<s>
Sunshine	B-Algorithm
duration	I-Algorithm
or	O
sunshine	B-Algorithm
hours	I-Algorithm
is	O
a	O
climatological	O
indicator	O
,	O
measuring	O
duration	O
of	O
sunshine	O
in	O
given	O
period	O
(	O
usually	O
,	O
a	O
day	O
or	O
a	O
year	O
)	O
for	O
a	O
given	O
location	O
on	O
Earth	O
,	O
typically	O
expressed	O
as	O
an	O
averaged	O
value	O
over	O
several	O
years	O
.	O
</s>
<s>
Sunshine	B-Algorithm
duration	I-Algorithm
is	O
usually	O
expressed	O
in	O
hours	O
per	O
year	O
,	O
or	O
in	O
(	O
average	O
)	O
hours	O
per	O
day	O
.	O
</s>
<s>
Another	O
often-used	O
measure	O
is	O
percentage	O
ratio	O
of	O
recorded	O
bright	O
sunshine	B-Algorithm
duration	I-Algorithm
and	O
daylight	O
duration	O
in	O
the	O
observed	O
period	O
.	O
</s>
<s>
An	O
important	O
use	O
of	O
sunshine	B-Algorithm
duration	I-Algorithm
data	O
is	O
to	O
characterize	O
the	O
climate	O
of	O
sites	O
,	O
especially	O
of	O
health	O
resorts	O
.	O
</s>
<s>
Given	O
the	O
theoretical	O
maximum	O
of	O
daytime	O
duration	O
for	O
a	O
given	O
location	O
,	O
there	O
is	O
also	O
a	O
practical	O
consideration	O
at	O
which	O
point	O
the	O
amount	O
of	O
daylight	O
is	O
sufficient	O
to	O
be	O
treated	O
as	O
a	O
"	O
sunshine	B-Algorithm
hour	I-Algorithm
"	O
.	O
</s>
<s>
"	O
Bright	O
"	O
sunshine	B-Algorithm
hours	I-Algorithm
represent	O
the	O
total	O
hours	O
when	O
the	O
sunlight	O
is	O
stronger	O
than	O
a	O
specified	O
threshold	O
,	O
as	O
opposed	O
to	O
just	O
"	O
visible	O
"	O
hours	O
.	O
</s>
<s>
For	O
the	O
specific	O
purpose	O
of	O
sunshine	B-Algorithm
duration	I-Algorithm
recording	O
,	O
Campbell	O
–	O
Stokes	O
recorders	O
are	O
used	O
,	O
which	O
use	O
a	O
spherical	O
glass	O
lens	O
to	O
focus	O
the	O
sun	O
rays	O
on	O
a	O
specially	O
designed	O
tape	O
.	O
</s>
<s>
In	O
2003	O
,	O
the	O
sunshine	B-Algorithm
duration	I-Algorithm
was	O
finally	O
defined	O
as	O
the	O
period	O
during	O
which	O
direct	O
solar	O
irradiance	O
exceeds	O
a	O
threshold	O
value	O
of	O
120W/m2	O
.	O
</s>
<s>
Sunshine	B-Algorithm
duration	I-Algorithm
follows	O
a	O
general	O
geographic	O
pattern	O
:	O
subtropical	O
latitudes	O
(	O
about	O
25°	O
to	O
35°	O
north/south	O
)	O
have	O
the	O
highest	O
sunshine	O
values	O
,	O
because	O
these	O
are	O
the	O
locations	O
of	O
the	O
eastern	O
sides	O
of	O
the	O
subtropical	O
high	O
pressure	O
systems	O
,	O
associated	O
with	O
the	O
large-scale	O
descent	O
of	O
air	O
from	O
the	O
upper-level	O
tropopause	O
.	O
</s>
<s>
Desert	O
regions	O
,	O
with	O
nearly	O
constant	O
high	O
pressure	O
aloft	O
and	O
rare	O
condensation	O
—	O
like	O
North	O
Africa	O
,	O
the	O
Southwestern	O
United	O
States	O
,	O
Western	O
Australia	O
,	O
and	O
the	O
southern	O
Middle	O
East	O
—	O
are	O
examples	O
of	O
hot	O
,	O
sunny	O
,	O
dry	O
climates	O
where	O
sunshine	B-Algorithm
duration	I-Algorithm
values	O
are	O
very	O
high	O
.	O
</s>
<s>
The	O
two	O
major	O
areas	O
with	O
the	O
highest	O
sunshine	B-Algorithm
duration	I-Algorithm
,	O
measured	O
as	O
annual	O
average	O
,	O
are	O
the	O
