Hyperspectral Coupled Ocean Dynamics Experiments (HyCODE)

This portion of the HyCode program provides an observational study of the roles of vertical turbulent mixing and coastal upwelling in transporting suspended sediments to optically relevant heights in optically deep water. The study will capitalize on recent development of field instruments, termed Laser In Situ Sizing and Transmissometry (LISST) sensors, which provide optical measurements of the particle size spectrum in the diameter range between approximately 1 and 250 microns. Supporting instrumentation will include an array of fluorometers, which will permit at least a crude distinction between suspended sediments and particles containing chlorophyll; an array of temperature sensors, which will provide measurements of stratification; and an array of velocity sensors, which will determine flow conditions. The tripods were deployed on July 24, 2000, near the NODE B at the LEO-15 site off central New Jersey at approximately 15 meters depth. Data were continuously logged through September 21, spanning the coastal upwelling season and extending into atmospheric cooling and wind forcing events of the early fall. The large tripod was redeployed on September 16 and the final recovery was on December 2, 2000.  A second deployment in the summer of 2001 included the same instruments, without the thermistor array, along with a Sontek Dopbeam, which profiled 125 1.2 cm bins below 1.3 mab at 375 Hz.
 

                                                   Trowbridge Tripod                                            Agrawal Tripod
Deployment Ia:                         7/24/00 - 9/15/00                                              7/24/00 - 9/13/00
                                                      39° 27.39´ N                                                          39° 27.40´ N
                                                      74° 14.31´ W                                                         74° 14.24´ W

Deployment Ib:                       9/16/00 - 12/2/00                                             10/11/00 - 12/2/00
                                                    39° 27.31´ N                                                             39° 27.39´ N
                                                    74° 14.32´ W                                                             74° 14.22´ W

Deployment II:                     6/20/01 - 8/6/01                                                  6/20/01 - 8/6/01
                                                      39° 27.39´ N                                                           39° 27.40´ N
                                                      74° 14.31´ W                                                          74° 14.24´ W

A large footprint tripod was instrumented with two Sontek ADV velocity sensors, which were designed to simultaneously sample temperature nearly colocated with the velocity sampling volume. The configuration of the two probes was designed to provide a means to remove waves from the velocity measurements to provide direct estimates of stress. The Sontek ADVs also provide signal strength, which will be used as a proxy to sediment concentration to estimate < c ´ w ´ >. The instruments measure horizontal and vertical velocity, signal strength and temperature at approximately 0.7 and 3.4 mab, sampling for approximately a half-hour of each hour at 5 Hz throughout the deployments. A Seaguage also was placed on the tripod to obtain salinity, temperature and pressure.  The Dopbeam, which was deployed during Deployment II, was placed at 1.3 mab between the two ADVs.

Figure 1.    The schematic shows the ADVs at 0.7 and 3.4 mab, which was the configuration for Deployment I. YSI thermistors are strapped to each ADV, as well as on the platform, near the Seagauge wave and tide recorder.

   For Deployment II, the ADVs were both mounted at 0.7 mab. Temperatures were not co-located with the velocity sensors. The Dopbeam was mounted to profile vertical velocity variance within the bottom boundar layer. (See attached figure.)

Another tripod was equipped with an array of LISST sensors, including a LISST-ST, which provided settling velocity, and an MSCAT, to determine particle size within 10 cm of the bottom.

Last Update: Mon May 13 12:35:40 2002.