WHOI IMET Mooring Subsurface Data
---------------------------------
These data are from the Woods Hole Oceanographic Institution (WHOI) surface 
(IMET) mooring deployed in the center of the Intensive Flux Array (IFA) at 
1.756S, 155.995E during the Tropical Ocean Global Atmosphere Coupled Ocean-
Atmosphere Response Experiment's Intensive Observing Period (TOGA COARE IOP).  
The mooring was deployed by the R/V Wecoma on 21 October 1992 (04:30 UTC) and 
recovered by the same vessel on 4 March 1993 (00:05 UTC).  The water depth at 
the mooring was 1744m.  These data were collected by Drs. Robert A. Weller 
and Albert J. Plueddemann with support from the U.S. National Science 
Foundation (NSF) under grants OCE 91-10559 (RAW) and OCE 91-10554 (AJP).  
Instrumentation from the surface to 30m was provided by Weller.  
Instrumentation from 30m to 300m was provided by Plueddemann, except for five 
conductivity/temperature loggers (SeaCats) originally deployed at 45.5, 60, 76, 
92 and 108m which were provided by Dr. Matthias Tomczak (Flinders University, 
School of Earth Sciences, Adelaide, Australia). Instrument preparation, mooring 
deployment, and data processing were done by the Upper Ocean Processes Group of 
the Woods Hole Oceanographic Institution (WHOI). If you use any of these data 
in a publication, please acknowledge NSF, WHOI, and Drs. Weller, Plueddemann 
and Tomczak.

A mooring servicing occurred between 9 and 13 December which resulted in 
changes in instrument depth. From 9 December 1992 00:45 UTC to 13 December 
05:25 UTC, the surface discus buoy was temporarily replaced with a toroid 
buoy.  A length of wire rope inserted below the toroid increased the depth
of all sub-surface instruments by 10m from their nominal deployment depths. 
When the discus buoy was replaced on 13 December, the 10m length of wire 
used with the toroid was removed and a 2.29m length of chain was permanently 
added below the bridle of the discus buoy.

These depth changes have been accounted for in all the WHOI mooring files by 
interpolating measurements to their original deployment depth plus 2.29m 
throughout the entire deployment.  For instruments attached to the buoy hull 
(i.e., temperatures above 4.65m and salinity at 2.0m), no interpolation was 
necessary and no data was available between 9 and 13 December when the discus 
buoy was removed from the water.  Because the mooring was lowered by 10m at this
time (between 9 and 13 December), no data from the water column was available 
shallower than 10m (the shallowest instrument, the 4.65m temperature sensor, was 
lowered to 14.65m).  The deepest temperature (260m) and salinity (124m) 
measurements were interpolated to their original deployment depth.  The resulting 
data files report depths as the depth of interpolation, not the original deployment 
depth.  Interpolation for temperature and east and north currents were linear with 
depth.  Interpolation for salinity was linear in temperature/salinity space where 
possible, linear with depth otherwise.

Velocities provided below the deepest VMCM (52.5m) were measured by the ADCP.

Mooring Instrumentation
-----------------------
                                              Deployment  Interpolated
Sensor              Measurement                  Depth       Depth
------              -----------               ----------  ------------
Brancker T-Pod      Temperature                   0.4         0.4
Brancker T-Pod      Temperature                   0.5         0.5
Brancker T-Pod      Temperature                   1.0         1.0
Brancker T-Pod      Temperature                   1.5         1.5
Brancker T-Pod      Temperature                   2.0         2.0
SeaCat              Conductivity/Temperature      2.0         2.0
Brancker T-Pod      Temperature                   2.5         2.5
PMEL T-Pod          Temperature                   4.65        6.94
VMCM                Current/Temperature           5.15        7.44
Brancker T-Pod      Temperature                   5.65      Failed
SeaCat              Conductivity/Temperature      7.48        9.77
VMCM                Current/Temperature           8.9        11.19
SeaCat              Conductivity/Temperature     11.52       13.81  (Conductivity Failed)
VMCM                Current/Temperature          12.97       15.26
SeaCat              Conductivity/Temperature     15.52       17.81
VMCM                Current/Temperature          17.01       19.30
SeaCat              Conductivity/Temperature     19.5        21.79
ADCP                Current                      20.5        22.79
VMCM                Current/Temperature          23.0       Failed
SeaCat              Conductivity/Temperature     23.5        25.79
Brancker T-Pod      Temperature                  27.5        29.79
VMCM                Current/Temperature          31.5        33.79
SeaCat              Conductivity/Temperature     31.5        33.79
Brancker T-Pod      Temperature                  35.5       Failed
VMCM                Current/Temperature          39.5        41.79
SeaCat              Conductivity/Temperature     40.0       Failed
SeaCat              Conductivity/Temperature     45.5        47.79
VMCM                Current/Temperature          52.5        54.79
SeaCat              Conductivity/Temperature     52.5        54.79
SeaCat              Conductivity/Temperature     60.0       Failed
SeaCat              Conductivity/Temperature     68.0        70.29
SeaCat              Conductivity/Temperature     76.0        78.29
SeaCat              Conductivity/Temperature     84.0        86.29
SeaCat              Conductivity/Temperature     92.0        94.29
SeaCat              Conductivity/Temperature    100.0       102.29
SeaCat              Conductivity/Temperature    108.0       110.29
Brancker T-Pod      Temperature                 116.0       118.29
SeaCat              Conductivity/Temperature    124.0       126.29
Brancker T-Pod      Temperature                 132.0       134.29
Brancker T-Pod      Temperature                 148.0       150.29
Brancker T-Pod      Temperature                 164.0       166.29
Brancker T-Pod      Temperature                 180.0       182.29
Brancker T-Pod      Temperature                 196.0       198.29
Brancker T-Pod      Temperature                 212.0       214.29
Brancker T-Pod      Temperature                 228.0       230.29
Brancker T-Pod      Temperature                 244.0       Failed
Brancker T-Pod      Temperature                 260.0       260.00

