渤海海冰中太阳辐射的光谱特征观测研究

Spectral features of solar radiation in sea ice of Bohai Sea

通过采用多光谱仪器,对渤海营口港一带的近岸固定冰进行了3个站位11个谱段的入射辐射、反射辐射和透射辐射随时间变化过程的观测和研究。结果表明,发生在海冰中的反射辐射和透射辐射与入射太阳辐射的谱分布有明显差别,而且有显著的日变化。文章确立了入射辐射、反射辐射和透射辐射随时间的变化与太阳高度角的正弦成精确的线性关系,海冰的积分反照率与太阳高度角的正弦满足二次函数关系,可将不同时刻的观测值归算到正午时刻的辐射值,使不同时刻的观测结果具有可比性。计算结果表明,海冰只衰减特定强度的辐射,衰减量与入射辐射光谱分布以及辐射的强度无关,导致绿光的透射辐射最强。该文是对渤海海冰透射辐射的初步尝试,所获得的结果对未来大范围海冰光学观测打下了基础。

Sea ice is a yearly occurred phenomenon in Bohai Sea of China.Optical feature of sea ice is important to the evolution of ice itself.In this study,a multi-spectral instrument system with 11 wavelengths was used to measure the incident,reflected,and transmitted radiations and their daily variations for the costal fast ice in three locations near the Yingkou Harbor,west flank of the Liaodong Peninsula.Although the spectral distribution of arrived solar radiation was a double peaks structure,the reflectance and transmission were discrepant with it.Integrals of incidence,reflectance and transmission radiations are perfectly simulated by linear functions of solar height,and the albedo is simulated by a quadric function of solar height,which can revert the observation values in different time of day to that in noontime and make them comparable.The attenuation feature of sea ice for solar light is quite special that the attenuated radiation by sea ice was independent of the solar radiation intensity and wavelength.As the ice thickness and of components in sea ice changed a little during the experiment,as a shortcoming of this paper,the impact from the thickness and microstructure of sea ice cannot be studied.