02 climate and weather (gi) Flashcards
How do you use a Maximum-minimum Thermometer?
Place the thermometer in a Stevenson Screen where it is out of direct sunlight. The lowest point of each metal index indicates the temperature. The diurnal temperature range is derived from the highest minus the lowest temperature of the day.
What are the do’s and don’ts of a Maximum-Minimum Thermometer?
- Placed/ Held 1.5m above ground as the ground absorbs heat and will transfer it to the thermometer, resulting in inaccurate readings.
- Shield the bulb from direct sunlight so that the temperature recorded is air temperature and not higher.
- Do not hold the thermometer by the bulb. Body heat through the fingers can cause the reading to be higher.
- Read reading at the height of the liquid to avoid parallax error.
- Take temperature readings for more than one day and average the readings out. Temperatures should vary day to day.
How do you represent the data collected from a Maximum-Minimum thermometer?
(Comparative) Line graph - to show trends (across multiple variables)
Scatter plot graph (with Best Fit Line) - to show a relationship between two variables
How do you use a Sling Psychrometer?
- Prepare the Wet Bulb by saturating the wick (piece of fabric) that covers the base of the thermometer with room temperature water.
- Hold the Hygrometer by its handle and swing it in a circular manner for at least 1 minute/ 30 times.
- Record the Wet Bulb temperature followed by the Dry Bulb temperature.
- Use the conversion table provided to convert the temperature difference into relative humidity.
- Record the humidity levels as a percentage in a recording spreadsheet with the corresponding date, time, location and overall weather condition.
What are the do’s and don’ts of a Sling Psychrometer?
- Stand in a shady spot as radiant heat from the Sun may affect the thermometers.
- Keep the psychrometer far enough from our body and facing the wind to ensure that it does not absorb heat and humidity from our body.
- Sling it for at least 1 minute/ 30 times so evaporation of the cloth on the Wet Bulb thermometer can take place.
- Do not hold the Wet Bulb with our bare hands as oil from our hand can affect the evaporation of the cloth of the Wet Bulb
- Do not hold the glass bulb of the thermometers as heat from our fingers can affect the accuracy of the reading of air temperature.
How do you represent the data collected from a Sling Psychrometer?
Scatter plot graph (with best fit line) - establish a relationship between 2 variables
How do you use a Wind Vane?
- Place it in an open area where there is wind blowing directly at it.
- Hold it slightly above your head while ensuring that it is not obstructed.
- Use a compass to determine the position of the Wind Vane. The north of the compass should correspond with the N on it. Turn it until it matches.
- Record the wind direction by seeing where the wind vane is pointing. This is the direction where wind is blowing from.
What are the do’s and don’ts of a Wind Vane.
- Use it in an open area as wind can be blocked by trees and tall buildings.
- Stand in a way that the body is not blocking the wind.
- Repeat it a few times and take the average reading.
How do you represent the data collected from a Wind Vane?
Use a wind rose with different directions on it. Shade a space that corresponds to the wind direction per day.
How do you use an Anemometer?
Stand at the end of an open corridor on the highest floor of a building or in an open area.
Hold up the Anemometer.
Read off the wind speed on the display on the Anemometer.
What are the do’s and don’ts of an Anemometer?
It must be used in an open area as wind directions can be deflected by trees and tall buildings.
How do you represent the data collected from an Anemometer?
Use a wind rose with a graduated scale. Shade it according to direction as well.
How do you use a Rain Gauge?
- Find an appropriate spot to place the Rain Gauge. Position it in an open area.
- Place it into the ground while keeping about 30cm protruding above the ground.
- Record the time when rainfall starts and stops.
- Pour the collcted water from the Rain Gauge into a Measuring Cylinder. Read and record water level.
What are the do’s and don’ts of a Rain Gauge?
- It should be sited in an open field, away from tall buildings, trees and other objects that could shelter it.
- It should be about 1/3 of a metre above the ground. This prevents splashing and allows the maximum amount of rainwater to be collected.
- Readings are taken at eye level to avoid parallex error.
- Do not place it in wide open spaces or elevated sites to avoid wind and the resulting turbulance problems.
How do you represented the data collected from a Rain Gauge?
Bar Graph
