Uncertainty in measured raindrop size distributions from four types of collocated instruments

This unique dataset was used to study the inherent measurement uncertainty due to the diversity of the measuring principles and sampling sizes of the four types of instruments.

The DSD intercomparison shows generally good agreement among them, except that the POSS and MRR had higher concentrations of small raindrops ( 5.2 mm). The measurement uncertainty ( sigma ) was obtained quantitatively after considering the zero or non-zero measurement error covariance between two instruments of the same type. The results indicate the measurement uncertainties were found to be neither independent nor identical among the same type of instruments.