Meredith Salmon – Page 3 – NOAA Teacher at Sea Blog

July 28, 2018August 24, 2018

Meredith Salmon: Fun in the Sun with the Sunphotometer, July 19, 2018

NOAA Teacher at Sea

Meredith Salmon

Aboard NOAA Ship Okeanos Explorer

July 12 – 31, 2018

Mission: Mapping Deep-Water Areas Southeast of Bermuda in Support of the Galway Statement on Atlantic Ocean Cooperation

Weather Data from the Okeanos Explorer Bridge

Latitude: 28.39°N

Longitude: 65.02°W

Air Temperature: 28.3°C

Wind Speed: 11.8 knots

Conditions: Partly sunny

Depth: 5092.22 meters

Science and Technology Log

“Explorations of opportunity” including NASA Maritime Aerosol Network are conducted on the Okeanos Explorer while underway. The Maritime Aerosol Network is an organized opportunity to collect aerosol data over oceans. Aerosols are liquid or solid particles that can be generated in two ways: natural phenomena (volcano, sand storm, pollination, waves, etc.) or anthropogenic sources (combustion of hydrocarbons, chemical industries, etc.). The open ocean is one of the major sources of natural aerosols of sea-salt aerosols. Sea-salt aerosols, together with wind-blown mineral dust, and naturally occurring sulfates and organic compounds, are part of natural tropospheric aerosols.

Depending on their color, aerosols absorb sunlight in different ways. For instance, soot particles generated from the combustion of hydrocarbons absorb all visible light, therefore generating a rise in atmospheric temperature. Conversely, crystals of salt reflect all visible light and cause climatic cooling. Other studies have shown that their presence is essential for the water cycle: without aerosols, water could not condense in the form of clouds. Therefore, these particles influence the climate balance. In order to achieve this, NASA provides sunphotometers to “Vessels of Opportunity.” These vessels can be either scientific or non-scientific in their nature of operations.

SunFun — Sunphotometer device used throughout the expedition

Garmin GPS used to collect coordinates before obtaining sunphotometer reading

How Does This Process Work?

Sunphotometer takes aerosol maritime measurements by using a photometer that is directed at the sun to measure the direct-sun radiance at the surface of the Earth. These measurements are then used to obtain a unit-less parameter: Aerosol Optical Depth (AOD). AOD is the fraction of the Sun’s energy that is either scattered or absorbed (attenuated) while it moves through the Earth’s atmosphere. The attenuation of the Sun’s energy is assumed to be a result of aerosols since the measurements are collected when the path between the sun and the sunphotometer instrument is cloud-free.

Why Is This Process Important?

This collaboration between NOAA and NASA allows for the addition of thirteen more data sets to the Maritime Aerosol Network. Regions in the open ocean are unable to be studied from land-based sunphotometers located on islands, so ships are the only other alternative to compile data. As a matter of fact, satellite based measurements are not as accurate over the ocean compared to hand-held surface measurements. Therefore, the measurements we have been logging serve as ground truth verification for satellites. In addition, the Maritime Aerosol Network allows for the expansion of data sets to the Arctic, thanks to NOAA Ship Ronald H. Brown and other West Coast hydrographic ships.

sunfun 4 (3)

Personal Log

Safety is an absolute priority while out at sea, so the team aboard the Okeanos Explorer conducts weekly fire/emergency and abandon ship drills, and a man overboard drill every three months. We completed a man overboard drill today with an orange buoy. Everyone on the ship has designated reporting locations once the alarm sounds and the drill commences. Once you arrive at your assigned area on the ship, you must scan the water for the target and point in its direction once you find it. The fast rescue boat (FRB) is deployed to go retrieve the target and once it is safely back aboard, the drill is complete.

MOB — Fast Rescue Boat used during the Man Overboard Drill

man over board 2 — Man Overboard Drill on the *Okeanos Explorer*

Did You Know?

The Mauna Loa Observatory record of solar transmission of sunlight is the longest continuous record in existence!

