METEO (FINALS)

Question 1

act as vast
conveyors of heat, nutrients, and moisture, significantly shaping the Earth’s climate system

Answer 1

Ocean currents

Question 2

, driven by wind and Earth’s rotation, move warm water from the equator toward the poles
and cold water from the poles back toward the equator

Answer 2

Surface currents

Question 3

transports warm water from the Gulf of Mexico to the North Atlantic, moderating
the climate of Western Europe, making it warmer than other regions at the same latitude

Answer 3

Gulf Stream

Question 4

cold currents like the _ bring cool, nutrient-rich waters down the western coast
of North America, which leads to cooler coastal temperatures

Answer 4

California Current

Question 5

These are large-scale interactions between ocean currents and atmospheric circulation in the Pacific Ocean,
which significantly alter global weather patterns

Answer 5

El Niño and La Niña Phenomena

Question 6

involves the weakening of trade winds and the warming of the central and eastern Pacific, leading to
increased precipitation in the Americas and droughts in Australia and Southeast Asia.

Answer 6

El Niño

Question 7

is the opposite, with stronger trade winds and colder-than-normal sea surface temperatures, often
leading to opposite weather extremes (dry conditions in the Americas and wet conditions in Southeast Asia).

Answer 7

La Niña

Question 8

help distribute moisture, affecting precipitation patterns around the world

Answer 8

Currents

Question 9

is influenced by the seasonal reversal of winds and the
movement of warm ocean water, causing intense rains during the summer monsoon

Answer 9

Indian Ocean Monsoon

Question 10

moves deep, cold, and salty water around the
globe. This system regulates long-term climate patterns by redistributing heat and nutrients, and
any disruption (such as from melting polar ice) could lead to significant climate changes

Answer 10

global conveyor belt (thermohaline circulation)

Question 11

If the _ were to weaken, it could lead
to colder winters in Europe and shifts in global climate patterns

Answer 11

Atlantic Meridional Overturning Circulation (AMOC)

Question 12

not only regulate temperatures locally but also influence large-scale climate
phenomena, making them essential to understanding global weather patterns. The interaction between
oceans and atmosphere is a key driver in determining weather variability, precipitation patterns, and
long-term climate changes across the globe.

Answer 12

Ocean currents

Question 13

Climate change is altering traditional ocean current patterns, such as the _. These changes can affect weather patterns, marine ecosystems, and
maritime navigation

Answer 13

weakening of the Gulf Stream or
shifts in the Pacific Decadal Oscillation

Question 14

is constantly evolving, driven by advances in technology, new discoveries, and the
changing nature of oceanic patterns due to climate change. Continuous learning is vital for professionals in
maritime operations and other fields related to oceanography to stay updated with new development

Answer 14

field of oceanography

Question 15

allow for real-time monitoring of sea surface heights and ocean current
movements.

Answer 15

Satellite altimetry and drifters

Question 16

provide critical data on ocean temperature and salinity profiles, improving our understanding of
the deep ocean’s role in heat distribution

Answer 16

Argo floats

Question 17

and remote sensing tools help in collecting vast amounts of
oceanographic data, facilitating more accurate predictions of ocean behavior and weather patterns

Answer 17

Autonomous underwater vehicles (AUVs)

Question 18

Changing ocean currents can influence shipping routes, with _ needing
adaptation to new current patterns

Answer 18

optimal route planning

Question 19

Utilizing updated editions of _ provides the latest information for safe and efficient maritime operations

Answer 19

Reed’s Nautical Almanac, Admiralty Tide Tables, and NOAA Ocean
Current Forecasts

Question 20

follow regular, cyclical patterns that are influenced by the gravitational forces of the moon, sun, and
Earth’s rotation.

Answer 20

tides

Question 21

three primary tidal cycles:

Answer 21

Semidiurnal Tides, Diurnal Tides, Mixed Tides

Question 22

These occur twice daily, with two high tides and two low tides of roughly equal
height within a 24-hour period. This is the most common type of tide and is seen in locations such as
the Atlantic coast of North America

Answer 22

Semidiurnal Tides

Question 23

In this cycle, there is only one high tide and one low tide per day. are typical in places like the Gulf of Mexico and parts of Southeast Asia

Answer 23

Diurnal Tides

Question 24

• These involve two high and two low tides per day, but the heights of each tide vary significantly. are seen in regions like the Pacific coast of North America.

