Meteorology part 2 Flashcards
Cyclones
-area of low pressure around which the winds flow counterclockwise
(opposite in Southern hemisphere– clockwise)
-converging air at the surface that rises
-cloudy, wet, stormy
Anticyclones
- high pressure systems
- clear, calm, fairly dry
- opposite of cyclone in every way!!!
thunderstorms
- small area storms formed by the strong upward movement of warm, moist, unstable air
- accompanied by lightning, thunder, rain, sometimes hail
- formed from cumulonimbus clouds
air mass thunderstorms
- form in warm, moist air mass
- occur in spring and summer
- last less than 1 hour, single, widely scattered
frontal thunderstorms
- occur in lines along a frontal surface
- stronger and may last several hours
- can produce heavy rain and flooding
lightning
- a discharge of electricity from a thundercloud to the ground, or cloud to cloud
- produced by all thunderstorms
tornado
- a narrow, funnel shaped column of spiral winds that extends downward from the cloud base and touches the ground
- usually occur during spring and summer and most occur in the late afternoon
- funnel is a mixture of clouds and dust
waterspout
a tornado over the water/weaker than a tornado
Fujita Scale
- scale used for categorizing tornados
- higher # = more danger
hurricane
an intense tropical low pressure area with sustained winds starting at 74mph
storm surge
- currents formed when hurricanes pile water up along the shore and blow it inland
- most damaging part of a hurricane
Saffir- Simpson
how hurricanes are measured
eye
- central area of sinking air; 15-20 km wide
- low pressure
- higher temperatures
- calmer winds
- winds most violent just outside the eye
watch
threat of storm conditions within 24-26 hours
warning
due to strike within 24 hours
air pressure
- pressure that the air exerts on the Earth
- directed equally in all directions
what affects air pressure
temperature, water vapor, elevation
barometer
instrument used to measure air pressure
falling barometer
warmer, humid weather, predictor of storms
rising barometer
cooler, drier weather
isobars
lines of equal pressure
what kind of systems are hurricanes
low pressure systems
rising air =
cloud formation and precipitation
sinking air =
clear skies
wind
movement of air
anemometer
instrument that measures wind speed
wind vane
- measures wind direction
- always points into the wind
||—->~~~~~~WIND
air flows from…
areas of higher pressure to areas of lower pressure
solar radiation
ultimate energy source for most wind
what 3 factors combine to control wind
pressure differences, Coriolis effect, friction
pressure gradient
high to low pressure
friction
only important close to surface, not at height
Coriolis force
inertia caused by earth’s rotation
Coriolis effect
deflection of wind and ocean currents caused by the earth’s rotation
what cause ocean currents
winds and the Coriolis effect
cold currents go…
warm currents go…
..along the west coasts of continents
..along east coasts
jet stream
- narrow belt of strong, high speed air
- height of about 10-15km
what more affects surface winds
friction with earth’s surface
what more affects Geostrophic winds
Coriolis force
polar easterlies
GLOBAL WIND
- cold, but weak winds start between 50 degrees and 60 degrees and go to the poles
- aren’t constant
westerlies
GLOBAL WIND
belt of very strong winds between 40 degrees and 50 degrees
trade winds
GLOBAL WIND
warm, steady winds between 0 degrees and 30 degrees
doldrums
GLOBAL WIND
calm, surface winds at the equator
sea breeze
LOCAL WIND
flow of cool air from water to land during the day
land breeze
LOCAL WIND
flow of cool air from land to water at night
el nino
- periodic warming of the ocean that occurs in the central and eastern Pacific (3-7 years) (strong)
- major el nino can cause extreme weather in many parts of the world
la nina
- surface temperatures in the eastern pacific are colder than avergae
- milder and drier weather in South
the Koppen Climate Classification
3 letter system
1st letter = temperature
2nd letter = precipitation
3rd letter = more specific temperature
climograph
graph showing the average temperatures and precipitation by month for a specific location
air mass
a large body of air that has the same temperature and humidity thruout
Air mass originates over land…
dry air mass (c) (continental)
Air mass originates in warm air…
warm air mass (T) (Tropical)
Air mass originates in cold air…
cold air mass (P) (Polar)
Air mass originates over ocean…
humid air mass (m) (maritime)
which air mass affects Wilmington
Maritime Tropical Atlantic (mT)
-brings mild, cloudy winters and hot, humid summers with hurricanes and thunderstorms
(moves North across eastern US)
radiosonde
- small balloon
- carried observatory which carries a radio transmitter
- sends signals about air pressure, temperature, and humidity
air front
boundary between 2 air masses having different temperatures and humidity
cold front
-transition zone where cold air mass replaces a warm air mass
-drawn as a blue line w/ blue triangles pointing in the direction of the fronts movement
-very strong storms w/ clear days following
(cold = more dense)
warm front
- transition zone where a warm air mass replaces a cold air mass
- drawn as red line w/ red half circles pointing in the direction of the fronts movement
- less severe weather, over a larger area
occluded front
- occurs when a faster moving cold front has caught up to a slower moving warm front
- drawn as a purple line w/ alternating semicircles and triangles
stationary front
- front is stalled (no movement -temp. gradient)
- drawn as alternating segements of red semicircles and blue triangles that point in opposite ways
- precipitation happens
locating fronts
strong temperature gradients, CCW rotation, lower pressure, precipitation, and clouds
