Jacquelyn Hams: 24 November 2011

NOAA Teacher at Sea
Jackie Hams
Aboard R/V Roger Revelle
November 6 — December 10, 2011

Mission: Project DYNAMO
Geographical area of cruise: Leg 3, Eastern Indian Ocean

Date: November 24, 2011

Weather Data from the R/V Revelle Meteorological Stations

Time: 0830
Wind Direction: 246.10
Wind Speed (m/s): 9.3
Air Temperature (C): 27.4
Relative Humidity: 86.1%
Dew Point: (C): 25.10
Precipitation (mm): 25.1

PAR (Photosynthetically Active Radiation) (microeinsteins): 177
Long Wave Radiation (w/m2): 454.3
Short Wave Radiation (w/m2): 36.7

Surface Water Temperature (C): 300
Sound Velocity: 1545.9
Salinity (ppm): 35
Fluorometer (micrograms/l): 0.9
Dissolved Oxygen (mg/l): 2.6
Water Depth (m): 4637

Wave Data from WAMOS Xband radar

Wave Height (m) 2.2
Wave Period (s): 15.3
Wavelength (m): 290
Wave Direction: 29000

Science and Technology Log

Aerosols Group

 The Aerosols Group consists of Derek Coffman, Langley Dewitt and Kristen Schultz from the NOAA Pacific Marine Environmental Lab (PMEL) in Seattle, Washington. The Aerosols group measures the chemical, physical, and optical properties of sub and supermicron aerosols (liquids or solids suspended in gas) in the lowest layer of the troposphere. Aerosols are important in the study of climate change and the largest unknown due to the complicated nature of the particles. Aerosols are being studied in the MJO experiment to determine how they affect the radiative balance and how the MJO affects aerosols.

The measurements and analyses include:

  • real-time and filter-based analysis of the aerosol chemical composition
  • size distributions from 20 nm to 10 microns (aitken mode to course mode aerosols)
  • particle number concentrations
  • aerosol scattering and absorption
  • cloud condensation nuclei (CCN)
  • total mass of filtered collected aerosol
  • O3 and SO2 gas phase measurements.

Aerosols are captured via an opening in the inlet (mast). The base of the inlet consists of 21 individual sample lines. The inlet is designed to collect particles in average marine conditions without preferentially selecting particles and is efficient in collecting particles up to 10 microns in diameter.  Each sample line connects to a specific instrument for analysis. The captured aerosols are sampled for physical, chemical, and optical properties. . In general, for the ocean, particle sizes that are <1 micron are typically more anthropogenic, while particles >1 micron are sea salts and generated by wind and rain.

Aerosols are captured through the Inlet (mast).

Aerosols are captured through the Inlet (mast).

Base of aerosol inlet with sample lines.

Base of aerosol inlet with sample lines.

Impactors are attached to the sample lines to separate and collect aerosols. Each impactor has a filter to capture a particular particle size range. The filters are removed from the Impactors in a clean lab for analysis. Half of the samples collected are analyzed on the ship and the remaining samples are analyzed at the NOAA PMEL Lab in Seattle, WA. Analytical methods used on the ship to measure chemical species are ion chromatography, liquid chromatography with mass spectrometry (LCMS), total organic carbons (TOC), and organic carbon and elemental carbon (OCEC). The optical properties measured include scattering and absorption. Scattering is measured by an instrument called a nephelometer and absorption is measured by a Particle Soot Absorption Photometer (PSAP). The physical properties measured are total particle concentration and size distribution of the particles. Condensation particle counters (CPCs) measure the particle concentrations and size distribution is measured by a Scanning Mobility Particle Sizer (SMPS), The Aerosol Mass Spectrometer measures the size and chemical composition of non-refractory submicron aerosols.

Kristen removes impactor for sampling

Kristen removes impactor for sampling

Vacuum Pump closet houses vacuum and pressure needs for the aerosol vans.

Vacuum Pump closet houses vacuum and pressure needs for the aerosol vans.

Filters are removed from the impactor.

