A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

Abstract

Abstract. Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25 % since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems.In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33 %, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50 % increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

Towards an assessment of riverine dissolved organic carbon in surface waters of the western Arctic Ocean based on remote sensing and biogeochemical modeling

“…2). Such a pattern observed for tDOC is also reported for terrigenous particulate organic matter (Doxaran et al, 2015). Further offshore on the Mackenzie Shelf, as delimited by the 300 m isobaths, both remotely sensed and simulated concentrations of tDOC were within the range of values measured in spring (∼ 110-230 mmol C m −3 ; Osburn et al, 2009) and summer (∼ 60-100 mmol C m −3 ; Para et al, 2013).…”

“…After geometric correction, remote sensing reflectance (Rrs(λ)) data at 412, 443, 488, 531, 555, and 667 nm were obtained by applying the atmospheric correction proposed by Wang and Shi (2007) with modifications adapted to Arctic environments (Doxaran et al, 2015;Matsuoka et al, 2016). tDOC concentrations were estimated from the a CDOM (443) data using an empirical relationship between DOC and a CDOM (443) established in the southern Beaufort Sea .…”

Atmospheric Corrections and Multi-Conditional Algorithm for Multi-Sensor Remote Sensing of Suspended Particulate Matter in Low-to-High Turbidity Levels Coastal Waters

“…The combination of several models adapted to each concentration range is the main reason for this result, together with the selection of the best-fitted models. As proved by other studies [35][36][37], the selection of a specific model combining different bands is an improvement when estimating the SPM concentration in coastal waters. Table 8 shows the in situ-satellite match-up results using different SPM models.…”

MODIS-Based Mapping of Secchi Disk Depth Using a Qualitative Algorithm in the Shallow Arabian Gulf

“…Pixels with cloud albedo and AOD_865 larger than the thresholds will be masked. Although relaxation of these criteria was tested by Doxaran et al [68] with careful visual check of the produced results, operational implementation of the approach with quality assured products is impossible. Therefore, regional specific atmospheric correction schemes would be required to improve the accuracy of application of ocean color data over the Gulf region with relatively high loads of airborne dust.…”