Meteorology

Meteorology is 4 PER questions, rising to 10 in PY and CY. Much of it is vocabulary, so learn that first.

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Pressure and wind

Standard sea-level pressure is 1013 hPa, or 760 mm. Isobars join points of equal pressure. Pressure is highest at the centre of an anticyclone, and lowest in a depression.

In the northern hemisphere wind turns clockwise around a high and anticlockwise around a low. Buys Ballot’s law: with your back to the wind, the low is on your left.

Wind vocabulary

Refrescar: strengthens. Caer: drops. Rolar: changes direction. Rachear: changes strength in bursts. Racha: a sudden brief increase.

Virazón: day breeze, sea to land. Terral: night breeze, land to sea.

Waves

Wave height depends on wind strength, persistence (hours blowing) and fetch (distance). Beaufort measures wind. Douglas measures sea state.

Activities

• Weather visualsClouds, fog, isobars, breezes and sea state.
• Read the skyCheck the sky, barometer and wind. What is coming?

Questions in this unit

• Coastal breezes that blow from land to sea are called:
• The term “virazón” refers to:
• Sailing ahead with the true wind dead astern, and boat speed equal to true wind speed:
• The time during which a wind blows with uniform direction and strength is called:
• The force the wind exerts on the sea surface, depending on its speed and the air pressure on the sea, is called:
• A wind “rola” (shifts) when:
• What is meant by “rolar”?
• The land breeze (terral) is a wind or breeze:
• In nautical terms, “rolar” means:
• Referring to the wind, “caer” means:
• Apparent wind:
• If we say the wind “refresca” (freshens), it means there is:
• Regarding temperature, what happens at 0º on the centigrade scale?
• When wind strikes our boat’s topsides, the force it exerts:
• What is true wind?
• What is the definition of temperature?
• On depressions, mark the INCORRECT statement:
• The Beaufort scale:
• The land breeze (terral) is:
• What is fetch?
• Atmospheric pressure:
• The device used to show wind direction, a long cone-shaped fabric sleeve open at both ends, is called:
• The expression “refrescar” for the wind means:
• In meteorology, up to what limit is pressure considered low?
• Atmospheric pressure is due to:
• What is the wind called that blows from the sea on coasts by day, alternating with the land breeze, when there is no storm?
• On the definition of temperature, mark the INCORRECT statement:
• Sailing NE at 5 knots in Santander Bay with a true headwind of 5 knots, the apparent wind will be:
• Depressions are regions where:
• Among coastal breezes, the sea breeze (virazón) generally blows:
• The wind we feel when the vessel is moving is called:
• In meteorology the millibar is used to measure:
• To find wind speed we use an…
• We say the wind has shifted (rolado) when…
• The wind is said to have shifted when:
• The wind is said to shift when:
• When the wind decreases and stays down, it is said to:
• The effect of the wind on a boat under way is:
• The anemometer is an instrument to measure:
• What are the reference points of the centigrade scale?
• What characterises a depression in the Northern Hemisphere?
• What characterises an anticyclone in the Northern Hemisphere?
• In the Northern Hemisphere the wind circulation in a depression:
• On the general wind circulation in the Northern Hemisphere, mark the correct option:
• In meteorology, what is an isobar?
• What phenomenon is known as "rolar"?
• Atmospheric pressure at a given point is called the...
• Winds turn anticlockwise in...
• The wind called "terral" blows:
• The Beaufort scale is used to find:
• Isobars: choose the incorrect answer:
• It occurs during the day: the land warms faster than the sea, creating relatively low pressure over it. As a result, a wind blows that is called:
• If we are under way ahead, the anemometer reading gives the speed of the:
• In an anticyclone in the northern hemisphere, winds circulate:
• Isobars are:
• What are terrales?
• The number of hours the wind has blown over the sea in the same direction
• On units of atmospheric pressure, one millibar equals:
• On depressions, mark the CORRECT statement.
• The term “rolar” means the wind:
• On anticyclones, mark the CORRECT statement.
• Winds around a low in the Northern Hemisphere:
• On temperature, mark the INCORRECT statement:
• An isobar is the line joining points of equal:
• On the centigrade scale, mark the CORRECT statement.
• If the wind direction changes, we say that:
• By “fetch” we mean:
• In general, depressions in the northern hemisphere:
• The scale classing sea states in 10 degrees by wave height is called:
• The wind blowing on the coast by day from sea to land is called:
• The fetch is:
• The land breeze (“terral”) is the wind that:
• What is the general wind motion in a northern-hemisphere depression?
• Northern-hemisphere depressions are characterised by:
• Mean atmospheric pressure at sea level is:
• On anticyclones, mark the INCORRECT statement:
• On depressions, mark the INCORRECT statement:
• The expression “refrescar” (to freshen) for the wind means:
• Atmospheric pressure at sea level, in millibars, is about:
• “Intensity” of the wind means:
• The Douglas scale tells us:
• What is meant by atmospheric pressure?
• Mean atmospheric pressure at sea level is:
• The vector sum of the wind we would feel stopped and the wind made by our own speed is called:
• What winds go with slow barometer movements?
• The instrument used to measure atmospheric pressure is:
• The Beaufort scale measures:
• What is understood by fetch?
• How does the wind turn in a northern-hemisphere anticyclone?
• With a barometer we measure:
• Mark the CORRECT statement about the aneroid barometer:
• On the centigrade scale, mark the CORRECT statement:
• Regarding atmospheric pressure, mark the CORRECT statement:
• Standard atmospheric pressure at sea level is…