Resources:

https://www.esrl.noaa.gov/gmd/grad/instruments.html

https://earthobservatory.nasa.gov/Features/Aerosols/page5.php

https://www.esrl.noaa.gov/gmd/obop/mlo/programs/esrl/solar/solar.html

July 28, 2018August 24, 2018

Meredith Salmon: Sonars, Sub-bottoms, and Summertime! July 18, 2018

NOAA Teacher at Sea

Meredith Salmon

Aboard NOAA Ship Okeanos Explorer

July 12 – 31, 2018

Mission: Mapping Deep-Water Areas Southeast of Bermuda in Support of the Galway Statement on Atlantic Ocean Cooperation

Weather Data from the Okeanos Explorer Bridge

Latitude: 29.03°N

Longitude: 62.11°W

Air Temperature: 27.5°C

Wind Speed: 6.38 knots

Conditions: Sunny

Depth: 5167.70 meters

Science and Technology Log

SIMRAD EK 60 echo sounder readings – 38kHz frequency is not pictured

In conjunction with the EM302 multibeam sonar, the Okeanos Explorer uses five different frequencies of SIMRAD single beam echo sounders to identify biomass in the water column: an 18 kHz, 38kHz, 70 kHz, 120 kHz, and 200kHz. (38 kHz is not pictured because it is not used in conjunction with the EM302 since the frequencies are too similar and they can cross talk). These sonar systems are common on fishing boats for estimating fish abundance and they’re used for other marine research, as well. In deeper waters, lower frequency sonar is used. Since we are surveying in approximately 5,000 meters of water, the 18 kHz will be used.

The third piece of important equipment used during this mission is a 3.5 kHz Knudsen sub-bottom profiler. This technology is used to assist in many surveys since these systems identify and characterize layers of sediment or rock under the seafloor. In sub-bottom profiling a sound source directs a pulse towards the seafloor and parts of this pulse reflect off the seafloor while others penetrate the seafloor. The portions of the pulse that penetrate the seafloor are both reflected and refracted as they pass into different layers of sediment. These signals return towards the surface and can be used to determine important features of the seafloor. For instance, the time it takes for the reflected sound pulses to return to the vessel can be used to determine the thickness and positioning (ex. Sloped or level) of the seafloor. The refracted pulses can provide information about the sub-bottom layers. The variability in density can be used to explain differences in composition (ex. greater density is representative of harder materials). Frequency differences can help scientists obtain optimal results that can be used when collecting data during a survey. Lower frequency pulses can penetrate the seafloor but produce a lower-resolution picture while higher-frequency pulses produce the opposite.

The EM 302, EK60, and Knudsen sub-bottom profiler are all used simultaneously during this seafloor mapping operation.

Personal Log

Throughout the cruise, one of the NOAA Corps Officers is in charge of planning fun morale events for everyone aboard to participate in. Today, we had a cookout complete with delicious food, music, and corn-hole on the fantail. Everyone had a great time! Additional morale events are planned throughout the rest of the mission so I will post about those later on!

cookout

Corn Hole! — Competitive Cornhole on the Fantail

NOAA Squad — Some of the Mapping Team aboard the *Okeanos Explorer!*

Did You Know?

The earliest technique of bathymetry (depth measurement in water) involved lowering a weighted-down rope or cable over the side of a ship, then measuring the length of the wet end when it reached the bottom. Inaccuracies were common occurrences using this technique because of the bending of the rope caused by deflection from subsurface currents and ship movements.

This technique was replaced in the 1920s by echo sounding, in which a sound pulse traveled from the ship to the ocean floor, where it was reflected and returned.

The multibeam echosounder was invented in the 1960’s.

Resources:

https://www.simrad.com/ek60

https://www.km.kongsberg.com/ks/web/nokbg0240.nsf/AllWeb/1AE8CC56C6F31E51C1256EA8002D3F2C?OpenDocument

Click to access 1259200b5dddf07c4043b97c1d753782183a.pdf

July 28, 2018August 24, 2018

Meredith Salmon: Let The Surveying Begin! July 15, 2018

NOAA Teacher at Sea

Meredith Salmon

Aboard NOAA Ship Okeanos Explorer

July 12 – 31, 2018

Mission: Mapping Deep-Water Areas Southeast of Bermuda in Support of the Galway Statement on Atlantic Ocean Cooperation

Weather Data from the Okeanos Explorer Bridge

Latitude: 28.12°N

Longitude: 62.04°W

Air Temperature: 27.0°C

Wind Speed: 14.08 knots

Conditions: Rain and clouds

Depth : 5133.67 meters

Science and Technology Log

Hypack for Line Planning

This morning, we learned how to upload a variety of planning lines for the survey that will be conducted for the Atlantic Seabed Mapping International Working Group (ASMIWG) established area Southeast of Bermuda.

