Posts Tagged ‘oceanography’

« Older Entries Newer Entries »

Salinity Processes in the Upper Ocean Regional Study (SPURS): A Routine Dipped in a Secret Sauce

September 6th, 2016 by Maria-Jose Viñas

By Eric Lindstrom

Food service on the R/V Revelle.

Food service on the R/V Revelle.

Food aboard the R/V Revelle is a cornerstone of happiness and good morale. Jay Erickson and Richard Buck are the cooks during this voyage and have many years of experience working together on R/V Revelle. I followed their daily routine all day on Friday, September 2, so that I can give you some beyond-consumer incite about food on the R/V Revelle. I will stipulate that their work is very good indeed and that we have been getting well fed. Since scales don’t work at sea, no weight gain can be observed. So says the fat blogger.

Jay Erickson, Chief Cook on the R/V Revelle.

Jay Erickson, Chief Cook on the R/V Revelle.

Richard Buck, Cook, R/V Revelle.

Richard Buck, Cook, R/V Revelle.

I think it is best to describe this important aspect of life on R/V Revelle in two ways. First is the routine that makes food service run like clockwork every day. Second are the secrets or magic of shipboard food service that those on land might find curious or amazing. I can touch on only a few highlights.

I’ll start with the clockwork routine. Richard and Jay alternate work assignments. Each day one them does the hot food preparation and other has salad/cold food preparation, cleaning/dishwashing, and supply runs to the stores (three decks down). The next day they switch. The key menu options for hot food are generally decided on the prior evening. Only one day has a predictable menu – Sunday is steak day! Jay and Richard’s workdays are over 12 hours long with two short breaks. That is a heavy, relentless duty.

Breakfast preparation starts at 6:00 am. Breakfast food options are those of a typical American diner (e.g., eggs several ways, several meats, potato, pancakes, oatmeal, cereal, fresh fruit), without the short orders, and do not vary substantially from day to day. Most people do not vary in their breakfast food choices so I’d characterize it as the constant, dependable meal (least challenging for the cooks).

Salad bar at every meal.

Salad bar at every meal.

Hot meal of Balboa chicken and shrimp noodle soup.

Hot meal of Balboa chicken and shrimp noodle soup.

After a short break from about 8:30 to 9:00 am, lunch preparation begins with galley and dining room cleaning. Typical lunch and dinner menus include a featured main course, a couple of side dishes, a vegetarian option, and a soup. After lunch cleanup there is another break in the action from around 1:30 to 2:30 pm. Some preparation for dinner will have been started during the lunch service.

Birthday cake for Andrew and Peter.

Birthday cake for Andrew and Peter.

Dinner preparation includes renewal and refreshment of the salad bar, bread baking, and work on the main meal from soup to nuts, as they say. Every day there are some extras or special events as well. On my day in the kitchen there were two birthdays, so a decorated birthday cake was prepared over the course of the day. Likewise, fresh bread, cookies, or a special dessert might be created for the dinner service.

As I learned over the course of the day, the vast share of labor goes into food preparation and cleanliness. The R/V Revelle professional facilities allow for the rapid and efficient cooking of food for 50-60 people. However, the washing and chopping of large quantities of fruit and vegetables, and meat handling are labor intensive. So too are the good habits of kitchen hygiene that assure that everything is done right and sparkling clean at all times. As you might expect, the work is hard enough without everything being shipshape and well organized. Fastidiousness was a hallmark of Jay and Richard’s work.

There are many challenges to creation of good meals at sea. Obviously motion of the ship can be a big issue. A ship’s cook is a cook who has mastered the art of corralling sloshing food! Richard told me of attempts to bake a level cake in the seas of the Southern Ocean. Rather than having it baked into the leaning cake of Pisa, he tried to balance the sea motion by turning the cake in the oven every few minutes to counter the sloshing of the batter. In that case, the ocean won…but I think the birthday recipient appreciated the effort nonetheless.

Fresh bread just out of the oven.

Fresh bread just out of the oven.

Jay shared an interesting secret of leftovers. Oatmeal is available for breakfast every day. Leftover oatmeal is mixed with water and yeast after breakfast and the slurry left to ferment. It is transformed by this effort of the microbes and a resourceful cook into the delicious bread at dinner!

Let us admire a three-week-old lettuce, looking like it was fresh.

