In Situ Disdrometer Calibration Using Multiple DSD Moments

TL;DR

This paper presents an improved in situ calibration method for impact disdrometers that uses multiple moments of the drop size distribution, enhancing calibration accuracy over methods relying solely on rainfall rate.

Contribution

It introduces a calibration algorithm that incorporates optical extinction second moment measurements alongside rainfall rate, utilizing multiple DSD moments for better accuracy.

Findings

Enhanced calibration accuracy demonstrated through simulation and real data.

Incorporating multiple moments reduces calibration error.

Improved parameter space error surface analysis.

Abstract

In situ calibration is a proposed strategy for continuous as well as initial calibration of an impact disdrometer. In previous work, a collocated tipping bucket had been utilized to provide a rainfall rate based ~11/3 moment reference to an impact disdrometer's signal processing system for implementation of adaptive calibration. Using rainfall rate only, transformation of impulse amplitude to a drop volume based on a simple power law was used to define an error surface in the model's parameter space. By incorporating optical extinction second moment measurements with rainfall rate data, an improved in situ disdrometer calibration algorithm results due to utilization of multiple (two or more) independent moments of the drop size distribution in the error function definition. The resulting improvement in calibration performance can be quantified by detailed examination of the parameter space error surface using simulation as well as real data.