central	O
and	O
the	O
eastern	O
Sahara	O
Desert	O
—	O
covering	O
vast	O
,	O
mainly	O
desert	O
countries	O
such	O
as	O
Egypt	O
,	O
Sudan	O
,	O
Libya	O
,	O
Chad	O
,	O
and	O
Niger	O
—	O
and	O
the	O
Southwestern	O
United	O
States	O
(	O
Arizona	O
,	O
California	O
,	O
Nevada	O
)	O
.	O
</s>
<s>
In	O
the	O
belt	O
encompassing	O
northern	O
Chad	O
and	O
the	O
Tibesti	O
Mountains	O
,	O
northern	O
Sudan	O
,	O
southern	O
Libya	O
,	O
and	O
Upper	O
Egypt	O
,	O
annual	O
sunshine	B-Algorithm
duration	I-Algorithm
is	O
estimated	O
at	O
over	O
4,000	O
hours	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
smaller	O
,	O
isolated	O
area	O
of	O
sunshine	O
maximum	O
in	O
the	O
heart	O
of	O
the	O
western	O
section	O
of	O
the	O
Sahara	O
Desert	O
around	O
the	O
Eglab	O
Massif	O
and	O
the	O
Erg	O
Chech	O
,	O
along	O
the	O
borders	O
of	O
Algeria	O
,	O
Mauritania	O
,	O
and	O
Mali	B-General_Concept
where	O
the	O
4,000	O
-hour	O
mark	O
is	O
exceeded	O
,	O
too	O
.	O
</s>
<s>
Conversely	O
,	O
higher	O
latitudes	O
(	O
above	O
50°	O
north/south	O
)	O
lying	O
in	O
stormy	O
westerlies	O
have	O
much	O
cloudier	O
and	O
more	O
unstable	O
and	O
rainy	O
weather	O
,	O
and	O
often	O
have	O
the	O
lowest	O
values	O
of	O
sunshine	B-Algorithm
duration	I-Algorithm
annually	O
.	O
</s>
<s>
Temperate	O
oceanic	O
climates	O
like	O
those	O
in	O
northwestern	O
Europe	O
,	O
the	O
northwestern	O
coast	O
of	O
Canada	O
,	O
and	O
areas	O
of	O
New	O
Zealand	O
's	O
South	O
Island	O
are	O
examples	O
of	O
cool	O
,	O
cloudy	O
,	O
wet	O
,	O
humid	O
climates	O
where	O
cloudless	O
sunshine	B-Algorithm
duration	I-Algorithm
values	O
are	O
very	O
low	O
.	O
</s>
<s>
The	O
areas	O
with	O
the	O
lowest	O
sunshine	B-Algorithm
duration	I-Algorithm
annually	O
lie	O
mostly	O
over	O
the	O
polar	O
oceans	O
,	O
as	O
well	O
as	O
parts	O
of	O
northern	O
Europe	O
,	O
southern	O
Alaska	O
,	O
northern	O
Russia	O
,	O
and	O
areas	O
near	O
the	O
Sea	O
of	O
Okhotsk	O
.	O
</s>
<s>
In	O
addition	O
to	O
these	O
oceanic	O
climates	O
,	O
certain	O
low-latitude	O
basins	O
enclosed	O
by	O
mountains	O
,	O
like	O
the	O
Sichuan	O
and	O
Taipei	O
Basins	O
,	O
can	O
have	O
sunshine	B-Algorithm
duration	I-Algorithm
as	O
low	O
as	O
1,000	O
hours	O
per	O
year	O
,	O
as	O
cool	O
air	O
consistently	O
sinks	O
to	O
form	O
fogs	O
that	O
winds	O
cannot	O
dissipate	O
.	O
</s>
<s>
Tórshavn	O
in	O
the	O
Faroe	O
Islands	O
is	O
among	O
the	O
cloudiest	O
places	O
in	O
the	O
world	O
with	O
yearly	O
only	O
840	O
sunshine	B-Algorithm
hours	I-Algorithm
.	O
</s>
<s>
Campbell	O
Island	O
/	O
Motu	O
Ihupuku	O
south	O
of	O
New	O
Zealand	O
is	O
even	O
cloudier	O
,	O
with	O
only	O
647	O
annual	O
sunshine	B-Algorithm
hours	I-Algorithm
,	O
while	O
Bellingshausen	O
Station	O
off	O
the	O
Antarctic	O
Peninsula	O
gets	O
only	O
591	O
annual	O
sunshine	B-Algorithm
hours	I-Algorithm
.	O
</s>
<s>
Also	O
Bear	O
Island	O
(	O
Norway	O
)	O
in	O
the	O
Svalbard	O
Archipelago	O
gets	O
only	O
595	O
annual	O
sunshine	B-Algorithm
hours	I-Algorithm
.	O
</s>
