Atmospheric Radiation Measurement Climate Research Facility US Department of Energy



ISDAC - Second Year Supplemental Surface Spectral Irradiance Measurements

7 April 2009 - 13 October 2009

Lead Scientist: Dan Lubin

Observatory: NSA

An ASD spectroradiometer was deployed, to make spectral measurements of downwelling shortwave irradiance in the wavelength range 350-2200 nm. This wavelength range encompasses most of the sun's energy, and the infrared portion contains information about cloud microphysical properties, such as optical depth, cloud phase, effective particle size. Scientifically, it was interesting to document how cloud phase transitions influence the surface shortwave radiation budget through spring and summer, and into autumn. Such phase transitions are identifiable immediately in the spectral signature of the surface irradiance in the 1.6 and 2.2 micron windows. For ARM researchers, the final product was a set of radiometrically calibrated irradiance spectra, recorded at 1-minute intervals throughout the daylight period.