Julia Harvey: More to a Mooring than meets the Eye, June 26, 2016

NOAA Teacher at Sea

Julia Harvey

Aboard NOAA Ship Hi’ialakai

June 25 – July 3, 2016


Mission: WHOI Hawaii Ocean Timeseries Station (WHOTS)

Geographical Area of Cruise: Pacific Ocean, north of Hawaii

Date: June 26th, 2016

Weather Data from the Bridge

Wind Speed: 15 knots

Wind Direction: 100 degrees (slightly east southeast)

Temperature: 24.5 degrees C

Barometric Pressure: 1014.7 mb

Science and Technology Log

One of the primary objectives of this WHOTS project is to deploy WHOTS-13 mooring. This will be accomplished on our second day at sea.

Site of Mooring-13 courtesy of WHOTS Project Instructions
Site of Mooring-13
(courtesy of WHOTS Project Instructions)

The mooring site was chosen because it is far enough away from Hawaii so that it is not influenced by the landmasses. Mooring 13 will be located near mooring 12 in the North Pacific Ocean where the Northeast Trade Winds blow. Data collected from the moorings will be used to better understand the interactions between the atmosphere and the ocean. Instruments on the buoy record atmospheric conditions and instruments attached to the mooring line record oceanic conditions.

A look at interactions between the atmosphere and the ocean.
A look at interactions between the atmosphere and the ocean. [R. Weller, WHOI]






There is a lot more going on than just plopping a mooring in the sea. Chief Scientist Al Plueddemann from Woods Hole Oceanographic Institution and his team began in-port prep work on June 16th. This included loading, positioning and securing the scientific equipment on the ship.  A meteorological system needed to be installed on the Hi’ialakai to collect data critical to the mission.  And then there was the assembly of the buoy which had been shipped to Hawaii in pieces.  Once assembled, the sensors on the buoy were tested.

Meteorological Station on the Bow
Meteorological Station

As we left Oahu, we stopped to perform a CTD (conductivity/temperature/depth) cast. This allowed for the testing of the equipment and once water samples were collected, the calibration of the conductivity sensors occurred.

Sunday, June 26th, was the day of deployment. Beginning very early in the morning, equipment was arranged on deck to make deployment efficient as possible. And the science team mentally prepared for the day’s task.

The deck before deployment began. The buoy is the blue item on the left.

Promptly at 7:30 am, deployment began. The first stage was to deploy the top 47 meters of the mooring with sensing instruments called microcats attached at 5 meter intervals. A microcats has a memory card and will collect temperature, conductivity and pressure data about every three minutes until the mooring is removed next year.

Sensing instruments for the morring
Microcats for recording oceanic conditions
readied microcats
Microcats readied for deployment. They are lined up on the deck based on their deployment depth.

This portion of the mooring is then attached to the surface buoy, which is lifted by a crane and lowered overboard. More of the mooring with instruments is lowered over the stern.

The remainder of the mooring is composed of wire, nylon, 68 glass balls and an anchor.  At one point, the mooring wire became damaged. To solve this problem, marine technicians and crew removed the damaged portions and replaced the section with wire from a new spool. This process delayed the completion of mooring deployment but it showed how problems can be solved even when far out at sea.

After dinner, the nylon section of the rope was deployed. Amazingly, this section is more than 2000 meters long and will be hand deployed followed by a section of 1500 m colmega line. It was dark by the time this portion was in the water. 68 glass floats were then attached and moved into the water. These floats will help in the recovery of the mooring next year. The attachment to the anchor was readied.

glass floats for recovery
These glass floats will help when the mooring is recovered next year.

The anchor weighs 9300 pounds on deck and will sit at a depth of 4756 meters. That is nearly 3 miles below the ocean surface. The crane is used to lift the anchor overboard. The anchor will drop at 1.6 m/s and may take about 50 minutes to reach the bottom.  As the anchor sinks, the wire, nylon and the rest of the mooring will be pulled down. Once it reaches the bottom, the mooring will be roughly vertical from the buoy to the anchor.


