weather not finished Flashcards
what does a stevenson screen do
provides shelter for meteorological instruments
adaptations a stevenson screen has (4)
- long legs
- white surface
- slatted sides
- made of wood
why does a stevenson screen ahve long legs
because the surface it is placed on can attract heat and reflect the sun’s rays and also humid so it needs to be further away from it ( so that it measures the airs conditions and not the grounds)
why does a stevenson screen have a white surface
so that it reflects the suns rays
why does a stevenson screen have slatted sides
so the air can move freely ( there is a free movement of air )
why is a stevenson screen made of wood
because wood is a bad conductor of heat so can insulate the instruments properly
What are the advantages of using digital weather recording instruments? (6)
Less maintenance needed
Better accuracy
Remote monitoring capabilities
Can easily integrate with other systems
Remote access to data
Instant readings
instruments that are found outside include (3)
- rain gauge
- wind vane
- anemometer
barometers and barographs are kept away from
strong air movements and direct sunlight and heat sources
wind vanes and anemometers are stationed where
in the open, away from trees or buildings, and away from the nearest obstacle by at least three times the height
The rain gauge must be in
an open space with a distance from the nearest object twice its height
Thermometers are kept
away from buildings that may radiate heat
wind direction is measured with a
wind vane
how does a wind vane work
arrow points in the direction that the wind is pointing
- has north, east south and west on it so you can tell where 8 compass points)
why is a wind vane kept away from buildings and trees or over them
because like that the wind direction isn’t altered by any of those factors and it measures correctly
wind speed is measured with an
anemometer
an anemometer consists of
3 or 4 cups fixed on metal arms that rotate freely on a 10m vertical shaft
what happens to the cups of an anemometer when the wind is strong
they rotate very fast, and more rotations are recorded on the counter
why are many anemometers digital
as they transmit data directly to apps and computers to show readings directly
The digital handheld anemometers need to be held where
held into the oncoming wind and as the fan rotates, the number is shown on the screen
what is precipitation
any water that falls to earth - hail, mist, rain, sleet, or snow
unit of measurement for precipitation
millimitres
what is used to measure precipitation
rain gauge
how does a rain gauge work
any water that is collected throughout the day is pured into a measuring cylinder AT THE SAME TIME EACH DAY then The water level is read with the eye at the same level as the lowest part of the meniscus of the water
what does a six’s thermometer measure
maximum and minimum temperature ( AKA maximum and minimum thermometer)
weather is
The state of the atmosphere at a particular place and time.
climate is
Generally prevailing weather conditions of a region averaged over a at least 30
meteorology is
the study of the atmosphere and its phenomena, especially weather and weather forecasting.
what is diurnal range
difference between daily maximum and daily minimum temperatures.
Wet bulb - dry bulb thermometer measures
relative humidity (AKA hygrometer).
relative humidity is
percentage of water vapor in the air compared to the maximum amount the air could hold at that temperature.
dew point
Temperature at which air is saturated and condensation forms.
barograph is a
barometer that records its readings on a moving chart.
barometer measures
measures air pressure
Air pressure
The force exerted on a surface by the air above it as gravity pulls it to Earth.
millibars are
The unit for air pressure
prevailing wind
The dominant wind in an area.
sunshine recorder
Instrument used to record hours of sunshine.
isobars
Lines joining places on the map that have the same air pressure.
Isohyets
A line drawn on a weather map connecting points that receive equal amounts of precipitation.
Isotherms
A line on a map connecting points having the same temperature.
Temperature range
Numerical difference between the minimum and maximum values of temperature. Can be measured as diurnal or annual.
Warm air can hold ___ water vapour than cold air
more
When the air is holding as much moisture as it can, it’s said to be ___
saturated
