By Eric Lindstrom
One of the popular topics of conversation during the first week of the voyage has been sleep. Whether it is poor sleep, good sleep, disturbed sleep, or deep sleep, almost everyone in the science party has had something to say about the subject of sleep.
Sleep on a ship is special. As you can imagine, the rocking and rolling (actually pitching, rolling, and yawing) can be a gentle sleep inducement – unless it is making you terribly sick! What those on land probably cannot imagine are all the noises associated with the ship – the engines, equipment, and the sea slapping at the ship. An amazing array of new hums, grinds, bangs, bumps, slams, alarms and conversations must be assimilated into one’s sleep life.
After a week of hard work preparing the ship for sea in Honolulu, it is no surprise that many slept well the first night. However, the next couple days were much harder for some. The mild seasickness and the abnormal noises from the ship unsettled sleeping patterns. More than one person commented to me that their adjustment and best sleep came around day 5. By that time all the seasickness had past and the sounds of being at sea had been incorporated into ones dreams. Soon we will start weeks of 24/7 operations and the luxury of long sleeps may be over until the transit back to Honolulu. Sleep may get interrupted when operations call.
Many scientists will be on 12-hour watches (noon to midnight or midnight to noon) so one should not be too worried out lack of sleep among your favorite scientists. It is more likely that one’s normal rhythm of sleep may be at odds with duties.At sea it is not abnormal to find people eating, sleeping, exercising, and working at odd hours.
Part of writing about sleep now is because (at this writing on Sunday afternoon, August 21) we have completed our transit from Honolulu to 125W longitude and are beginning 24-hour scientific operations with a southbound trek along the meridian. We will be deploying drifters at regular intervals, profiling temperature and salinity while underway, and deploying three moorings along this meridian.
Let me finish today with a little local story about sleep. Andrew Meyer, the mooring technician from the National Oceanic and Atmospheric Administration, has a son, Jack, who is 3 and a half years old. Jack sleeps with his plush toy Monkey every night. When dad left home for the SPURS-2 expedition, Jack sent Monkey along so Andy would not be lonely. So Monkey is having a good time, sending pictures to Jack and family regularly. Monkey is certainly helping Andy keep in touch with his loved ones and that also means that Monkey is helping Andy sleep better at night. So, dear readers, Monkey joins the blog today to honor all that we do to sleep well and to remember those we left at home as we work, and sleep.
I leave you today with a sunset and hope that all of you will sleep well!
By Eric Lindstrom
As I mentioned in a previous blog post, the R/V Revelle is bristling with meteorological sensors. Some are permanently installed aboard, some are just for SPURS-2, and some are on the moorings we will deploy. Raymond Graham, a graduate student at University of Connecticut, did a quick count of meteorological sensors and we were amazed to find out that on a ship of less than 300 feet we had deployed eight wind sensors, 16 air temperature probes, 15 humidity sensors, 15 rain gauges, 11 radiometers, and four barometric pressure sensors! The reason for the overkill is the critical nature of meteorology for our work and the difficulty of obtaining clean data from the ship. Wind and rain especially are notoriously difficult to sample because of flow distortions or shadowing around the ship. By deploying gear at a number of locations (bow, stern, bridge deck, etc.), we will more likely collect clean data no matter which direction the ship is headed relative to the wind. During analysis of the data, one ideal time series of ship data can be assembled from the numerous sensors based on ship heading and true wind direction.
For SPURS-2, a group from Woods Hole Oceanographic Institution led by Carol Anne Clayson and a group from University of Connecticut led by Jim Edson are gathering state-of-the-art measurements of key meteorological variables. They will estimate the transfers of heat, freshwater, and momentum between atmosphere and ocean. Today, for example, Jim Edson launched the first of their balloons for atmospheric sounding. The balloon carries a small expendable package that transmits temperature, humidity, and pressure data until the balloon pops in the upper atmosphere.
Elizabeth Thompson from the University of Washington’s Applied Physics Laboratory is also working the meteorological angles for SPURS-2 by providing the daily meteorological briefings and analysis of radar data (to help us track rain events). She and Audrey Hasson are providing daily briefings at 4 pm to apprise us of the weather and oceanographic conditions to be encountered over the next day of operations. For the moment they are practicing and perfecting the best information and products to utilize and share. Prediction sure is an activity to sharpen a scientist’s skills!
