NPS Offshore Directional RDI ADCP Data from NCEX Experiment, 2003

Data provided by:  Ed Thornton and Tim Stanton
                   Dept of Oceanography
                   Naval Postgraduate School
                   Monterey, CA 93943
                   
                   thornton@nps.edu,  stanton@nps.edu

                   
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For directional ADCP coordinate location and sampling information, see the file 

                   "ncex_locations_nps_metadata.txt"           


Filename syntaxes:

   DPSVSpec.tar = tarred, gzipped compilation of all DSpec*.txt, PSpec*.txt,
                  SSpec*.txt, and VSpec*.txt files (described below), to
                  allow easier download of all these files simultaneously.
                  (To uncompress, use "tar xzvf DPSVSpec.tar".)
   
   DSpec*.txt = standard output directional spectrum file generated by
                RDI WAVES software.  Matlab loadable.  Initial (commented)
                lines describe number of frequencies and frequency-direction
                spacing of spectrum.  Remaining lines are ordered with
                rows corresponding to frequency bins and columns corresponding
                to direction (with first column corresponding to degree value
                on the last commented line at top, and succeeding columns
                corresponding to increasing degree values; angles return to
                zero after passing 360 degrees).  Spectral density values
                are not in standard units.  Based on suggestions from RDI,
                we now use the following conversion algorithms:
                
                    S(f) = sum(DSpec,2)/(ndir*1e6);
                    S(f,dir) = DSpec/(ndir*1e6*ddir);
                
                where S(f) is the frequency spectrum in m^2/Hz, S(f,dir) is
                the freq-directional spectrum in m^2/(Hz deg), ndir is
                the total number of directions spaced at ddir, and
                DSpec contains the originally loaded matrix values.
                (Note that we are not 100% confident in these algorithms!
                Use at own risk and contact RDI if clearly erroneous
                values result.)
   
   PSpec*.txt = standard output pressure spectrum file generated by 
                RDI WAVES software.  Matlab loadable.  Initial (commented)
                lines provide number and spacing of frequency bands,
                with modified spectral units.  According to RDI, these
                values may be squared and then multiplied by 1e6 to
                convert them to m^2/Hz.
   
   SSpec*.txt = standard output surface spectrum file generated by 
                RDI WAVES software from echosounder data.  Matlab loadable.  
                Initial (commented) lines provide number and spacing of 
                frequency bands, with modified spectral units.  According to 
                RDI, these values may be squared and then multiplied by 1e6 
                to convert them to m^2/Hz.
   
   VSpec*.txt = standard output surface spectrum file generated from velocity
                data by RDI WAVES software.  Matlab loadable.  Initial 
                (commented) lines provide number and spacing of frequency bands,
                with modified spectral units.  Same conversion method
                may be applied to convert to m^2/Hz as with PSpec*.txt files.
   
   dspec.tar = tarred, gzipped compilation of all dspec*.jpg and dspec*.mat
                  files (described below), to allow easier download of all 
                  these files simultaneously.
                  (To uncompress, use "tar xzvf dspec.tar" in unix/linux
                   or WinZip/other compression utility in Windows/Mac.)  
                            
   dspec*.jpg = rough plots of spectral magnitudes from DSpec*.txt files with
                corresponding date and time in filename.  These values are
                intended to show only RELATIVE spectral magnitudes and
                distribution over frequency and direction; they have not
                been converted in the manner described below.  Direction
                axis adjusted so that spectrum runs from -180 to 180 degrees 
                (rather than 0 to 360).
   
   dspec*.mat = files containing spectral matrices corresponding to the
                data in corresponding DSpec*.txt file, together with a vector
                for frequency (Hz) and a vector for direction (deg).  
   
                
Numbering syntax for [D,P,V]Spec*.txt files: 

               [D,P,V]SpecYYMMDDHHmm.txt
               
               YY = two-digit year (03 ==> 2003)
               MM = month (01-12)
               DD = date (01-31)
               HH = hour (00-23)
               mm = minute (00-59)
               
               Times are recorded in Pacific Standard Time, 2003.



For further data-related questions, contact Mark Orzech, orzech@nps.edu