Posts Tagged ‘sea surface salinity’

Salinity Processes in the Upper Ocean Regional Study (SPURS): Mooring Deployments

August 25th, 2016 by Maria-Jose Viñas
Ben Pietro readies a buoy for deployment.

Ben Pietro readies a buoy for deployment.

For SPURS-2 we are installing three moorings that will stay in place for over a year. Our moorings are arrays of instruments dangling from a surface floatation and anchored at the bottom. The moorings eventually will be recovered by R/V Thompson in September or October 2017. They will be recovered by using a release mechanism (acoustically operated) above the anchor.

Emerson Hasbrouck, working in his office.

Emerson Hasbrouck, working in his office.

Two of the moorings are supplied by William Kessler at the NOAA Pacific Marine Envionmental Laboratory. They will use the Prawler (profiler + crawler) technology – an instrument system that crawls up and down the mooring wire to sample the upper ocean on a regular basis. This technology has been perfected since SPURS-1. Andrew Meyer and is buddy Monkey are working the deployment of those moorings.

Two instruments, ready for the WHOI mooring.

Two instruments, ready for the WHOI mooring.

The SPURS-2 Central Mooring is supplied by Tom Farrar from Woods Hole Oceanographic Institution under a grant from NASA. This mooring is heavily instrumented with temperature, salinity, and current sensors as well as a sophisticated meteorological package at the surface. This gear is the hub around which the rest of the experiment works. It provides the contextual environmental data over then entire year in which other shorter term more intensive measurement campaigns by R/Vs Revelle, Thompson, and Lady Amber will fit.

Andrew Meyer and Monkey pose with the SPURS-2 Central Mooring buoy.

Andrew Meyer and Monkey pose with the SPURS-2 Central Mooring buoy.

Each mooring effectively takes one day of ship time to deploy, since daylight and a morning start is preferred. Each deployment starts with the surface buoy and continues with instruments and line/cable until the release and anchor remain on deck with about 3 miles of mooring strung out behind the ship. If all planning and estimating is correct, the ship will be appropriately positioned with regard to the target site so that the anchor can then be dropped. The ocean bottom – 3 miles down – is relatively flat here at SPURS-2 so precise aiming of the anchor drop zone is not necessary.

WHOI mooring with anchor.

WHOI mooring with anchor.

Deployment of the central mooring in particular is labor intensive and many in the science party contributed to the effort. he deployment effort was orchestrated by Ben Pietro and Emerson Hasbrouck from the mooring group at Woods Hole. Drew Cole and Carmen Greto provided essential expertise as ship’s scientific technical support. Ben and Drew together lead the team through a solid 10 hours of work. Leah Trafford monitored and logged all the equipment as it was deployed. She was ever present with the clipboard and eyes on the instruments. Raymond Graham had a terrific day serving as Ben’s extra pair of hands, handling all manner of assignments with great dexterity.

Leah Trafford with the mooring log.

Leah Trafford with the mooring log.

Mooring action on the fantail.

Mooring action on the fantail.

Anchor away for the SPURS-2 Central Mooring.

Anchor away for the SPURS-2 Central Mooring.

We’ll spend a full day post-deployment with a variety of projects related to the central mooring. We’ll complete a survey of the site to determine the precise location of the anchor (and acoustic release mechanism). We’ll check meteorological equipment against shipboard measurements. We’ll use a small boat operation to the surface buoy to add additional equipment that could not be launched during the primary operation.

After the second PMEL mooring is deployed, Revelle will be moving to begin mapping of the ocean around the central mooring. A box of approximately 180 miles on a side will be the focus of our sampling for more than a week. There is also a deployment of free-floating sensors. I’ll tell you more in the next post about how we sample the ocean with sensors fixed in space versus those fixed to a water parcel.

Meanwhile, we are enjoying our first serious rainstorm of the voyage at our study location. We hope for many more. If we are going to study how the rainfall mixes into the ocean, we really are hailing the rain dowsers to bring more showers!

Stay dry out there folks, but hope that we get soaked!

Salinity Processes in the Upper Ocean Regional Study (SPURS): SPURS supporters beyond the R/V Knorr

August 29th, 2012 by Maria-Jose Viñas

By Eric Lindstrom

The Surface Salinity Profiler from University of Washington’s Applied Physics Lab, shown here while it was being tested at sea, is now deployed on R/V Thalassa.

The SPURS experiment involves not only sea-going oceanographers but modelers, and of course, remote sensing scientists using satellite data. As part of the daily posts from R/V Knorr I will go into more detail on the role of the models and satellite data in the overall scientific enterprise. I will profile the modeling teams and their interaction with the ship-based team during the voyage.

Numerical models of the ocean, run on supercomputers, can provide high-resolution animations of the physical environment for us sea-going scientists. In order to actually simulate the environment, the models need to take in data from the expedition and make sure the model solution is one that best fits the available data. This process is called data assimilation. (You are more familiar with data assimilation in models than you think – daily weather maps are the result of models and forecasts are done using data assimilation into sophisticated models of atmospheric physics.)

An objective of SPURS is to provide a high-resolution, near-real-time stream of data that can be assimilated into ocean models. Because the ocean is so big and complex, and our at-sea capacity to measure it so puny, we rely on ocean modeling and data assimilation to help us interpret the environment. The model results can be used in planning work at sea and to diagnose the balance of salinity in the upper ocean. The observations are essential to locking model results into the real oceanographic environment. The model is essential to estimating things we cannot measure directly and expanding upon the interpretations provided by the observations.

In SPURS, we hope that we scientists at sea and those ashore can collaborate through the exchange of data and model results. This was not possible as late as a decade ago. Now we have Internet at sea and can exchange information and results for daily planning and analysis.

I will discuss the synergy of models and data much more during posts from the ship in September.

SPURS as an International Enterprise

The SPURS experiment involves a number of expeditions and nations working in cooperation at the single location in the North Atlantic.

The French R/V Thalassa is in the SPURS region now with one U.S. team aboard from University of Washington’s Applied Physics Laboratory. I will give more details in future posts.

Follow-on U.S. expeditions will use R/V Endeavor from University of Rhode Island to follow-up the measurements of R/V Knorr. The first of these two expeditions is in the spring of 2013 and will service SPURS equipment that requires maintenance after 6 months at sea. That expedition will also do more of the “feature” characterization. A second expedition in the fall of 2013 will recover all the moored equipment and gliders, among other duties.

A Spanish cruise is also planned for next spring. The details of this expedition will be subject of a post.

What’s up next?

Next up will be the loading of R/V Knorr on 5 September and a media event at 10 am that day. We set sail on 9/6 at 10 am.

Notes from the Field