Brainscape's Knowledge GenomeTM

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


See full index

Oral prep flash cards > Meteorology > Flashcards

Meteorology Flashcards

1
Q

What to do before reading a barometer?

A

gently tap the glass

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

What is the purpose of the 2nd pointer on a barometer

A

Adjusted manually to current pressure, can see later if rising or falling

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

Difference between barograph and barometer
How do they work?

A

Barograph draws a graph!
shows readings/ Trend for 7 days
Aneroid cell - Thin metal cylinder, partly exhausted of air and sealed. sensitive to the slightest changes in pressure, and connected to a pointer to magnify the movement

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

Why is there a daily range of pressure shown on the barograph?

A

The Diurnal Range
Atmospheric pressure waves, period of nearly 12 hrs
caused by daily heating and cooling
sweep around the earth from East to west
Max in tropics of 3mb, decreasing north and south

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

What is a Psychrometer

A

Wet and dry bulb thermometer
Known as Masons Hygrometer (Stevensons Screen - the box)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does a stevensons screen work

A

White box to shade thermometers from radiation heat, giving only air temp
2 thermometers, 1 regular, giving air temp,
1 kept wet by muslin dipped in a reservoir of distilled water, to give humidity. As the water evaporates, it loses heat, so the wet bulb is a lower temperature

The difference between the thermometers indicates the relative humidity.
Very little difference - 100% humidity
Large difference - low humidity

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

How do you use a Masons hygrometer to predict fog

A

Use the table in the Mariners Handbook
Dry bulb temp down the side/ depression of the wet bulb along the top
Read off the dew point
If Dew point is within 5ºC of the Sea temp, fog may form
Frequent observations allow you to graph dew point and sea temp to predict fog ahead of time

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

What is the Whirling Psychrometer?

A

Another hygrometer - wet and dry bulb thermometer
Both thermometers side by side, 1 wrapped in wet cloth
Whirl that MoFo around for 1 minute
Repeat several times until bored or lowest Wet bulb Temp obtained

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

What is Relative Humidity

A

the amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature

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

What causes all fog?

A

The cooling of air, so that it becomes fully saturated by the water vapour in it, called its Dewpoint

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

Sea or advection Fog
What causes it?
characteristics?
Location and time of year?

A

Warm moist air flows over a relatively cool sea
Main type of fog experienced at sea,
Will persist until conditions change
Often shallow, so mastheads may protude above it
Sometime the base sits above sea level, clear low level
In temperate and high latitudes, most common in spring and early summer, when the sea temp is lowest
Prevelant in certain areas, where prevailing winds transport warm moist air over cold ocean current.
Incuding British isles and english channel,

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

Radiation fog
Causes?

A

Low lying land on clear nights
land radiates heat and cools down, cooling the air
Forming fog, this can occasionally drift out to sea but no more than 10-15 miles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Frontal Fog?
which Fronts?
Causes?

A

Warm or Occluded Front
Common if the Air temp ahead of the front is very low
Caused by mixing of warm and cold air at the front
Rain ahead of the front may help to raise humidty
Usually confined to a narrow belt at the front, but Sea fog may develop after.

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

Katabatic wind

A

Prevelant in high coastal areas
Land/Air cooling on high ground, cold dense air
Wind runs down hills/cliffs, accelerating with gravity
Can give little warning and be very powerful

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

The Mistral?

A

A violent, cold, North or NW wind that accelerates through France into the Med
Caused by a high pressure in Biscay, and a Low pressure in Genoa, funneling Cold Northerly winds through

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Stratus/strato:
Cumulus/cumulo
Cirrus/cirro:
Alto:
Nimbus/Nimbo

A

Stratus/strato: flat/layered and smooth
Cumulus/cumulo: heaped up/puffy, like cauliflower
Cirrus/cirro: high up/wispy
Alto: medium level
Nimbus/Nimbo: rain-bearing cloud

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Sources of weather forecasts?

A

Own ships instruments
VHF
SafetyNET info via Inmarsat
MSI Via Navtex
Weather Routing
SatC
WeatherFax
Internet
TimeZero

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Publications with weather info?

A

Mariners Handbook
ALRS 3,4
Admiralty Routing Charts
Admiralty Sailing Directions
Admiralty Ocean Passages of the World

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Mariners handbook for weather?

A

TRS - Causes and avoidance
Formation of Fronts and depressions
Fog
Ice
Heavy weather handling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

ALRS for Weather?

A

Vol 3 frequencies for radio weather services and MSI
Vol 4 list of Met observational stations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Admiralty routing charts for weather?

A

All major oceans for each month of the year
Display average conditions for that month
Wind roses
currents
sea temps
fog and ice
tracks of TRS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Admiralty sailing directions for weather?

A

details of coastal areas, safe anchorages, nav hazards
prevailing conditions
Gives some average pressures for certain areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Ocean passages of the world for weather

A

wealth of info on ocean voyage planning
for each of the worlds oceans
notes on weather, currents, swell and Ice for common routes

24
Q

What is a TRS

A

A tropical Revolving Storm
a Fecking hurricane, typhoon, cyclone

25
Q

Causes and characteristics of a TRS?

A

Sea surface temps of at least 26ºC
Latitudes between 8-15ºN or S
Generally form at the east end of Oceans and track West
May re-curve upon reaching 20ºN/S and hitting the westerly trade winds

26
Q

Hurricane seasons?
in the Caribbean?

A

At the end of the local summer, when sea temps are highest
Caribbean June - October

27
Q

Signs of an approaching TRS?

A

Barometer drops 3mb below average (within 5 hrs)
Significant change in wind direction or strength
Long low swell from approximate centre of storm
Heavy rain
High cirrus cloud followed by broken cumulous

28
Q

Imminent?
Soon?
Later?

