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Главная / Предметы / География / Climate and Weather in Great Britain (Климат и погода в Великобритании)


Climate and Weather in Great Britain (Климат и погода в Великобритании) - География - Скачать бесплатно


Climate and Weather in Great Britain

       Weather is not the same as climate. The weather at  a  place  is  the
state of the atmosphere there at a given time or over a  short  period.  The
weather of the British Isles is greatly variable.
      The climate of a place or region, on the other  hand,  represents  the
average weather conditions over a long period of time.
      The climate of any place results from the interaction of a  number  of
determining factors, of which the  most  important  are  latitude,  distance
from the sea, relief and the direction of the prevailing winds.
      The geographical position of the British Isles within latitudes 50o to
60o N  is a basic factor in determining  the  main  characteristics  of  the
climate. Temperature, the most   important  climatic  element,  depends  not
only on the angle at which the sun’s rays strike the  earth’s  surface,  but
also on the duration of daylight. The length of day at  London  ranges  from
16 hours 35 minutes on June to 7 hours 50 minutes on  21  December.  British
latitudes form the temperate nature of the British climate, for the  sun  is
never directly overhead as in the tropical areas.
      Britain’s climate is dominated by the influence of the sea. It is much
milder than that in any other country in the same  latitudes.  This  is  due
partly to the presence of the North Atlantic Drift, or the Gulf Stream,  and
partly to the fact that north-west Europe lies in a  predominantly  westerly
wind-belt. This means that marine influences warm the  land  in  winter  and
cool in summer. This moderating effect of the sea is in fact, the  cause  of
the relatively small seasonal contrasts experienced in Britain.
      The moderating effect of the ocean on air temperature is also stronger
in winter than in summer. When the surface water  is  cooler  than  the  air
above it – as  frequently happens during the  summer  months  –  the     air
tends to lose its heat to the water. The lowest layers of  air  are  chilled
and become denser by contradiction, and the chilled air tends to  remain  at
low levels. The surface water expands because it is warmed, and  remains  on
the surface of the ocean. Unless the air is turbulent, little of it  can  be
cooled, for little heat is exchanged.
      Opposite conditions apply in winter. The air in winter is likely to be
cooler than the surface water, so that the heat passes from  water  to  air.
Air at low levels is warmed and expands and  rises,  carrying  oceanic  heat
with it, while  the  chilled  surface  water  contracts  and  sinks,  to  be
replaced by unchilled water from below. This convectional  overturning  both
of water and of air leads to a vigorous exchange of heat.
      The prevailing winds in the British Isles  are  westerlies.  They  are
extremely moist, as a result of their long passage over warm waters  of  the
North Atlantic. On their arrival to Britain, the winds are  forced  upwards,
and as a result  large-scale  condensation  takes  place,  clouds  form  and
precipitation follows, especially over the mountainous areas.
      North and north-west winds often bring heavy falls of  snow  to  north
Britain during late October and November, but they are usually  short-lived.
Continental winds from the east sometimes reach the British Isles in  summer
as a warm, dry air-stream, but  they  are  more  frequently  experienced  in
winter when they cross  the  north  sea  and  bring  cold,  continental-type
weather to eastern and inland districts of Great Britain.
      Relief is the most important factor controlling  the  distribution  of
temperature  and  precipitation  within  Britain.  The  actual  temperatures
experienced in the hilly and mountainous parts are considerably  lower  than
those in the lowlands. The effect of relief on precipitation  is  even  more
striking. Average annual rainfall in Britain is  about  1,100  mm.  But  the
geographical distribution of rainfall is largely determined  by  topography.
The mountainous areas of the west and north  have  more  rainfall  than  the
lowlands of the south and east. The western  Scottish  Highlands,  the  Lake
District (the Cumbrian mountains), Welsh uplands and  parts   of  Devon  and
Cornwall in the south-west receive more  than  2,000  mm  of  rainfall  each
year.
      In contrast, the eastern lowlands, lying in a  rain-shadow  area,  are
much drier and usually receive little precipitation.  Much  of  eastern  and
