Estimating spectral irradiance from a limited number of discrete bands in the visible / near infrared

1 Corresponding author. Abstract – Accurate measurement and characterisation of fluctuations in the irradiance environment is important in many areas of optical remote sensing. This paper reports a method of estimating spectral irradiance over the VNIR region (400 1100nm) from the radiance of a calibrated reference panel, measured in seven narrow (10nm) spectral bands. The irradiance spectrum was partitioned into a number of distinct regions within each of which the spectral irradiance was estimated from irradiance measured at one of the reference wavelengths. The accuracy of the method was found to be better than ±5% over most wavelengths from 400nm to 1100nm.