MET

Question 1

What does a barometer measure?

Answer 1

A barometer measures air pressure and forecasts short-term weather changes.

Question 2

What are the two types of barometers?

Answer 2

The two types of barometers are Mercury and Aneroid.

Question 3

What is the purpose of the pointer and thumbscrew on a barometer?

Answer 3

The pointer and thumbscrew are used to compare rising and falling pressure.

Question 4

What should you do before reading a barometer?

Answer 4

Always tap the glass before reading.

Question 5

What is a Precision Aneroid Barometer Mk.2?

Answer 5

It uses a light thread and provides correct readings to mean sea level.

Question 6

What is a barograph?

Answer 6

A barograph records continuous pressure on a chart drum.

Question 7

What is diurnal range in relation to barometers?

Answer 7

Diurnal range refers to 12-hour pressure waves, with a maximum of ~3mb in the tropics.

Question 8

What does a psychrometer measure?

Answer 8

A psychrometer measures humidity using dry bulb temperature (DBT) and wet bulb temperature (WBT).

Question 9

What is wet bulb depression?

Answer 9

Wet bulb depression is calculated as DBT - WBT. High depression indicates drier air.

Question 10

What is a whirling psychrometer?

Answer 10

A whirling psychrometer has two thermometers, one wet, and is rotated to get the lowest possible WBT.

Question 11

What is the use of a whirling psychrometer?

Answer 11

It is used to forecast fog by plotting sea and air temperatures against the dew point.

Question 12

What is sea/advection fog?

Answer 12

Sea fog occurs when warm moist air moves over cold sea, common in spring/summer in temperate latitudes.

Question 13

What is radiation fog?

Answer 13

Radiation fog forms on clear, calm winter nights over land and may drift offshore.

Question 14

What causes frontal fog?

Answer 14

Frontal fog is caused by mixing at fronts, especially warm fronts.

Question 15

What is anabatic wind?

Answer 15

Anabatic wind is an up-slope wind caused by daytime heating.

Question 16

What is katabatic wind?

Answer 16

Katabatic wind is a down-slope wind caused by gravity and cold dense air.

Question 17

What is a land breeze?

Answer 17

A land breeze occurs at night when land cools faster than the sea.

Question 18

What is a sea breeze?

Answer 18

A sea breeze occurs during the day when land heats faster than the sea.

Question 19

What is a mistral?

Answer 19

A mistral is a cold, violent northwest wind in the Mediterranean.

Question 20

What are clouds composed of?

Answer 20

Clouds are composed of water droplets or ice crystals.

Question 21

What are the families of clouds?

Answer 21

Cloud families include: High - Cirrus (Ci), Middle - Altocumulus (Ac), Low - Stratocumulus (Sc).

Question 22

What are some weather sources?

Answer 22

Weather sources include own ship, VHF, NAVTEX/SafetyNET, Sat C, Weather Fax, and the Internet.

Question 23

What are some publications for weather information?

Answer 23

Publications include Mariner’s Handbook, Admiralty Radio Signals (Vol 3 & 4), Routing Charts, Sailing Directions, and Ocean Passages of the World.

Question 24

Where do tropical revolving storms (TRS) form?

Answer 24

TRS form between 8°–15° N/S where sea temperature is ≥ 26°C.

Question 25

What is the typical movement pattern of tropical revolving storms?

Answer 25

They move west and then re-curve around 20°.

Question 26

What are signs of an approaching tropical revolving storm?

Answer 26

Signs include falling pressure, wind shift, long swell, cirrus clouds, and heavy rain.

Question 27

What is the dangerous semicircle in relation to tropical storms?

Answer 27

In the Northern Hemisphere, the dangerous semicircle has wind on the starboard bow; in the Southern Hemisphere, it has wind on the port bow.

Question 28

What is the navigable semicircle in relation to tropical storms?

Answer 28

In the Northern Hemisphere, the navigable semicircle has wind on the starboard quarter; in the Southern Hemisphere, it has wind on the port quarter.

Question 29

What does 'imminent' mean in weather forecasting?

Answer 29

'Imminent' means less than 6 hours.

Question 30

What does 'soon' mean in weather forecasting?

Answer 30

'Soon' means 6 to 12 hours.

Question 31

What does 'later' mean in weather forecasting?

Answer 31

'Later' means more than 12 hours.

Question 32

What are the visibility categories in weather forecasting?

Answer 32

Visibility categories are: Very poor (<1km), Poor (1–2NM), Moderate (2–5NM), Good (>5NM).

Question 33

What are the sea state categories?

Answer 33

Sea states range from Smooth (<0.5m) to Very High (9–14m).

Question 34

What happens ahead of a warm front?

Answer 34

Cloud thickens, pressure falls, wind backs, and rain increases.

Question 35

What occurs in the warm sector of a low?

Answer 35

Cloud breaks, drizzle/fog occurs, temperature rises, and pressure remains steady.

Question 36

What happens when approaching a cold front?

Answer 36

Cloud increases (Cb), rain recommences, and pressure falls.

Question 37

What occurs at a cold front?

Answer 37

Sudden squalls, wind veers W/NW, heavy rain, sharp pressure rise, and temperature drops.