New Geography in Action Junior Cycle Geography Precipitation
1. Precipitation is any form of liquid or solid water particles that fall from the atmosphere and reach the surface of the Earth. It includes rain, snow, sleet, hail and drizzle.
2. A rain gauge is used to measure the amount of rainfall.
A measuring cylinder with a funnel on top is placed in an open area, not sheltered by buildings and trees, in order to ensure an accurate reading.
The rain falls through a funnel into the cylinder, which is marked in millimetres. When the cylinder is removed, the amount of rain that has fallen can be recorded
3. The unit of measurement of rainfall is millimetres (mm).
4. The lines on a weather map showing areas of equal rainfall are called isohyets.
Sunshine
1. Sunshine is when the sun’s rays reach the surface of the Earth.
2. Sunshine is measured using a Campbell-Stokes sunshine recorder.
A glass sphere focuses the sun’s rays onto a spot on a sensitive strip of paper slotted into the semi- circular frame surrounding the ball. The sun’s rays burn a mark on the paper. As the sun moves across the sky during the day, the burn marks move along the paper. At the end of the day, the paper can be examined to see how much the sun shone during the day.
3. Sunshine is measured in hours per day.
4. The lines on a weather map showing areas of equal sunshine are called isohels.
: Figure 13.35 A Campbell-Stokes sunshine recorder : Figure 13.34 A rain gauge
( Figure 13.36 Readout from a Campbell-Stokes recorder
Go to page 52 of your Portfolio to find out how to make your own weather station. PORTFOLIO ACT VITY 13.1