A

Imminent: within 6 hrs
Soon: within 6-12 hrs
Later: more than 12 hrs
From time of issue

29
Q

Average speed of a weather system?

A

20 knots,
Steadily = 15-25 knots

30
Q

Gale and Hurricane force winds?

A

Gale = Bf 8 - 34-40 Kn
Hurricane Bf 12 - 64Kn or More

31
Q

Visbility?
Very Poor
Poor
Moderate
Good

A

Very Poor = less than 1000m
Poor = 1000m - 2M
Moderate = 2-5M
Good = 5M +

32
Q

Wind
Becoming Cyclonic
Veering
Backing

A

Becoming Cyclonic = considerable change in wind direction across the path of a depression within the forecast area.

Veering = Clockwise - SW to W
Backing = Anitclockwise - SW to S

33
Q

Sea State:

Smooth

Slight

Moderate

Rough

Very Rough

High

Very High

Phenomenal

A

Smooth
Wave height less than 0.5 m.

Slight
Wave height of 0.5 to 1.25 m.

Moderate
Wave height of 1.25 to 2.5 m.

Rough
Wave height of 2.5 to 4.0 m.

Very Rough
Wave height of 4.0 to 6.0 m.

High
Wave height of 6.0 to 9.0 m.

Very High
Wave height of 9.0 to 14.0.

Phenomenal
14+

34
Q

Passage of a low
Conditions of an approaching Warm Front

A

Wind Backs and increase
Cloud Thickens into lowering layers
Weather Increasing rain
Pressure Decreasing
Temperature Increasing
Visability Decreases in rain

35
Q

Passage of a low
Conditions in the Warm Sector

A

Wind Veers and increases
Cloud Low level layers
Weather drizzle and maybe fog
Pressure rate of fall slows and steadies
Temperature increasess ad steadies
Visability Mod or poor

36
Q

Passage of a low
Conditions of an approaching Cold Front

A

Wind Backs and increases
Cloud Increasing mid/high clouds (maybe Large Cumulonimbus)
Weather Rain recommences
Pressure Decreasing
Temperature steady
Visability Moderate

37
Q

Passage of a low
Conditions at the cold Front

A

Wind Veers and increases
Cloud Cumulonimbus, breaks as front clears
Weather heavy rain / squalls
Pressure sharp increase
Temperature sharp decrease
Visability Sharp increase after squalls

38
Q

Wind at:
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Backs and increases
Warm Sector Veers and increases
Approaching cold front Backs and increases
Cold Front Veers and increases

39
Q

Cloud at:
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Thickening into lower layers
Warm Sector Low level layers
Approaching cold front Increasing mid/High cloud
Cold Front Cumulonimbus

40
Q

Weather at:
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Increasing rain
Warm Sector Drizzle, potentially fog
Approaching cold front Precipitation restarts
Cold Front Squalls and heavy showers

41
Q

Pressure at:
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Decreasing
Warm Sector Decreasing and steadying
Approaching cold front Decreasing
Cold Front Sharp increase

42
Q

Temperature at:
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Increasing
Warm Sector Increasing and then Steady
Approaching cold front Steady
Cold Front Sharp decrease

43
Q

Visability at:
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Decreasing in rain
Warm Sector Mod or Poor
Approaching cold front Mod
Cold Front Poor in squall, improving after

44
Q

Dew point at
Approaching warm Front
Warm Sector
Approaching cold front
Cold Front

A

Approaching warm Front Increasing
Warm Sector Increasing
Approaching cold front Steady
Cold Front Sharp fall

45
Q

What info do we need to easure wind speed on a synoptic chart?

A

Our latitude
Measure the distance between the isobars at the location
Then compare to the scale to get the geostrophic wind speed
Wind at sea level is 70% the geostrophic wind speed

46
Q

How high are geostrophic winds?

A

600m

47
Q

What is the ITCZ?
What effect does it have

A

Intertropical Convergence Zone/ Equatorial Trough
Thermal equator, As it moves N/S with the season, has a marked changed on weather conditions
It pulls pushes the Cells as it moves

48
Q

What effect does land and sea friction have on the wind?

A

Reduces the coriolis Force
Cause wind to back in Northern hemisphere
deflected 15º and slowed 25% over sea
Deflected 30º and slowed 50% over Land

49
Q

When does wind Convergence occur in the Northen hemisphere

A

When the wind is behind you and Land is on you right

50
Q

What Is buys Ballot Law?

A

In the Northern Hemisphere, with the wind on your back the lower pressure is on your left side

51
Q

Where are the Trade winds?
what direction to they blow?

Where are the westerlies?

A

up to 30º N/S
NE in the N hemisphere

40-60º N/S

52
Q

Where are the Horse latitudes?

A

30-40º N. Light and variable winds

53
Q

Average pressure at sea level?
WHat is key for using pressure for forcasting

A

1013 mb
The Trend, one measurement is useless
The barometer does not even need to be calibrated correctly, just need to know if it is going up or down

54
Q

How can you tell which side of a trs you are?
Which is the navigable side?

A

If the Wind is Veering, you are north of it NE to E
Backing, you are south of it NW to W
Steady, you are right in front of it! Northerly

The south side, in the Northern hemisphere, system moves east but wind is from west, so relatively safe
Also, South side the wind will push you away

55
Q

How to use a precision barometer

A

adjust the dial until the light breaks on/off
Read off the pressure
Correct to sea level via table

56
Q

What is a trough

A

Black line on a synoptic chart
Show an area of relatively low pressure

57
Q

How can you tell if a front is building or fading?

A

Building/frontogenesis - Dots in the line
Fading/frontolysis - Hashes accross the line

Oral prep flash cards (35 decks)

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