Answer 24

Mixed Tides

Question 25

is the vertical difference between the high tide and the low tide. It is influenced by the relative positions of the Earth, moon, and sun

Answer 25

tidal range

Question 26

These occur when the Earth, moon, and sun are aligned during full or new moons. The gravitational forces of the moon and the sun work together, resulting in the highest high tides and the lowest low tides, producing a large tidal range

Answer 26

Spring Tides-

Question 27

tidal ranges

Answer 27

Spring Tides- Neap Tides-

Question 28

These occur when the sun and moon are at right angles relative to the Earth (during the first and third quarters of the moon). The gravitational forces partially cancel each other out, leading to lower high tides and higher low tides, creating a small tidal range

Answer 28

Neap Tides-

Question 29

In the Bay of Fundy, Canada, which has one of the highest tidal ranges in the world, spring tides can result in a difference of _ between high and low tides

Answer 29

over 16 meters

Question 30

Occur when the gravitational pull of the moon (and to a lesser extent, the sun) causes the water to bulge outward. This happens on the side of the Earth facing the moon, as well as on the opposite side due to the Earth being pulled slightly away from the water.

Answer 30

High Tides-

Question 31

x Occur between the high tides when water levels fall. Low tides represent the areas of least gravitational pull, as the moon’s influence is weakest at the positions roughly perpendicular to the moon-Earth axis.

Answer 31

Low Tides-

Question 32

A coastal region like _ experiences semidiurnal tides, with two high and two low tides each day, with the height difference fluctuating with the lunar cycle

Answer 32

San Francisco Bay

Question 33

are the horizontal movement of water caused by the rise and fall of tides. These currents are crucial for navigation, as they can significantly affect a vessel's speed and course

Answer 33

Tidal currents

Question 34

The horizontal water movement toward the shore, associated with rising (incoming) tides

Answer 34

Flood Current-

Question 35

The horizontal water movement away from the shore, associated with falling (outgoing) tides

Answer 35

Ebb Current

Question 36

The period when the tidal current is at its weakest, occurring between flood and ebb currents

Answer 36

Slack Water-

Question 37

Tidal Currents

Answer 37

Flood Current, Ebb Current, Slack Water

Question 38

in narrow channels like the _, tidal currents can reach several knots, strongly influencing navigation, particularly during flood and ebb tides

Answer 38

Strait of Gibraltar

Question 39

are primarily driven by the gravitational pull of the moon, with the sun also exerting a significant but lesser influence. Together, these celestial bodies create the regular tidal patterns experienced across the globe

Answer 39

Tides

Question 40

The moon’s gravity causes water to bulge outward on the side of the Earth facing it, creating a high tide. Due to the Earth's rotation, a second high tide occurs on the opposite side. The moon is the dominant force behind the tides because it is much closer to Earth than the sun

Answer 40

Moon’s Gravitational Influence-

Question 41

The sun also influences tides, but its effect is weaker due to the greater distance from Earth. However, during spring tides, when the sun, moon, and Earth are aligned, the combined gravitational pull results in stronger tides

Answer 41

Sun’s Gravitational Influence-

Question 42

During a full moon or new moon, the Earth, moon, and sun align, enhancing the tidal range, leading to higher high tides and lower low tides

Answer 42

Spring Tide Alignment:

Question 43

provide a consistent basis for measuring and predicting tides, and they are defined in relation to specific tidal events

Answer 43

Tidal datums

Question 44

is a reference point from which tidal heights are measured. It is established by averaging observed tidal data over a specified period, typically over 19 years

Answer 44

tidal datum

Question 45

most common tidal datums include

Answer 45

Mean High Water (MHW), Mean Low Water (MLW)

Question 46

The average height of the high water over a specified period (usually 19 years). is often used as a reference point for maritime navigation and coastal development

Answer 46

Mean High Water (MHW)-

Question 47

The average height of the low water over the same specified period. is used to define the lowest expected tide in a region

Answer 47

Mean Low Water (MLW)-

Question 48

Other Common Tidal Datums

Answer 48

Mean Sea Level (MSL), Mean Low Water Springs (MLWS), Mean High Water Springs (MHWS)-

Question 49

The average sea level measured over a long period (typically 19 years), which serves as a baseline for determining elevations in coastal areas.

Answer 49

Mean Sea Level (MSL)-

Question 50

The average of the lower low waters that occur during spring tides, which provides a reference for the lowest tides during high tidal ranges.

