Posts Tagged ‘salinity’

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Salinity Processes in the Upper Ocean Regional Study (SPURS): Measurements by long-term autonomous platforms in SPURS

October 6th, 2012 by Maria-Jose Viñas

By Eric Lindstrom

A team of scientists from University of Washington is focusing on long-term observations in SPURS region with autonomous instruments: Argo floats (Drs. Stephen C. Riser, Jeffrey Nystuen, and student Jessica Anderson), Seagliders (Drs. Craig Lee, Charlie Eriksen, and Luc Rainville), and Lagrangian floats (Drs. Eric D’Asaro and Andrey Shcherbina). Their sentinel instruments will provide a larger-scale context for the SPURS moorings for the next year. Jessica (Jesse) and Andrey are aboard Knorr to look after all the deployments.

Andrey Shcherbina.

Jessica Anderson.

In order to connect the salinity that Aquarius sees at the ocean surface with processes throughout the ocean, SPURS is devoting resources to understanding of the processes happening in the near-surface layer. This area from the surface “skin” of the ocean to depths of 10-20 feet is where salinity measurements are most lacking.

In SPURS we added salinity sensors to normal global surface drifters. Enhanced Argo floats have extra sensors for the top 20 feet of the ocean. These will help to fill this gap in our salinity observations and help us better interpret Aquarius satellite data. SPURS data will be used to better characterize the near-surface variability, structure, and response of temperature and salinity to rain, wind, and ocean currents on time scales of hours to months.

Some of the details are fascinating. Twenty-six Argo-type profiling floats are being deployed over the course of the SPURS expedition and will remain in operation for four to five years. These floats will join the network of over 3,500 Argo floats currently monitoring the world’s oceans. Their additional sensor suites include the Surface Temperature and Salinity (STS) and Passive Acoustic Listener (PAL) packages. To ensure float longevity, typical Argo floats quit collecting data about 20 feet below the sea surface. The STS sensor, however, makes high vertical resolution (about 4 inches, or 10 centimeters) measurements of temperature and salinity from 100 ft depth all the way to the sea surface. The PAL sensor uses a hydrophone to acoustically measure wind speed and rainfall while the float is drifting between vertical profiles.

An Argo float at the ocean surface awaiting descent to more than 3,000 feet.

Additionally, the floats use Iridium satellite telemetry so the mission (time, depth, frequency of profiles) of the float can be modified after launch. Currently, sixteen of the floats deployed in a grid around the SPURS central mooring are making synchronous profiles once a day at noon, providing a daily “snapshot” of the SPURS region. In the future, the mission of these floats will be altered once again, so that both diurnal and longer time scale processes can be resolved.

Three Seagliders have been deployed in SPURS. They are built for endurance and efficiency. They will slowly patrol the salinity-maximum region moving up and down through the water column and monitoring temperature, salinity, oxygen and chlorophyll content of the waters surrounding the moorings. These Seagliders will operate continuously until spring 2013, when they will be recovered and replaced with a new threesome.

SeaGlider 190 away.

SPURS Seagliders are specially equipped to monitor ocean mixing. The upper ocean is filled with turbulence – chaotic assemblages of eddies that mix warmer and saltier water near the surface with cooler and fresher water below. Seagliders will record minute fluctuations of temperature associated with the tiniest of the turbulent eddies, hundreds of times per second. The gliders will navigate a racetrack pattern around the moorings for the duration of the experiment, allowing us to see how mixing varies with depth and time in response to changing winds, weather patterns, and ocean currents.

The final awesome piece of technology from our Seattle team is the Mixed-layer Lagrangian floats (MLFs) that will characterize turbulent mixing from another perspective. A “Lagrangian” description of a fluid motion (named after mathemetician Joseph Lagrange) is taken from the perspective of particles moving with the fluid flow. In that sense, most floats and drifters are Lagrangian instruments to some extent since they follow ocean currents. MLFs are fully Lagrangian: they can also follow much weaker vertical motion of the water. They do it by closely monitoring surrounding water and changing their volume to remain neutrally buoyant.  They also have a set of six flexible wings that can be extended horizontally and “anchor” the float to the surrounding water. As a result, the MLFs can directly follow the large turbulent eddies in the mixed layer and observe their evolution. It is the interplay of the large and small eddies that controls ocean mixing, so MLF observations uniquely complement microstructure turbulence measurements obtained by Seagliders.

