Lab 1 – The collection of oceanographic data
The ocean has vast resources for humans, it supplies food, medicines, jobs in fisheries, the transportation of goods, tourism and recreation. All of these industries are more efficient if they can predict ocean processes. For example, it doesn’t make sense to go fishing in an area if your target fish are not there. Ship routes may need to be changed when there is bad weather and poor sea conditions predicted. Tourism activities that depend on weather, water clarity, or whale sightings opportunities all benefit if the operators have an understanding of the local ocean conditions. These are all examples where the knowledge of oceanography can be beneficial for businesses.
In this activity we will look at some of the different ways that oceanographic data are collected. These data help oceanographers make decisions on questions like “When are conditions optimal for fishing?”, “When will waves become extreme and thus potentially be dangerous?” These questions won’t be answered in this lab, but instead you will learn about the data collection tools that oceanographers use to answer such questions. Then you will be equipped for the rest of the labs in this set.
Data as a Tool video is a nice introduction to OOI, and talks about data collection and analysis. Watch it as an introduction to this lab activity.
Activities in this Lab
- Lab 1.1 – Where are the OOI arrays located?
- Lab 1.2 – What types of science questions can the OOI answer?
- Lab 1.3 – How do you know where you are on the Earth?
After completing this lab students will be able to:
- LO1. Recognize several of the common sensors and platforms used to collect oceanographic data
- LO2. Locate OOI arrays on a world map by latitude/longitude and ocean basin name
- LO3. Identify OOI tools used in examples of scientific research
- L04. Determine latitude and longitude for locations
How are data about the ocean collected?
Oceanographers use a variety of underwater technology to collect data about the oceans using ships, submersibles, sensors and sampling in the ocean for in-situ sensing to satellites in the sky that use remote sensing. In-situ observations are data collected in the ocean water and are very useful, but don’t exist everywhere. Remote sensing is a method of collecting data without direct contact with the medium it is sensing such as satellites, and has become a big part of data collection. Together, in-situ and remote sensing provide oceanographers with a better picture of natural phenomenon in our oceans. Some of our technologies record data only at a single specific date and time, while others can be programmed to collect data on a daily or weekly interval, or even collect data continuously 24/7.
- Platforms – Oceanographic instruments can be installed on a variety of platforms. These platforms are just the physical setting for the instruments. They can be ships, buoys, remotely operated vehicles, satellites or the sea floor. The platform and instruments chosen are matched to the questions being asked. Below is a short description of some of the platforms used by oceanographers, and an explanation of when they might choose to use them.
- Gliders – Gliders are essentially underwater drones, except that rather than having an operator drive them in real time they are programmed to follow a particular path. Gliders are capable of moving in both the horizontal and vertical. They typically have instruments installed on them and record the data until they come to the sea surface. Then they radio the data to a satellite. Scientists can download the data from the satellite for analysis. While at the surface scientists can also give the glider new instructions, via the satellite link. Glider data can be the same type of data that is collected from research vessels. The glider offers the opportunity to collect the data at a very reduced cost. Such data are used to get a 3-D map of the properties of seawater, such as temperature or salinity.
- Moorings – Moorings are comprised of an anchor, a buoy and some instruments either on the buoy or on the line connecting the anchor and buoy. They provide a platform where continuous measurements can be made at a particular location. In the OOI program there are often instruments that measure atmospheric data, like wind speed and direction. Instruments on the line between the buoy and the anchor could be measuring current speed and direction, or properties of the water, like temperature, salinity, dissolved oxygen concentration, etc.
- Cabled – In some places there are many instruments installed on the seafloor, such as at the site of an active volcano. These instruments collect data related to volcanism, like earthquake magnitude and frequency and the change in tilt of the sea floor. Since these instruments are far below the sea surface they have to use underwater cables to transmit this data to shore. Thus these collections of instruments (arrays) are called cabled arrays.
- Telemetered – Many of the OOI locations have several buoys located close to each other (thus these are also called arrays). The data from the instruments on these buoys is transmitted to the top of the mooring, and then telemetered through a satellite to land where scientists can easily access the data. Therefore these are called telemetered arrays.
- Ships – Ships as a platform provide flexibility, but at a cost. When oceanographers go to sea on a research vessel they can examine data as it is collected and make changes to the sampling program based on what they observe. But ship time is expensive, and not an efficient way to repeatedly take the same type of samples in the same location (as can be done with moorings or arrays) or locations (as can be done with gliders). Neither arrays nor gliders allow scientists to collect physical samples, so if water or rock samples are required a ship is the platform to choose.
- Satellites – Satellites are used to both collect and transmit data. With the right instruments they can collect any type of data that can be remotely measured. There are ways to do this so we can measure sea surface temperature, sea surface height and the color of the water. This last property helps in remotely measuring phytoplankton concentrations. And satellites are useful in collecting data from moorings and arrays and transmitting it to scientists in the lab.
- Thermistor – moorings, arrays, research vessels and gliders often have a temperature sensor called a thermistor.
- Pressure sensor – pressure sensors are also common on most platforms. Why would scientists be interested in pressure? Because that tells them the depth of the pressure sensor. For this reason pressure sensors are usually paired with other sensors so we know the depth of the measurement.
- Conductivity sensor – Seawater conducts electricity, and the amount of electricity that is conducted depends on the salinity of the water. Salinity is an important control on water density so conductivity sensors are found on many of the platforms mentioned above.
- Seismometer – Seismometers measure the shaking of the Earth, with several one can determine the location and magnitude of earthquakes. Earthquakes provide information about solid earth processes, for example they may be useful in predicting volcanic eruptions.
- Other sensors – there are lots of different types of sensors in the OOI program, only a few have been described above. There are sensors to measure the intensity of sunlight in the ocean (important in studies looking at primary productivity), the pH of sea water (important especially to the health of shelled organisms), and there are video cameras recording changes at the seafloor near an active volcano. Explore the OOI website to see all of the types of data that are collected in the program. In this lab we will work with just a few to sharpen your data analysis skills. Other labs in this series will introduce you to other sensors as you are presented with the data from the sensors.
Quick Check on Platforms
Quick Check on instruments