Mooring Structure
Mooring Structure

Personal Log

I sailed aboard NOAA ship Oscar Dyson in 2013 so I already had a general idea of what life aboard a ship would be. Both ships have workout areas, laundry facilities, lounges, and of course messes where we all eat. But on the Hi’ialakai, I am less likely to get lost because of the layout. A door that goes up is near a door that goes down.

On our first day aboard, we held two safety drills. The first was the abandon ship drill. As soon as we heard 6 short and 1 long whistles, we grabbed our life jacket, survival suit and a hat. We reported to our muster stations. I am assigned to lifeboat #1 and I report the starboard side of 0-3 deck ( 2 levels up from my room). Once I arrived, a NOAA officer began taking role and told us to don the survival suit. This being my first time putting the suit on, I was excited. But that didn’t last long. Getting the legs on after taking off shoes was easy as was putting one arm in. After that, it was challenging. It was about 84 F outside. The suit is made of neoprene. And my hands were the shapes of mittens so imagine trying to zip it up. I finally was successful and suffered a bit to get a few photos. This was followed by a lesson for how to release the lifeboats. There are enough lifeboats on each side of the ship, to hold 150% of the capacity on board.

Survival Suit & Julia
Abandon Ship drill with Survival Suit

Safety is an important aspect of living aboard a NOAA ship. It is critical to practice drills just like we do at school. So when something does happen, everyone knows what to do. A long whistle signals a fire. All of the scientists report to the Dry Lab for a head count and to wait for further instruction.

I am reminded of how small our world really is.  At dinner Saturday, I discovered one of the new NOAA officers was from Cottage Grove, Oregon. Cottage Grove is just a short drive south of Eugene. She had a friend of mine as her calculus teacher.  Then a research associate asked me if I knew a kid, who had graduated from South Eugene High School and swam in Virginia. I did. He had not only been in my class but also swam with my oldest son on a number of relay teams growing up. Small world indeed.


Did You Know?

The Hi’ialakai was once a Navy surveillance ship (USNS Vindicator) during the Cold War. NOAA acquired it in 2001 and converted it to support oceanic research.




Mary Cook, December 19, 2004

NOAA Teacher at Sea
Mary Cook
Onboard NOAA Ship Ronald H. Brown
December 5, 2004 – January 7, 2005

Mission: Climate Prediction for the Americas
Geographical Area: Chilean Coast
Date: December 19, 2004

Location: Latitude 25°07.83’S, Longitude 81°54.62’W
Time: 0830

Weather Data from the Bridge
Air Temperature (Celsius) 19.04
Water Temperature (Celsius) 19.42
Relative Humidity (percent) 56.95
Air Pressure (millibars) 1018.17
Wind Direction (degrees) 155.6
Wind Speed (knots) 15.91
Wind Speed (meters/sec) 7.99
Sunrise 0734
Sunset 2116 (9:16 pm)

Questions of the Day

Why is the sunset so late in the day?

Positive Quote for the Day

“The world of achievement has always belonged to the optimist.” J. Harold Wilkins

Science and Technology Log

We tossed the last of fifteen drifting buoys this morning! It’s not the end, but the beginning of a wonderful new program. I’d say the Adopt-a-Drifter program got underway with a big splash! Teachers and their students around the world can adopt a drifting buoy just like my students at Southside Middle School in Batesville, Arkansas. They can map its path as it goes with the flow of the ocean currents. These drifting buoys also provide sea surface temperature and air pressure. This information can be utilized to gain a better understanding of the global oceans. I watched as Jeff and Bob deployed another Argo float. These floats are lowered over the back of the ship and when the quick-release mechanism comes in contact with the water, the powder in a small device dissolves and this releases a spring that unhinges the float from the straps. The straps are pulled back onboard as the ship leaves the Argo float in its wake.

