The estimate of cloud attenuation factor for real-time incoming solar radiation by using geostationary satellite data

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Nov 3, 2013 (3 years and 9 months ago)

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The
estimate of cloud attenuation factor for

real
-
time
incoming solar radiation by using
geostationary

satellite

data


Jong
-
Min
Yeom
1
,

Kyung
-
Soo Han
2
,

Y
o
un
-
S
oo Kim
1

and
San
g
-
I
ll

Kim
2


1
Satellite Data Application Department, Satellite Information Research
Institute, Korea
Aerospace Research Institute, 115 Gwahanno [45 Eoeun
-
Dong], Yuseong Daejeon, Korea


2
Department of geoinformatic engineering, Pukyong National University, Daeyeon
-
3
Nam
-
Gu, Busan 608
-
737, Korea

E
-
mail: Kyung
-
soo.han@pknu.ac.kr


The incomin
g solar radiation
provides information on how much solar radiation energy
reaches the Earth’s surface at a specified location during the daytime. The amount of solar
radiation reaching surface is
important variable for surface energy balance system,
determ
ining the amount of reflected radiative energy

to the atmosphere
, agriculture
meteorological system. In this study, we calculate incident solar radiation
from
the
multifunctional transport satellite
-
1 Replacement

(
MTSAT
-
1R
)

data using
physical

model
for

Ch
ollian communication, ocean and meteorological satellite (
COMS
)

operational system
with
simplified
cloud factor.

The use of retrieved incoming solar radiation

data

mainly

depends on
how to accurately parameterize cloud attenuation effects
, which

have large

spatial and
temporal variability
.

W
e present a cloud factor optimized for the modified Kawamura
physical model to calculate attenuated cloud transmittance from

MTSAT
-
1R channel data.
Before the new clo
ud attenuation coefficients
are

determined, a referenc
e data set that agree
s

well with pyranometer measurements
is

selected from all the collocated data sets to determine
the cloud factor. Estimating or measuring real cloud attenuation values impinging on solar
radiation from the top of the atmosphere is gene
rally difficult, as these values depend on
various factors, including the cloud type, the structure of the vertical profile, multiple
scattering among cloud droplets, height, and relative temperature and pressure.
Applying the
new
cloud factor

with dimensi
ons of 8 (10
°

solar zenith angle interval) by 10 (10% cloudy
reflectance interval) result
s

in improved estimated accuracy
.