Answer 50

Mean Low Water Springs (MLWS)-

Question 51

The average of the higher high waters that occur during spring tides, providing insight into the upper tidal ranges

Answer 51

Mean High Water Springs (MHWS)-

Question 52

are physical markers set by surveying organizations to indicate the elevation of a specific tidal datum at a particular location. they provide essential reference points for various applications, including coastal engineering, flood risk management, and habitat restoration.

Answer 52

Benchmarks

Question 53

are typically determined through long-term tidal observations at tide gauges, which measure sea level changes over time. Data collected over a 19-year cycle allows for the calculation of averages, providing a reliable basis for establishing MHW, MLW, and other tidal datums

Answer 53

Tidal datums

Question 54

are essential for navigation charts, ensuring safe passage for vessels by indicating safe water depths. They are used in coastal development projects to assess flood risk, manage wetlands, and support infrastructure planning. helps predict the impact of sea-level rise on coastal areas

Answer 54

Tidal datums

Question 55

is a powerful tool in oceanography and tidal studies, allowing researchers and practitioners to decompose tidal observations into their constituent components. This analysis helps accurately predict tidal patterns and understand the underlying physical processes driving tides

Answer 55

Harmonic analysis

Question 56

Tides that occur once every lunar day, with a period of approximately 24 hours. The principal diurnal constituent is the K1 tide (solar semi-diurnal)

Answer 56

Diurnal Components-

Question 57

Tides that occur twice daily, with a period of approximately 12 hours. The major semidiurnal constituents include the M2 tide (principal lunar semi-diurnal), S2 tide (solar semi-diurnal), and N2 tide (larger elliptic lunar tide)

Answer 57

Semidiurnal Components

Question 58

Tides can be decomposed into various components based on their periodicity. The two primary categories of tidal components are:

Answer 58

Diurnal Components- Semidiurnal Components

Question 59

employs Fourier series to express tidal observations as a sum of sine and cosine functions. This mathematical representation allows for the separation of various tidal frequencies. Each tidal component has its amplitude (height) and phase (timing), which can be derived from historical tidal data

Answer 59

Harmonic analysis

Question 60

The following steps outline a typical process for harmonic analysis

Answer 60

*Data Preparation- Collect and preprocess tidal observations to remove noise and irregularities.i. *Fourier Analysis- Apply Fourier transforms to the data, breaking it down into its harmonic components.ii. *Fitting Models- Fit harmonic models to the observed data, estimating the amplitude and phase for each tidal constituent. *Validation- Compare predicted tidal heights with actual observations to validate the accuracy of the harmonic model.

Question 61

Applications of Harmonic Analysis

Answer 61

*Tidal Prediction- Harmonic analysis provides the foundation for predicting future tides based on historical data, essential for navigation and coastal management. *Understanding Tidal Dynamics- By analyzing the components of tides, researchers can gain insights into how various factors (e.g., gravitational forces, wind, and atmospheric pressure) influence tidal behavior. *Climate Change Studies- Harmonic analysis helps assess how changing sea levels and climate patterns might affect tidal ranges and frequencies

Question 62

are specific values derived from harmonic analysis that describe the characteristics of tidal constituents at a given location.

Answer 62

Tidal constants

Question 63

The height of the tidal wave associated with a specific tidal component (e.g., M2, S2).

Answer 63

Amplitude-

Question 64

The timing of the tidal component relative to a reference point (usually the time of a known high or low tide)

Answer 64

Phase-

Question 65

The phase difference between the actual tide observed and the theoretical tide calculated based on tidal constants. This lag can be due to local conditions such as wind or atmospheric pressure

Answer 65

Tidal Lag-

Question 66

Adjustments made to account for the height of the tide at a specific location relative to the datum (e.g., Mean Sea Level). For example, if a location is 5 meters above MSL, the calculated tidal height must be adjusted upward by 5 meters

Answer 66

Elevation Corrections-

Question 67

Adjustments based on local geography, such as the shape of the coastline or the presence of islands and bays, which can influence tidal behavior

Answer 67

Geographical Corrections-

Question 68

is the time lag between the theoretical tide and the observed tide

Answer 68

phase difference

Question 69

The movement of the Earth affects the timing of tides

Answer 69

Earth’s Rotation-

Question 70

Geographic features, weather patterns, and human activities can shift the timing of high and low tides.

