About correlation

Hi,

    I have a question about the correlation and data quality. We surveyed in a estuary, and the fig is the correlation in a burst, the lateral axis is correlation between 0~10,10~20,and so on, and the longitudinal axis is the number of samples. I want to know, can we use the data to calculate turbulenct feature, such as Reynold stress, turbulence spectral. And I wonder the sediment concentration whether effect the correlation or not?

Thank you! 

Dear Liu Huan

The correlation is affected by the strength of the acoustic echo that comes back from the water but also by other processes such as pulse-to-pulse interference (see HR primer).

If the reduced correlation comes from a lack of scatterers in the water (i.e. low sediment concentration), you can generally perform turubulent analyses. However, you will find that the spectra are quite noisy in the high frequency range.  If the reduced correlation comes  from other processes (for example, SNR>20 dB and Correlation < 90), then you have to be more careful since the velocity data may be biased.

Best regards, Atle Lohrmann

Dear Atle Lohrmann,

Thank you very much!

Best regards.