I sat down and had a conversation with Chief Scientist Dr. Robert Weller of Woods Hole Oceanographic Institution about the importance of oceanic/atmospheric studies. He made some very good points that highlighted the fact that when just 1ºC of heat energy is released from the ocean water into the atmosphere it affects the air flows for thousands of miles. This then can be like a domino effect and continue around the globe influencing weather patterns for people everywhere.

At 2:00 we interviewed Richard Whitehead, Chief Steward. Richard is over the food preparation in the galley. Richard shared that he has been working on ships for over 40 years and has had several trainings for the position he now holds. He said that the menus were developed based on nutritional guidelines and availability of produce. Richard shared with us that they keep the produce fresh for weeks by keeping it very cool and placing it in special bags that slows the deterioration. He also said that there are many safety issues that concern food preparation on a moving ship. All the pots and pans are deep, there are railings on the stovetop, and special care must be taken with knives. The countertops must be covered with anti-slip cloths to keep everything from sliding around. He also said that they consider the weather when deciding what to prepare because you wouldn’t want to bake a cake while the ship was moving through rough waters.

We changed “6:00 Science on the Fantail” to “6:00 Science in the Van on the Bow” because we wanted to interview Jason Tomlinson of Texas A & M about his work with aerosols. First of all, Jason explained that an aerosol is not a spray can. It is a small particle in the air. Jason showed us the Tandem Differential Mobility Analyzer (TDMA). It looks like a mad scientist’s invention with wires, tubes, canisters, and radioactive components! It is one of the best devices in the world for analyzing small particles in the air. It draws in air from outside then dries the air. It then separates the particles according to size. Jason said that these particles are too small to see with the naked eye but they have a great influence on cloud formation and cloud life length. The TDMA can determine what the particles are made of by adding moisture or by adding heat. The TDMA costs about $70,000! He also showed us the Aerodynamic Particle Sizer (APS) which analyzes larger particles. They mostly get sea salt and dust out here in the ocean. Jason said that there’s a mystery about the sea salt and its influence on clouds. The APS costs about $35,000. He also said that occasionally they take in the ship’s exhaust and that destroys their data for that particular time. He concluded by saying that it all gets back to climate change and using these data to make better models for predictions.

After our interview with Jason, we ran outside to glimpse San Felix and San Ambrosio Islands! Our first land sighting in over two weeks! These small islands, located about 300 nautical miles from Chile, are volcanic in origin. They are basically huge, desolate rocks protruding up from the ocean floor. As far as I could tell nothing is growing on them. Seafaring birds do nest on the cliffs. Since 1975 the Chilean Navy has had an installation on San Felix Island where they operate a short airstrip, a weather station and a tide station.

Personal Log

I’m just beginning to realize that this trip is nearly over. We only have four days left. I knew it wouldn’t go on forever but as the old saying goes “time flies when you’re having fun”. What a superb voyage this has been for me-a voyage that is continuing my personal quest to search out the majesty of Earth. In doing so it is my heart’s desire to absorb the inexplicable magnificence of our Earth. I want to be permeated with awe for the splendor as I soak it in with my eyes and ears and nose and skin. I am amazed. How can I take it all in? Where was I when the Earth was formed and hung in the nothingness of space? From where did this splendor come? Clouds and rain and snow and hail are amazing! Mountains and valleys and canyons and caves are amazing! Oceans and rivers and glaciers and springs are amazing! Rocks and minerals and soil and sand are amazing! People and animals and languages and ideas are amazing! And they all work together in a symphony of overwhelming magnitude. I believe that we’re all an inextricable part of this grand masterpiece. Traveling is not the essential element in a voyage. Life is a voyage no matter where you are. Our voyage is how we perceive our surroundings, how we face our challenges, and how we come to Truth. Actually, none of us ask for this voyage called life. We’ve been thrust into it by forces greater than ourselves. So here we are. We do have some choices, though. Will we make the most of this journey or will we let it sweep us along without ever wondering, and questioning and being amazed?

