Tag: Chilean Coast

Posted on

Debra Brice, November 22, 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 22, 2003

Data from the Bridge
1.  221600Z Nov 03
2.  Position: LAT: 20-00.0’S, LONG: 083-44.8’W
3.  Course: 090-T
4.  Speed: 12.6 Kts
5.  Distance: 102.7 NM
6.  Steaming Time:  8H 06M
7.  Station Time:  15H 54M
8.  Fuel: 2583 GAL
9.  Sky: OvrCst
10. Wind: 140-T, 14 Kts
11. Sea: 140-T, 2-3 Ft
12. Swell: 130-T, 3-4 Ft
13. Barometer: 1015.9 mb
14. Temperature: Air: 20.0 C, Sea 19.4 C
15. Equipment Status: NORMAL
16. Comments: Deployment of surface drifter array #4 in progress.

Science and Technology Log

NOAA Climate Studies of Stratocumulus Clouds and the Air-Sea Interaction in Subtropical Cloud Belts. Today we are still underway and I am going to talk about another science group that is onboard and how their research is related to the Stratus Project. We are presently located along the coast of Northern Chile and I just finished interviewing scientist Chris Fairall with NOAA’s Environmental Technology Laboratory in Boulder, Colorado.  A group of 4 ETL scientists are participating in a study of oceanography and meteorology in a region of the ocean that is known for its persistent stratus clouds.

The Woods Hole Oceanographic Institution (WHOI) has maintained a climate monitoring buoy at this location for the last 3 years.  Each year they come out to take out the old buoy and replace it with a brand new one with fresh batteries and new sensors.  A year in the marine environment takes a toll on the toughest instruments.  This is a special buoy which is festooned with atmospheric sensors to measure air-sea fluxes and with a long chain of subsurface instruments to measure ocean currents, temperature and salinity.  If you go to the WHOI website ( http://uop.whoi.edu/stratus) you can read about this project and see the data from the buoy.  The data are transmitted via satellite everyday.  WHOI removed the old buoy on Nov 17 and put in a new one on Nov 19.

Why are these clouds so important?  Because the earth’s climate is driven by energy from the sun and clouds dominate how much solar energy reaches the surface.  On average, almost 40% of the sun’s energy is reflected back into space and half of that is reflected by clouds.  In the cloudy regions more than 60% of the sun’s energy can be reflected by clouds.  The surface temperature of the ocean is a result in a near balance between solar heating and cooling by evaporation and cooling by infrared (IR) radiation from the water surface into the sky.  The global circulation of the atmosphere and ocean are driven by region differences in this net heat input, so clouds have a direct effect on the winds and currents. Cloud effects on the ocean surface energy balance are very tricky because clouds affect both the solar flux (i.e., by reflecting energy back into space) and the IR flux.  It might surprise you, but the sky is ‘warmer’ when there are low clouds present than when the sky is clear.  Think about those cold clear nights in the winter and note the ‘cold’ often appears with ‘clear’. More specifically, the IR radiation coming down from the sky is higher when clouds are present than when skies are clear.  In the tropics and sub-tropics, the solar reflection cooling effect of the clouds is much stronger than their compensating IR warming effect.  Thus, these stratus clouds play an important role in keeping the subtropical oceans cool.

The region we are studying is one of 5 stratus regions around the globe (west coast of U.S.. west coast of S. America, west coast of S. Africa, west coast of N. Africa/Europe, and the west coast of Australia) that occupy vast expanses of ocean.  Both of the pictures I attached to this log show the stratocumulus clouds in this region.  Each of these cloud types has about the same area-average liquid water content but, because of the horizontal distribution, vastly different radiative properties.  The physical processes that lead to these different forms are one of the objective of the ETL studies.

Clouds are formed through various related mechanisms; most involve cooling air to below its dew point temperature so droplets condense ( i.e., clouds are suspensions of liquid water drops with typical sizes of about 10 micrometers radius).  Convective clouds are associated with cooling in strong updrafts; fog and many mid-atmospheric clouds form when an atmospheric layer cools by IR radiation.  The stratus clouds we are studying are quite different.  The key elements are a strong atmospheric cap that traps ocean moisture in a fairly thin ( about 1 km high) boundary layer over the surface.  The stratus clouds occupy the top of the trapped layer from just below the cap to down the altitude ( cloud base height) where temperature and dew point just meet.  Below that, the relative humidity is less than 100%.  The ‘cap’ on the atmosphere boundary layer is warm/dry air descending in subtropical regions, particularly on the western boundaries of continents.  This descending air is actually driven by deep convection in the tropics.  To meteo- nerds this is an amusing paradox – cool stratus clouds off Chile and California are essentially caused by thunderstorms near the Equator.

