velocity measurements

Hello,

I have a question which might be quite simple, and I apologize if I am wasting your time, but I tried to search the forum in order to get an answer and did not succeed.

When I measure current velocity profiles with an 1Mhz ADCP HR profiler (extended velocity range turned off, using beam coordinates), I get after converting the*.prf  to ASCII files,  velocity data for each beam X,Y and Z direction(.v1, .v2,.v3).

Are these velocities the projections of the current velocity along the X, Y or Z coordinate?

I took a preliminary look at my data using the ExploreP program, in which you have a velocity button.

Is this velocity, the velocity of the incoming current along the direction it is incoming(which I will be able to see from the direction data)?

How is this velocity calculated, using the data from the X,Y and Z directions? 

Kind regards,

Christian

Hi Christian,

If you chose Beam coordinates for your deployment in the planning section, the three velocity files (v1, v2, v3) will report beam velocities. You can verify the coordinate system of a data file by checking the header file produced during ASCII conversion.

I'm unfortunately not familiar with ExploreP enough to answer your second question. I suspect ExploreP uses the data file's coordinate system but I could be wrong.

P.J.

Hallo P.J.,

thank you for your quick response, I checked the coordinate system via the header-file.

regards,

Christian