PRESSURE SYSTEMES Flashcards
Temperate Latitudes
- zone between tropics / polar cercles
- between 40 - 60 Latitude N/S
- have a wide temperature range
- where polar front depression forms(large scale low)
- where tropical warm air masses meet polar cold air masses
- where kinks forms (warm air intrudes into the cooler air)
Tropics (tropical region)
- regions between 0 ‘ / 23.5 ‘ N/S
- receives solar radiation at 90 “
- tropic of cancer 23.5 N
- Tropic of Capricorn 23.5 S
- where small scale lows forms
Polar frontal depressions
- are a large scale low
- found abt 40’ / 60 ‘ latitude N/S depending upon the season
- moves WEST to EAST
Depressions or (small scale low)
- small scale lows
- found almost anywhere on earth surface
- small scale lows commonly forms over land masses in summer months (the most occurrence. Is around the equator so they create:THE EQUATORIAL LOW PRESSURE BELT (very extensive cumuliform cloud development) + can develop into some of the violent weather phenomena TRS-hurricanes-cyclone-typhoons (can be 700NM diameter +rotational speed of 200 NM/H ) (generally found ONLY OVER THE TROPICAL OCEANS/REQUIRE SPECIFIC ENVIRONMENTAL CONDITIONS)
- created by unequal heating which gives rise to convection
- raising air heated by conduction
- inward moving air slows down by surface friction-than more diverging air than can can be replaced (that’s how low pressure above warm surface is maintained)
- convections leads to development of cumulus cloud
- hazards ( turbulence-precipitation- icing-poor visibility)
KInks
Found in temperate latitudes
The warm front
- warm air being forced over cooler air
- air forced upward expand-condenses-stratiform cloud
- 1:150 slop
Warm fronts (clouds type)
Ci
Cs
As
Ns
St
2 types of interaction between
Warm and cold air
Warm fronts (red demi-cercle)
Cold fronts (blue triangles)
Low pressure systems or !!
High pressure system or !!!
1- dépressions
2- cyclones
————————-
1 - anticyclones
Cold Fronts (blue triangles symbols)
-air being forced against warmer air undercut it
-as it advances it forces warm air upwards causing it to cool condensés than forms cloud
-has a steeper slope 1:50 than the warm fronts
-cloud still take stratiform apparence
-cold fronts slopes forward first then backwards creating a WEDGE SHAPE - due to that portion of air in contact with the ground slows down while the fronts advances /as a result will lag behind the air immediately above it
This creates instability in a warm air which in direct contact with the wedge
- cool air undercut the the warm air forcing it to raise (ahead of cold fronts vigorous ascent of warm air /creates cumuliform cliud )
Cold fronts clouds types
1-Cs 2- As 3- Ns 4-Cu 5- Cb
Polar front depression (formation)
- Polar front depression are formed by kinks
- kinks developed in the boundary between tropical and polar air
- warm air is forced upward by the cold air then clouds is formed
TROUGH OF (of the low pressure)
Surface TROUGH is a finger-like protrusion of low pressure away from the center of low trough weather can be as
Active as that in the main depression with active cumuliform cloud
Trough-Line
- Are area of strong uplift giving rise to cumuliform clouds
- significant formation of cumuliform storm cloud can occur along these trough lines
HIGH PRESSURE SYSTEMS-ANTICYCLONES
- Created when a weight of a column of air is increased.causing substance of the air mass
- this occurs in many ways the most common one
- is convergence of the air in the upper atmosphere
- the descent of air in high pressure areas is called SUBSIDENCE
- SUBSIDENCE in high pressure areas (anticyclones)is the principal characteristic of weather within an anticyclone
- (subsidence = air compressed =temperature rise )=ADIABATIC WARMING (rising temperatures in inhabits condensation and formation of the cloud)
