Question

what precautions should be taken while measuring rainfall

Answer 1

brainliest please

The Weather Bureau solicits the observation and record of rain, snow, and hail, at carefully selected stations, with a three-fold object: to benefit commerce on navigable streams, to assist the operations of agriculture by irrigation and water storage in regions where the rain- fall is insufficient at the time when the crops most require water, to enable specialists of the Bureau to gain such knowledge of the climate of the several regions of the country as will permit them to supply engineers and others with the facts which are needed to govern them in the construction of water and other works. These eminently prac- tical benefits are to be obtained only by carefully prepared records of observations of the rainfall made at many stations. To secure this accuracy each observer should study the simple instructions herewith offered for his guidance. 1. Each station will be equipped with a standard rain-gauge, and if possible, a wooden box support, complete, which is to be mounted in the manner described below. The rain-gauge consists of three parts The receiver, A. The overflow attachment, B. The measuring tube, C. The top cylindrical portion of the receiver, marked a in Fig. 2, is exactly 8 inches in diameter, inside, and is provided with a funnel- shaped bottom, which conducts any precipitation falling into the re- ceiver into the tall cylindrical measuring tube, (7, the total height of which, inside, is exactly 20 inches. The diameter of this tube is much smaller than the large receiving tube, a, being only 2.53 inches. In consequence of this a small amount of rain falling into the receiver and flowing into C fills the latter to a depth greater than the actual rainfall in proportion as the area of the receiver is greater than the area of the measuring tube. In the standard gauges of the Weather Bureau the depth of the rainfall, in accordance with this principle, is magnified just ten times. The receiver, A, has a sleeve, d, Fig. 3, which slips over the tube, (7, and very effectually prevents any loss of rainfall. Again, when the rainfall is very heavy the tube, (7, may be more than 2 filled. In this case to still prevent loss a little opening, shown at e, Fig. 2, is made in the sleeve, d, just on a level with the top of the tube, C. The excess of rainfall escapes through this opening, and is retained in the large overflow attachment, J9, and can be measured afterwards, as will be described below. In the drawing the diameter of the over- flow attachment is shown as less than 8 inches, but in the latest style gauges this part is now also made just 8 inches inside diameter. The object of this is to be able to use this portion of the instrument as a snow gauge, as will be explained hereafter.