Answer 70

Local Effects-

Question 71

To calculate the tide height accounting for phase differences:

Answer 71

1. Identify the tidal constants for the location. 2. Adjust the timing of the predicted tide based on the known phase difference. 3. Use the adjusted phase to determine the expected height of the tide

Question 72

are theoretical points in the ocean where there is little to no tidal range due to the rotation of the Earth and the shape of ocean basins. As tides propagate, they rotate around these points, and tidal heights decrease with distance from the

Answer 72

Amphidromic points

Question 73

Shallow water affects tidal behavior significantly due to the following reasons:

Answer 73

Friction- In shallow areas, tides encounter more friction, which can lead to a reduction in tidal heights. Wave Propagation- The speed of tidal waves changes in shallow water, affecting timing and height. Resonance- In some locations, shallow bays can amplify tidal ranges due to resonance effects

Question 74

Calculation Steps

Answer 74

1. Obtain Tidal Constants- Gather data for the relevant tidal components (M2, S2, etc.) and their amplitudes and phases. 2. Calculate Theoretical Tide- Use the constants to calculate the theoretical tidal height at the specific time. 3. Apply Corrections- Adjust for phase differences, geographical factors, and shallow water effects to arrive at a corrected tidal height. 4. Account for Amphidromic Points- Factor in the proximity to amphidromic points if applicable. 5. Predict Currents- Calculate tidal currents based on the height differences and the local bathymetry (depth of water) to estimate flow rates during flood and ebb conditions.

Question 75

The captain must refer to tide tables to ascertain the tidal heights and plan the arrival during high tide to ensure enough draft

Answer 75

Impact on Water Depths-

Question 76

The captain may need to plot a route that avoids shallower areas that could become hazards at low tide

Answer 76

Safe Passage Planning-

Question 77

If a vessel arrives at low tide and the berth has a minimum depth requirement, it may not be able to dock. The captain needs to coordinate with port authorities to find an alternative berth or adjust the arrival time

Answer 77

Berth Availability-

Question 78

Understanding the timing of tides is crucial. If a vessel is scheduled to leave the port, it must do so when the tide is high enough to safely clear the channel

Answer 78

Timing of Entrances/Exits-

Question 80

Which of the ff. best describes the concept of “slack water” in tidal current?

Answer 80

C. When there is little to no current

Question 81

What is the main influence of the moon on Earth’s tide?

Answer 81

B. It pulls water towards itself, causing high tides

Question 82

7. Which tidal cycle is characterized by one high tide and one low tide each day?

Answer 82

C. Diurnal Tides

Question 83

What tidal range results from the gravitational forces of the sun and moon being at right angles?

Answer 83

B. Neap Tides

Question 84

Which tidal datum is defined as the average height of low water over a specified period?

Answer 84

A. Mean Low Water (MLW)

Question 85

How do Argo floats contribute to oceanographic studies?

Answer 85

B. By providing data on temperature/salinity

Question 86

If the Gulf Stream weakens, which of the ff. could be a potential impact on Europe’s climate?

Answer 86

B. Cooler winters and more severe weather

Question 87

Which term describes a reference point from which tidal heights are measured?

Answer 87

C. Tidal Datum

Question 88

What is the primary tidal component that occurs twice daily, with a period of approximately 12 hours?

Answer 88

B. M2

Question 89

Which tidal current describes the horizontal water movement toward the shore during rising tides?

Answer 89

C. Flood Current

Question 90

What is the purpose of tidal stream atlases in navigation?

Answer 90

A. To measure sea level, direction, and strength of current

Question 91

. A vessel is navigating a channel with a significant ebb current. To compensate for the drift, what should the navigator consider?

Answer 91

C. Decrease speed to prevent drift

Question 92

What might strong wind condition influence the accuracy of tidal height predictions based on tidal constants alone?

Answer 92

A. They may lead to underestimation of high and low tides C. They can result in either increase or decrease tides

Question 93

The captain must account for the direction and strength of the tidal current, which can significantly alter the ship's course. For example, if the current is flowing east at 3 knots and the ship is trying to head north at 5 knots, the effective ground speed will be influenced by the current.

Answer 93

Tidal Streams

Question 94

The captain uses vector analysis to calculate the resultant course. If the ship's intended path is 350° at 5 knots, and the current pushes it 3 knots to the east, the effective course might change to 010°

Answer 94

Calculating Drift-

Question 95

By analyzing current tables and weather forecasts, the captain may decide to wait for a slack tide or adjust the route to minimize the effect of the current, ensuring a more efficient and safe passage.

Answer 95

Voyage Planning-

Question 96

The navigator annotates tidal diamonds on the chart to indicate the expected tidal heights and times. Each diamond indicates the direction and strength of currents, which can guide the vessel’s route.

Answer 96

Tidal Information-