Meteorology Flashcards
How would you predict fog?
To predict fog you will need a wet & dry hygrometer,
you compare the wet & dry temperature and enter the dewpoint table in NP100,
then you plot dewpoint against sea temperature to give you an indication of the likelyhood of fog.
What is a stevenson screen?
A shelter for met instruments against rain and direct heat, still allowing air to circulate around the instrument
What is advection fog?
Warm moist air over cold sea.
Advection fog is a type of fog formed when warm, moist air moves over a cooler surface, causing the air to cool and condense into fog.
What is radiation fog?
Fog that forms when the ground loses heat through radiation, cooling the air near the surface to its dew point, leading to condensation and fog formation.
What is sea breeze?
A sea breeze is a wind that blows from the sea to the land
Caused by the land heating up faster than the sea, creating a pressure difference.
Typically occurs in the afternoon when the temperature difference is greatest.
What is land breeze?
A land breeze is a wind that blows from the land to the sea
Caused by the land cooling down faster than the sea, creating a pressure difference.
Typically occurs at night or early morning.
What is katabatic winds?
Katabatic winds are gravity-driven winds that occur when cold, dense air descends from higher elevations to lower areas, typically forming at night.
What are the 4 big winds in the meds?
Mistral - Gulf of Lyon, is a type of katabatic wind, cold air descends from the Alps and flows toward the Mediterranean Sea.
Meltemi - Greece
Bernoulli - Gibraltar
Sirocco - from Africa
What is a anomometer?
Instrument to determine apparent wind direction & speed, placed eg on top of the mast
Sources of weather information?
Own ship, VHF, Navtex, local forecasts, SAT-C, weather fax, synoptic charts,
Reference publications for more weather information?
NP100 (Mariners Handbook)
Admiralty list of radio signals vol.3
Admiralty routeing charts
Admiralty Sailing directions
Ocean passages of the world
Tropical revolving storm? “Hurricane” “Typhoon” “Cyclone”
Non-frontal low pressure system
Intense rotating depression
Require right position and right time of the year
Require warm water (sea surface temp of at least 26-28°C)
Requires low wind shear
Requires Coriolis effect
Tend to form towards the eastern part of an ocean between 5° & 15° latitude North or South.
They move in a east-westerly fashion due to the trade winds
Signs of an approaching TRS? (5)
Barometer drops 3 millibars below the mean reading
significant change of direction or strength of wind
Long low swell is observed from the approximate centre of the storm
Heavy rain.
Lack of wildlife
General atmosphere is very oppressive and dark
Where do I get synoptic charts?
Metoffice
Geostrophic windspeed?
Wind 600m over sea level
over sea level 2/3
over land 1/3