Clouds are a pain to study because they are so inaccessible.  To get into clouds with sensors you need a really tall tower, a tall building or an aircraft.  Most of these are hard to come by 500 miles from land. Thus, most climate studies of clouds rely on remote sensing methods using satellites and surface based sensors.

ETL has deployed a suite of remote sensors on the R/V Revelle to study clouds from the bottom. The showcase sensors are a special high frequency cloud radar and a 2-frequency microwave radiometer system (this system is the attached picture of the large, white van).  This is the 6th time such sensors have ever been deployed from ships and only the second time to a stratocumulus region.  The first time was to this same spot in 2001; see the web site: http://www.etl.noaa.gov/programs/2001/epic for information on that cruise.

The radar has a wavelength of 8mm, which is so small that it is sensitive enough to receive  detectable signals from scattering cloud droplets.  With this device the ETL group can determine profiles of cloud properties ( such as size of the droplets) through the entire cloud.  The microwave radiometer uses the emissions from the atmosphere at 2 frequencies ( 21 and 31 GHz, or wavelengths of 14 and 9mm) to determine cloud base height and, most importantly, we also measure IR and solar radiative energy reaching the surface.  Instead of just looking at the cloud, they collect megabytes of data every minute.  The beauty of this set up is that they can simultaneously measure the effect the clouds have on the surface energy budget of the ocean and the cloud properties ( liquid water content, thickness, soiled versus broken, number of cloud droplets per unit volume) that go with the radiative effects.  The ETL group are only out here a few weeks each year, but their detailed measurements provide vital information to interpret long-term continuous time series measured by the buoy or inferred from satellite overpasses.

Personal Log

We are surveying for a location for the PMEL Tsunami buoy and the weather is beautiful.  Due to our heading we have lost internet connections periodically.  The food on the REVELLE  is really amazing; last night we had steak and King crab for dinner and a group of the crew and science party met in the lounge to watch a movie.  Card games and cribbage are popular in the dining room and some of us just sit outside and enjoy the sunsets.  I’m going to sleep early as I have the late watch.

Cheers

Posted on

Debra Brice, November 16, 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 16, 2003

Data from the Bridge
1.  161700Z Nov 03
2.  Position: LAT: 20-10.6’S, LONG: 085-08.0’W
3.  Course: Hove to
4.  Speed: 0 Kts
5.  Distance: 20.8 NM
6.  Steaming Time:  1H 48M
7.  Station Time:  22H 12M
8.  Fuel: 2215 GAL
9.  Sky: Ptly Cldy
10. Wind: 120-T, 14 Kts
11. Sea: 120-T, 2-3 Ft
12. Swell: 150-T, 3-5 Ft
13. Barometer: 1019.7 mb
14. Temperature: Air: 20.3 C, Sea 19.5 C
15. Equipment Status: NORMAL
16. Comments: On station in vicinity of WHOI buoy.

Science and Technology Log

We are at the STRATUS buoy from last year and are preparing to trigger the acoustical releases so that the glass ball floats will bring up the instruments, almost 50 of them!  it will take about 40 minutes from triggering the release until they surface and they the retrieval will begin in earnest.  We will spend the day bring them all aboard, recording the depth, serial number and condition of each of them before Dr. Weller’s group will begin downloading the data.  Then we will clean them and begin to pack them for the return to WHOI. A little background on the project first:  The purpose of the cruise was to recover and then deploy a well-instrumented surface mooring under the stratocumulus clouds found off Chile and Peru in the vicinity of 20’S and 85’W.  The mooring has been deployed for  for 3 years as a component  of the Enhanced Monitoring element of the Eastern Pacific Investigation of Climate ( EPIC) programs.  Cruises for recovery and redeployment have occurred each October or November.  The science objectives of the Stratus Project are to observe the surface meteorology and air-sea exchanges of heat, freshwater, and momentum, to observe the temporal evolution of the vertical structure of the upper 500m of the ocean.  This year the Stratus project was joined by the ETL/NOAA group out of Boulder, Colorado.  The Environmental Technology Laboratory people are meteorologists who are looking at the formation of the stratocumulus clouds that are formed off the coast of Chile and Peru.  They brought and are using cloud radar and radiosondes to look at these phenomena. The Stratus moorings carry two redundant sets of meteorological sensors and the mooring line also carries a set of oceanographic instruments.  Although Acoustic rain gauges were deployed on the last 3 moorings, this year there will not be one on the buoy and there will be several more current meters and temperature gauges.  The Chlorophyll sensors will not be on the new one either.

