c7/8 key terms Flashcards
(24 cards)
define the bergeron process
process of ice growth that occurs through the rapid evaporation of liquid water which results in rapid ice crystal growth through deposition
Riming vs aggregation
riming is when supercooled water droplets freeze on contact with a solid object
aggregation is when ice crystals stick to one another and increase in size
Precipitation measurement systems for rain and snow
rain gauge- overflow rate from c1 to c2 is measured to determine intensity of rainfall over time
modified ‘snow’ gauge- a device that melts snow in order to record it in a manner similar to rain gauge measurements
global vs synoptic vs mesoscale
global scale- self explanatory
synoptic scale- hundreds/thousands of km
mesoscale- few km to 1k,km
inter-tropical convergence zone
belt of low pressure encircling the earth near the equator. Site where trade winds of north/south hemisphere come together; generates storms
westerlies
aka anti trade winds, blow from west and originate from high pressure areas in horse latitudes and blow towards poles
trade winds
blow from north/southeast depending on hemisphere and dominate tropics/subtropics in equatorial zone
polar easterlies
dry, cold winds that blow from polar zones to low pressure zones within westerlies at higher latitudes
hadley cell
air which rises at equator and sinks at medium latitude
3 cell model
hadley, ferrel, polar cells included in model, incorporates interaction between them to produce complex weather phenomena
atmospheric column and temperature
atmospheric pressure decreases more rapidly with height essentially
temp and pressure gradients and jet streams
differences in temp cause differences in pressure gradients
when a jet stream forms along pressure gradients, it is reflected by sedimentary layers of pressure gradients which in turn come from temp changes
subtropical vs polar jets
subtropical- 30N latitude, because of temp differences between mid-lats and equatorial air
polar- 60N, location due to polar front extending from arctic; changes based on seasonal extension of front
el nino/la nina/ENSO
enso- el nino southern oscillation cycle
el nino- periodic warming in sea temp across central/east central equatorial pacific
la nina- cold version of el nino in same location
ekman spiral definition/function
when flow direction rotates as you move away from a boundary
results in transport of fluids/air parcels across pressure gradients, resulting in changes to jet streams/large scale pressure gradient structures
upwelling/downwelling
up-when cold water rises to the surface
down-when cold air sinks under warm air
Monsoons formation/location
Typically form in west africa/asia-australia
Form due to land temp rising quicker than ocean temp, creating a low pressure well that results in the formation of a large cyclone and generates rain/heavy winds
sea/land breeze
sea breeze- from ocean towards land, high to low pressure, cold air moves towards warm air
land breeze- when cold air is blown inland towards ocean, causing air to rise and move inland
santa ana winds
winds created through uphill convectional lifting in the Santa Ana mountain range that often exacerbate forest fires
Chinook winds
Powerful wind deposited on valley side of a mountain after uphill movement on polar opposite side, resulting in melting/evaporation of snows, regionally domestic to interior West of North America
Downslope wind
Strong wind blowing down leeward side of mountain, peaks at foot of mountain
Cyclone overview
Air mass rotating around low pressure center
BOFA- cyclone: Air converges onto a low pressure center at the surface, rises and diverges aloft
BOFA- acyclone: Air converges aloft, sinks to high pressure center at surface and diverges at the surface
Geostrophic balance in a cyclone
Partially explains different rotations of cyclone in N/S hemispheres (clockwise in N, cc in S)
Gradient vs geostrophic balance in cyclones
3 forces: coriolis force, pressure gradient force, centrifugal force
pressure gradient force serves as balancing element between coriolis/centrifugal force
when one force doesn’t change, other forces must compensate by strength/weakness