Until tomorrow,


Kevin McMahon, July 30, 2004

NOAA Teacher at Sea
Kevin McMahon
Onboard NOAA Ship Ronald H. Brown

July 26 – August 7, 2004

Mission: New England Air Quality Study (NEAQS)
Geographical Area:
Northwest Atlantic Ocean
July 30, 2004

Weather Data from the Bridge
Lat. 42 deg 37.86 N
Lon. 70 deg 12.37 W
Speed 8.6 kts
Barometer 1018.96 mb
Rel Humidity 93.16%
Temp. 18.9 C

The seas are calm. The skies have a distant haze. The New England atmosphere so common at this time of year. As is usual for the day, at 0700 we sent aloft a radiosonde, and then at 1000 an ozonesonde.

I was lucky enough to see a couple of finback whales; but unfortunately I had left my camera on my bunk, before beginning a discussion with Drew Hamilton about alternative power generation. Many of the scientists lead very diverse lives. Drew has a house in Seattle and wants to get off the electrical grid. He has worked for NOAA for 25 years and has seen much of the world. Thirty years ago he started out at the University of Miami, never in a thousand years dreaming he’d be involved in the kind of research he’s doing.

Ever hear of di-methyl sulfide DMS? As chemistry teacher I’d heard the name but never understood its significance to the atmospheric work the scientist aboard the ship are undertaking. It turns out that di-methyl sulfide is produced by plankton and is part of a planktons waste process. DMS is one of the major contributors of atmospheric sulfur. Overly high levels in the atmosphere can act as a reflective unit not allowing enough sunlight through our atmosphere. As a result, in certain areas the Earth does not receive the needed heat for some of the biological processes to take place.

Weather Data from the Bridge
Lat. 43 deg 17.84 N
Lon. 69 deg 33.83 W
Speed 9.3 kts
Barometer 1018.3 mb
Rel Humidity 86.16%
Temp. 20.65 C

1530 hours and there seems to be a flurry of activity among many of the scientist. A radiosonde is being rapidly readied to be sent aloft. It seems that the ship has reached a position somewhat east of Portland, ME and we have found a plume of ozone. The initial spike on the instrumentation showed 80-85 ppb (parts per billion) but then it jumped again to 101 ppb. This spike in the ozone was enough to request that another ozonesonde be readied and sent aloft. They have also requested a fly over by the DC3 out of Pease. Onboard the DC3 is a LIDAR (Light Radar) which measures atmospheric ozone. I am told that the cost of one ozonesonde is approximately one thousand dollars, so I assume that the readings on the instrumentation are justifying the expense. It will be interesting to see what they all have to say at the evening science meeting which is held each evening at 1930 hours.

We seemed to have found a large plume of ozone. It is as everyone, the science staff at least, had assumed. We have indeed found a large plume of ozone.

1930 hours. We are now heading in a westerly direction for Cape Elizabeth, ME.

Debra Brice, November 15, 2003

NOAA Teacher at Sea
Debra Brice
Onboard R/V Roger Revelle
November 11-25, 2003

Mission: Ocean Observation
Geographical Area: Chilean Coast
Date: November 15, 2003

Data from the Bridge
1.  151700Z Nov 03
2.  Position: LAT: 19-50.1’S, LONG: 085-03.3’W
3.  Course: 189-T
4.  Speed: 12.3 Kts
5.  Distance: 295.6 NM
6.  Steaming Time: 24H 00M
7.  Station Time:  00H 00M
8.  Fuel: 4233 GAL
9.  Sky: OvrCst
10. Wind: 110-T, 09 Kts
11. Sea: 110-T, 2-3 Ft
12. Swell: 200-T, 3-5 Ft
13. Barometer: 1018.9 mb
14. Temperature: Air: 23.5 C, Sea 19.0 C
15. Equipment Status: NORMAL
16. Comments: None.

