Ground-Based Direct Measurement

Rain gauges and disdrometers provide direct in situ measurements of rainfall properties at relatively high temporal resolutions. In this chapter, the most common types of these instruments are described. While rain gauges measure rainfall accumulations and intensities, disdrometers provide data on the drop size distribution that describes the rainfall microphysical structure. In addition, some disdrometers can also measure the fall velocities of the drops. The most significant error sources, problems of automated data quality control of rain gauge data and example schemes for correcting their systematic errors, as well as selected issues of disdrometer data representation are presented here.