Unit 2: Meteorological Data

Question 1

What are the aspects that determine the hydrology of the region (3)

Answer 1

1. Climate: the geographical position on the earth’s surface e.g. precipitation and humility
2. Topography: effects of precipitation, the occurrence of lakes, marshland and rates of runoff
3. Geology: influences topography and groundwater flow

Question 2

What is atmospheric circulation

Answer 2

The movement of air around the planet. It is influenced by the earth’s daily rotation, which gives alternating 12 hour heating and cooling.

Question 3

What is seasonal variation

Answer 3

The changes in weather and climate patterns that occur throughout the year due to the tilt of the Earth’s axis relative to its orbit around the sun.

Question 4

What is humidity

Answer 4

The amount of water vapour in the air.

Question 5

Define the following:
1. Saturation vapour pressure
2. Saturation deficit
3. Dew point temperature (td)
4. Wet bulb temperature

Answer 5

1. The maximum amount of water vapour the air can hold at a specific temperature.
2. The difference between the actual vapour pressure in the air and the saturation vapour pressure at the same temperature.
3. The temperature at which a parcel of air must be cooled down for water vapour to condense into H2O.
4. The temperature to which the original air can be cooled by evaporating water into it.

Question 6

What instruments are used to measure the following:
1. Temperature
2. Radiation
3. Wind

Answer 6

1. Thermometer
2. Radiometer
3. Anemometer

Question 7

Name the four sources of precipitation and one of the factors it depends upon.

Answer 7

The sources of precipitation are snow, hail, sleet and rainfall. It is also temperature dependant as cooler air results in less water vapour being retained.

Question 8

Name and describe the processes responsible for precipitation (2)

Answer 8

• Collison (coalescence): water droplets collide and form heavier droplets big enough to overcome air resistance and thus it falls to the earth’s surface.
• Crystal process: at 40 degrees Celsius ice crystals form because particles like clay, organic materials and ocean salts act as freezing agents.

Question 9

Name and describe 3 types of precipitation

Answer 9

1. Convective: typically occurs during the summer season and is caused by rising warm air, often leading to thunderstorms.
2. Orographic: occurs near coastlines when moist air is lifted over a mountain, cooling and condensing.
3. Cyclonic: occurs over open sea and is formed when cyclones grow in size and allow moist air to be drawn into the cyclone vortex.

Question 10

What are other types of precipitation (2)

Answer 10

• Frontal: warm front, cold front and stationary front
• Non-frontal

Question 11

How is precipitation collected and measured?

Answer 11

By a rain gauge

Question 12

What are the important considerations for properly sitting a rain gauge to ensure accurate rainfall measurement (4)

Answer 12

• Ground must be level, open, with a horizontal catch surface.
• Gauge should be near the ground to reduce wind effects but high enough to prevent splashing and flooding.
• Surrounded by an open-fenced area.
• No obstructions within 30m or twice the height of the obstruction.

Question 13

Name and describe the types of rain gauges and the categories they belong to.

Answer 13

1. Non-recording Rain Gauges: Measures the amount of rainfall over a period manually.
2. Recording Rain Gauges
   - Tipping-bucket type: Records rainfall by counting the number of times a bucket tips.
   - Weighing-bucket type: Measures rainfall by the weight of the collected water.
   - Floating-type gauge
   - Radar Measurement
   - Satellite remote sensing