BasedontheopticaldatafortransmittedradiationthroughseaiceintheArcticduringthelateautumnandearlywinterof2007,theauthorsstudiedthearrivingsolarradiation,reflectedradiationandtransmittedradiationunderverylowsolaraltitude.Throughtheatmosphere,thelightofthearrivingsolarradiationatshortwavelengthwasweakened,withthespectraldistributionofdoublepeakscenteredat490nmand683nm.Themagnitudeofthepeakat683nmevenexceededthatat490nmundertheverylowsolarradiationcondition.Thereflectionwaslowerthanthatinsummertimebecauseofthethinthicknessesoficeandsnow,allowinghigherratioofheattoentertheseaiceandsnow.Whenhigherratioofsolarradiationenteredseaiceinlateautumn,thenewicefreezingwouldbeaffected.Thespectralreflectivityfromsnowsurfacewasalmostaconstant,butthereflectionwithoutsnowde-creasedatlongerwavelengths.Inthetransmissionspectrum,thelightof490nmwasdominant.Itindicatesthattheradiationatlongerwavelengthwasweakenedbyseaice.Therefore,undertheconditionoflowsolaraltitude,theradiationatshorterwavelengthwasweakenedbytheatmospherewhiletheradiationatlongerwavelengthwasweakenedbytheseaice.Thecombinedeffectofat-mosphereandseaicemadethesolarradiationunderseaicemuchweaker.Theabsorptionofseaiceforthelonger-wavelengthradiationallowedtheseaicetogainmoreheattoslowdownthefreezingprocess.
