How do meteorologists measure inches of rain?

The standard instrument for the measurement of rainfall is the 203mm (8 inch) rain gauge. This is essentially a circular funnel with a diameter of 203mm which collects the rain into a graduated and calibrated cylinder. The measuring cylinder can record up to 25mm of precipitation.

How do you measure rainfall accurately?

The most accurate way to measure rainfall is to take a rain bucket of a known diameter (usually 12 or 24 inches) and place it on a scale. The scale subtracts the mass of the container from the mass of the rain.

Why are rain amounts in the US reported in inches and tenths of inches rather than inches and half quarter eighth of inches?

The inner tube’s diameter is just small enough to make the depth of rain ten times what it would be in a gauge without the tube and funnel. Thus, each inch in the tube is equivalent to 0.1 inches (a tenth of an inch) of rainfall. This makes it easier to read accurately!

Why are rainfall measurements expressed in terms of depth and not by volume?

Because rainfall is highly spatially variable so it would make more sense to measure it as depth at a given point (x,y,z which is the location of the rain gauging station) rather than volume because volume implies a given application area (which is often unknown and can only be extrapolated by scrutinising rainfall …

What instrument measures rainfall?

rain gauges
Instruments for measuring precipitation include rain gauges and snow gauges, and various types are manufactured according to the purpose at hand. Rain gauges are discussed in this chapter. Rain gauges are classified into recording and non-recording types.

What does an inch of rain mean?

Rainfall amount is described as the depth of water reaching the ground, typically in inches or millimeters (25 mm equals one inch). An inch of rain is exactly that, water that is one inch deep. One inch of rainfall equals 4.7 gallons of water per square yard or 22,650 gallons of water per acre!

What does rainfall in inches mean?

How is rainfall measured in US?

As you probably know, rainfall amounts in the United States are typically measured in inches. Actually, although we usually just say “inches,” we really mean “inches in the storm” or “inches in the last 24 hours” or “inches in some time period.” Why does that matter?

Why are rainfall measurements expressed in terms of depth?

The total amount of rainfall over a given period is expressed as the depth of water which would cover a horizontal area if there is no runoff, infiltration and evaporation. Accuracy of rainfall measurement is mainly affected by wind, by the height of the gauge and exposure.

Is rainfall measured with centimeters in inches?

Precipitation is measured in units of depth, e.g. centimeters, inches, etc.

How do you measure inches of rain?

As we talked about earlier for the straight-sided gauge, the number of inches of rain must be equal to the volume of water divided by the area of the collector. So, by measuring the volume and area, you can determine the number of inches of rain.

What are the methods of measuring rainfall?

This gauge for measuring rainfall is used so widely that even meteorological departments have opted for this method. In this mechanism, an 8-inch diameter funnel-shaped or cylindrical collected is linked with a measuring tube and is placed in an open area where it can receive rain.

Why is exposure important when measuring rainfall?

According to the National Weather Service and CoCoRAHS (both of which use citizen volunteers to measure rainfall), “exposure” of the rain gauge is important. Rain may be blocked by nearby obstacles causing the number to be lower than it should. Or, rain may be blown into or away from the gauge by wind gusts.

How do you find the average volume of rain?

Calculate the average of the two diameters. Divide by two to find the average radius. Find the average volume of rain = Depth x radius x radius x 3.14. Find the area at the top of the bucket (this is the area over which the rain is collected). Divide the rainfall volume by this area to get the rainfall.