Filters are removed from the impactor.

Example of a clean filter (left) and sampled filter containing exhaust from the ship (right).

Example of a clean filter (left) and sampled filter containing exhaust from the ship (right).

The Aerosol Mass Spectrometer captures and analyzes the chemical composition of aerosol particles in near real time (every 5 minutes).

The Aerosol Mass Spectrometer captures and analyzes the chemical composition of aerosol particles in near real time (every 5 minutes).

Derek in the Aerosol van pictured with various instrumentation.

Derek in the Aerosol van pictured with various instrumentation.

The diagrams pictured above are based on a model prepared by Derek Coffman. The back trajectories on the left show that sub micron aerosols are dominant in the continental air mass and there is also more organic aerosol that is likely causing the absorption in the continental air mass. The clean marine diagram shows that sub micron aerosol is greatly reduced and aerosols >1 micron (coarse mode) play a dominant role in scattering in the air mass.

The diagrams pictured above are based on a model prepared by Derek Coffman. The back trajectories on the left show that sub micron aerosols are dominant in the continental air mass and there is also more organic aerosol that is likely causing the absorption in the continental air mass. The clean marine diagram shows that sub micron aerosol is greatly reduced and aerosols >1 micron (coarse mode) play a dominant role in scattering in the air mass.

Personal Log

Thanksgiving week proved to be the most interesting weather of the cruise. The winds picked up to 48 knots on Thanksgiving Day. This made for a real exciting time on the winch. During several drops (each time Chameleon is lowered in the water column), I had to hold on to the canopy with one hand, and the winch with the other so I would not fall over when the swells hit the stern of the ship.

I was surprised that Chief Scientist Jim Moum continued to work on his computer and did not run out to snatch me away from his valuable research instrument! If he had that much confidence in my ability to handle the situation, I had to prevail. Just as I was convincing myself I had to prevail, I heard the bridge call on the hand-held radio. I could not understand the communication and did not want to release the winch since it was difficult to control in the wind. Someone from the Ocean Mixing Group came out to tell me that the bridge called and could not control the ship direction and to take Chameleon out of the water. By this time Chameleon was trailing behind the ship and I could not see if it had gone under the ship. A bit of chaos ensued and I saw a boat hook out of the corner of my eye as crew prepared to get Chameleon out. Somewhere in the midst of the chaos, Jim Moum came on deck and decided that profiling could continue. By that time the ship had re-positioned, however, the wind speed was the same. Jim surveyed the situation and said that he had profiled in far worse weather conditions and went back to his work. I breathed a huge sigh of relief when my shift was over that night and Chameleon was not damaged.

Thanksgiving Day was another day of collecting data. The cooks prepared a Thanksgiving Dinner and I think I speak for all of the scientists when I say we appreciated the turkey and all the trimmings.

Scott, a Wiper in the Engineering Department asked me if I would like an interesting video of a crew job for the website. Scott is a polite crew member and has an interest in education. My first question was “What is the job description for a wiper?” I was told that a wiper is an unlicensed engine room staff member. According to Scott, he empties trash, cleans, and performs other projects as needed such as needle gunning (removing paint and rust from metal surfaces) natural air vent shafts as seen in the video below. I wasn’t prepared for the noise when I shot this video.

There are no gorgeous sunrise and sunset photographs to end this blog – we are probably in the beginning stages of the MJO. There is a tropical cyclone to our north and the outer bands were reaching the ship. We are experiencing squalls with high winds. It is unusual to have cyclones during the MJO event – they usually develop in the wake of the cycle according to the Atmospheric Soundings Group. I get dressed in rain boots and gear and run to the winch and run back inside when my shift is over. Although I am sure you would like to see a photo, it is not exactly a desirable Kodak moment for cameras. Stay tuned, the weather is bound to change.

For this post’s quiz, please answer in the comments of this post:

Using the Aerosol source diagram above, what particle size aerosols are dominant in
continental air masses and what particle size aerosols are dominant in clean marine air masses?

