Sensitivity analysis of mesoscale simulations to physics parameterizations: a case study of storm Ciara over the Belgian North Sea using WRF-ARW

The Weather, Research and Forecasting (WRF) model includes a multitude of physics parameterizations to account for atmospheric dynamics and interactions such as turbulent fluxes within the planetary boundary layer (PBL), long and short wave radiation, hydrometeor representation in microphysics, cloud ensemble representation in cumulus, amongst others. A sensitivity analysis is conducted in order to identify the optimal WRF-physics set-up and impact of temporal resolution of re-analysis dataset for the event of sudden changes in wind direction that can become challenging for reliable wind energy operations. In this context, Storm Ciara has been selected as a case study to investigate the influence of a broad combination of different interacting physics-schemes on quantities of interest that are relevant for energy yield assessment. Of particular relevance to fast transient weather events, two different temporal resolutions (1-hourly and 3-hourly) of the lateral boundary condition's re-analysis dataset, ERA5, are considered. Physics parameterizations considered in this study include: two PBL schemes (MYNN2.5 and scale-aware Shin Hong PBL), four cumulus schemes (Kain-Fritsch, Grell-Devenyi, and scale-aware Grell-Freitas and multi-scale Kain-Fritsch,) and three microphysics schemes (WSM5, Thompson and Morrison) coupled with two geospatial configurations for WRF simulation domains. The resulting WRF predictions are assessed by comparison to observational RADAR reflectivity data on precipitation. In addition, SCADA data on wind direction and wind speed from an offshore wind farm located in the Belgian North Sea is considered to assess modeling capabilities for local wind behavior at farm level. For precipitation, results are shown to be very sensitive to model setup, but no clear trends can be observed. For wind-related variables on the other hand, results show a definite improvement in accuracy when both scale-aware cumulus and PBL parameterizations are used in combination with 1-hourly temporal resolution reanalysis data and extended domain sizes.

Assessing the impact degree and areal degradation extent of the benthic ecosystem caused by different human activities.

How sustainable are human activities and at what pace do they impact the ecosystem? An ongoing debate urging for uniform assessments. The EU Nature Directives (Marine Strategy Framework, Habitat and Water Framework Directives) provide good bases for scientifically sound assessments. However, they all have different assessment criteria, hampering the objective comparison of the impact degree and the areal extent of degradation caused by human activities. In this study, we applied a harmonized and uniform set of biodiversity indicators, as defined for MSFD-Descriptor 1 with respect to the benthic ecosystem in the Belgian North Sea. We assessed the impact of dredge disposal and aggregate extraction, two activities only allowed in dedicated zones, and compared this to the impact of the more widespread fishery activity. At certain pressure thresholds (e.g. volume disposed, volume and frequency of extraction, number of trawls), all activities caused a decrease in benthic habitat quality. However, for each activity the thresholds and the areal extent of degradation were quite different dependent on the benthic habitat type in which the activity took place. Such detailed insights on pressure footprints are necessary, to allow for an integrated evaluation of the biodiversity status across multiple activities within different marine regions.

Assessing the impact degree and areal degradation extent of the benthic ecosystem caused by different human activities.

How sustainable are human activities and at what pace do they impact the ecosystem? An ongoing debate urging for uniform assessments. The EU Nature Directives (Marine Strategy Framework, Habitat and Water Framework Directives) provide good bases for scientifically sound assessments. However, they all have different assessment criteria, hampering the objective comparison of the impact degree and the areal extent of degradation caused by human activities. In this study, we applied a harmonized and uniform set of biodiversity indicators, as defined for MSFD-Descriptor 1 with respect to the benthic ecosystem in the Belgian North Sea. We assessed the impact of dredge disposal and aggregate extraction, two activities only allowed in dedicated zones, and compared this to the impact of the more widespread fishery activity. At certain pressure thresholds (e.g. volume disposed, volume and frequency of extraction, number of trawls), all activities caused a decrease in benthic habitat quality. However, for each activity the thresholds and the areal extent of degradation were quite different dependent on the benthic habitat type in which the activity took place. Such detailed insights on pressure footprints are necessary, to allow for an integrated evaluation of the biodiversity status across multiple activities within different marine regions.

DEVELOPMENT OF AN EFFICIENT APPROACH OF ARCHAEOLOGICAL HERITAGE IN THE INTERTIDAL ZONE OF THE BELGIAN NORTH SEA

The knowledge of the submerged cultural heritage in the North Sea is rather limited. The Belgian North Sea is being used for a lot of different purposes, such as fishing, aggregate extraction, wind farms, dredging, etc. Due to these increasing economic activities, the underwater archive is in danger. In the context of the UNESCO Convention on the Protection of the Underwater Cultural Heritage of 2001, gathering more information about the submerged cultural heritage in the intertidal zones of the North Sea is one of the main objectives of the Belgian scientific project ‘SeArch’. It will give a clearer picture of the broader cultural and archaeological heritage in the region and it can be used as a basis for a sustainable management by government agencies. The Department of Geography (Ghent University, Belgium) contributes to the SeArch project in two ways. First, an innovative survey methodology has been developed which allows an accurate and cost-efficient evaluation of the archaeological potential in the intertidal zones of the Belgian beaches. Secondly, the Department of Geography is developing an interactive webGIS platform, which makes it possible to share, integrate and visualize the gathered archaeological and environmental data and information in a user-friendly way. Hereby, the total potential of this project is fully exploited in a time-efficient manner. To create an interactive webGIS platform, a good structured spatial database is needed. It enables manipulation of a wide variety of georeferenced information in both raster and vector formats. This paper provides more information about the configuration and application of the spatial database. Moreover, it focusses on the development of a fully functional Spatial Data Infrastructure (SDI) using the most reliable, powerful and state-of-the-art technological components. Besides, a new way of collecting geomatic data in a fast and accurate manner will be discussed. Some processing results will show the possibilities for detecting and visualizing underground structures and archaeological objects.