Let us admire a three-week-old lettuce, looking like it was fresh.

A great deal of science and experience goes into the food storage on a ship. Three weeks at sea and we still have lettuce and perfect avocados. That never happens for me at home! While each fruit and vegetable seems to have its own story with regard to ripeness at purchase, storage, and revitalization, the keys to longevity seem to be in the cold room temperature and humidity plus the skills of Jay and Richard to give foods a second chance. Lettuce, for example, might look finished due to a dehydrating stay in the cold storage, but skilled knife work, a cold bath, and a little secret chemistry can return lettuce to salad fitness!

We are all in debt to the skill and labor of Richard and Jay. We will feel the full extent of the deliciousness they loaned to us when we climb on the scale back home!

Salinity Processes in the Upper Ocean Regional Study (SPURS): Chasing the Elusive Surface Salinity Profile

September 2nd, 2016 by Maria-Jose Viñas

By Eric Lindstrom

The R/V Revelle and the Lighter-Than-Air InfraRed System, as seen from the Surface Salinity Profiler.

The R/V Revelle and the Lighter-Than-Air InfraRed System (on the left corner), as seen from the Surface Salinity Profiler. Credit: Dan Clark.

Kyla Drushka from University of Washington Applied Physics Laboratory (APL) received a National Science Foundation grant to participate in SPURS-2. It is one cornerstone of our work and is entitled “Rain-Formed Fresh Lenses in SPURS-2.” The idea of rainfall resulting in freshwater puddles or lenses at the sea surface is (perhaps) easy to imagine but is very tricky to observe and study in the real world. SPURS-2 will provide a wealth of new data on this subject with which to test the fidelity of our scientific imagination.

A beauty shot of the Surface Salinity Profiler.

A beauty shot of the Surface Salinity Profiler.

Kyla and the APL crew have a variety of instruments aboard R/V Revelle but the Surface Salinity Profiler (SSP) is central to SPURS-2 science objectives. When you want to know the fate of rainwater after it hits the sea surface, measuring salinity (or equivalently the amount of freshwater) in the upper meter of the ocean is crucial. The profile of salinity in that top meter of the ocean is elusive for a number of reasons – technical and logistical. Technically, salinity sensors require some time and bubble-free water flow to make the measurement. However, normally the sea surface is rapidly moving up and down (because of waves!) so a sensor is not always in the water and away from bubbles until it is several meters below the surface. Finding a way to tow salinity (and other) sensors at fixed, shallow depths following the motions of the sea is another approach. APL scientists and engineers including Andy Jessup, Bill Asher, and Dan Clark designed the SSP to apply this approach.

How the Surface Salinity Profiler runs outboard the ship -- photo taken from the Lighter-Than-Air InfraRed System balloon camera.

How the Surface Salinity Profiler runs outboard the ship — photo taken from the Lighter-Than-Air InfraRed System balloon camera.

Dan Clark, APL engineer extraordinaire.

Dan Clark, APL engineer extraordinaire.

The SSP platform is a converted paddleboard with a keel and surfboard outrigger. It is tethered to the ship so it skims the sea surface outside the wake or influence of the ship. Below the paddleboard, on the leading edge of the keel, are salinity (and temperature) sensors at depths of 10 centimeters (4 inches), 30 centimeters (1 foot), 50 centimeters (1.64 feet), and 100 centimeters (3.28 feet), microstructure sensors (to estimate turbulence), and cameras. The Salinity Snake (see my last blog entry) supplements the SSP by providing temperature and salinity in the upper few centimeters of the ocean. The SSP can be towed for many hours before the instrument batteries need refreshing.

Deployment of SSP is most informative when there is a rain event, leading to stratification of the near-surface ocean with less dense fresher water on top of denser saltier water. If there is a rain event ahead of the ship, the SSP goes in the water. Then it can measure how the ocean changes over the periods from before rain, during rain, and recovering from rain. Salinity from several depths and simultaneous turbulence estimates are then used to determine how rainwater mixes into the ocean.