Science and Technology Log

We arrived at the Stratus Buoy at 1:30pm.  We had some problems putting out the zodiac and will have to go and do a survey of the buoy up close tomorrow.  Dr. Weller’s group will be calibrating the instruments on the buoy all day tomorrow and the following day they will be taking it out of the water in preparation to store it and ship it home.  The new Stratus Buoy will be deployed in a couple of days.  We continued to release radiosondes at 6 hour intervals.  We are finished drooping surface drifters for awhile as well as ARGO floats. Dr. Weller did 2 CTD casts tonight to 4000m and we attached our styrofoam cups to the CTDs.  I have attached some photos of our cups and my wig head after their trip into the abyss.  We filmed a video of the cast that should be up in a couple of days.

A CTD stands for Conductivity, Temperature and Density.  Sea water conducts electricity as a function of the amount of dissolved salts, in other words it will be a better conductor of an electrical current if it has a higher amount of salts dissolved in it.  The density is calculated based on the salinity and the temperature.  The salinity is calculated using the conductivity and temperature. Warm water is less dense than cold water and water with a higher salinity is more dense than water with a lower salinity.  Evaporation removes water but leaves behind the salts and creates more dense water at the surface.  The densest (heaviest) water sinks and the less dense water rises and you get stratification or layering of different water masses.  The wind does cause mixing of the surface layer but this varies with wind speed and can vary in depth between 1 meter to 1500 meters in some areas.  The CTD that we just took shows a very shallow mixed layer and we will be analyzing it a bit more closely later today.  I have included a picture of the temperature/salinity/density plot from the CTD cast.   The green line represents density, which is increasing from the surface down.  The red line is salinity which is decreasing from the surface down but you can see some variations which show different water masses and some mixing.  The brown is conductivity and the blue is temperature. We sent down the styrofoam cups and the wig heads as a demonstration of  the effects of pressure.  All of the air piled on top of us from the surface of the earth up into the stratosphere equals one atmosphere, but water is much more dense so if you go down 33 feet you are under 2 atmospheres of pressure and another atmosphere for every 33 feet.  So how many atmospheres were our cups under?  E-mail me (Debra.Brice@noaa.gov)and let me know your answer?

Personal Log

Long day punctuated by being on watch.  Food is wonderful, the cooks are really creative and we have enjoyed all the meals.  After dinner a lot of people will go into the lounge and watch DVDs or play board games.  Most of us read or check e-mail.  There is always something to do or sea and sometimes it is just nice to go outside and watch the sunset or the cloud shapes.  At the CTD cast we had a spotlight on the water where the CTD went in and it attracted quite a group of large squid up to the surface.  They were over 3 feet long and quite fast.  The buoy has a group of 4 boobies that live on or near it feeding on the fish that gather around it.  They will be most unhappy when we take it out but they will have a nice new one soon.  Well, my watch is almost over and I am fading fast and this will be a busy day coming up…rumor has it that those styrofoam “cup of soup” cups shrink really well, hmmmm we need to do some more experiments on pressure……can we carve some pieces of packing styrofoam…..getting a bit carried away here:)


Jane Temoshok, October 20, 2001

NOAA Teacher at Sea
Jane Temoshok
Onboard NOAA Ship Ronald H. Brown
October 2 – 24, 2001

Mission: Eastern Pacific Investigation of Climate Processes
Geographical Area: Eastern Pacific
Date: October 20, 2001

Latitude: 20º S
Longitude: 85º W
Air Temp. 19.7º C
Sea Temp. 18.6º C
Sea Wave: 4 – 6 ft.
Swell Wave: 4 – 6 ft.
Visibility: 8 – 10 miles
Cloud cover: 7/8

Science Log

Several students have asked about seeing the stars in the Southern Hemisphere. Well I hate to disappoint, but I haven’t seen one star on this voyage. There’s a good reason though (and it’s not because I’m in the lounge watching movies). One of the main reasons this cruise is in the Eastern Pacific is because a layer of stratus clouds almost always covers it. While that’s not good for stargazing it’s great for the atmospheric meteorologists on board. One theory is that the clouds have a cooling effect on the ocean by reflecting the solar radiation back upwards and letting little of it penetrate to the surface. But it really isn’t completely understood at this time.

