Framework for Improving Land Boundary Conditions in Ocean Regional Products

Abstract

The coupling of coastal or regional ocean models to hydrological models or observed data is currently an uncommon practice in operational oceanography. Though hydrological models are regarded as a powerful and useful tool for estimating the quantity and quality of freshwater running in a watershed, they fail to provide accurate results for river flow reaching the coastal area due to water-management activities occurring within the river catchment, activities such as human consumption, irrigation, storage, etc. For this reason, many coastal and regional ocean models continue to impose surface zero-salinity discharges as land boundary conditions for representing such a dynamic boundary. Moreover, river flows are based in climatologies, thus neglecting seasonal and interannual variability. To achieve those objectives, this study proposes an integrated methodology ranging from watershed models to validation in the coastal area and passing through methods and proxies for integrating the freshwater flows into regional ocean models. The main objective of this study is to explore the results obtained by using more sophisticated land boundary conditions based on the capacities of state-of-the-art hydrologic models combined with observation networks. In addition to the evaluation of the source of river-flow data, this work also explores the use of estuarine proxies based on simple modelling grids. The estuarine proxies enable the incorporation of the mixing processes that take place in estuaries into the land fluxes and obtain the plume momentum. The watershed, estuarine proxies, and ocean were modelled using the MOHID Water modelling system and evaluated in western Iberia waters. The modelling results served to illustrate the sea surface salinity extension of the Western Iberia Buoyant Plume (WIBP) during an extreme event in March 2018.

Evaluation of SMOS L4 Sea Surface Salinity Product in the Western Iberian Coast

“…The satellite-derived sea surface salinity data used was produced and distributed by the Barcelona Expert Centre (BEC) team through its data visualization and distribution service (http://bec.icm.csic.es/bec-ftp-service/, accessed on 2 July 2021). Specifically, data from version 2 of a level 4 (L4) product that resulted from merging the SMOS salinity data (0.25 • × 0.25 • ) with OSTIA sea surface temperature (0.05 • × 0.05 • ) was used [22,34]. The product has a spatial resolution of 5 km, a temporal resolution of 1 day and full temporal coverage of 9 years, with data available between 2011 and 2019.…”

Ocean Modelling in Support of Operational Ocean and Coastal Services

“…The book "Ocean Modelling in Support of Operational Ocean and Coastal Services" includes eleven contributions [1][2][3][4][5][6][7][8][9][10][11] to this Special Issue published during 2021-2022. The overall objective of this Special Issue is to draw an updated picture of the heterogeneous challenges that are being addressed in operational oceanographic regional and coastal services, gathering novel and cutting-edge techniques and methods to advance the state of the art of forecast and analysis products.…”

“…Finally, with respect to the inclusion of a contribution regarding the river hydrological system, Campuzano et al [11] aim to explore the potential impacts on the ocean system that can be obtained by using sophisticated land boundary conditions based on the capacities of state-of-the-art hydrologic models combined with observation networks. Together with the assessment of the source of river-flow data, this work also explores the use of estuarine proxies based on simple modelling grids.…”