HLY1803  shipboard ADCP velocity, from OS150                
                                                            
 The data were collected UHDAS. They were post-cruise       
 processed with the University of Hawaii software package   
 CODAS. The text file hly1803_procnotes.txt lists the       
 processing steps and parameters used, though in a cryptic  
 way meant to folks familiar with CODAS (i.e., its mostly   
 for myself).      

 This file contains the data in "Dan Torres" convention using
 the structure "vm_data" that Bob Pickart is familiar with
 (as opposed to F.Bahr's default format of matrices txy, u, v, etc).                                         
            

 All velocities are in m/s. Time is in GMT.   
                                                   
contents: (using the example of section DBO6; the number of profiles will
           vary from section to section)                                             

vm_data = 
          dday: [1x442 double]     decimal day, CODAS convention (see note below)
          time: [6x442 double]     [year month day hour minute second]
             u: [80x442 double]    zonal (eastward) velocity
             v: [80x442 double]    meridional (northward) velocity
         depth: [80x442 double]    ADCP bin depth
           lat: [1x442 double]     latitude, decimal degrees
           lon: [1x442 double]     longitude, decimal degrees
            ur: [80x442 double]    cross-section velocity
            vr: [80x442 double]    along-section velocity
          dist: [1x442 double]     distance along section [km]
      dist_ori: [1x1 struct]       describes CTD station used for distance origin
    proj_angle: -64.4013           section angle (deg T)
        tide_u: [442x1 double]     barotropic tide, zonal, already removed
        tide_v: [442x1 double]     barotropic tide, meridional, already removed
       tide_ur: [442x1 double]     barotropic tide, cross-section component
       tide_vr: [442x1 double]     barotropic tide, along-section component
    tide_depth: [442x1 double]     water depth according to tidal model
       et1botm: [442×1 double]     bottom depth interpolated from ETOPO1
        readme: [68×109 char]
    ship_speed: [1×442 double]     ship's speed in m/s


ctd_thissect: information about the CTD stations along this line;
              there were 20 stations for the DBO6 section.

ctd_thissect = 

1x20 struct array with fields:
    log           copy of the string in Bob's log file
    dday          station time in 2018 decimal days
    lon           - station longitude, decimal degrees
    lat           - station latitude, decimal degrees
    depth         - station depth, from the log file
    stat_id       - station number
    type          - 1: CTD; 2: XCTD; 3: XBT
    datenum       - station time in matlab convention 
    dist          - location in along-section distance [km]


 Note on CODAS "decimal_day" time conventions:                                               
        noon of Jan 1 is dec. day 0.5; 
        so day 19.5 is noon on Jan 20 of the reference year.
        6am on Nov 0, 2018 is dday 304.25.                 
       

Frank Bahr (fbahr@whoi.edu, frank.bahr@healy.polarscience.net)
Nov 10, 2018