Spectral albedos and incident spectral irradiances have been measured over the wavelength range 400 to 2400 nm on the sea ice near the Naval Arctic Research Laboratory (NARL) at Pt. Barrow, Alaska. The observation interval extended from mid-May, when the ice was still relatively cold, until mid-June, when summer melting was fully established. The temporal dependence of albedo for the available surface types was obtained over this time interval showing a general decrease from snow and snow-covered ice to blue ice and melt ponds. Data were also obtained for glacier ice on the Athabasca glacier, for melting lake ice, and for certain other nonice surfaces in the vicinity of NARL. Snow and ice albedos are characteristically highest at visible wavlengths, decreasing strongly in the infrared because of the increase in absorption by ice and water. Local maxima in the spectra correspond to minima in the ice and water absorption. Variations in albedo are due primarily to differences in the vapor bubble density, crystal structure, and free water content of the upper layers of the ice. Incident spectral shortwave radiation was measured as a function of cloudiness, and the optical thickness of arctic clouds is significantly less than the thickest clouds at lower latitudes. The decrease of the infrared component relative to the visible portion of the irradiance with increasing cloud cover is determined. This can give rise to an increase in wavelength-integrated albedos of as much as 15%. Using the present data, a graphical method is outlined by which visible near-infrared satellite imagery can be used to distinguish among melt ponds, open leads, and other spring and summer sea ice surface types.