Data Files
----------

Each file is uniformly spaced in time.  
Bad values or missing data are indicated by the value 9.96921e+36

Salinity
         Filename: togaSalinity.epic
  Sample interval: 900 seconds
Number of samples: 12846
            Start: 21 October 1992 04:31:53 UTC
              End: 3 March 1993 23:46:53 UTC
 Number of depths: 15
      Depth range: 2.0 - 124.0m
            Units: PSU

Temperature
         Filename: togaTemperature.epic
  Sample interval: 900 seconds
Number of samples: 12846
            Start: 21 October 1992 04:31:53 UTC
              End: 3 March 1993 23:46:53 UTC
 Number of depths: 41
      Depth range: 0.45 - 260.0m
            Units: degrees C

Velocity
         Filename: togaVelocity.epic
  Sample interval: 900 seconds
Number of samples: 12846
            Start: 21 October 1992 04:31:53 UTC
              End: 3 March 1993 23:46:53 UTC
 Number of depths: 25
      Depth range: 7.44 - 340.5m
            Units: cm/s

Calibration
-----------
The following is documentation for calibrations applied to the original
data.  Data supplied in the archive files (togaSalinity.epic, 
togaTemperature.epic and togaVelocity.epic) have had the corrections
described here already applied.  DO NOT apply these corrections again.

Salinity

A time-dependent drift was detected in the 2.0m and 9.77m salinity 
measurements.  Correction constants are provided below.

    A = 1.023E-02    B = 7.054E-05    C = -2.247E-08
    A = 6.721E-03    B = 2.478E-04    C = -1.898E-06

The corrections took the form:

  days = days since start of deployment
  offset = A + B * days + C * (days * days)     [PSU]

The computed offset was subtracted from the original salinity measurements.

Velocity

Magnetic variation correction of +7.67 degrees has been applied to currents

We gratefully acknowledge Eric Antonissen's (OSU,USA) intercomparison of
the shipboard ADCP and the moored VMCMs and ADCP.  Based on this 
intercomparison and additional analyses, directional errors were discovered 
in each VMCM and the ADCP compass.  Rotational correction constants are 
provided below.

   7.44m VMCM:   A =  5.4784   B =  -43.6205   C = -1.5389
  11.19m VMCM:   A = -1.6658   B = -304.3457   C = -0.4148
  15.26m VMCM:   A =  4.0246   B =  -65.7481   C = -0.8506
  19.30m VMCM:   A = -5.2206   B = -333.9808   C =  0.8737
  33.79m VMCM:   A =  8.0419   B =  -62.5923   C = -0.4753
  41.79m VMCM:   A =  6.6423   B =  299.8813   C = -6.7539
  54.79m VMCM:   A = -6.4865   B =  287.5624   C = -5.8766

Each VMCM was rotated by the angle theta as follows:
    theta = -1 * [A * sin(compass_direction + B) + C]     [degrees]
where a positive theta rotates east of north.

The ADCP rotational correction constants are as follows:
         ADCP:   A = -5.6058   B = -241.2480   C =  6.0464
where the rotation correction angle, theta, for the ADCP is equal to:
    theta = -1 * [A * sin(current_direction + B) + C]     [degrees]

ADCP velocities have NOT been corrected for soundspeed variations from the 
reference value of 1536 m/s. This will be a small correction (<1%) given the 
in-situ sound speed near 1540 m/s at the transducers. The bin depths have 
NOT been corrected for soundspeed variations from the reference value of 
1475 m/s. The true bin depths will be approximately 1540/1475=4.4% larger 
than the nominal values. 

Contacts
--------
If you have any questions regarding these data, please contact:

   Dr. Robert Weller
   Woods Hole Oceanographic Institution
   Woods Hole, MA 02543
   (508) 289 - 2508
   rweller@whoi.edu

   Dr. Albert Plueddemann
   Woods Hole Oceanographic Institution
   Woods Hole, MA 02543
   (508) 289 - 2789
   aplueddemann@whoi.edu

   Dr. Steven Anderson
   Woods Hole Oceanographic Institution
   Woods Hole, MA 02543
   (508) 289 - 2876
   sanderson@whoi.edu

   Mr. Mark Baumgartner
   Woods Hole Oceanographic Institution
   Woods Hole, MA 02543
   (508) 289 - 2677
   mbaumgartner@whoi.edu

References
----------
Plueddemann, A.J., R.P. Trask, W.M. Ostrom, R.A. Weller, B.S. Way, S.P. 
Anderson, N. Bogue, J. Shillingford and S. Hill, 1993: TOGA COARE mooring 
deployment, check-out, and recovery cruises. Woods Hole Oceanographic 
Institution Technical Report WHOI-93-30, 54 pp.