Types of measurements taken by Stratus moorings:

  • Surface measurements
  • Subsurface measurements
  • Wind speed
  • Water temperature
  • Wind direction
  • Conductivity
  • Air temperature
  • Current speed
  • Sea Surface temp
  • Salinitybarometric pressure
  • Current direction
  • Relative humidity
  • Incoming short-wave radiation
  • Incoming long wave radiation
  • Precipitation

Most of the equipment , including the new buoy, was loaded on the R/V REVELLE in San Diego with some of the equipment being shipped to Guayaqil, Ecuador and loaded onboard in Manta, Ecuador.  The science party flew into Manta to meet the ship and we will fly out of Arica to return to the U.S. On November 15, we stopped to lower and test the acoustic releases to be used in the mooring.  They were lowered to  500,  and 1500m depths.  Jason Smith (WHOI) communicated with the releases at each depth.  After the release test two CTD casts were made to 4000m.  When we arrived at the buoy mooring ship and buoy data comparisons began.  This is a check to see whether the sensors on the mooring are still calibrated. At 7:20 the release of the glass balls was triggered and they should surface about 45 minutes later.  The small boat will go out to put a line on the mooring and bring it back to the ship.  The line will be secured on deck the the recovery will begin.  As the instruments are brought onboard they will be laid out in the order they are hung on the mooring up the starboard side of the ship and photographed and labeled by depth and type of instrument.  This is to document the condition of each instrument before cleaning begins.  Most of the instruments are covered by barnacles and a host of other organisms, this is termed Bio-fouling.  The bio-fouling is dominated by goose-neck barnacles.  These are quite thick on the buoy hull and down to 30m; some goosenecks were even found down to 135m last year.  These can be quite a problem for the data collection, for example: last year the floating SST on the buoy hull was stuck in the down position by the barnacles.  This is why it is important to document the condition of the instruments with photographs so that when you are looking at your data and it suddenly changes or stops you might get some clue as to why the flow on the current meters changes significantly in one of the sensors ( bio-fouling for example).  We will finish recovery of the instruments today and tomorrow will recover the buoy late today.

Personal Log

Went out on the zodiac in the morning to look over the buoy.  Sunny, beautiful, water was 20’C and 30 to 35′ visibility.  There were 3′ swells and it was a wonderful view of the REVELLE, see the attached photos.  Many fish around the buoy and there will be many around the back of the boat today when we bring up the mooring.  We are 800 miles off the coast of Chile and the ship is in water  of about 4400m depth.  Nothing but blue ocean all around and it is breathtaking, reminds you why oceanographers go to sea.  You are surrounded by a mysterious blue liquid and it becomes a lifelong fascination to learn what lies beneath.  We began our “Fantail Interviews” last night with the chief engineer, Paul Mauricio, Nan Galbraith, WHOI Information systems associate and Paquita Zuidema a scientist with NOAA Environmental Technology Laboratory.  We talked about their research, jobs and experiences working at sea.  Our first videos should be online today.  We will be touring the ship and video taping interviews with other science party and crew members all week as well as filming the work onboard. There is something special about being part of science as the observations are made.  Jason was checking his aerosol readings last night and sharing his graphs.  He was seeing some things he expected and some he didn’t.  Many things he was seeing had as much to do with visual observations of the changing cloud shapes and precipitation as the sensor readings.  This kind of on-site observation is irreplaceable in science and definitely what makes science exciting.  Chris Fairwell of ETL was talking about the stratocumulus formations and how the behavior of the clouds was not necessarily what was expected, but then observations in this area had never really been done before and this was really exciting.  For me as a teacher it is interesting because these are things that my students can share by logging onto the internet and seeing on various NOAA , WHOI and SIO web sites as well as many other good science web sites and no text book can hope to compare with this.  We can also e-mail these scientists to ask questions about what they are seeing and a possible explanation.  Well they just call the acoustical release and may watch is almost over which just means the real work begins:)

