Level-4 satellite-derived aCDOM(443) and DOC concentrations in the Mackenzie River-Beaufort Sea region (V.1.0) [Dataset]

Level-3 daily merged Copernicus-GlobColour multi-sensor Remote Sensing Reflectance (Rrs(λ)) from the Copernicus Marine Environmental Monitoring Service (CMEMS) is used as data source. The aCDOM(443) was estimated using the gsmA parametrizations for the southern Beaufort Sea (Matsuoka et al., 2013) with some modifications; while DOC was retrieved using an empirical aCDOM(443)-DOC relationship developed by Juhls et al. (2022), valid across the fluvial-marine transition zone of the Mackenzie River–Beaufort Sea region

Level-4 daily maps of aCDOM(443) and DOC for the Mackenzie River-Beaufort Sea region (122-142ºW and 68-73ºN) are distributed in the regular latitude–longitude grid at a spatial resolution of 4 km. The data is available from 1st January 2002 to 31st October 2023. Additionally, 8-day means, and monthly mean data are also provided. The dataset consists of four variables: (i) Chromophoric Dissolved Organic Matter at 443 nm (aCDOM(443) [m-1]) (ii) Dissolved Organic Carbon (DOC [µM]) (iii) water type mask (coastal/oceanic) (iv) model relative error for Rrs(443) (∆Rrs(443) [%]) (v) aCDOM(443) uncertainty (σaCDOM [m-1]) (vi) DOC uncertainty (σDOC [µM])

YYYYMMDD_aCDOM443_DOC_l4_4km_P1D.nc (This dataset contains daily Level-4 aCDOM and DOC product from satellite observations for the Mackenzie River-Beaufort Sea region) YYYYMMDD_YYYYMMDD_aCDOM443_DOC_l4_4km_P8D.nc (This dataset contains daily Level-4 aCDOM and DOC product from satellite observations for the Mackenzie River-Beaufort Sea region) YYYYMMDD_YYYYMMDD_aCDOM443_DOC_l4_4km_P1M.nc (This dataset contains monthly Level-4 aCDOM and DOC product from satellite observations for the Mackenzie River-Beaufort Sea region)

In the regime-shifting Arctic, organic carbon export from river watersheds is expected to increase due to changes in hydrological regimes and permafrost thawing. Given the impact these changes have on the biogeochemical cycles of coastal and shelf areas, robust monitoring of major Arctic rivers is needed. During ice-free season, ocean color remote sensing has shown to be an effective monitoring tool for remote, under-sampled areas with limited access such as the Beaufort Sea region. It offers synoptic spatio-temporal coverage, filling in the gaps among the scarce in situ data and improving our knowledge of land-to-ocean transport pathways and coastal ocean dynamics near riverine zones. Remote sensing of Chromophoric Dissolved Organic Matter (CDOM) and Dissolved Organic Carbon (DOC) has proven to be a valuable approach for assessing variations in terrestrial carbon export. However, seasonal fluctuations and diverse vegetation and soil conditions of each river watershed make it difficult to establish a single retrieval method for the entire Arctic. This complexity has led to a development of several regional algorithms, yet accessible long-term series remain a challenge. We present the first long-term satellite-derived dataset quantifying the absorption coefficient of CDOM at 443 nm and DOC concentrations in the Mackenzie River–Beaufort Sea region (122–142ºW and 68–73ºN) from 1st January 1998 to 31st October 2023. We employed a modified version of the GIOP (Generalized Inherent Optical Properties) algorithm to retrieve CDOM(443) for the southern Beaufort Sea; DOC was then derived using a region-specific relationship between aCDOM(443) and DOC. The product has been validated using in situ observations from several field campaigns conducted in the area. We provide a consistent dataset that can be used to assess DOM spatial and temporal variability, trends, and export to the coastal seas

This work has been carried out as part of the ARCTIC-MON project (Advances in monitoring sea ice thickness and snow depth, ocean dynamics, and freshwater content in the Arctic using remote sensing data), funded through the Consejo Superior de Investigaciones Científicas (CSIC) (grant no. PID2021-125324OB-I00)

With the institutional support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S)

Level-4 daily maps of aCDOM(443) and DOC for the Mackenzie River-Beaufort Sea region (122-142ºW and 68-73ºN) are distributed in the regular latitude–longitude grid at a spatial resolution of 4 km. The data is available from 1st January 2002 to 31st October 2023. Additionally, 8-day means, and monthly mean data are also provided. The dataset consists of four variables: (i) Chromophoric Dissolved Organic Matter at 443 nm (aCDOM(443) [m-1]) (ii) Dissolved Organic Carbon (DOC [µM]) (iii) water type mask (coastal/oceanic) (iv) model relative error for Rrs(443) (∆Rrs(443) [%]) (v) aCDOM(443) uncertainty (σaCDOM [m-1]) (vi) DOC uncertainty (σDOC [µM])

Peer reviewed