MLF deployment (A.Shcherbina on the line.)

MLF being carefully lowered during deployment.

Aboard Knorr, Jesse and Andrey work closely together to support then entire Seattle-based SPURS team. Jesse makes sure the Argo floats get deployed at their appropriate location and will continue to check up on the floats over the coming weeks/years.

Together they look after the gliders testing and deployment – making sure they are well trimmed – not too light, not too heavy – like Goldilocks, everything has to be just right! Once deployed glider operations go to a group of pilots back in Seattle, who will keep track of the gliders’ progress, collect the ocean data, and direct the instruments on their sampling track. We worked with them directly via satellite phone so we could do simultaneous profiles with the ship’s instruments and the glider. When they say “dive” to a glider from Seattle, we can watch from the ship as it slips beneath the waves just yards away!

Lagrangian floats are even more sensitive to the precise ballasting – even the amount of paint that they may wear off over the next year needs to be taken in consideration! However, some things are impossible to predict – such as algal growth or how much fish love the float. So the pilots in Seattle need to keep constant track of the float telemetry and instruct it to go through the ballasting routine on a regular basis. They also balance the sampling strategy to optimize battery life throughout the floats’ one-year deployment. Overall, the operators have remote control of about 300 variables that determine the float’s behavior. Keeping those in check will be Andrey’s job for the next year, once we get him back home.

Your blogger asked Jesse and Andrey to describe their feelings about SPURS. Their responses were superb, so I won’t paraphrase!

Jesse said: “It’s been great to be a part of such a large, well-planned field campaign. I am amazed at all the varied data we are collecting and can’t wait to start piecing a small part of it together to further unravel the ocean’s roll in the global freshwater cycle as part of my PhD work. I am also excited to finally deploy (after a failed attempt on my last research cruise) my first Argo float! Working with the data from these floats for years, it is about time I finally wave one off to begin its journey in the great wild blue yonder. Working in front of your computer screen, it is easy to feel disconnected from the dynamic environment I am trying to understand. So being out a sea is a great rejuvenator. There is a unique beauty that is found only in the middle of the ocean with no land in sight. The stars are that much brighter, the sky that much bigger and the color of the ocean – the most unreal crystalline blue!”

Andrey said: “Taking part in a concerted effort to understand the physics behind the formation of the saltiest water in the open ocean is truly fascinating. The latest technology and support from NASA enables us to study this unique area at an entirely new level. I am looking forward to observing turbulent mixing of heat and salt in the upper ocean as it varies daily, monthly, seasonally. Relating these observations to the pathways of salt and fresh water in the ocean is a fascinating puzzle to unravel. But the best thing is that it is nearly impossible to predict what we will discover, as each new voyage brings in something totally unexpected. I’m sure every scientist aboard Knorr would agree that it is this sense of wonder that keeps us going out to sea again and again.”

Salinity Processes in the Upper Ocean Regional Study (SPURS): Prawlers, Engineers, and the Future of Oceanography at Sea

October 5th, 2012 by Maria-Jose Viñas

By Eric Lindstrom

A number of the instruments deployed during SPURS are “works in progress.”  They work well, but need exercise in new or more challenging environments to perfect them. The whole of SPURS is an experiment, taking salinity measurement in the ocean to an entirely new level. Extended deployment of sensor webs in hostile and distant environments is something NASA needs to perfect for the future of Earth System Science research and for planetary exploration.  One of the overarching goals for those involved is to advance the use of autonomous measurement platforms for real-time global oceanography.

The Prawler (Profiler + Crawler) instrument from NOAA Pacific Marine Environmental Laboratory (PMEL) is one example of SPURS exercising a work in progress. It is also a place where we can see common goals between NASA and NOAA in physical oceanography.

Prawler closed on the laboratory bench.

The Prawler is a wave-powered subsea instrument that eliminates the need for multiple sensors on a mooring line. During descent, it makes a profile using whatever sensors have been installed and communicates those via inductive modem to the surface buoy (from there they are communicated via satellite to shore). Once the Prawler falls to the pre-determined bottom depth (arount 1,640 feet, or 500 meters), a micro-processor activates a ratcheting mechanism and harnesses the wave motion of the mooring to crawl back up the mooring line.

Diagram showing the ratchet mechanism on Prawler that allows it to climb the mooring wire.

