Chapter 1 - Accuracy assessment and intercomparison of precipitation measurement instruments

Abstract

A high accuracy of in situ liquid and solid precipitation measurements, though understated in most research studies and technical applications, is imperative to substantiate both scientific achievements and decision-making. However, both operational and dedicated scientific measurements are still currently performed with a much lower accuracy than the available scientific knowledge and technological development would permit. Beyond the assessment of the measurement uncertainty, and the need to ensure full traceability of precipitation measurements, significant instrumental and environmental sources of measurement bias still affect the knowledge and monitoring of precipitation. In this chapter, based on the most recent research, the accuracy of precipitation measurements is shown to rely on the interpretation and adjustment of high-resolution raw data from traditional sensors and on the knowledge of the particle size distribution and other microphysical characteristics of the precipitation process. The recent international intercomparison results corroborate this conclusion by confirming that only well-calibrated and bias-corrected instruments show acceptable performance against the reference precipitation.