Suneil Iyer with Surface Slainity Profiler on deck (sensor to bottom left on keel)

Suneil Iyer with Surface Salinity Profiler on deck (sensor to bottom left on keel)

Suneil Iyer is a new graduate student at University of Washington who will work with Kyla on interpretation of the microstructure measurements from the SSP data. He just arrived in Seattle from his hometown of Kansas City, Kansas, one week before the R/V Revelle departure from Honolulu. He just had time to find an apartment before jumping on a plane for SPURS-2. Graduate school in oceanography can be a blast of new experiences! This is not his first exposure to physical oceanography: Suneil worked on tides in estuaries during his undergraduate work at University of South Carolina.

-Kyla Drushka working on the Surface Salinity Profiler.

Kyla Drushka working on the Surface Salinity Profiler.

Kyla Drushka joined UW in 2014 after PhD work at Scripps Institution of Oceanography. She is now an active member of NASA’s Ocean Salinity Science Team and the mission science team for the Surface Water Ocean Topography satellite that is planned for launch in April 2021.

This blog entry goes to press near an auspicious moment on R/V Revelle SPURS-2 voyage. Saturday at 2 am (local time) is the halfway point of our expedition! In our oceanography lexicon we would call this the “hump day” for our voyage. For all you land-loving 5-day-a-weekers hump day might mean Wednesday. For the 24/7 work at sea, we really have only a “hump moment” to mark the halfway point of a continuous work schedule. Like any good NASA activity, people aboard have countdowns running to both our hump moment and our arrival back in Honolulu (8 am on Sept. 23). Amusement is in short supply!

Salinity Processes in the Upper Ocean Regional Study (SPURS): Snakes on a Ship!

August 31st, 2016 by Eric Lindstrom

By Eric Lindstrom

Salinity snake

A longstanding technical challenge for oceanography has been how to measure the sea surface – temperature, salinity, gas exchange, or surfactants – to name a few examples. Obviously enough, the surface is where the ocean and atmosphere interact and exchange heat, freshwater, gases, momentum, and particles of all kinds. So, how do we measure the properties and exchanges right at the surface? If we are on a ship or any floating platform, the platform disturbs the surface. From satellites we can measure many properties of the surface but only on very broad scales. The R/V Revelle, right now, is the ship showing how modern science is meeting the challenge. Let me tell you about some key elements.

Julian Schanze from Earth and Space Research in Seattle and Jim Edson from University of Connecticut have brought two instruments aboard with innovative ways to measure the temperature and salinity at the surface – the Sea Snake for temperature (Edson) and the Surface Salinity Snake (Shanze) for, obviously, surface salinity. The former places a temperature sensor at the end of flexible hose that is hung outboard from the bow of the ship (near the wake), to continuously measure temperature. The Salinity Snake, outboard of the wake passes water through a vortex de-bubbler and thermosalinograph to obtain an estimate of salinity within inches of the ocean surface. It is an awesome “contraption” (with no offense to Julian).

The Salinity Snake being deployed over the starboard side.

The Salinity Snake being deployed over the starboard side.

Julian Schanze's birthday balloon.

Julian Schanze’s birthday balloon.

Today is Julian’s birthday so all the Salinity Snake gear has been draped with colorful paper snakes carrying birthday greetings. Julian participated in SPURS-1 in 2012 and has since received his PhD and is making a name for himself by tackling surface salinity science from gadget to satellite and from seawater intake to space. It is wonderful to have someone so capable on the NASA Ocean Salinity Science Team!

Andy Jessup, our chief scientist from University of Washington Applied Physics Laboratory and Michael Reynolds from Remote Measurements and Research Co. in Seattle have brought a dazzling array of instruments for measuring and probing the skin temperature of the ocean. The surface of the ocean is known to have a cool skin at the molecular level. Photos of the sea surface with infrared cameras reveal complex and interesting patterns as a result of mixing, wave breaking, surfactant conditions, and wind. NASA has always had a deep interest in skin temperature because satellites do measure this skin temperature while every probe you stick in the ocean measures something deeper and different than skin temperature. From the Revelle, Andy and Michael are using several infrared radiometers and cameras to measure and depict the sea surface skin temperature. There is one on a boom to measure outboard of the ship wake, one mounted on the rail to look outward from the ship and another on a balloon to take infrared photos of the skin from 300 feet above the ship (the Lighter-Than-Air InfraRed System – LTAIRS.)

The laboratory end of the Salinity Snake and Carbon Dioxide analysis.

The laboratory end of the Salinity Snake and Carbon Dioxide analysis.

LTAIRS ascends toward 300 feet.

