REMUS tests

REMUS – Remote Environmental Monitoring UnitS is an autonomous underwater vehicle that swims in a pre-programmed mission to sample the water currents, salinity, temperature, and dye concentration. Here you can see us testing out REMUS the week before our first dye release on September 16th! Things did not quite go as planned as you can see…

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visit to Playas de Tijuana

On September 15th, Falk and Sarah drove down to Tijuana to check out the release location on Playas de Tijuana and meet with our amazing collaborator Margarita Diaz at the Proyecto Fronterizo de Educaciòn Ambiental A.C.. Here you see Falk and Margarita talking on the beach.

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It just started raining when we were on the beach, the rain turned into a large storm and extensive flooding in Tijuana (making our trip back from TJ… memorable!) This flooding led to the shutdown of the Mexican pumps and thus contaminated water entering the Tijuana Estuary and flowing into the ocean near Imperial Beach that afternoon through the following several days. Beaches in IB had to be closed because of the contamination and we had to make sure they were clean before we started our first dye release.

MCIP training

September 9, 11, and 12th we completed several more MCIP training sessions for volunteers, undergraduates, and lifeguards. Everyone had a blast!

Tijuana Estuary deployments!

Early September, we deployed instruments in the Tijuana Estuary so that we could monitor if the estuary received any dye from the coast.

CSIDE MX Dye release simulation!

Below is a movie of a MX dye release similar to the other rleases that Nirnimesh has put together.    The dye release location here is at the very southern part of Playas Tijuana, where we will be doing our dye release.     Again, Nirnimesh is simulating the week from 9/30-10/7 2014 for moderate waves from 200 deg south, similar to the previous movies.   The movie lasts for a week.  The first dye release lasts 2 hours and the 2nd release lasts 6 hrs.   From these simulations it really does seem that the surfzone is a leaky pipe in exchanging with the shelf.  The proof will be in the actual dye release experiment.

  • Left panel is temperature anomoly (subtracting T=18 deg C), Right panel is dye concentration (ppb) in log scale.
  • Each frame is one hour. The counter (dT) indicates how long since the dye release.
  • About 100 L of Rhodamine WT was released over (2 hrs/6 hrs) for each releas,  a realistic amount of dye.
  • Magenta dots are planned instrument locations

CSIDE US/MX border dye release simulation

Nirnimesh has completed another round of dye release simulations to help us prepare for the upcoming dye releases.   For this release Nirnimesh is simulating the week from 9/30-10/7 2014 for moderate waves from 200 deg south.     The movie lasts for a week.  The first dye release lasts 2 hours and the 2nd release lasts 6 hrs.   In this case the dye makes it up to Navy SSTC north property but not quite to Coronado and the second releases exchanges significantly offshore.

* Left panel is temperature anomoly (subtracting T=18 deg C), Right panel is dye concentration (ppb) in log scale.

* Each frame is one hour. The counter (dT) indicates how long since the dye release.

* About 100 L of Rhodamine WT was released over (2 hrs/6 hrs) for each release.  This is a realistic amount of dye to be released.

* Magenta dots are planned instrument locations

 

Now it is interesting to contrast this release with what happens with larger south swell.   The video below is for the same conditions but waves that are 1.4X bigger.

 

What happens here is that the larger waves drive a stronger alongshore current and the dye just rockets all the way up to Coronado.   This could have significant implications for pollution transport.  But remember, this is just a model of two short dye releases for very specific conditions.   These simulations are only representative of what could happen.

Dye releases can start as early as 14 September!

 

ADCP boat mount for the Sally Ann

Kent and the SIO machine shop have fabricated a sweet ADCP mount for the Sally Ann.   This will enable tracer flux calculations from the coupled ADCP and towed aray measurements.    Kent got it done on Friday and did the first test mount Friday late afternoon up at Seaweed Canyon.   Pretty awesome.

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First Test of MCIP carts

On Wed 26 August, we had the first full field test of the MCIP carts which went really well.  A MCIP cart stands for Mobile Cart Instrumentation Platform.  An instrumented MCIP is shown in the first picture of the gallery below. It is basically a steel wheelbarrow that can roll into the surfzone. It has a range of instrumentation, including an ADV current meter, pressures sensor, thermistor, dye fluorometer, turbidity sensor, pitch/yaw/roll, and GPS, that go to a data acquisition system.

This system enables easy measurements of surfzone quantities. Normally it is much more intensive to deploy an instrumented tripod in the surfzone. This can be easily and rapidly deployed!

With these easy conditions on the test day it was no sweat. We got the MCIP out to waist deep water, locked it into place and then let it take data. On this day we did not actually put dye in the water so we did not take any dye measurements, but we do have temperature measurements over an hour.

MCIP_Temp_Test

What is very interesting is that the ocean is unusually warm for Southern California (25 deg C is 77 deg F!!!). But also over an hour the temperature changes by about 0.7 degC (1.3 deg F). What causes these large and fast fluctuations?

Moored current-meter setup

On Monday and tuesday August 24-25, we prepared moored current meters for deployment. This included installing battery packs, calibrating their compasses, performing instrument checks, preparing the frames they will sit on, and preliminary programming amongst other things. In these pictures, you see acoustic current meters, specifically Acoustic Doppler Current Profilers (ADCP), which using the Doppler shift to measure the water currents (speed and direction) throughout the water column and Acoustic Doppler Velocimeters (ADV) which also measure water currents but at only one location in space. The ADCPs will be deployed offshore throughout our experiment while the ADV will be deployed inside of the Tijuana Estuary to give us an idea of the currents driving the dye transport.

New pre-experiment CSIDE dye release simulations: comparing 2hr and 6 hr releases

In the previous post we presented the first dye simulation that Nirnimesh has done.  That simulation was for a release that totalled 2 hrs.  Now, Nirnimesh has performed an identical experiment for dye released for 6 hrs and compared the two.  The modeling details are the same:  This is with the COAWST model that couples waves and currents and has a 20 m grid resolution.  This simulation is for a period of time in Fall 2014 with northward winds.  Nirnimesh also sent in waves with significant wave height of 1 m, peak period Tp=14 s, and offshore angle of 200 deg.   He did two dye releases separated by about 3 days.


* Left panel is temperature anomoly (subtracting T=18 deg C), Right panel is dye concentration (ppb) in log scale.

* Each frame is one hour. The counter (dT) indicates how long since the dye release.

* About 100 L of Rhodamine WT was released over 2 hrs for each release.  This is a realistic amount of dye to be released.

* Green square is dye release location, Magenta dots are planned instrument locations/

* Both dye releases are at high tide.

Now the movie above is for surface temperature and dye.  It does not address the question of what dye does in the vertical.  ROMS works in vertical layers called sigma layers.  Each sigma layer fills up a part of the water column.   Below is a movie of the dye field on different sigma layers.   Note the differences between near bottom (left) and surface (right) panels!

Also, it is important to remember that in each movie the depth z varies on the sigma layer.  The way it works is that z = sigma * depth.    So the panels go from bottom to surface from left to right.   But they are not  fixed depth levels.

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