The Prawler has been years in development and testing. This expedition we deployed two NOAA moorings where the Prawler is the primary instrument. The Prawler will make from five to 30 profiles per day (the average is about 20 profiles per day). For SPURS, the Prawler measures temperature, conductivity, and pressure. Those are core variables that are easily conversed to temperature, salinity, and depth.

An example (from a prior test of Prawler in the Pacific Ocean) of how many profiles one can expect to make using one Prawler during the course of a year. Provided by Billy Kessler, NOAA PMEL.

Billy Kessler at NOAA PMEL and University  of Washington is leading a NOAA SPURS project to test the Prawler technology. Billy and I were in graduate school at University of Washington together in the early 1980s and shared the same PhD mentor, Prof. Bruce Taft. It’s wonderful to be working with Billy again after all these years!

John Shanley and Andrew Meyer (aboard the Knorr) are two NOAA PMEL engineers who have been involved with Prawler mooring design tests for the last 3 years. They have already participated in some major tests of Prawler on moorings (a 7-month and a 4-month deployment in Hawaii, each time with two Prawlers, and many tests in Puget Sound). SPURS offered a great opportunity for a full year deployment near the heavily-instrumented Woods Hole mooring whose deployment I described in an earlier post.

John Shanley.

Andrew Meyer.

John and Andrew are fortunate to work in a small group of engineers where they get to work on all aspects of the Prawler, from design input to the actual fabrication of the instruments, to testing materials and components, to full ocean deployments. “From art to part,” as the boss likes to say! The NOAA PMEL mooring shop has a long history of excellence providing products that meet both researcher and operational requirements.

Seeing the Prawler used in SPURS after years of development is the light at the end of the tunnel for John and Andrew. This project has been a cumulative effort involving their entire engineering group. There have been four radically different versions, countless numbers of modifications, long days and weekends of machining parts. They have seen Prawler grow from just a few scribbles on a white board to deployment of the “finished” product over the stern of Knorr on this voyage. They both describe persistence as the key to success.  It almost brings a tear to your eye to hear Andrew describe to me “the last few touches before deployment as we assemble and ballast, to bolting it on the mooring line and dropping it into the ocean, bring a great sense of accomplishment.”

For Andrew and John being out here on Knorr to deploy the Prawler is just icing on the cake. The interaction with people from other institutions and seeing many different ways and means of measuring salinity truly puts the Prawler capability in a new perspective. They are both standing watches and working with the other teams to expand their ocean instrumentation expertise. They certainly now know that they too are on the leading edge of global real-time ocean observing in the 21st century. From interactions aboard ship they go home energized with ideas for the next innovation!

Salinity Processes in the Upper Ocean Regional Study (SPURS): What is ocean microstructure and why study it?

October 4th, 2012 by Maria-Jose Viñas

By Eric Lindstrom

“The techniques I developed for studying turbulence, like weather, also apply to the stock market.”
Benoit Mandelbrot

If Mandelbrot’s statement is true, maybe oceanographers studying ocean microstructure (caused by turbulence), besides writing journal articles about mixing in the ocean also work on padding their retirement accounts with stunning stock market acumen?

Jokes apart, how does ocean microstructure work? The microstructure component of SPURS features measurements of very small-scale (inch or smaller) variations of temperature, salinity, and velocity, used to infer mixing rates due to turbulence and convection in the upper ocean.

Profiles of Temperature, Salinity, two channels of small-scale temperature gradient and two channels of small-scale shear from a dive of the Vertical Microstructure Profiler (VMP). The depth intervals with the strongest variations in temperature gradient and vertical shear are the places where the ocean is mixing the strongest. These raw data are carefully processed to tell us how much of the salinity change that we see is due to the vertical mixing rates. They can also tell us which processes are causing the mixing, such as shear instability or salt fingers.

Lou St. Laurent, together with Woods Hole Oceanographic Institution colleagues Carol Anne Clayson and Ray Schmitt, are the scientists principally focused on these issues. Their work is supported by the National Science Foundation and is another good example of the inter-agency cooperation spanning SPURS.

Ken Decoteau, a WHOI engineer, leads the microstructure group’s sea-going effort. Together with James Reilly, a research technician from UMass-Dartmouth/SMAST, Oliver Sun, a WHOI postdoctoral investigator, and Alec Bogdanoff, a graduate student in the MIT/WHOI Joint Program for Physical Oceanography, they run 24-hr operations of two instrument systems, a vertical microstructure profiler (VMP) and turbulence-sensing gliders (T-gliders).

