I have bought the final tank! Another milestone passed!
I now have two tanks, the small box that was used for the stairway experiments and the new 0.8m diameter circular tank, on the roof collecting data. The small box is still lined in the anechoic, but the large is not. Because of this, we get lots of nasty reflections.
What I have been able to do is start processing the total sound field, much like the many acoustic disdrometers of Nystuen et. al. but in a more sophisticated statistical way. He fits a distribution around the spectrum of the sound via various fudge factors, as its know in the electronics world. What we have done is used Principal Component Analysis to find the parts of the signal that really are changing with different disdributions and rain rates. This way we get the optimal conversion between a sound spectrum and a DSD.
Up to now I have only processed it on second-by-second data due to a lack of it. But in time I aim to try minute-long datasets in order to properly correlate against the optical disdrometer and the extrapolate back down to one second.
Below are some images of the process; they are self explanatory:
Post a Comment