 

Jacquelyn Hams: 14 November 2011

NOAA Teacher at Sea
Jackie Hams
Aboard R/V Roger Revelle
November 6 — December 10, 2011

Mission: Project DYNAMO
Geographical area of cruise: Leg 3, Eastern Indian Ocean

Date: November 14, 2011

Weather Data from the R/V Revelle Meteorological Stations

Time: 1045
Wind Direction: 262.60
Wind Speed (m/s): 135.8
Air Temperature (C): 28
Relative Humidity: 79.7%
Dew Point: (C): 24.20
Precipitation (mm): 42.4

PAR (Photosynthetically Active Radiation) (microeinsteins): 1101.5
Long Wave Radiation (w/m2): 410.3
Short Wave Radiation (w/m2): 192.5

Surface Water Temperature (C): 29.8
Sound Velocity: 1545.1
Salinity (ppm): 34.8
Fluorometer (micrograms/l): 0.2
Dissolved Oxygen (mg/l): 2.8
Water Depth (m): 4637

Wave Data from WAMOS Xband radar

Wave Height (m) 1.3
Wave Period (s): 13.2
Wavelength (m): 236
Wave Direction: 2800

Science and Technology Log

Ocean Mixing

All about CTDs

A CTD is a standard instrument used on ships to measure conductivity, temperature and depth. Three CTD systems are being used during Leg 3 of Project DYNAMO to measure CTD.

  • The Revelle deploys the ship’s CTD twice a day to a depth of 1,000 m. The CTD measurements can be viewed on a monitor in the computer room.
Ship's CTD

Ship's CTD

Ship's CTD in water

Ship's CTD in water

Ship's CTD data display

Ship's CTD data display

Data obtained from the ship's CTD

Data obtained from the ship's CTD

  • The Ocean Mixing group is using a specialized profiling instrument that was designed, constructed, and deployed by the microstructure group at the College of Oceanic and Atmospheric Sciences, Oregon State University. The instrument, called “Chameleon”, measures CTD and turbulence. Chameleon takes continuous readings to a depth of 300 m as it is lowered through the water column. The top of the instrument has brushes to keep the instrument upright in the water and make it hydrodynamically stable so that very precise measurements of turbulence can be achieved. These measurements allow computations of mixing, hence the name Ocean Mixing Group. The instrument freely falls on a slack line to a depth of 300 m after which it is retrieved using a winch. The Chameleon has been taking continuous profiles at the rate of about 150/day since we have been on station and will continue taking measurements for the next 28 days.
Photograph of Chameleon

Photograph of Chameleon

Close-up of Chameleon's sensors

Close-up of Chameleon's sensors

Data obtained from the Chameleon
  • The T Chain CTD aboard the ship was also designed by the microstructure group at the College of Oceanic and Atmospheric Sciences, Oregon State University. This instrument measures CTD in the near-surface (upper 10 m) using bow chain-mounted sensors (7 Seabird microcats + 8 fast thermistors). The T Chain takes data every 3 seconds, and although that is not very fast, the data is extremely accurate (within 1/1000th of a degree – 3/1,000th of a degree). The T Chain is mounted on the bow and has been taking measurements continuously since we have been on station. These measurements focus on the daytime heating of the sea surface and the freshwater pools created by the extreme rainfall we have been observing and which is associated with the MJO.
Photograph of T Chain

Photograph of T Chain

Data obtained from T Chain

Data obtained from T Chain

NOAA High Resolution Doppler LIDAR (Light Detection And Ranging) Group

A Brief Introduction to LIDAR

The following introduction to LIDAR systems was provided by Raul Alvarez.

In LIDAR, a pulse of laser light is transmitted through the atmosphere. As the pulse travels through the atmosphere and encounters various particles in its path, a small part of the light is scattered back toward the receiver which is located next to the transmitter. (You may have seen similar scattering off of dust particles in the air when sunlight or a laser pointer hits them.) The particles in the atmosphere include water droplets or ice crystals in clouds, dust, rain, snow, aircraft, or even the air molecules themselves. The amount of signal collected by the receiver will vary as the pulse moves through the atmosphere and is dependent on the distance to the particles and on the size, type, and number of particles present. By keeping track of the elapsed time from when the pulse was transmitted to when the scattered signal is detected, it is possible to determine the distance to the particles since we know the speed of the light.