The black circle pictured on the map below is Bermuda’s Exclusive Economic Zone (EEZ). Bermuda’s EEZ is an area of ocean within 200 nautical miles of the island that covers 464,940 km2 of ocean. Under the United Nations Convention on the Law of the Sea, Bermuda has special jurisdiction over the use and exploration, management, and conservation of those resources. According to Bermuda’s Department of Environment and Natural Resources, this zone was established in 1996 and this distinction allows Bermuda to gain important economic value from these resources.

The red line (ASMIWG Galway mapping box) displayed on the screen is the outline of the survey area. This area is 145,120 km2; however, during this expedition, we will be mapping a quarter to a third of the region. Within the survey area are small blue lines that are considered to be planning lines. These lines were crafted on the computer using Hypack and are 180 nautical miles in length. For efficiency, it is important for them to be oriented to follow the contour lines, and to be long because it requires less turns, which saves time while mapping. The distance between the lines is 4,300 meters and may be subject to change at the discretion of the mapping team.

The green lines are existing multibeam or bathymetric data in the region. This is crucial information to consider because the Okeanos Explorer’s goal is to map what has not been investigated and combine it with the data that already exists in those areas. The previously collected data was recorded from a variety of ships such as Atlantis, Healy, and Knorr, so we will use our EM 302 sonar to edge match their data.

In addition to the existing data, there is a background telemetry layer (blue background) that shows satellite measurements to predict what the seafloor may look like. Scientists use the existing data to update the layers to create a more accurate depiction of the seafloor.

So far, the data collected in transit has been very reliable due to weather conditions and the flat abyssal seafloor. As survey data is incoming, the personnel on watch must ensure that the sonar and computer systems are operating correctly. We will begin the actual surveying this afternoon once we reach the first line!

Line Plans in Hypack — Red 180 nautical mile planning lines created for the survey area in Hypack

Personal Log

Now that we have begun the survey, everyone is busy collecting, processing, cleaning, and updating data files in the Mission Control room. We have been learning all about the software used to create files, and it is very interesting to learn how all of the different systems are being used to make sense of the data from multiple sources (ex. EM 302, EK 60, and sub-bottom profiler). Everyone on board is really enjoying each other’s company and is eager to collaborate to help one another learn. It is really fun! One of the best parts of being in the middle of the ocean has definitely been watching the sunsets. They are incredible!

Did You Know?

The Sargasso Sea is considered to be one of the great ecological wonders of the world! It is home to golden algae known as Sargassum. This algae serves as a floating habitat and provides food, refuge, and breeding grounds for an array of marine organisms such as fish, sea turtles, marine birds, crabs, shrimp, and more!

The Sargasso Sea is the only sea in the world surrounded by currents, rather than land and Bermuda is the only island within it.

The algae directly benefits Bermuda when it washes ashore and sinks into the sand since it fertilizes the soil and protects the island against storms and erosion.

sargassum — *Sargassum* off the side of the bow

Resources:

https://www.gov.bm/articles/monitoring-bermuda%E2%80%99s-exclusive-economic-zone-eez

http://www.bermuda-online.org/environ.htm

July 18, 2018September 19, 2018

Meredith Salmon: Xtreme XBTs, July 14, 2018

NOAA Teacher at Sea

Meredith Salmon

Aboard NOAA Ship Okeanos Explorer

July 12 – 31, 2018

Mission: Mapping Deep-Water Areas Southeast of Bermuda in Support of the Galway Statement on Atlantic Ocean Cooperation

Geographic Area: Atlantic Ocean, south of Bermuda

Date: July 14, 2018

Weather Data from the Okeanos Explorer Bridge – July 14, 2018

Latitude: 28.58°N

Longitude: 65.48°W

Air Temperature: 27.4°C

Wind Speed: 13.96 knots

Conditions: Rain and clouds

Depth: 5183 meters

Science and Technology Log

Temperature and salinity are two main variables when determining the density of water. The density of water or any acoustic medium is a very important factor in determining the speed of sound in water. Therefore, temperature data collected by Expendable Bathythermograph (XBT) probes, as well as historical salinity profiles from the World Ocean Atlas, are used to create sound velocity profiles to use to correct for sound speed changes in the water column.