south-eastern England (including London)  receive  less  than  700  mm  each
year, and snow falls on only 15 to 18 days on the average.
      Rainfall is fairly well  distributed  throughout  the  year,  although
March to June are the driest months and October to January are the wettest.
      Ireland is in the rather  a different category,  for  here  the  rain-
bearing winds have not been deprived of their  moisture,  and  much  of  the
Irish plain receives up to 1,200 mm of rainfall per  year,  usually  in  the
form of steady and prolonged drizzle. Snow, on  the  other  hand,  is  rare,
owing to the warming effects of the Gulf Stream. The combined influences  of
the sea and prevailing winds are equally evident in the general  pattern  of
rainfall over the country.
      Because of the North Atlantic Drift  and  predominantly  maritime  air
masses that reach the British Isles from the west, the range in  temperature
throughout the year is never very great.  The  annual  mean  temperature  in
England and Wales is about 10oC , in Scotland  and  Northern  Ireland  about
9oC. July and August are the warmest months of the  year,  and  January  and
February the coldest.
       The mean winter temperature in  the  north  is  3OC,the  mean  summer
temperature 12oC. The corresponding figures for the south are 5oC and  16oC.
The  mean  January  temperature  for  London  is  4oC,  and  the  mean  July
temperature 17oC.
      During a normal summer the temperature  may  occasionally  rise  above
30oC in the south. Minimum temperatures of –10oC may occur on a still  clear
winter’s night in inland areas.
      The distribution of sunshine shows a general decrease  from  south  to
north – the south has much longer periods of sunshine than the north.
      It is frequently said that Great Britain does not experience  climate,
but only weather. This statement suggests that there is  such  a  day-to-day
variation in temperature, rainfall, wind direction, wind speed and  sunshine
that the “average weather  conditions”,  there  is  usually  no  very  great
variation from year  to year or between corresponding seasons  of  different
years.
      No place in Britain is more than 120 km from the sea. But although the
British are crowded very closely in a  very  small  country,  there  is  one
respect in which they are very fortunate. This is  their  climate.  Perhaps,
this is a  surprising  statement  because  almost  everyone  has  heard  how
annoying the weather usually is in England. Because of the  frequent  clouds
and the moisture that hangs in the air even on fairly  clear  days,  England
has less sunshine than most countries, and the sunlight is  weaker  then  in
other places where the air is dry and clear. What is worse, sunshine  rarely
lasts long enough for a person  to  have  time  to  enjoy  it.  The  weather
changes constantly. No ordinary person can guess from  one  day  to  another
which season he  will  find  himself  in  when  he  wakes  in  the  morning.
Moreover, a day in January may be as warm as a warm day in July  and  a  day
in July may be as cold as the coldest in January.
      But although the English weather is more unreliable than  any  weather
in the world, the English climate –  average   weather  –  is  a  good  one.
English winters are seldom very cold and the summers  are  seldom  hot.  Men
ride to work on bicycles  all  through  the  year.  Along  the  south  coast
English gardens even contain occasional palm trees.
      The most remarkable feature of English weather, the London fog, has as
exaggerated reputation. What makes fog thick in big industrial areas is  not
so much the moisture in the air  as the soot from millions  of  coal  fires.
Such smogs (smoke + fog) are not frequent today. Since 1965 as a  result  of
changes in fuel usage and the introduction of clean  air  legislation,  they
have become less severe. It is quite  natural that in  fine,  still  weather
there is occasionally haze in summer and mist and fog in winter.
      The amount of rainfall in Britain is exaggerated, too.  Britain  seems
to have a great deal of rain because there are so many showers. But  usually
very little rain falls at a  time.  Often  the  rain  is  hardly  more  than
floating mist in which you can hardly get wet. Although a period of as  long
as three weeks without rain is exceptional in Britain.
      It is no wonder that, living in such an  unbearable  climate  with  so
many rules and with still more exceptions, the Englishmen talk  about  their
weather, whatever it may be, and their climate, too.



                                       Literature

      1.Baranovski L.S., Kozikis D.D.. How Do  You  Do,  Britain?  –  Moscow
,1997.
 



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