Summary Cambridge International AS and A Level Geography second edition - arid environments

A R 1 D l T Y IN DE ✗



WAGONER BABBAGE




qq.IE?:: : : : : :. . . .
ratio of average precipitation (D) to
a
potential evapotranspiration (Etp )

water losses due to evaporation i☒%*eµµ :


into account 0.03 Etp
and arid ✗

transpiration Pless than
→
hyper


⑧µ⑧&/④fÉ⑧☒
P between 0.03 and 0.2 ✗
Etp
avid →
0.20 and as ✗ Etp
semiarid -
op between




Ñ⑤§¥gg
could depends the amount of water


¥
occur on " ""

explanation
available soil moisture
-1
which receives less EVAPOTRANSPIRATION ( PE)

yearµjµy
/i. till > E
an area
rainfall per
= POTENTIAL
'
f deficit
extreme -
than zsovum of
6 Im GOD
-1020,8
-

p=o aridity , 12 p E through
'




P greatly exceeds E
-
-



consecutive
between measures the
amount Among hout out the



ye.at/
an area receiving this year throughout the year
51=-1%1 E rainfall annually that soi , PE
the months ago :p

of evapotranspiration
zso -500mm of moisture
← potential
would take place with a limitless
surplus evapotranspiration
less than
1:41 Eli lil :( 1
'
, :
izsmm per year SUPPLY of water
←
ARID SEMI ARID SUB - HUMID HUMID
.
WHEN p =
PE throughout year
↳ index is 0

. When P = 0 throughout year
↳ index is -60 Index -60 -56 -40 -20 0 +100
PE
WHEN greatly exceeds
P
4% 15% 14% percentage of total world land mass
throughout the year
v0 index is 100

so :

⑧-⑥0⑥PAfÑ⑧f⑧W semiarid
Arid is -56
is -40s Im
< I'M s -
< -20

40
arid is
located between 20 -30° Nes Hyper c- SGIM




µgµµÑ§dµµµ¥☒ѵIµ=µ✓Ñ
µ µ ÑJfH
ARID environment are
of the equator )
semiarid are between 's -
• ones


→ west of continents
→ middle / centre of continents ⑧ AID GORAM ⑧ pimentos
→
bring cool dense air that displaces



↳µg
warmer air over the land
their is rain
BAA.AM BAHAMA
→ whilst no .
there
coastal which brings
is fog
some moisture high pressure



µdMy
" "" " "9 air condensation
cooling ,

warms and dries and rainon the

%\ Windward slopes




µµ>µ
B☒BµAfbIMµq µdµpg§


÷÷:µf¥*☒_B¥*¥☒ ÷,←÷i*j
on snore




µ
⑧ÑÑT

mab1et0MJgpemaFB@TTfgfAR1.D
"" "" "" "
yimnds
are

areas prevailing
no
in not arid
many
•
,

land to


*÷*m*☒←¥☒☒¥j÷*
winds are
blowing from
\ trade winds




MM
gea .




carry ante
semi *.
moisture
-




•
. -




COLD NE trade wind from N Africa to . .

Sahara
OCEAN
CURRENT
Atlantic influencing .
Rain shadow prevents moist air
↳
winds
called the Harmattan
µq• from arriving
the air is forced
to rise over mountains



☒k%⑥B¥µ☒AB②F④B§§§
.




CANARIES
( ↳ air cools and condenses forming
current ciouase rain
EG : ATACAMA DESERT ( Andes acts as a




zggµg§hMh&eµtina
barrier stopping SE trade winds

Hf
CALIFORNIAN
current
and Atlantic



arid semiarid
not and
found in the
⑧BABYAK BORKEN BAHMANI
.




FB
deserts are
and subtropics MP ☒ ADA : →



/£t£ CR BUT NBMfTAf BOTH
tropics
BEN " " "
that control
low pressure
€ yaon

?÷%I¥jgµfµJgµ
west cells
CURRENT due to Hadley

Mdgµ
PERUVIAN AUSTRALIAN between the
current the air circulating "
""
deserts are in the middle
many
current
equator and the tropics descending
limbo.
from rain
of continents far away
-




they are on the descending
limb
""
( winds
high pressure 30N
bearing

÷÷!YI¥fyÉ÷¥¥€¥ÉEqg
in
of the Hadley cell high
Desert in Australia
III. t.sk#-----*o
isw
eg simpson
:
Zones .


pressure compression o



WHY IS CAIRO DRY ? no rain

→ locatedaround 30N of the equator
→
descending limb of Hadley cell

-