Maritime West Margin European type-mid latitude 35 to 55
degrees
# Relatively mild temperatures average seasonal range 5 – 20
degrees Centigrade
# humidity is generally relatively high and
precipitation occurs all the year round
# average amount 600 mm. but
significantly higher over upland areas e.g. Welsh. Uplands in the face
of the prevailing moist westerly winds coming off the ocean
but conversely low in rainfall shadow areas e.g. lowland East Anglia.
# The
temperatures and precipitation are mainly influenced by the mid latitude
position, low pressure belt and the mild westerly prevailing winds which
are warmed by warm currents on the west margin of land masses e.g. the
Gulf Stream and California Current.
# The weather is strongly influenced
by the position of the Polar Front and the passage of westerly moving
depressions along it with intervening spells of anticyclonic conditions.
These are linked to the position and extent of the main air masses
influencing the continental west margins in mid latitudes i.e. the Polar
Continental, Polar Maritime, Arctic Maritime, Tropical Maritime and
Tropical Continental Air Masses
# Persistence of one of the continental air masses across these western margins can bring long spells of dry summer weather but in winter 'anticyclonic gloom' conditions may occur.
# In contrast the passage over the area of a deep fast moving depression can bring storm conditions with gale force winds and heavy rainfall.
Continental Interior type – mid latitude 35 – 55 degrees
#
The Continental type is marked by a large seasonal range of
temperature averaging 25 to –5 degrees centigrade but towards the
latitude margins extremes are greater than this.
# Winters are dominated
by the continental high pressure with subsiding air and light
precipitation usually snowfall.
# Winds are out blowing and the interior
is too remote and cut off from moderating maritime influences.
# In the
summers occasioned by the higher angle of the sun and longer daylight
hours together with the differential heating of the land compared to the
oceans, temperatures are warm 25 to 35 degrees.
# Intermontane basins may be cut off from incoming depressions leading to temperate desert conditions as in the Gobi Desert of Central Asia and the Great Basin in the Western United States. Here climatic conditions are similar to the hot deserts but the seasonal range of temperature is greater, on average 0 degrees to 35 degrees Centigrade.
East Margin Maritime – latitude 35 – 55 degrees e.g.
North East United States, Japan, South East Australia.
# Low pressure
generally prevails and temperature on average range from 30 degrees to 0
degrees centigrade
# precipitation occurs all the year round but tends
to a summer maximum - average annual amount around 600 mm.
# summer
inward deflection of prevailing winds along ocean margins brings the
area under some depressions
# relatively high humidity in summer.
# occasional incursion of depressions in winter can bring heavy snowfall in the higher latitudes.
Main basic influences on Temperate Region climates are
1. Mid latitude position.
2. Generally under influence of the mid latitude low pressure belt and the atmospheric conditions along the Polar Front and the influence of the upper jet stream – except for continental areas in winter.
3. Seasonal shift of the pressure and wind belts.
4. The position and interaction at the margins of the different air masses affecting areas in temperate latitudes.
5. Differential heating of the continental interior and ocean margins.
6. The effects of ocean currents and the air above these.
7. Location of upland ranges vis-a-vis prevailing winds (eg Relief Rainfall and rain shadow)
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A |
B |
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C |
D |
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E |
F |
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G |
H |
| Equatorial = | Warm Temperate - Mediterranean = |
| Monsoon = | Cool West Margin = |
| Savanna = | Continental Interior = |
| Hot Desert = | Temperate East Margin = |