海洋光学中的优美代数表达:■as的两流模型

Beauty of Math in Ocean Optics:Two-Stream Equations of■as

太阳辐射(光)能够穿透水体,照耀水体的上层,驱动浮游植物的光合作用和加热水体。同时,水中物质对光的散射导致一部分光逃离水体并进入大气层,从而成为从卫星高度反演水中物质的含量、成分的信息源。因此,理解、刻画光在水中的传播形式以及其与水中物质的关系是海洋光学和水色遥感的最基础的要求和课题。光的空间变化由辐射传递方程决定,但该方程不能够直接用于遥感反演,也不能够直接表达表观光学量与固有光学量之间的关系。通过简单的数学推导,■as将辐射传递方程转换成一个优美的两流模式来描述上行和下行辐照度随深度的变化形式,并进一步推导出表观光学量与固有光学量之间的解析关系。该模型给出了海洋光学中最基本的关系式,为水色遥感的半解析算法的研发奠定了基础。

Solar radiation in the visible domain can penetrate aquatic environment,which drives photon-related processes including phytoplankton photosynthesis and heating of the upper water column.In addition,the scattered light in the water column can emerge(escape)from water,which forms the bases to sense properties in aquatic environments using sensors onboard satellites.Thus,an understanding of the processes and properties related to the propagation of solar radiation in-and-out of water is a basic requirement in ocean optics and ocean color remote sensing.The spatial(and spectral for inelastic scattering)variation of radiance is governed by the radiative transfer equation,which is not directly applicable to infer in-water optical properties or to describe the relationships between the optical properties measured in the field and inherent optical properties related to environmental properties.Through simple mathematical derivations,or manipulations,of the radiative transfer equation(RTE),■as transferred the RTE into a set of two equations describing the change of upwelling and downwelling irradiance with depth,and further obtained concise analytical relationships between the apparent and inherent optical properties.These equations not only form the basic theoretical relationships in ocean optics,but also lay the foundation of semianalytical algorithms in ocean color remote sensing.