Additionally the southeasterly winds in this in this area cause the surface water to move away from the coastline allowing deeper water to move up to the ocean surface, creating an upwelling current. Upwelling currents replenish the surface layers with nutrients which is why the fishing and marine life is so plentiful along the coast. The shifts in the temperature of masses of water, along with the effects of the clouds are what the scientists onboard are hoping to understand.

What I have learned on this cruise is that the study of climate is very complex and that this area is particularly important. The Eastern Pacific may hold the key to a better understanding of the processes that affect the climate of the entire globe.

Travel Journal

The Chief Engineer Mike Gowan gave me a tour of the engine rooms today. He works down in the bottom of the ship and is responsible for overseeing all the major mechanics that keep the ship moving and habitable. There are 6 huge engines, air conditioning, water filtration, and sewage systems. It was really loud and we had to wear ear protection while we toured. He is assisted by Patrick,the Junior Engineer, and June, the “oiler”. (Isn’t it great to see women in the engineering room?!) Frankly I found it hard to conceive of working in that environment on a daily basis but they sure love it.

TAS Jane Temoshok and Chief Engineer Mike.
TAS Jane Temoshok and Chief Engineer Mike.
Temoshok 10-20-01 crewpatrick
This is Junior Engineer Patrick McManos.
Temoshok 10-20-01 crewjune2
June, another crew member of the BROWN’s Engineering Department.
Temoshok 10-20-01 peopleclaudiaandjane1
TAS Jane Temoshok (L) and her roommate, Claudia (R).
Temoshok 10-20-01 brownworkingondeck
A view of the crew at work on deck.

Question of the day: How long will it take the RON BROWN to travel from here to Arica (800 miles) averaging 13 knots/hour?

Keep in touch,

Jane Temoshok, October 14, 2001

NOAA Teacher at Sea
Jane Temoshok
Onboard NOAA Ship Ronald H. Brown
October 2 – 24, 2001

Mission: Eastern Pacific Investigation of Climate Processes
Geographical Area: Eastern Pacific
Date: October 14, 2001

Latitude: 15º S
Longitude: 89º W
Air Temp: 19.2.0º C
Sea Temp: 19.3º C
Sea Wave: 2 – 4 ft.
Swell Wave: 4 – 5 ft.
Visibility: 8 miles
Cloud cover: 8/8

Science Log

Wes Atkins & Robert Schaaf- Weather Balloons, University of Washington

Wes and Robert study the atmosphere. To do this they send up a big helium balloon that has a small box dangling from a string. In the box has an antenna that can communicate with up to 8 satellites, and several sensors that measure things like temperature, pressure, and moisture. The fancy name for this balloon and sensor package is called a radiosonde. The information that comes back to their computers is called an upper-air sounding. The data is graphed to show what’s going on in that atmosphere, on that day, in that location. Wes and Robert are part of a team that launches balloons every 3 hours! The idea is that the more data they collect the more accurate their “profile” or picture of the atmosphere will be. Also, they look for changes in the atmosphere as the ship moves along its track.

Another thing Wes and Robert are also interested in the sizes of raindrops. Have you ever been out in a light, misty rain? Compare that feeling to the big fat raindrops during a thunderstorm. What makes some rain drops tiny and some raindrops really big? For this experiment they use a special paper soaked in a chemical called “meth blue”. They put this out for a short period of time in a plastic tub. When the rain falls on the blue paper it leaves a mark which can be measured using a special tool – like a round ruler. They examine the sizes of the drops to learn about the clouds from which they came.

