WireWalker #1 Deployment 1 results

We now have our first look at the wirewalker (WW) mooring observations.   The wirewalkers use the up and down motion of the sea-surface to move a CTD+fluorometer profiling package up and down the water column.   As such, good vertical and tempral resolution of the watercolumn can be acheived with a single sensor.    During RIVET-I, we deployed 2 WW in appoximately 8 m depth.  WW1 was deployed just offshore of the “new” channel at approximate locations (x,y) = (1000,0) m.    See the legend of the figure below summarizing instrument locations.

Map of New Rivet Inlet NC bathymetry (from the ASACE FRF) in the RIVET coordinate system with the SIO (Feddersen/Guza) and WHOI (Raubenheimer/Elgar) ADV, ADCP, and wirewalker (WW) instrument locations as noted in the legend. The TopSail side of the inlet is below and the Camp Lejuene side is on top. SIO ADV locations are marked V1-V8. All locations also had a co-located pressure sensor Map of New Rivet Inlet NC bathymetry (from the ASACE FRF) in the RIVET coordinate system and many locations also had a co-located Rhodamine WT dye fluorometer. Dye was released either near x ≈ −600 m and y ≈ −300 m, or about 1.2 km further up the inlet towards the Inter-Coastal Waterway.

Each WW as deployed twice for ~11 days.    Below is the results of the 1st deployment of WW1.    A semi-diurnal temperature signal is evident over the 11 days as inlet water comes out the New River Inlet on ebb tide.   Typically a salinity signal is associated as well.

Wirewalker #1 Deployment #1 data from 0000 1 May and spanning 1-6 m in the watercolumn. Gridded are temperature (top), salinity (middle), and Rhodamine WT dye (log10 – bottom).

Dye was released on May 6, 7, 8th (note this is equivalent to time 5, 6, 7) on the plot above as the xaxis is days from 0000 1 May.   Note also data collection had begun on Apr 30th (day = -1).     For each of the dye releases there is a clear dye signal at WW!.  For the 1st two releases, the dye passes the WW relatively quickly and appears to be well mixed consistent with the temperature and salinity.    However, on the 3rd release, the resulting dye signal is more complex.    The dye first passes at t=7.7, and superficially does not appear to be well mixed.   However, approximately 12 hours later, dye is again present at WW1.   This indicates that dye had been recirculated back into the inlet on the flood tide and ejected again on the subsequent ebb.    There is another weaker dye signal on the next semi-diurnal cycle as well.

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