Once we know the signal at each distance, it is now possible to determine the distribution of the particles in the atmosphere. By measuring how the light was affected by the particles and the atmosphere between the LIDAR and the particles, it is possible to determine things such as the particle velocity which can yield information about the winds, particle shape which can indicate whether a cloud is made up of water droplets or ice crystals, or the concentration of some atmospheric gases such as water vapor or ozone. The many kinds of LIDARs are used in many different types of atmospheric research including climate studies, weather monitoring and modeling, and pollution studies.

Typical lidar signal as a funciton of range

Typical lidar signal as a function of range

Photograph of Ann and Raul inside the LIDAR van.

Photograph of Ann and Raul inside the LIDAR van.

Raul explains the inner workings of LIDAR aboard the ship. From left to right: 1st photo shows Raul and the LIDAR system; 2nd and 3rd photos display the optical components of the LIDAR; 4th photo is the rotating scanner base.

Raul explains the inner workings of LIDAR aboard the ship. From left to right: 1st photo shows Raul and the LIDAR system; 2nd and 3rd photos display the optical components of the LIDAR; 4th photo is the rotating scanner base.

The four cone-shaped devices are differential GPS antennae used to correct for the motion of the boat.

The four cone-shaped devices are differential GPS antennae used to correct for the motion of the boat.

An integrated motion compensation system is used to stabilize the scanner to maintain pointing accuracy. As you can see from the video below, the scanner maintains its position relative to the horizon while the ship moves.

The slides below represent a Doppler LIDAR data sample from Leg 3 of the Revelle cruise. The images and slides were provided courtesy of Ann Weickmann.

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image Credit: Ann Weickmann

Image Credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Personal Log

The R/V Revelle is not a NOAA ship. It is part of the University-National Oceanographic Laboratory System (UNOLS) and part of the Scripps Institution of Oceanography research fleet. A few crew members were kind enough to take time from busy schedules to talk with me about their careers. Students may find these interviews interesting especially if they are exploring career options.

The food aboard the Revelle is very good thanks to our cooks, Mark and Ahsha. They are very friendly crew members and always happy to accommodate the diverse eating schedules of scientists who have to work during meal hours.

Mark Smith, Senior Cook

Mark Smith, Senior Cook

Ahsha Staiger, Cook

Ahsha Staiger, Cook

Meanwhile back on the winch, I am beginning to get the hang of it. I will not say that I am comfortable, because I am always aware that I am in charge of a very expensive piece of equipment. I alternate between operating the winch, operating the computer, standby time (to assist as needed) and free time.

Jackie on the computer in the Hydro lab.

Jackie on the computer in the Hydro lab.

Dramatic cloud formation at sunrise.

Dramatic cloud formation at sunrise.

Jacquelyn Hams: 12 November 2011

NOAA Teacher at Sea
Jackie Hams
Aboard R/V Roger Revelle
November 6 — December 10, 2011

Mission: Project DYNAMO
Geographical area of cruise: Leg 3, Eastern Indian Ocean

Date: November 12, 2011

Weather Data from the R/V Revelle Meteorological Stations

Time: 1045
Wind Direction: 2580
Wind Speed (m/s): 2.8
Air Temperature (C): 28
Relative Humidity: 67.6%
Dew Point: (C): 21.4
Precipitation (mm): 40.3

PAR (Photosynthetically Active Radiation) (microeinsteins): 2274.5
Long Wave Radiation (w/m2): 429
Short Wave Radiation (w/m2): 659

Surface Water Temperature (C): 29.7
Sound Velocity: 1545.1
Salinity (ppm): 35.2
Fluorometer (micrograms/l): 65.5
Dissolved Oxygen (mg/l): 3.3
Water Depth (m): 4640