LTAIRS ascends toward 300 feet.

Eric Chan, from University of Hawaii, is aboard measuring making a suite of carbon dioxide, pH, and Dissolved Inorganic Carbon measurements for principal investigator David Ho. They study the exchange of carbon dioxide across the air-sea interface and they’re particularly interested in how rainwater on the surface of the ocean impacts the gas exchanges.

The array of instrumentation aboard Revelle is quite astonishing and the technical innovations displayed in measuring the sea surface are truly remarkable. And I haven’t even mentioned the Surface Salinity Profiler yet in this blog post. I have been teasing you with that since the start of the voyage and I PROMISE to give it a blog entry all to itself!

Today is also the birthday of the R/V Revelle Captain, Christopher Curl. I am sure I speak on behalf of the entire SPURS-2 science party when I offer him a hearty “HAPPY BIRTHDAY!” and say how pleased we are with the entire ship and crew of R/V Revelle. I guess that sharing the ship with a group of rare ocean-skin specialists with sea snakes is not how he imagined this birthday, but he is quick with a smile and will roll with our skinny offerings!

Salinity Processes in the Upper Ocean Regional Study (SPURS): Whither Life in the Sea

August 30th, 2016 by Maria-Jose Viñas

By Eric Lindstrom

Sam Levang from WHOI catches a flying fish in flight.

Sam Levang from WHOI catches a flying fish in flight.

I figured I would go off topic today and discuss a disturbing observation by someone who has spent more than half a lifetime going to sea. This is my personal opinion and does not reflect any policy or perspective of NASA. However, those of you on land really need to know that humans have had an enormous impact on the large life forms in the ocean. Sure, you probably know about how we took whales to the brink of extinction, but what about the fish on your dinner table. Do you really know how much is left in the sea?

A sea turtle near Honolulu.

A sea turtle near Honolulu.

First, to minimize stating a bunch of boring facts and figures, I give you some brief but informative links below to research for yourself. This blog post is more of an emotional statement of alarm from my personal experience than that of a fisheries biologist or an expert on marine biota of any kind.

I became an observer of marine life from a very young age. I was raised in Seal Beach, California in the 1950’s when sea lions still roamed the beach. They have long departed. Most of my oceanographic life was spent in the tropical Pacific Ocean from late 1970s to present. My experience tells me has been an enormous change in the frequency of sightings of marine organisms from shipboard during those years. In the 1970s and 1980s it was a daily occurrence to see sharks, tuna, squid, and birds. Now, in the 21st century, we are lucky to see ANY of the former and few birds. Flying fish are still around but disturbingly little else swims by the ship during shipboard work in recent years. To put this in land-loving terms it feels like a rainforest filled with life is replaced by a desert of bleak lifeless sand. Sadly, this trend has been clear to me for decades and is substantiated in many ways by scientific studies. I particularly note that my personal observations coincide in time with the dramatic increase in tropical fisheries from the 1980s. Rapid depletion of large and visible marine organisms at the top of the food chain has been well-documented. A good book on this subject is “An Unnatural History of the Sea” By Callum Roberts.

Monkey geared up for fishing.

Monkey geared up for fishing.

Monkey actually caught a fish!

Monkey actually caught a fish!

Another aspect of the alarming trends in the ocean over recent decades is the growing abundance of marine debris, particularly plastics in the far reaches of the open ocean. I will devote a future blog to this subject (as I did during SPURS-1)

I do not wish to leave you with only a picture of doom and gloom. We should all pitch in to alleviate pressure on ocean ecosystems. The National Oceanic and Atmospheric Administration has created Fish Watch to help guide concerned consumers to sustainable seafood choices. I urge all who follow my blog to become concerned consumers! Also, any lessons from your past about the limitless abundance of the ocean should certainly be buried and replaced by thoughts about care and stewardship of precious and limited marine resources.

Masked booby.

Masked booby.

References:

Wild Marine Catch.

Overfishing (Wikipedia).

Marine Fisheries — The State of the Affairs.

Salinity Processes in the Upper Ocean Regional Study (SPURS): Monkey Business over the Tropical Thermocline

August 29th, 2016 by Maria-Jose Viñas

By Eric Lindstrom

The CTD team (Spencer, Leah, Janet, and Kristin).

The CTD team (Spencer, Leah, Janet, and Kristin).