Ken Decoteau.

Jim Reilly.

Oliver Sun.

Alec Bogdanoff.

The first, a vertical profiler (Rockland Scientific VMP5500), is lowered into the water and released. In its pressure housing, it carries batteries and electronics. The data collected by the external sensors is recorded to a disk drive inside the instrument. The steel ballast weights it carries cause it to sink to a pre-set depth. Upon reaching this depth, a trigger mechanism is fired, causing the weights to be released, and the instrument to float back to the surface. The instrument is then recovered, the data downloaded, and preparation for the next deployment begins. Although the instrument is capable of profiling to a depth of 18,000 feet (about 5,500m), most of the profiles on this expedition are being done to a depth of 4,000 feet (1,200m). These deployments take about one hour from the time we release the instrument until it re-surfaces.

The Vertical Microstructure Profiler, ready for deployment.

A second kind of measurement (of longer duration) is conducted using two Teledyne-Webb Slocum Gliders (T-gliders), each carrying a Rockland Scientific MicroRider. The MicroRider is similar to the VMP, but is much smaller in size since it is not designed to go as deep, and does not carry its own batteries and CTD; it draws battery power from the glider. The T-glider does not utilize direct propulsion (as in a motor), instead changing its buoyancy to move up and down in the water column and using wings to translate this motion from vertical to horizontal (a.k.a. gliding). This low power design means microstructure data can be collected continuously over a time period covering weeks, even months, with minimal intervention.

Small boat crew filming a T-glider in trial deployment.

During SPURS, one T-glider is covering the upper 230 feet (70m) of the water column while stationed in a small area close to the highly-instrumented WHOI mooring, while the other T-glider is covering the upper 660 feet (200m) of the water column while doing continuous transits between the WHOI mooring and PMEL-N mooring.

So far, more than 30 VMP microstructure profiles have been taken by two twelve-hour shifts working 24/7. With the minimal additional amount of effort required to deploy and to periodically checkup on the two gliders, we have collected over 700 additional profiles of the upper ocean from the gliders. Utilizing these two different platforms simultaneously has a dramatic positive effect on our sampling efficiency, and illustrates why autonomous sampling techniques have become much more common in recent years.

The measurements of microstructure variations in temperature, salinity, and velocity are crucial to SPURS estimating the salinity balance.  We need to know how the less saline waters to the south and south are mixed with the saltier waters near the salinity maximum in the North Atlantic.

Maybe, after all, it is like the stock market! The “value” (measurement) of our “commodity” (salinity) depends on a complex global “marketplace” (a salinity balance equation) forced by wind, evaporation and precipitation and “trading” in complex oceanic processes (circulation and eddies) acting in the end through “derivatives” (turbulent mixing) to determine the values we see.  Maybe these oceanographers are in fact sitting on a gold mine!

Truth be told, their mathematical wizardry is focused on understanding the ocean and the water cycle, not the stock market and the business cycle. However, old Benoit Mandelbrot was entirely correct! A few brilliant men like him can live in both worlds and we all profit.

Salinity Processes in the Upper Ocean Regional Study (SPURS): Managing SPURS Data

October 2nd, 2012 by Maria-Jose Viñas

By Eric Lindstrom

A high-level concept for SPURS data flow whereby data collected by the many devices will be relayed via satellite to shore and integrated with numerical ocean models and satellite observations.

The complex job of managing the data from SPURS is daunting because of the number of different platforms and data streams that need to be logged and cross-calibrated. Overall, by NASA standards, we are dealing with relatively small quantities of data (Gigabytes) but there are many,many different sensors and platforms involved.  The value of the SPURS dataset comes from analyzing together the measurements made by all the different instruments at a variety of time and space scales. Such an analysis would not be credible without detailed comparison and calibration between all the instruments. SPURS interpretation is dependent on all the salinity measurements being comparable to one another and that one ocean salinity field is derived from the variety of measurements. Let me go into a little more detail on these points (forgive me for getting nerdy about this, but its important to the expedition, so I gotta tell you!)

To give you an example of the range of platforms and instruments measuring salinity in SPURS, consider that we are trying to measure surface salinity from space using Aquarius, surface drifters, Argo floats, Wavegliders, Seagliders, thermosalinographs on ships, moored salinity sensors, underway and station CTD, and bucket samples (it’s just what it sounds like!). NASA data systems are not generally working the entire buckets-to-satellites range of seawater analysis, so we are learning as we go — and doing just fine so far!

