have a low coefficient of expansion, and its diameter should not exceed S of the gauge diameter. Graduation should be in units of rainfall and at least every 0.2 mm should be marked. Dip rods are mainly used to measure rainfall in monthly or seasonal gauges. However, these measurement should be checked using cylinders as well. - As far as the exposure of rain gauges is concerned, sites sheltered from wind but not from the rain should be chosen. Early disturbances of the airflow due to obstructions and the instrument itself have to be avoided. It is important that the orifice of the gauge be horizontally exposed and is high enough to prevent splashing from the ground. (In different countries standard heights of 30 to 150 cm are used). 2.4.22 Recording rain gauges 2.4.221 Rainfall recorders to record the total amount of rainfall. - In the float type of instruments, the rain is led into ab bfloat chamber, and the vertical movement of alight float
