocean currents
warm currents (Gulf stream) keeps the west coast of UK much warmer and cold current (Benguela current) keeps Namibia cooler
Altitude
temp decreases by 1 every 150m ascended. Low altitude dust and water vapor prevent heat from escaping back into space
How to measure temperature.
Six’s thermometer
Temp falls so mercury contracts up the left hand tube pushing the pin upwards while increasing temp causes mercury to rise up the right hand tube, pushing the metal tube up with it
Reset each day with a magnet and housed in Stevenson screen
How to measure humidity
Wet and dry bulb thermometer
Dry bulb records normal temperature
Water evaporating from the cloth around the wet bulb causes a cooling effect resulting in the wet bulb recording a lower temperature
The drier the air the more evaporation will take place and so the greater the temperature difference between wet and dry bulb
How to measure wind strength
Anemometer
3 cups rotate on a spindle attached to a meter
The stronger the wind, the faster the rotation
Can also be estimated by observing the effects of wind on objects and comparing these observations to Beaufort scale
How to measure wind
Wind vane
Horizontal rotating arm on a vertical shaft
Directions are marked with fixed arms
Pushes tail which has greater surface area causing the arrow to move and face the wind
