<s>
The	O
Angstrom	B-Algorithm
exponent	I-Algorithm
or	O
Ångström	B-Algorithm
exponent	I-Algorithm
is	O
a	O
parameter	O
that	O
describes	O
how	O
the	O
optical	O
thickness	O
of	O
an	O
aerosol	O
typically	O
depends	O
on	O
the	O
wavelength	O
of	O
the	O
light	O
.	O
</s>
<s>
The	O
parameter	O
is	O
the	O
Angstrom	B-Algorithm
exponent	I-Algorithm
of	O
the	O
aerosol	O
.	O
</s>
<s>
The	O
Angstrom	B-Algorithm
exponent	I-Algorithm
is	O
inversely	O
related	O
to	O
the	O
average	O
size	O
of	O
the	O
particles	O
in	O
the	O
aerosol	O
:	O
the	O
smaller	O
the	O
particles	O
,	O
the	O
larger	O
the	O
exponent	O
.	O
</s>
<s>
For	O
example	O
,	O
cloud	O
droplets	O
are	O
usually	O
large	O
,	O
and	O
thus	O
clouds	O
have	O
very	O
small	O
Angstrom	B-Algorithm
exponent	I-Algorithm
(	O
nearly	O
zero	O
)	O
,	O
and	O
the	O
optical	O
depth	O
does	O
not	O
change	O
with	O
wavelength	O
.	O
</s>
<s>
In	O
principle	O
,	O
if	O
the	O
optical	O
thickness	O
at	O
one	O
wavelength	O
and	O
the	O
Angstrom	B-Algorithm
exponent	I-Algorithm
are	O
known	O
,	O
the	O
optical	O
thickness	O
can	O
be	O
computed	O
at	O
a	O
different	O
wavelength	O
.	O
</s>
<s>
In	O
practice	O
,	O
measurements	O
are	O
made	O
of	O
the	O
optical	O
thickness	O
of	O
an	O
aerosol	O
layer	O
at	O
two	O
different	O
wavelengths	O
,	O
and	O
the	O
Angstrom	B-Algorithm
exponent	I-Algorithm
is	O
estimated	O
from	O
these	O
measurements	O
using	O
this	O
formula	O
.	O
</s>
<s>
The	O
Angstrom	B-Algorithm
exponent	I-Algorithm
is	O
now	O
routinely	O
estimated	O
by	O
analyzing	O
radiation	O
measurements	O
acquired	O
on	O
Earth	O
Observation	O
platforms	O
,	O
such	O
as	O
AErosol	O
RObotic	O
NETwork	O
,	O
or	O
AERONET	O
.	O
</s>
