ADEOS-I OCTS Level-3 Global Binned Inherent Optical Properties (IOP) Data, version 2022.0

The Inherent Optical Properties (IOP) suite provides per-pixel inherent optical properties - quantities that describe how seawater and its constituents absorb and scatter light, independent of illumination or viewing geometry. IOPs are retrieved from spectral Remote Sensing Reflectance (Rrs) using the default configuration of the Generalized Inherent Optical Properties (GIOP) model framework. These products support water-type classification, water-clarity assessment, biogeochemical studies, and forward/adjoint radiative-transfer applications, and they enable more robust cross-sensor comparisons than purely apparent (AOP) products.

Geophysical variables in this suite include:
- a — Total absorption coefficient (sum of pure water + phytoplankton + CDOM/detritus, m⁻¹)
- bb — Total backscattering coefficient (m⁻¹)

- aph_443 — Phytoplankton absorption coefficient at 443 nm (m⁻¹)
- aph_unc_443 — Uncertainty in absorption due to phytoplankton at 443 nm (m⁻¹)
- adg_443 — Combined CDOM + non-algal detritus absorption coefficient at 443nm; accompanied by adg_s (spectral slope, units nm⁻¹).
- adg_unc_443 — Uncertainty in absorption due to gelbstoff and detrital material at 443 nm (m⁻¹).
- bbp_443 — Particulate backscattering coefficient at 443nm (m⁻¹); include bbp_s (power-law slope, unitless) describing spectral shape.
- bbp_unc_443 — Uncertainty in particulate backscattering at 443 nm (m⁻¹).
- rrsdiff — Fractional mean Rrs difference.

固有光学特性（Inherent Optical Properties, IOP）数据集套件提供逐像素的固有光学特性——即描述海水及其组分如何吸收和散射光线、且与光照或观测几何无关的物理量。固有光学特性（IOP）通过广义固有光学特性（Generalized Inherent Optical Properties, GIOP）模型框架的默认配置，从光谱遥感反射率（Remote Sensing Reflectance, Rrs）中反演得到。此类产品可支持水体类型分类、水体透明度评估、生物地球化学研究以及正演/伴随辐射传输应用，相较于纯表观光学特性（Apparent Optical Properties, AOP）产品，能够实现更可靠的跨传感器对比。

该套件包含的地球物理变量如下：
- a：总吸收系数（纯水+浮游植物+有色可溶性有机物（CDOM）/碎屑之和，单位：m⁻¹）
- bb：总后向散射系数（单位：m⁻¹）
- aph_443：443 nm处的浮游植物吸收系数（单位：m⁻¹）
- aph_unc_443：443 nm处由浮游植物导致的吸收不确定性（单位：m⁻¹）
- adg_443：443 nm处有色可溶性有机物与非藻类碎屑的综合吸收系数；附带参数adg_s（光谱斜率，单位：nm⁻¹）。
- adg_unc_443：443 nm处由黄色物质（gelbstoff）与碎屑物质导致的吸收不确定性（单位：m⁻¹）。
- bbp_443：443 nm处的颗粒后向散射系数（单位：m⁻¹）；包含描述光谱形状的幂律斜率参数bbp_s（无单位）。
- bbp_unc_443：443 nm处的颗粒后向散射不确定性（单位：m⁻¹）。
- rrsdiff：遥感反射率平均相对偏差。