Wave Data from WAMOS Xband radar

Wave Height (m) 1.7
Wave Period (s): 12.8
Wavelength (m): 226
Wave Direction: 1950

Science and Technology Log

The Revelle is now on station and will remain in this location for approximately 28 days to conduct measurements of surface fluxes, wind profiles, C-band radar, atmospheric soundings, aerosols, sonar- based ocean profiling and profiling of ocean structure including turbulence.  Please note that the exact position and course of the ship will not be posted in this blog until Leg 3 has been completed and the ship is back in port in Phuket, Thailand. Although piracy is not anticipated at the station location, it has been a problem in other parts of the Indian Ocean and the policy is not to publicize the coordinates of the ship.

Surface Fluxes

The Surface Fluxes group measures the amount of radiation and heat into and out of the ocean. There are several dome instruments on the Revelle to measure atmospheric radiation, acoustic and propeller sensors to measure winds and a “sea snake” to measure the sea surface temperature. The term flux is defined as a transfer or exchange of heat. The sum of the terms in the equation below indicates how much radiation is in the ocean. If the sum >0, the ocean is warming.  If the sum is <0, the ocean is cooling. Below each term is a photograph of the ship-board instrument used to measure it.

Ocean Mixing

Today I deployed the Los Angeles Valley College drifting buoy. Before leaving Los Angeles, the students in my introductory Physical Geology and Oceanography classes signed NOAA stickers that I placed on the buoy before releasing it into the Indian Ocean.  A drifting buoy floats in the ocean water and is powered by batteries located in the dome. The drifting buoys last approximately 400 days unless they collide with land or the batteries fail. The buoy collects sea surface temperature and GPS data that are sent to a satellite and then to a land station where the data can be accessed. Drifting buoys are useful in tracking current direction and speed. Approximately 12 drifting buoys will be deployed from the Revelle during Leg 3 of the Project DYNAMO cruise.

Personal Log

Can you have pirates before a pirate drill?

After we arrived on station, a science meeting was held to provide instructions regarding safety and emergency procedures for mandatory drills such as fire safety, abandon ship, and pirate drills.  Drills are typically scheduled once a week and we have already assembled for a fire drill.  A pirate drill was scheduled for the following week.

I began my orientation working with the Oregon State University Ocean Mixing Group. My role on the research team is to assist with the operation of the “Chameleon”, a specially designed ocean profiling instrument that is continuously lowered and raised to the surface taking measurements while on station.  My job is to rotate between operating the winch (used to lower and raise the instrument) and the computer station. The computer station operator is in constant communication with the winch operator and tells the operator when to raise and lower Chameleon.  In addition, the computer operator logs the critical start and end times of each run and keeps track of the depth of the instrument.

Jackie operates the winch. My goal is to keep the instrument safe and have a perfect wind.

Jackie operates the winch. My goal is to keep the instrument safe and have a perfect wind.

I was just beginning to learn to operate the winch when an alarm sounded followed by the words “Go to your pirate stations, this is not a drill, repeat, this is not a drill”.  I must admit I was a bit stressed.  When I came on this trip, I knew there was a remote risk, but I thought it was extremely remote.  Everyone assembled in the designated area and it turns out that a fishing boat was approaching the ship and the Revelle does not take chances if the boat appears to be approaching boarding distance to the ship.  There have been two instances where we have assembled for safety following the alarm and the words “This is not a drill, repeat, this is not a drill.”  In both cases, fishing boats were too close for comfort.  As I began operating the winch, I watched a fishing boat off in the distance for a few days and became more comfortable knowing that the ship is taking extreme caution to protect all on board. All this excitement and before we even had a pirate drill!

Fishing boat spotted near the Revelle

Fishing boat spotted near the Revelle


But all is well somewhere out here on the equator and the Indian Ocean provides many opportunities for photographing amazing sunrises and sunsets.

Sunrise on the Indian Ocean

Sunrise on the Indian Ocean (photo by Jackie Hams)

Sunset on the Indian Ocean

Sunset on the Indian Ocean (Photo by Jackie Hams)