• In general, surface air moves:
• Which instrument measures temperature without recording it?
• The greater the thermal contrast between land and sea, the sea breeze (virazón) will be:
• When speaking of fetch in sea waves, mark the correct answer:
• The coastal wind caused at night when the land cools faster than the adjacent sea water is known as the:
• A marine barometer is an instrument that measures:
• The device consisting of an elongated frustoconical fabric sleeve open at both ends, which aligns with the wind to show wind direction, is called a:
• Apparent wind is defined aboard as the…
• We say that the wind is gusty (racheado) when it…
• The Douglas scale describes the state of the sea…
• What is meant in seamanship by the expression “rolar”?
• Which meteorological instrument is used to measure air temperature?
• If we see on our barometer that atmospheric pressure is falling…
• Which wind parameter does a windsock or telltale (catavientos) show us?
• The length of time the wind blows over the sea in the same direction and with the same strength is called:
• The weight of the column of air above the sea surface is known as:
• Coastal weather bulletins prepared by AEMET are broadcast by coastal radio stations on:
• Apparent wind is the result of adding the vector forces of:
• The Douglas scale classifies conditions according to:
• What is relative wind (viento relativo) aboard a vessel?
• What is fetch in marine meteorology?
• The centres of the Spanish Maritime Safety Agency (SASEMAR) broadcast coastal weather bulletins after a prior announcement on:
• In meteorology, air temperature is defined as:
• The centigrade (Celsius) scale is a temperature scale that assigns the value zero (0 ºC) to water in the process of:
• The sea breeze (virazón) takes place during:
• Sailing at 4 knots through the Ría de Vigo, we stop feeling any apparent wind (apparent wind = 0 knots). This means that:
• What does the wind term “rolar” mean?
• The speed or strength of the wind:
• What is the general track of depressions in the Northern Hemisphere?
• What does a sudden, rapid rise in pressure on an aneroid barometer indicate?
• How does the wind circulate around an anticyclone in the northern hemisphere?
• In the northern hemisphere, in a depression, winds circulate...
• We call Fetch:
• If the wind changes direction and stays there, we say it has:
• The coastal breeze blowing from sea to land without a pressure gradient is called:
• Weather bulletins can be obtained through:
• If we are stopped, the anemometer reading gives the wind speed that is:
• Regarding the centigrade temperature scale:
• The wind is said to freshen:
• If we sail at 10 knots and the anemometer shows zero wind speed, the real wind comes from:
• The straight-line extent over which wind of constant direction and strength blows is called:
• Which quantity relates to the weight per unit area of the column of air above a place?
• Depressions in the northern hemisphere generally travel:
• If a barometer shows pressure changing over a given period, and a slow, gentle fall is detected, what does this variation express?
• While under way we see a slow, gentle rise in pressure on the barometer. This means:
• What factor is essential for predicting how the weather will develop at sea using an aneroid barometer?
• What does an aneroid barometer measure?
• The Douglas scale is used to:
• Regarding the Douglas scale, indicate which statement is INCORRECT.
• Regarding depressions, which statement is CORRECT?
• The time a wind (of the same direction and strength) has been blowing over an area is called:
• The Douglas scale:
• Areas characterised by pressure rising from the centre to the edge, with winds turning anticlockwise in the Northern Hemisphere:
• Regarding coastal breezes:
• In a depression in the Northern Hemisphere:
• The scale naming the different states of the wind is called:
• Isobars are defined as:
• If the strength of the wind varies continually, both up and down, we say that:
• Regarding anticyclones and depressions in the Northern Hemisphere, choose the correct option.
• A millibar is:
• Anticyclones in the Northern Hemisphere are characterised by wind turning:
• If on a daytime passage we keep the coast to starboard and feel a sea breeze (virazón), it will mainly come from:
• At what value on the centigrade scale does water boil?
• By “the wind drops” (caer el viento) we mean:
• If there is a very sharp and sudden increase in wind strength while under way, we can say a wind event has occurred called:
• A NW wind is one that:
• Anticyclones are:
• Can the weather forecast be obtained by VHF?
• Official weather information can be obtained from:
• What is the definition of temperature?
• In nautical terms, refrescar means:
• Sailing 12 miles off, with no mobile phone, satellite TV or internet, we get the weather forecast:
• A catavientos (telltale):
• In Spain, the body that produces weather information is:
• At night the land loses the day's heat faster than the sea, causing relatively low pressure over the sea and relatively high pressure over the land. The wind this produces is called:
• We define Persistence as:
• The wind is said to freshen (refrescar) when:
• Coastal breezes are named:
• The virazón is a wind or breeze:
• Which instrument tells us the wind speed?
• The value of atmospheric pressure at sea level is...
• The millibar is a unit of:
• A pressure system in which pressure rises towards the centre is:
• On what three variables does wave height depend?
• A change in the wind's strength over generally short intervals is called...
• In the northern hemisphere, on a weather map showing a low, the wind blows around the low:
• On weather maps, the lines joining points of equal atmospheric pressure are called:
• The Douglas Scale measures...
• We define a gust as:
• The greatest straight-line length of a body of surface water evenly affected by the wind's direction and strength is called...