Somehow, there is never just the right amount of rain. Sometimes there is just too much. This can cause flooding, soil erosion, crop damage, and property damage. Often, there is simply not enough rain. This can cause minor problems, such as home lawns that are not green. More significant problems include crop loss due to draught and industrial shortfalls. Severe water shortage can result in loss of livestock. And in many areas of the world, the human population can suffer from lack of potable water. The academic scientific community has great interest in recording precipitation over short, medium and long periods of time. Governmental organizations also share this interest. Precipitation during the course of a few days can predict possible flood conditions downstream. This may be critical for avoiding dangerous conditions and economic loss. Snowfall during the course of the winter is critical for water availability the following spring and summer. Accurate measurement can provide necessary information for agricultural purposes as to the types and variety of crops that would be planted dependent on the amount of irrigation water that would become available for them. Long term measurements can give climate trends and global warming information. There are a variety of different types of devices that may be used to measure precipitation. The simplest type is an open bucket, tube or column. Water can accumulate over time. Readings need to be recorded on a regular basis. In order to avoid inaccurate readings, recordings must be taken before the collection device overflows. Generally, the device would be emptied after recording. This is not a very efficient way to obtain information since it requires a considerable amount of human time and effort. A preferable method is to place the collection bucket on top of an electronic scale. The weight detected on the scale platform would be directly proportional to the amount of rain water in the bucket. In fact, the rain gauge scale would be just as effective in determining the amount of water if the precipitation was in the form of snow. While the volume is vastly different between rain and frozen precipitation, the amount of water is properly calculated from the weight. Of course, a human operator could still collect data by manually recording readings from the electronic scale. But it is even better to provide the rain gauge scale with an electronic output that can be connected to a chart recorder. Not only does this provide total precipitation information, but it also relates the precipitation to time and date. More sophisticated systems can also automatically empty the collection device before it overflows. The rain gauge scale must be designed with a number of important specifications. Most industrial scales are meant to operate within a fairly narrow range of temperature. Generally, accuracy in negatively impacted by wide ranges of temperature. Of course precipitation measurement occurs outdoors. The environment may vary from exceedingly hot to freezing cold. In order to provide proper accuracy, the scale has to be temperature compensated to work over this very wide range of temperature. The most critical aspect of this is the load cell. Careful construction, calibration and resistor compensation can result in excellent accuracy under all conditions. There are also a number of electronic devices that process the signal from the load cell and convert it to useful information. This includes amplifiers and digitizing devices. These must also be designed to eliminate errors caused by changes in temperature. Even though a good rain gauge scale will provide some protection from humidity and water, the type of material used to fabricate the load cell should be chosen to avoid corrosion. Two of the best choices are stainless steel and aluminum. Although chart recorders have been used for many years, a more modern and convenient type of recording device is a USB memory stick. Of course the rain gauge scale will need to include a Universal Serial Bus interface and a real time clock. The memory stick has to have enough capacity to collect data during a long enough period of time. Available USB memory sticks are now so large and inexpensive that they can collect year’s worth of data. In this case, the scale operator can simply collect the memory stick and bring it back to any PC for data download and evaluation. Even better, it is now possible to design the rain gauge scale with a wireless interface. In this case, data can be collected automatically. The range and type of wireless communication may be dependent on the location of the devices.
Home Precipitation Measurement and Study with Rain Gage Sales