Expendable Bathythermograph (XBT) probes are devices that are used to measure water temperature as a function of depth. Small copper wires transmit the temperature data back to the ship where it is recorded and analyzed. At first, I was surprised to learn that temperature data is such an important component of multibeam mapping operations; however, I learned that scientists need to know how fast the sound waves emitted from the sonar unit travel through seawater. Since these probes are designed to fall at a determined rate, the depth of the probe can be inferred from the time it was launched. By plotting temperature as a function of depth, the scientists can get a picture of the temperature profile of the water.

On our expedition, we have been deploying XBTs on a schedule as the ship is making its way to the survey area. The XBT Launcher is connected to a deck box, which translates information to computer systems onboard so the data can be logged when the probes are deployed into the water. Aboard the Okeanos Explorer, up to 8 tubes can be loaded at one time and launched by scientists.

xbt 1 — Savannah and I after a successful XBT load

XBT Data from a launch aboard the Okeanos Explorer. The colors on the graph indicate the XBT number and the data is plotted on a temperature and depth scale.

In addition to launching XBTs and collecting data, we completed a Daily Product so that we can communicate the data we have collected to anyone on shore. The Daily Products are completed not only to ensure that the hydrographic software systems are working correctly but to also inform the public our current location, where we have collected data, and if we are meeting the objectives of the mission. Once onshore, NOAA uses this information to analyze the quality of the data and use it for analysis for dive planning. In order to generate the Daily Field Products, we use hydrographic computer systems such as QPS Qimera for advanced multibeam bathymetry processing, Fledermaus for 4D geo-spatial processing, and Geocap Seafloor for digital terrain modeling. In addition, the Daily Field Products allow us to double check the quality of the data and search for any noise interferences due to the speed of the ship or the type of seafloor bottom (hard vs soft).

Personal Log

One of the coolest parts of learning aboard the Okeanos Explorer is the fact that I am a part of scientific exploration and discovery in real time. Known as “America’s Ship for Ocean Exploration,” the Okeanos Explorer is the only federally funded U.S. ship assigned to systematically explore our largely unknown ocean for the sole purpose of discovery and the advancement of knowledge. This is the first U.S.-led mapping effort in support of the Galway Statement on Atlantic Ocean Cooperation and all of this information is going to be available for public use. Not only do I get the opportunity to be involved with “real-time” research, but I am also responsible for communicating this information to a variety of different parties on shore.

Being immersed in the “hands-on” science, learning from the survey techs and watch leads, and observing all of the work that is being done to collect, process, and analyze the data is a really exciting experience. I am definitely out of my element when it comes to the content since I do not have any prior experience with seafloor mapping, sonars, etc., but I am really enjoying playing the role as the “student” in this situation. There is definitely a lot to learn and I am trying to soak it all in!

Did You Know?

XBTs contain approximately 1,500 meters of copper wire that is as thin as a strand of hair!

Resources:

http://www.aoml.noaa.gov/phod/goos/xbtscience/news.php

https://oceanexplorer.noaa.gov/facts/xbt.html

July 18, 2018September 19, 2018

Meredith Salmon: Setting Sail! July 12, 2018

NOAA Teacher at Sea

Meredith Salmon

Aboard NOAA Ship Okeanos Explorer

July 12 – 31, 2018

Mission: Mapping Deep-Water Areas Southeast of Bermuda in Support of the Galway Statement on Atlantic Ocean Cooperation

Geographic Area: Atlantic Ocean, south of Bermuda

Date: July 12, 2018

Weather Data from the Okeanos Explorer Bridge – July 12, 2018

Latitude: 32.094°N

Longitude: 69.591°W

Air Temperature: 26.2°C

Wind Speed: 10.7 knots

Conditions: Sunny

Depth: 693 meters

Survey Area — Map showing the planned operations area for the expedition outlined in yellow. Image courtesy of the NOAA Office of Ocean Exploration and Research.