While much of the time aboard Revelle is focused on oceanographic measurements, the meteorology is key to synthesis of the overall story of SPURS. In the end we will want to assess the ocean response to forcing – whether in the form of rain, wind, or sun’s radiation. It is quite difficult to tell the story of the near surface ocean without understanding how it is interacting with the atmosphere. Likewise, it is quite difficult to tell the story of the evolving atmosphere without understanding how it interacts with the ocean. This coupled system is an especially powerful engine for Earth’s climate here in the tropics. The warmer the ocean and atmosphere, the more energy in the form of water vapor is exchanged. Hurricanes are a good example of this interaction and exchange – and a reason to worry about stronger or more frequent hurricanes in a warmer world. Air sea exchange is very sensitive and very powerful when ocean waters are greater than about 83 degrees Fahrenheit (28.5 degrees Celsius) as is found in the deep tropics and here in the Intertropical Convergence Zone.
By Eric Lindstrom
One of the most common questions I get (and the first comment to this blog) is “How do you measure ocean salinity from space?” During the SPURS-1 campaign in 2012 I wrote a blog post on this topic. Basically the story is one of building a very sensitive instrument (a radiometer) to detect subtle variations of L-band microwave emissions from the ocean. Aquarius, launched in June 2011 was designed specifically for that purpose. Unfortunately, the spacecraft on which the Aquarius instrument flew suffered an unrecoverable failure in spring of 2015. Fortunately for oceanography, NASA launched Soil Moisture Active-Passive mission (SMAP) in January 2015. SMAP uses similar technology (an L-band radiometer) to measure soil moisture. While SMAP is not as sensitive as Aquarius, NASA is successfully producing a salinity product from this mission’s data.
The satellite missions detect only the salinity at the surface of the ocean. This tells us much about the exchanges of water with the atmosphere once we learn how to interpret the signals. The SPURS expeditions are all about learning how the surface salinity of the ocean changes so we can use the global surface salinity maps from space to diagnose matters of the water cycle over the ocean.
The European Space Agency also launched the Soil Moisture and Ocean Salinity mission (SMOS). It uses a different technology (a synthetic aperture antenna array) to make the measurements, but also provides a salinity product we use daily. Audrey Hasson from the French space agency is aboard R/V Revelle and helping us bring all the space data (salinity, temperature, winds, sea height, waves) to the ship to guide our daily operations.
Most of the oceanographic work on this voyage is focused on measuring and understanding the variations of salinity in the top 10 meters (~30 feet) of the ocean. Here, in one of the rainier spots on the planet, rainwater freshens the surface ocean. The degree of freshening was not really appreciated until we saw the surface salinity from space. Measurements from ships and buoys usually miss sampling the upper few meters of the ocean because it is technically difficult to make those measurements. Taking full advantage of Aquarius and SMOS surface salinity observations has required a scientific revolution in measurement of salinity in the top 10 meters of the ocean.
Getting back to shipboard life, I am happy to report that all the minor cases of seasickness are abating. Those that suffered from it are now smiling and eating. No serious cases of seasickness occurred at all, so my guess is that all the first-timers will return to sea in future!
Also, today was the first trial deployment of one of our key instruments, the Surface Salinity Profiler (SSP), from University of Washington Applied Physics Lab. It’s a salinity measurement “laboratory on a sailboard” that can be towed at outboard of the ship. The instrument can measure salinity simultaneously and continuously at several shallow depths away from the ship’s influence and wake. The trial was devoted to the mechanics of deployment and recovery and the dynamics of towing the system. You will hear much more about SSP as the voyage progresses.
Winds dropped over night and whitecaps have largely disappeared. The sky is broken clouds with an occasional very light rain shower. Air temperature is 80°F. So overall, the weather conditions for test deployments off the ship are much better today!
By Eric Lindstrom
Fieldwork in physical oceanography, like many sciences, requires enormous preparation followed by a shorter very intensive period of action. SPURS-2 is no exception. The work over the next six weeks has been in the planning and staging for several years. Now, all the gear and scientists have reached the ship and we are on our way to completing all of our the carefully laid plans.
It is tempting to express the mood aboard the R/V Revelle as a great sense of anticipation. From discussion around the ship, it seems like no one has seen a voyage with these many sensors and equipment installed aboard this ship. There seem to be instruments mounted everywhere from bow to stern! And, of course, the scientists and technicians are deeply interested in what each sensor will tell them and what kind of scientific discoveries will emerge. These instruments are designed to see the delicate slow dance between the ocean and atmosphere around the ship over the coming weeks. Other gear will be deployed to continue the careful watch on ocean and atmosphere for the next year. All our time and investment is focused on understanding the aspects of this “slow dance” that involve water exchanges between ocean and atmosphere. In the atmosphere we will be looking at the characteristics of rainfall and evaporation at the sea surface. In the ocean we will be study the characteristics of the temperature and salinity patterns induced by the rain. These interactions are a newly accessible field of study resulting from the advent of satellite rainfall and salinity measurements and new shipboard tools for studying the upper few meters of the ocean.
