Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Marine Geomatics > Water Flow Monitoring & ADCP > Flashcards

Water Flow Monitoring & ADCP Flashcards

1
Q

What is a Eulerian Method?

A

One that determines the water velocity at one fixed point in the ocean

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is a Lagrangian Method?

A

One that is carried by ocean currents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Is a current meter a eulerian or langrangian method?

A

Eulerian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a current meter useful for?

A

Ground-Thruthing ADCP data

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Give 3 points about the principle of operation of a current meter

A
  1. Time revolutions (1 min) are converted to revolutions per second using calibration equations
  2. Data is usually averaged over a specified time frame (1–5 mins) to remove spikes in velocity and non-tidal effects (e.g. wind)
  3. Provides speed and velocity at a specified depth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What 2 additional sensors can be included on a current meter?

A

Temperature & Heading

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does ADCP stand for?

A

Acoustic Doppler Current Profiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is ADCP a eulerian or langrangian method?

A

Eulerian

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does ADCP measure?

A

The 3D velocity of particles suspended in the water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When using an ADCP, if the distance between the transmitted pulse and received signal is decreasing, what is happening to the frequency?

A

It will be increasing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How are the three beam velocities for an ADCP system used?

A

They are combined at each range cell to calculate the 3D velocity at that depth layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 6 ADCP deployment configurations?

A
  1. Vessel Mounted (Downward Looking)
  2. Bed Mounted (Upward Looking)
  3. On a Buoy (Downward Looking)
  4. Attached to a Structure (Horizontal Looking)
  5. On a Fixed Oil Rig (Looking in any Direction)
  6. Upwards or Downwards on a Mooring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many ADCPs are used for a VMADCP and where are they installed?

A

2 - side mounted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What can BMADCP be used for and why?

A

Coastal model calibrations because of the high temporal resolution and measuring wave height and direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give 3 disadvantages of BMADCP

A
  1. Low Spatial Resolution
  2. Challenging to Deploy/Recover
  3. Can go missing or get damaged
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give 8 challenges of ADCP surveys

A
  1. Fast spatial and temporal varying flow
  2. Low flow conditions
  3. Up and Down Welling
  4. Turbulence/Poor Weather
  5. Fouling
  6. Battering Life vs. Sampling Frequency
  7. Vessel needs to travel slowly
  8. Depth vs. Resolution Limitations
17
Q

What happens in ADCP post-processing?

A

Errors are removed and velocity is corrected for errors in bottom-tracking in order to get flow homogeneity

18
Q

Give 2 applications of ADCP

A
  1. Model Calibration

2. Tidal Energy

19
Q

Where in the UK have ADCP surveys been used to determined tidal energy potential?

A

Ramsey Sound, Pembrokeshire

20
Q

What is VHF radar good for?

A

Surface flow/complimenting ADCP

21
Q

What 2 types of VHF radar systems can you have?

A
  1. Ship Based

2. Land Based

22
Q

How does a VHF radar system work?

A

Doppler radar sends radio waves in the 10-50 mHz band and listens to the scattered signal from surface waves that have WL of 3-15m. The system directly measures the speed of the waves that scatter the radar signal and the difference between the measured speed and known speed of the waves is the ocean surface currents

23
Q

What is the +ve and -ve of VHF radar?

A

Good coverage but can be poor in very flat and poor/rough conditions

24
Q

Is drogue tracking a eulerian or langrangian method?

A

Lagrangian

25
Q

What makes ups the Drogue Tracking System (4 components)?

A
  1. Drogue (Cruciform/Tabular/Parachute)
  2. Surface Buoy
  3. Identification Flag
  4. GPS
26
Q

Where does a Drogue Tracking need to be deployed so not be impacted by winds?

A

> 1m below the surface

27
Q

What can Drogue Tracking be used for but why isn’t it done often?

A

Model Calibrations, not done often because of their random tracks

Marine Geomatics (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions