Lecture 2- Observing the Oceans Flashcards
What does it take to have a oceanic expedition?
- Detailed planning and prep
- cumulation of several years of research and work
- focuses on questions about scientific objectives
What are some scientific objective questions?
- What do we want to study?
- Where?
- What type of measurements are needed?
- Which instruments will we need to use?
- How many stations will we need? And how far apart should they be placed?
- Are there previous measurements in that area?
- Who is in charge of what?
- How long will we be at sea?
What do ocean monitoring programs involve?
- going back to the same place, usually multiple times a year, and taking measurements
What are some examples of ocean monitoring programs?
- Hawaii Ocean Time Series (HOT)
- Bermuda Atlantic Time Series (BATS)
What are some places we see the ocean being poorly explored?
- Spacial Gaps
- Temporal Gaps
- Parameter Gaps
- Depth Gaps
What are property sampling methods commonly currently used?
- Point measurements (bottle sample)
- Depth profiles (CDT profile)
- Time series (Moorings)
- Fixed Geographically (Euleriah)
- Moving with currents ( Lagangian)
How do sampling bottles work?
- collect samples to be brought up for future examination
- must be very careful to not contaminate the bottle
- thermometers added to bottles for additional temperature measurements
What are sampling bottles also sometimes called?
- Nansen, Nisken, or Go-Flo bottles
What does CTD stand for?
Conductivity-temperature-depth
How do CTD’s Work?
- measures temp electronically
- also measures conductivity, which gives salinity
- allows continuous measurement at all depths the probe descends to
- deployed on a wire from stationary ship or ice hole
- extremely high accuracy
How does the Rosette Sampler work?
- Includes CTD and sampler bottles
- bottles can be activated at any depth and signalled by a wire
What does XBT stand for?
eXpendable Bathy Thermograph
How do XBT’s work?
- Cheap and expendable
- measures only in top 1000-1500m
- can be launched by merchant ships or airplanes
How do Moorings work?
- Fixed line anchored to the bottom of the ocean with a top float
- Sets of sensors at different depths that measure temporal variation at different depths
What is a Mooring Array?
- Multiple Moorings
- allow for spacial variation to be observed
What do we want to know when measuring ocean currents?
- How the ocean is moving at an instant and over time
What are the 2 main ways to determine ocean currents?
- Indirect methods
- Direct methods (2 types passive and active)
What is the difference between direct and indirect methods of determining ocean currents?
Direct- directly determines speed and direction of ocean movement either passively or actively
Indirect- infers motion form other types of measurements