All the scientific party on R/V Revelle likely feel some sense of adventure, since the precise nature of what we will see and discover is a matter of conjecture. We do know from the Aquarius satellite data that there is a large pool of relatively fresh water built up seasonally at the surface of the eastern tropical Pacific north of the equator. Oceanographers are curious as to how this pool is trapped in the region for part of the year and how it is seasonally released to the west. As physicists, we are tackling the problem by careful examination of the individual processes that bring the water into the ocean (rain), maintain the fresh pool in the ocean (dynamics), and subsequently release the water to the west or to the deep (dynamics and mixing). If we knew the answers, it wouldn’t be research. The unknown beckons! The combined feelings of curiosity and anticipation –and that our work may result in deeper understanding of nature–, just seem to make this feel like an adventure!
So here we are, all primed for discovery but with five days more to go before being where we really want to work. We are like kids in the back seat of the car asking “are we there yet?” Every piece of gear is at the ready and the teams are completing their training. We are doing dry runs to iron out the deployments of new devices that just have not seen that much action. In later entries, I’ll introduce you to the Sea Snake and the Surface Salinity Profiler and the Lighter-than-Air InfraRed System (LTAIRS), a balloon. These are very new ways of examining the air-sea interaction near the ship. They will be used in conjunction with many of our standard tools – drifters, wavegliders, and moorings, for example. We hope they will lead us to deeper insights about the water cycle at the ocean surface. I will give you a preliminary view of what is discovered during the week-long return voyage to Honolulu at the end of September. For now, we simply prepare for action!
By Eric Lindstrom
Two ships in Honolulu were abuzz with action this last week preparing for SPURS-2, a detailed study of ocean salinity in the eastern tropical Pacific Ocean. The Roger Revelle, upon which all the scientific party sails, had to be loaded with many tons of scientific equipment and installations completed all over the ship. Lady Amber, the 20-meter (66-feet) schooner, was also readied for action with the installation of meteorological and oceanographic gear.
It was amazing to see what was completed in only a week under the supervision of chief scientist Andy Jessup (University of Washington). Containers from Seattle, Woods Hole, and San Diego were unloaded and equipment hauled to the ships. Many scientists and technicians dedicated the entire week prior to Revelle’s departure on August 13 for stowage, assembly, installation, testing, and securing of instruments and gear. It was a very quiet ship over the last 24 hours after we departed as everyone had a well-deserved rest and acquired their sea legs!
The Lady Amber crew successfully tested its new installation of scientific gear but suffered a schedule setback when the crew discovered that the ship required a new engine prior to departure from Honolulu. These arrangements are underway and we are appreciative of the support provided by the University of Hawaii as the Lady Amber work gets completed. Lady Amber is expected to leave Honolulu in about a week and catch up with Revelle at the SPURS central work site, eight days southwest of Hawaii.
Weather was fine on Saturday afternoon for Revelle departure. It was a quick trip out of the harbor with a great view of Waikiki skyline and Diamond Head. We passed by the Big Island of Hawaii on Sunday morning, August 14, giving people one last chance at cell phone calls. The island, really the largest mountain on our planet (from ocean bottom to summit), is a phenomenal sight.
On Sunday we had our first of weekly safety drills. Everyone got to learn how to decode the various horns that call for assembly, all clear, and abandon ship. We learned about survival suits and life raft deployment. Especially, we learned how to be safe on the Revelle and watch out for one another. We were encouraged to see the expert knowledge and conduct of the crew in their drills. It is over 2000 miles from Hawaii to the site where we begin work in earnest (deployment of moorings that pack the after deck). In the coming week, as we make the transit, the primary occupation will be testing and checking out various systems and training everyone for the complex operations to come. Once we are on site, we will quickly enter 24/7 scientific operations and we hopefully will have worked out all the glitches!
On a sad note, we had to leave our colleague Fred Bingham standing on the wharf in Honolulu, when we had expected him to sail with us. He was struck down with an illness that required he remain ashore and head home to Wilmington, North Carolina. His primary role in SPURS is as data manager. We are all assured that he will be on the mend very soon but we will miss his sunny manner and organizational skills.
The scientific party aboard Revelle is quite diverse – from first timers to old veterans. I’ll try to introduce you to the team in the weeks ahead. I am happy to report that I have seen no severe cases of seasickness during our initial day at sea. No doubt a few people are feeling a bit “green” but all are adapting well.
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