The focus of SPURS-2 is the upper ocean and the fate of rainwater. However, in order to study the top of the ocean one needs to know what is going on deeper down. The beauty of SPURS-2 is not skin-deep! SPURS-2, like many prior physical oceanography experiments, requires a basic background and context of the ocean circulation environment upon which many of our other more specialized or detailed measurements can be interpreted. The two major pieces of the contextual information for us are the surface circulation and the surface salinity pattern.

The surface salinity pattern is provided by remote sensing for the largest scale and by the array of drifters and profiling floats that have been deployed with salinity sensors. Also, the R/V Revelle is collecting a treasure trove of upper ocean salinity measurements wherever she goes – with continuous underway measurements of salinity from intakes at the surface, 2 meters (6.5 feet), 3 meters (9.8 feet), and 5 meters (16.4 feet) depths. I’ll go into that in more detail in a later blog on the Surface Salinity Profiler.

The surface circulation of the ocean is largely the result of the wind and the shape of the massive deep layers below the surface. In fact it can be crudely estimated if one knows the precise shape of the thermocline – the boundary between the warm upper ocean and the vast deep cold ocean. Here in the tropics the thermocline is pretty well represented by the 20°C (68° F) isotherm. Think of the warm upper ocean as all the water warmer than 20°C and the layer below as all the water colder than 20°C. Tropical oceanographers can use the depth of the 20°C isotherm much like meteorologists use surface atmospheric pressure maps to chart the highs and lows of weather and their associated winds. Here, if the 20°C isotherm rises toward the surface locally it is associated with a counterclockwise ocean surface current. The signature of the westward North Equatorial Current is a gentle slope of the isotherm from deeper in the north to shallower in the south. This is where our Conductivity-Temperature-Depth (CTD) instrument comes into the SPURS-2 plan. We can use it to track the shape of the thermocline. I wrote about the CTD during the SPURS-1 campaign. It is still the workhorse of physical oceanography – or maybe the monkey on the back of every physical oceanographer! Our show seldom goes on without it.

Preparing the CTD to go over the side.

Preparing the CTD to go over the side.

Janet Sprintall from Scripps Institution of Oceanography and her team (Spencer Kawamoto, Leah Trafford, and Kristin Fitzmorris) are now mapping the temperature and salinity structure of the ocean well into the deep cold abyss (to 1.5 kilometers –0.93 miles– below the surface). The ocean depth is about 4.5 kilometers (2.8 miles) and the lower 3 kilometers (1.86 miles) are (for our purposes) relatively uniform and cold. Janet has planned a grid of 49 stations 30 miles apart around the SPURS-2 central mooring. These will be completed over about a week’s time. Simultaneously there will be regular sampling with the Surface Salinity Profiler between some of the CTD stations and we will optimize our meteorological measurements by limiting our speed to 10 knots (11.5 mph). So, while studies of the meteorology and near surface salinity are ongoing, as we move about the ocean, Revelle stops for an hour every 30 miles to collect necessary information on the background oceanographic conditions.

The CTD instrumentation remains largely unchanged (although perfected) in recent decades. Temperature, salinity, and oxygen sensors are mounted on the bottom of a large frame. Water sample bottles are mounted around the outside of the frame. Other instruments, such at the acoustic Doppler current profiler, may also be mounted on the frame. All data is transmitted up the conducting wire cable that is used to raise and lower the instrument. This bulky package is now easier to deploy and recover than in yesteryear due to innovations on today’s vessels. Now the Revelle has a specialized mechanical arm to get the CTD over the side and back on deck safely without much human intervention.

Monkey climbing over the water sample bottles on the CTD.

Monkey climbing over the water sample bottles on the CTD.

For my entire career oceanography has been spelled “CTD.” Knowing the temperature and salinity structure from surface to ocean depths is the key to our understanding of the ocean’s role in climate. The first global mapping of these characteristics (with CTDs) was not realized until the World Ocean Circulation Experiment in the 1990’s. Now oceanographers are working hard to understand all the physical, chemical, and biological changes associated with global warming, rising carbon dioxide levels, and industrial fishing. In that big picture, SPURS-2 might look like a small bit of monkey business over the tropical thermocline. However, we know that the resulting scientific understanding will long outlive the memory of our tiny field program in this vast Pacific Ocean!

Notes from the Field