Cheers

Posted on

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:)

Cheers

Posted on

Debra Brice, November 14, 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 14, 2003

Data from the Bridge

1.  141700Z Nov 03
2.  Position: LAT: 14-54.6’S, LONG: 084-55.0’W
3.  Course: 180-T
4.  Speed: 12.2 Kts
5.  Distance: 293.6 NM
6.  Steaming Time: 24H 00M
7.  Station Time:  00H 00M
8.  Fuel: 4245 GAL
9.  Sky: OvrCst
10. Wind: 120-T, 17 Kts
11. Sea: 120-T, 2-3 Ft
12. Swell: 140-T, 3-5 Ft
13. Barometer: 1016.2 mb
14. Temperature: Air: 21.5 C, Sea 19.0 C
15. Equipment Status: NORMAL
16. Comments: None.

Science and Technology Log

We are still underway, about 800 miles off the coast of Peru.  We will arrive at the Woods Hole Stratus Buoy tomorrow at about noon.  We will be taking out a small boat ( zodiac or the RHIB) to look it over before we try to bring it in.  It is heavily instrumented and will be covered in many animals.  They will have to be cleaned off and I will enjoy preserving and identifying some of them.  I found a copy of my old invertebrate zoology book onboard so this should be worth several hours of entertainment for me.  Dr. Weller’s group will be removing the instruments in preparation for taking the buoy out of the water and loading it onboard.  Then we will spend another day deploying the new Stratus Buoy.  The old one will be shipped back to Woods Hole Oceanographic Institution for Arica, Chile.

Most of the day we were deploying sea surface drifters and several radiosondes for the ETL group.  Tomorrow Jason Tomlinson, from Texas A&M will be taking some aerosol samples for his research.  I will be interviewing the Chief Engineer, Paul Maurice and touring the engine room of the REVELLE. Radiosondes are used to collect data on atmospheric temperature, humidity, pressure and uses onboard GPS for wind direction and windspeed from the surface up to the lowest part of the Stratusphere.  I have put up some pictures of the radiosondes.  My e-mails and internet access are being made possible by the ROADnet system that is installed here on the R/V REVELLE.  We have “live” cameras off the fantail of the boat and in the main lab as well as telphone and internet capabilities due to ROADnet.  The Visualization Center at Scripps Institution of Oceanography, located at the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics ( IGPP),houses the state of the art system  that allows scientists to take enormous data sets, such as earthquake activity east of San Diego, the morphology of the global seafloor, or the topography of Mars and illustrate them on a large screen in 3 dimensions.  One new project taking advantage of the Visualization’s data management capabilities is termed ROADnet ( Real time Observatories, Applications, and Data Management Network). ROADnet sensors, located throughout the world and on Scripp’s largest ship, the Roger Revelle, deliver real-time data to the center for nearly instantaneous review by scientists on campus.  I will be using ROADnet to do a broadcast to a geography class next week at San Marcos HIgh School in San Marcos, California.  The class of teacher Larry Osen will be able to see me and the scientists on the Revelle as we deploy a CTD as it is happening and ask questions of the scientists.  This system is presently being installed on Scripps other large ship the R/V MELVILLE.  This is an exciting example of how technological innovations help advance scientific understanding of the oceans.

Personal Log

I’m a little disoriented on my times as I am doing the 12am to 4am watch.  I get up a little later that I normally would, about 10:30am.  Tomorrow we will come up on the buoy so I need to be up earlier enough to participate.  We will be filming and doing interviews during the recovery.  Besides if I get up earlier enough they might let me go out in the zodiac!  I will ride on any boat that floats, so this is too good an opportunity to miss.  Since the buoy has been out at sea for a year it will be covered in animals and surrounded by fish.  Anything that floats in the open ocean becomes a little miniature ecosystem,  So there will be some fishing and lots to see.  We will also being doing our first CTD cast tomorrow and I will have some pictures and descriptions of what a CTD is and why we are deploying it ( actually some of us are deploying it just to shrink our decorated styrofoam cups!)  I will be explaining that tomorrow too.  What oceanographers do for entertainment on long voyages.  So tune in tomorrow for some fun at sea!

Cheers