Salinity is a difficult variable to measure properly. It is determined by measuring the ability of seawater to conduct electricity. Though this sounds simple in principle, in practice, the measurement of salinity requires exacting standards of quality. The relevant variations in SPURS are one part in ten thousand (for comparison, a pinch of salt in a gallon of water changes its salinity by about 2 parts in ten thousand). Our instruments can measure salinity differences down to a few parts in a million.

The ocean salinity standard by which all of our ocean salinity measurements are compared is created by using a laboratory salinometer and a standard for seawater salinity, the “IAPSO Standard Seawater”. Operating the salinometer is a critical but tedious job, taking place daily in a temperature-controlled room just off the Knorr’s main laboratory.  We collect dozens of water samples every day, all of which need to be examined by the salinometer with exacting adherence to procedures and recording of results. The salinometer is calibrated for each batch using the standard seawater with known salinity of exactly 35 parts per thousand.

The salinometer on Knorr.

Bottles of seawater collected during CTD profiles and from the ship’s thermosalinograph system are analyzed on a regular basis and compared with the Standard Seawater. The fully-calibrated measurements from the CTD and the ship’s underway system are then used to standardize all of the other instruments being operated in SPURS (by comparison of nearby simultaneous observations).

A SPURS project led by Prof. Frederick Bingham of University of North Carolina Wilmington and Yi Chao at Remote Sensing Solutions in California has been focused in part on cross-calibration of the different data streams. Fred and student Andrew Whitley are on the Knorr from UNCW.

Fred and Andrew at work.

Fred is an observational physical oceanographer who has worked with many different kinds of oceanographic data over the years, including CTD, drifter, mooring, velocity, float and satellite data. In addition to his PhD in Oceanography, he has a Masters degree in computer science and information systems. This helps him manage and understand the sometimes complicated and confusing data structures the different oceanographic instruments produce.

Andrew Whitley is a graduate student at UNCW in Physical Oceanography studying large-scale coastline modeling. He has undergraduate degrees from UNC Chapel Hill (in music) and UNCW (in physics).

Andrew is a first-timer to long oceanographic expeditions.  He told me “I’ve always been fascinated with shipboard operations and research, but being a student of modeling rather than observing the ocean, I had not had opportunities to get aboard a research vessel. Thankfully, Dr. Bingham heard about my desire to go to sea, and I am very grateful that he asked me to come along. This has truly been one of the most extraordinary experiences of my life!”

I think he might have nightmares about seawater sampling for years to come! 

At sea, Andrew is also helping Fred with his data processing efforts. Andrew works up daily reports and plots on sea surface temperature and height, and drifter positions.  He is processing daily CTD data for general shipboard use. Like many first-timers Andrew is soaking in the experience. It seems like no matter the hours or the watch to stand, he is loving every minute!

Another one of Fred’s duties on Knorr is to add to our “situational awareness” of ocean conditions and our sensor web. The SPURS instrument array is complex and constantly evolving in time as instruments drift or maneuver through the water. Satellites overhead provide information about sea surface salinity, temperature, currents, winds and weather. Onshore models make forecasts of ocean conditions 24-48 hours ahead. Much of this real-time data flow is unique to SPURS. In the new world of real-time oceanography, the ship can be directed to features of interest, instruments can be deployed based on analysis of satellite data or autonomous vehicles directed to travel to where they are needed away from the ship. Fred’s job is to keep the chief scientist aware of what observing assets are where and what the status of the array is.

In his every day work on board, Fred keeps a constant watch on the ship’s position and the positions of all of the other assets in the water. (An example of the type of display he uses can be seen on this website — click on “SPURS Data” and then on “Visualization”). When the need arises, he downloads and plots satellite imagery. He extracts data from the different data streams that are updating regularly and analyses them. It requires daily interaction with the modeling team at NASA’s Jet Propulsion Laboratory. All of the scientific team aboard Knorr use the daily updates on the environment and observing system provided by the UNCW team. It is an essential element for SPURS success!

Salinity Processes in the Upper Ocean Regional Study (SPURS): Modeling And The Dry Side of SPURS

October 1st, 2012 by Maria-Jose Viñas

By Eric Lindstrom

SPURS dry team members. From left to right: Peggy Li, Yi Chao and Gene Li.