Travel Log

As you can tell from the data above, the sea is remaining pretty calm. The weather changes constantly from windy and gray to bright and clear. Every half hour is different. Today I saw a beautiful rainbow off in the distance.J (No pot of gold though.L) Still haven’t seen any other ships out here. We are very much alone at sea. This suits some people on board just fine. The crew (meaning the people who work on the boat all year long) really enjoy the solitude. They generally get news via email and whenever the ship puts into port, which can be anywhere from 3 weeks to 3 months. That’s a long time to go without hearing from your loved ones! There is a phone on board, but it costs $10 for just 3 minutes! There isn’t any TV on board but they do show 2 videos every night on a big screen in the lounge. There is a store on the ship where you can buy popcorn and candybars for the movie. Dinner is served really early (by my clock anyway) at 4:30! The kitchen closes by 5:30 so you better get your food by then or your on your own. The food is excellent, with a printed menu each day. I think the hardest working people onboard are the cooks! Can you imagine serving breakfast, lunch, and dinner for 50 people everyday? And they give us lots of choices too. Tonight we could choose from a complete turkey dinner (just like on Thanksgiving), Italian spaghetti with sausages, or salmon loaf.

Question of the day: How do updrafts affect the size of a raindrop? Do you think the size changes? If so, which way?

Keep in touch,

Jennifer Richards, September 12, 2001

NOAA Teacher at Sea
Jennifer Richards
Onboard NOAA Ship Ronald H. Brown
September 5 – October 6, 2001

Mission: Eastern Pacific Investigation of Climate Processes
Geographical Area: Eastern Pacific
Date: September 12, 2001

Latitude: 9º 56.5 N
Longitude: 95º 2.5 W
Temperature: 31.2º C
Seas: Sea wave height: 2-3 feet
Swell wave height: 4-5 feet
Visibility: 10 miles
Cloud cover: 5/8
Water Temp: 29.3ºC

Research Objective for the day: Begin taking measurements with the Lidar (ETL), the MMP (UW), weather balloons (CSU), and the SPMR (UCSB). Every group on the ship is in full swing, and will continue their operations for the next 18 days.

Science Log

Today I met with part of the group from NOAA’s Environmental Technology Laboratory in Boulder, Colorado. There are three sets of instruments being used by this team, and today I will introduce you to the researchers associated with two of those groups- the lidar group and the kaband group.

Ms. Janet Intrieri, an Atmospheric Scientist, and Dr. Raul Alvarez, a Physicist, have been working long hours each day on the Mini MOPA Lidar. This is the most labor-intensive piece of equipment on the ship, requiring constant watch and intervention to keep it running properly. It is also probably the fanciest piece of equipment on the ship, using CO2 lasers and an intricate network of lenses and mirrors to measure wind velocity and water vapor in the atmosphere. The really cool thing about the lidar is that it can measure these things at various altitudes simultaneously, up to 6-8 kilometers in range. Without the lidar, scientists could measure a specific point in the atmosphere using planes, satellites, or weather balloons, but the lidar allows Ms. Intrieri and Dr. Alvarez to see everything in a horizontal column of the sky at the same time.

How does lidar work? Lidar (which stands for Light Detection and Ranging, similar to the term Radar as used for radio waves) is a remote sensing technique that allows measurements of atmospheric conditions using laser light. The typical lidar system emits a short pulse of laser light that travels through the atmosphere. As this pulse of light goes through the atmosphere, it can interact or scatter off of various components in that atmosphere. These components can include dust, clouds, water vapor, pollutants, and even the air molecules themselves. When the light scatters off of these things, a small part of that scattered light is going back toward the receiver part of the lidar which is usually composed of a telescope (to collect as much of this light as possible) and a detector that converts the light signals into electronic signals that can be input to a computer.

How the signals that are collected are processed depends on what atmospheric properties are being measured. For information on the total amount of light scattering due to dust and clouds, we can simply look at the strength of the return signal as a function of time (which is proportional to the distance that the pulse has traveled). To gather information about the amount of water vapor in the atmosphere, one technique is to transmit two laser pulses that are at different wavelengths. One of the wavelengths is selected so that it is not affected by the water vapor, while the other is selected so that it is partially absorbed by water vapor. (Each different chemical that we might try to measure has a different absorption of light that will determine which wavelengths and types of laser must be used.) Now, as the laser pulses go through the atmosphere and as the scattered light returns to the receiver, one of the signals is attenuated (reduced) more than the other because it is being absorbed by the water vapor. The amount of water vapor that must have been in the atmosphere to cause a particular amount of signal reduction can then be calculated.

