How can you measure rainfall

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Cookie Settings. Learn why people trust wikiHow. Download Article Explore this Article parts. Tips and Warnings. Related Articles. Article Summary. Part 1. Find a clear, cylindrical container. This cylinder can be either glass or plastic, and should be at least 12 inches tall. The shape is important: if the top is wider than the bottom or narrower it will require much more calculation and measurement.

As the volume of the container gets bigger—from say, a coke can to a mop bucket—so does the area which collects the rain. Because of this, one inch of rainfall will be recorded consistently between cylinders of varying sizes. Make a container. Using scissors or a knife, cut the top 4 inches of the bottle off. Don't worry about the uneven bottom of the bottle. That will be taken care of in the next step. Weigh your gauge down with pebbles.

As an alternative to placing pebbles in your gauge, you could place it within a sturdy container, such as a heavy bucket or flowerpot. Inscribe a scale upon your container.

This can be done with a waterproof sharpie. Hold a ruler or measuring tape up against your bottle, and line its zero up with the current water level of your gauge. In this case, zero will be at the bottom of your container. Place it under the open sky, on level ground.

You need level ground to lessen the chance of your gauge tipping over. Ensure your gauge has no obstructions above it, e.. Part 2. Check your gauge every day. Read the gauge by looking at the waterline straight on, at eye level. The water line's surface will be curved; this is the meniscus, formed as the water comes in contact with the container and creates surface tension.

You can lose water from evaporation, and water mysteriously showing up in your rain gauge without the accompanying rain clouds might mean your rain gauge needs a new spot sprinklers are a common culprit. Mark the amount of rainfall on a graph or chart. For example, you could make a 7 x 7 chart, marking the days of the week along the x-axis and 1 to 7 inches 2.

After filling in a dot at each appropriate intersection of rainfall in inches and the day of the week, you can use a ruler to connect the dots and see the fluctuations in the rain measurement for that week. Empty the rain gauge. Ensure you keep the same stones in your gauge, and refill water up to the zero on your scale. If you ever add or subtract stones from your gauge, ensure the water is again filled to the zero point before setting your rain gauge back in place.

The recorded precipitation is always expressed in terms of rainfall or melted snow. The snow depth doesn't count? Sometimes a foot of snow amounts to just a half-inch of water, other times it amounts to three inches of water. It really depends on the water equivalent of the snow, which varies widely. On the average, 10 inches of snow is equivalent to one inch of rain, but that's only an average.

If a rain gauge measures one inch of water during a snowstorm, an observer can't automatically assume that 10 inches of snow has fallen. The snow depth can only be determined the old-fashioned way? That depth is determined by taking an average of three or more representative spots. A ruler is stuck into the snow, and its depth is recorded. Because of blowing and drifting, the determination of three or more representative locations is not always easy.

You would think that there would be a better way, but there really isn't. Most recently, Doppler radar has been used to estimate rainfall. We'll take a look at this newest technology in the next section.

All rights reserved including the right of reproduction in whole or in part in any form. Where an observer is not available to provide daily rainfall, readings may be made at weekly or monthly intervals. How we measure rainfall. You might also like. Temperatures is taken using specialist thermometers dependent upon the surface for which temperature is required.

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