EKO MS-802 Instruction Manual page 26

APPENDIX
A- 1. Ra diom et ri c Ter ms
Table A-1. Definitions of Terms
Hemispheric Solar Irradiance
Global Solar Irradiance, Global
Horizontal Irradiance (GHI)
Direct Solar Irradiance, Direct
Normal Irradiance (DNI)
Diffused Solar Irradiance, Diffused
Horizontal Irradiance (DHI)
Pyranometer
Pyrheliometer
World Radiation Reference
(WRR)
ISO9060
EKO INSTRUMENTS CO., LTD. - Pyranometers
Cosine-weighted solar irradiance received over a solid angle of
2πsr on a plane surface, expressed in units of W/m
Hemispherical solar irradiance received on a horizontal plane
surface, expressed in units of W/m
Normal-incidence solar irradiance received over a small solid angle
which includes the circum solar irradiance, expressed in units of
2 2
W/m or kW/m .
Hemispherical solar irradiance without the direct solar irradiance,
i.e. indirect irradiance of the scattered solar radiation (by air
molecules, aerosol particles, clouds, etc.), expressed in units of
2 2
W/m or kW/m .
A radiometer designed to measure the hemispheric solar irradiance
over the wavelength range of about 300 to 3,000nm.
A radiometer which measures the direct solar irradiance over a
certain solid angle including the circumsolar irradiance.
Radiometric reference instrument system which has an uncertainty
of less than +/-0.3%, expressed in SI units.
This reference is maintained by the World Meteorological
Organization (WMO), and it has been issued since January 1, 1980
An ISO norm (International Standard). The first edition was
published in 1990, then the second edition was revised in 2018.
Based on the performance of each characteristic, Pyranometer is
classified into three classes A, B, and C, and specifications of
"Spectrally flat radiometer" and "Fast response radiometer" are set
as sub-categories.
Pyrheliometer is classified into 4 classes of AA, A, B and C based
on the performance of each characteristic, and specifications of
"spectrally flat radiometer" and "Fast response radiometer" are set
as sub-categories.
MS-802/802F/402/402F/602
2 2
or kW/m .
2 2
or kW/m .
- Instruction Manual Ver.13
Pg. 25