Another thing that can be measured with lidar is the wind velocity. To do this, we rely on the Doppler Effect. This effect states that as the light scatters off of the particles in the atmosphere, the frequency of the light may be shifted if the particles are moving. If they are moving towards the lidar, the frequency will be shifted up while the frequency will be shifted down for particles moving away. Since the frequency of light is extremely high and the Doppler frequency shift is very small, we need to bring the signal (light) frequency down to a manageable level. We can do this by a process called mixing. In essence, the light signal is shone onto a detector along with a small sample of laser light that is at the same frequency as the original pulse that was sent into the atmosphere. When these two beams interfere with each other, the result is a signal on the detector that is the difference in the two light frequencies. At this point, this difference signal tells us the speed of the wind, but not the direction of the wind. A shift of a few megahertz (MHz)(depending on the laser wavelength) could be due to a wind either towards or away from the lidar at a meter per second (m/s). To resolve this uncertainty, the transmitted laser pulse is shifted by a fixed amount of 10 megahertz. Now, when the atmospheric light signal and the laser sample are mixed, the shift in frequency will be offset by the 10 MHz signal. (As an example, let’s suppose that the Doppler shift due to the wind is 2 MHz. Then, the first example without a 10 MHz offset will give you simply a resultant 2 MHz signal for either a +1 m/s or -1 m/s wind, while the 10 MHz offset makes the resultant 12 MHz for a wind toward the lidar and 8 MHz for a wind away from the lidar.)

An additional piece of equipment being used by ETL is the Ka-band radar, operated by Ms. Michelle Ryan. Ms. Ryan uses Ka-band radar to study the clouds- water droplet size, condensation, and the changes between liquid, gas, and solid water. She also uses radiometers to study liquid water and vapor in a column from the ship to the sky. Her equipment complements the lidar by providing information about what’s going on above the cloud base (the lidar focuses on everything between the ocean surface and the clouds).

Thank you very much to Dr. Alvarez for translating enormously complex physics into what you just read about how the lidar works. If you read it through a couple times, it really makes sense! And they say laser physics is complex.

Travel Log

People always wonder what the food is like on the ship. Well, there is lots of it, and it’s better than what you would expect. In fact, I’ve heard some of the scientists challenging each other to see who can gain the most weight on the trip- just an excuse to try a little of everything on the buffet line, and dessert twice. There’s always a salad bar, a couple meat entrees, a couple meatless entrees, and several vegetables. One night we even had crab legs and steak! We eat during designated meal times in the mess hall, and since there are more people on the ship than there are seats in the mess, they try to get you to “eat it and beat it.” The most dangerous part of the mess is the freezer stocked with Haagen Daas ice cream, but I am challenging myself to avoid it until the last night on the ship. There are three stewards on the ship that do all the cooking and kitchen stuff. They’re really nice and friendly.

Question of the day: How much money did the U.S. spend last year on scientific research? What percent of the total budget does it represent? (Please cite your source when you send your answer)

Photo Descriptions:Today’s photos – Since today’s science log focused on the Lidar operated by NOAA Environmental Technology Laboratory (ETL), that’s what is highlighted in today’s pictures. You’ll see the ETL lab on the ship- a large container that travelled via tractor-trailor, plane, and barge to get onto the ship. There are two “vans” like this on the ship, which is where this group of ETL scientists spends most of their time. Inside the van, you’ll see Ms. Intieri at the computer controls, Dr. Alvarez tweaking the lenses in the Lidar, and in another picture, Dr. Alvarez pouring liquid nitrogen into the Lidar to keep the optics cool. Finally, you’ll see Ms. Ryan standing next to the kaband radar (looks like a large drum in the photo).

Until tomorrow,