Yi Chao is one of the “spiritual leaders” of our “dry” team in SPURS (those people who help from land). He is an ocean modeler in California who has been involved with Aquarius and SPURS for many years. He long ago decided to be on the dry team because of the seasickness that he experienced ten years ago during the tests of the Aquarius precursor instrument. Worse of all, he tells me, he had to stay on deck for days during the entire expedition because his seasickness got much worse if he went inside. He decided right then that it would be the last voyage in his oceanographic career. Since then, Yi has been an “armchair” oceanographer, working on satellites and computer models of the 3-D changing ocean. With outstanding results, I might add. Stay dry, Yi!

Other key members of the dry team include Zhijin “Gene” Li, Peggy Li, Quoc Vu, and Fred Bingham (on the Knorr to supply dry humor). Gene has dedicated more than a decade to formulate, develop and refine an ocean data assimilation system at JPL. This system integrates measurements from satellite, underwater autonomous vehicles and other ocean measurements into sophisticated computer models to depict the ocean. To support SPURS, this system is based on the community Regional Ocean Modeling System (ROMS), configuring as a nested set of three spatial domains and zooming in using horizontal resolutions of 9,3 to 1 kilometer to represent flow systems from hundreds of to a few kilometers in size.

Sea surface salinities from the three model domains.

Before Knorr began its voyage, using the ROMS model, the dry team predicted for the “wet team” (as we the expeditioners are fondly known) that the SPURS area of research would be warmer and saltier than normal this year. Since then, the model system has been providing nowcast and forecast of the conditions of the SPURS ocean on a daily basis. The forecasts have helped to refine our sampling strategies aboard Knorr. Only time and more observations will determine whether their prediction is correct!

As the data stream from SPURS comes in, the model system will synthesize the observations and deliver more accurate forecasts of the ocean conditions, which will in turn help adjust the measurement strategy as needed. In essence, we use ROMS at NASA’s Jet Propulsion Laboratory (JPL) as our virtual ocean. It’s an estimate of the three-dimensional evolution of the ocean in the region given the data and physics of the ROMS model (both of which we try to improve).

Peggy Li is a dry team specialist in computer science (not an oceanographer) who is interested in building real-time visualization systems, convert data into useful information and present said systems in the fastest and most intuitive way. She has been providing outstanding support to SPURS investigators. She makes sure the information is flowing smoothly from the observation and model sources to the SPURS Data Management System. She is “on watch,” like those aboard Knorr. She initiates her day by checking to see if all the data are present on the SPURS visualization page. Only then she allows herself to have some coffee… such dedication! She has supported several field campaigns, but claims that this one is the most interesting by far.

A goal of the dry team is to integrate all the salinity data sets into a one-stop shopping web site for SPURS situation awareness. This includes data collected by both in situ and satellite platforms as well as output from computer models. Gathering the data from a distributed in situ (in place) sensor network is a challenge. All the in situ sensors send the collected data to their home institutions through satellite communication, where a quick first round of quality control is done by technicians who are experts in those instruments. For example, the ship R/V Knorr, flux mooring, wave glider, and Slocum glider send data to Woods Hole Oceanographic Institution in Massachusetts, the surface drifting buoys send data to the Scripps Institution of Oceanography in La Jolla, California, and the profiling floats and Seagliders send data to University of Washington in Seattle. The dry team computer at JPL in Pasadena, California, is checking all these computer servers around the country on the hourly basis, transferring and updating the data on the SPURS web site.

A screen shot for the SPURS data management system visualization using the Google Earth interface for monitoring the location for various instruments deployed from Knorr.

Using the well-known Google Earth interface, users on both the wet and dry teams can zoom in and out of the SPURS region to locate the most updated ship position, to read the salinity measurements from both in situ sensors and the Aquarius instrument in space, and to compare observations against the most recent model forecast.

A closer look at the SPURS instruments’ deployment.

Communicating between the wet and dry teams has also been a challenge. The Internet link to shore is a shared resource between many U.S. research vessels at sea. It works well, but it is not like having a cable running right into your house!

All in all, the wet team on Knorr is much better informed because of the dry team’s efforts at JPL. Likewise, since one objective of SPURS is to improve our modeling of ocean salinity variations, the dry team is reaping great rewards from interaction with the wet team.