Science and Technology Log

According to the Oceanic Institute, the oceans cover 71% of the Earth’s surface. This is calculated to be 335,258,000 square kilometers! Recently, the Okeanos Explorer mapped over 1,000,000 square kilometers of the seafloor using high- resolution multibeam sonar. Although this may not seem like much, that region is larger than the areas of Arizona and Texas combined!

So why is it so important for the Okeanos Explorer to map the seafloor? The ocean’s terrain plays a very important role in ecosystems since underwater valleys determine currents and weather patterns, sea topography influences fishery management, and seamounts serve as protection against unpredictable storms. Therefore, high-resolution maps allow scientists to categorize marine habitats, provide information vital to protecting and tracking marine life, and enable us to make smart decisions for solid, sustainable conservation measures.

In order to successfully map the ocean floor, multibeam sonar is used. The Okeanos Explorer uses an EM 302 multibeam system that is designed to map a large portion of the ocean floor with exceptional resolution and accuracy. The EM 302 transducers point at different angles on both sides of the ship to create a swath of signals. Transducers are underwater speakers that are responsible for sending an acoustic pulse (known as a ping) into the water. If the seafloor or object is in the path of the ping, then sound bounces off the object and returns an echo to the transducer. The EM 302 has the ability to produce up to 864 depth soundings in a single ping. The time interval between the actual signal transmission and arrival of the return echo (two way travel time) are combined with a sound velocity profile to estimate depth over the area of the swath. In addition, the intensity of the return echo can be used to infer bottom characteristics that can be utilized for habitat mapping. Since the EM 302 creates high density, high-resolution data as well as water column features, this sonar system is ideal for exploring the seabed for geographic features.

The image below shows data being collected by the multibeam sonar on the Okeanos Explorer. The colors are used to indicate swath depth (warm colors indicate shallow waters while cool colors indicate deeper waters).

Multibeam sonar data including backscatter (lower left), depth (upper center) and water column data (lower center) from 7/12/2018 the Okeanos Explorer

As this data is being collected, it must be “cleaned” to eliminate any erroneous points. Data is collected and cleaned in both the Dry Lab and Mission Control Room.

Mission Control Room aboard the Okeanos Explorer

Since we have not reached the survey area yet, we have been monitoring the depth of our path thus far. We are collecting transit data which is considered to still be valuable data for unmapped seafloor area, but it may not be as high quality as focused mapping data. We will continue to collect transit data until we reach the survey area near Bermuda.

Personal Log

Life onboard the Okeanos Explorer has been a very interesting and fun learning experience! The ship runs on a 24/7 operation schedule and people are working diligently at all hours of the day. Everyone on the ship has been really welcoming and willing to share their stories and insights about their careers at sea. I am really looking forward to speaking with more people to learn about their experiences!

We set sail out of Norfolk today and began our 3.5 day/4 day transit to the survey area near Bermuda. This morning, we found out that we will need to schedule an emergency dry dock towards the end of our mission to solve an issue with a stern thruster necessary for ROV cruises. As a result, we will not be ending up in port in St. George, but we will still be able to map the area 200 nautical miles off the coast of Bermuda, so that is great!

norfolk out to sea! — NOAAS Okeanos Explorer (port quarter aspect) navigating the Elizabeth River outbound for sea from the NOAA pier in Norfolk, VA on July 12, 2018. [Photo by Commander Briana Hillstrom, NOAA

Did You Know?

Sonar is short for Sound Navigation and Ranging.

Check out this video for a visual representation of the process sonar uses to generate data! https://oceanservice.noaa.gov/caribbean-mapping/mapping-video.html

Resources:

https://www.oceanicinstitute.org/aboutoceans/aquafacts.html

https://oceanexplorer.noaa.gov/okeanos/one-million/welcome.html