<s>
Cloud	B-Application
fraction	I-Application
is	O
the	O
percentage	O
of	O
each	O
pixel	B-Algorithm
in	O
satellite	O
imagery	O
or	O
each	O
gridbox	O
in	O
a	O
weather	O
or	O
climate	B-Application
model	I-Application
that	O
is	O
covered	O
with	O
clouds	O
.	O
</s>
<s>
A	O
cloud	B-Application
fraction	I-Application
of	O
one	O
means	O
the	O
pixel	B-Algorithm
is	O
completely	O
covered	O
with	O
clouds	O
,	O
while	O
a	O
cloud	B-Application
fraction	I-Application
of	O
zero	O
represents	O
a	O
totally	O
cloud	O
free	O
pixel	B-Algorithm
.	O
</s>
<s>
Cloud	B-Application
fraction	I-Application
is	O
important	O
for	O
the	O
modeling	O
of	O
downward	O
radiation	O
.	O
</s>
