## 1 Introduction  
An interest in ultraviolet (UV) radiation effects on aquatic ecosystems is particularly driven by increased levels of biologically harmful UV radiation (290-400 nm) resulting from the depletion of Earth's ozone layer. A recent review of studies of the UV radiation effects on aquatic ecosystems and interactions with other environmental factors is provided in [PERSON] et al. [1]. One of the important effects of enhanced levels of UV radiation is a reduction in the productivity of phytoplankton, caused by inhibition of photosynthesis due to damage to the photosynthetic apparatus, see, e.g., [2]. This effect is described by the spectral biological weighting functions (BWF), which depend on wavelength, phytoplankton species and environmental factors [3; 4; 5]. Knowledge of UV radiation penetration is important for the evaluation of ecosystem properties, including ecosystem health and primary productivity [1]. Enhanced UV radiation can also affect the photochemical decomposition of dissolved organic matter [6] and the photochemical production of carbonyl sulfide in seawater [7], thereby affecting long-term global biogeochemical cycles. A few models of the UV radiation field in ocean waters have been developed over the past two decades. An essential component of the in-water radiation field model is a model of ocean water-inherent optical properties (IOPs) in the UV region (290 to 400 nm). A simplified version of the IOP model in UV was already used for calculations of underwater UV radiation fields on local and global scales [8; 9]. The IOP model in the UV region was updated [10] and used for radiative transfer (RT) calculations in the ocean with the Hydrolight RT model [11]. With the use of these IOP and RT models, the seasonal variability of the UV radiation field in the ocean was studied [12]. An algorithm for deriving the UV diffuse attenuation coefficient from remote sensing reflectance was proposed [13]. Penetration of UV irradiance into the ocean was studied [14] using empirical diffuse attenuation coefficient relationships derived from in situ measured profiles of IOPs at visible and UV wavelengths. A semianalytical model of the UV diffuse attenuation coefficient based on ocean color remote sensing has been proposed [15]. [PERSON] et al. [16] evaluate several algorithms developed for the diffuse attenuation coefficient in the UV region (specifically 360, 380, and 400 nm), as well as their performance with satellite observations using comparisons with measurements from the open ocean to coastal waters. Algorithms have also been developed to estimate UV and visible underwater light attenuation from satellite hyperspectral observations from the in-water vibrational Raman scattering signal [17; 18; 19]. The authors of [20] explained a need for satellite-retrieving underwater ocean radiation in the UV region globally. They suggest utilizing current satellite hyperspectral missions Aura/OMI and Sentinel-5P/TROPOMI for UV products such as \"spectral fluxes below the surface and diffuse attenuation in the UV (or integrated over UV-A and UV-B ranges), in both photon and energy units\". In recent years, the interest in UV radiation studies has grown in relation to the future Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission scheduled to launch in 2024. The PACE mission includes the hyperspectral Ocean Color Instrument (OCI) that has UV channels down to 340 nm. As compared with other ocean color instruments, the OCI measurements in the UV will help identify phytoplankton composition and quantify the colored dissolved organic matter (CDOM) absorption by discriminating CDOM from other absorbers [21]. A main goal of the current paper is to test our prototype satellite-based algorithms for computing the hyperspectral surface and in-water UV solar radiation being developed for the OCI. For this purpose, we use data from the current Ozone Monitoring Instrument (OMI) flying on the NASA Aura satellite as a proxy for OCI.