Martin Holt

Can Saltwater Toxicity be Predicted from Freshwater Data

The regulation of substances discharged to estuarine and coastal environments relies upon data derived from ecotoxicity tests. Most such data are generated for freshwater rather than saltwater species. If freshwater toxicity data are related to saltwater toxic effects in a systematic and predictable way, the former can be used to predict the latter. This would have economic advantages due to a reduction in toxicity testing of saltwater species. If toxicity data are plotted as species sensitivity distributions, four theoretical relationships between freshwater and saltwater can be envisaged. Examples show that each one of these relationships is supported by empirical data. These examples show that although there is considerable potential for freshwater to saltwater prediction, species parity and representativeness need to be examined for each chemical substance to avoid bias.

Operational Wave, Current, and Wind Measurements With the Pisces HF Radar

This paper presents results of a trial of a Pisces HF radar system aimed at assessing its use as a component of a wave-monitoring network being installed around the coasts of England and Wales. The radar system has been operating since December 2003 and the trial continued to June 2005. The data have been processed in near-real time and displayed on a website. Radar measurements of the directional spectrum and derived parameters are compared with those measured with a directional waverider and with products from the Met Office, United Kingdom, operational wave model. Radar measurements of currents and winds are also compared with Met Office model products and, in the case of winds, with the QuikSCAT scatterometer. Statistics on data availability and accuracy are presented. The results demonstrate that useful availability and accuracy in wave and wind parameters are obtained above a waveheight threshold of 2 m and at ranges up to 120 km at the radar operating frequencies (7-10 MHz) used. Waveheight measurements above about 1 m can be made with reasonable accuracy (e.g., mean difference of 2.5% during January-February 2004). Period and direction parameters in low seas are often contaminated by noise in the radar signal. The comparisons provide some evidence of wave model limitations in offshore wind and swell conditions

Mode of action and aquatic exposure thresholds of no concern

Threshold concepts of toxicological concern are based on the possibility of establishing an exposure threshold value for chemicals below which no significant risk is to be expected. The objective of the present study is to address environmental thresholds of no toxicological concern for freshwater systems (ETNCaq) for organic chemicals. We analyzed environmental toxicological databases (acute and chronic endpoints) and substance hazard assessments. Lowest numbers and 95th-percentile values were derived using data stratification based on mode of action (MOA; 1 = inert chemicals; 2 = less inert chemicals; 3 = reactive chemicals; 4 = specifically acting chemicals). The ETNCaq values were derived by multiplying the lowest 95th percentile values with appropriate application factors; ETNCaq,MOA1-3 is approximately 0.1 microg/L. A preliminary analysis with complete MOA stratification of the databases shows that in the case of MOA1 or MOA2, the ETNCaq value could be even higher than 0.1 microg/L. A significantly lower ETNCaq,MOA4 value was observed based on the long-term toxicity information in the European Centre for the Ecotoxicology and Toxicology of Chemicals database. Application of the ETNCaq value in a tiered risk-assessment scheme may help chemical producers to set data-generation priorities and to refine or reduce animal use. It also may help to inform downstream users concerning the relative risk associated with their specific uses and be of value in putting environmental monitoring data into a risk-assessment perspective.

Real-time forecast modelling for the NW European Shelf Seas

Abstract The UK Met Office is preparing a baroclinic model of the NW European continental shelf seas for operational implementation. For the Met Office, Proudman Oceanographic Laboratory have implemented their model on the 1/9 by 1/6 degree grid of the storm surge model. The model predicts the synoptic scale evolution of elevation, temperature, salinity and current profiles, over the continental shelf and shelf break. The model now runs in near-real time, having been spun up from March 1998. It is driven at the surface by hourly winds and pressures, and 6-hourly heat fluxes from the Met Office global weather prediction model, and at open ocean boundaries with tidal harmonics. Verification shows that the model represents well the evolution of SST in the North Sea. Over the Dogger Bank during a short period in May 1998, with neap tides, low winds, and strong surface heating, the model became stratified. As conditions changed the waters over Dogger Bank became well mixed again, but warmer than the week before. Developments include taking boundary data from the Met Office Forecast Ocean Atmosphere Model (FOAM), and surface fluxes from the Met Office mesoscale NWP model.

Towards NOOS—the eurogoos nw shelf task team 1996–2002

Abstract EuroGOOS initiated the NW European Shelf Seas Task Team in 1996. With members from operational agencies around the NW shelf the team set about an initial inventory of models and observations, and project proposals were formulated for MAST III and later FP5. In 1998 the EC-funded concerted action ESODAE (European Shelf Seas Ocean Data Assimilation Experiment) was initiated. During 2000–2001 a strategic plan for the NW Shelf Operational Oceanographic System was drafted and published, and the NOOS memorandum of understanding was finalised. In 2002, with eight agencies signed up to the MoU, NOOS was established at a meeting held at RIKZ. This paper gives an overview of the activities of the task team and the plans for NOOS.

Performance of the PISCES HF radar during the DEFRA trials

Abstract HF radar is being considered as a potential instrument for the UK Department for Environment, Food & Rural Affairs (DEFRA) wave monitoring network, WAVENET. A six month trial of the Pisces HF radar was commissioned for the period November 2001 to May 2002. This paper discusses the results of this trial in terms of radar performance, oceanographic parameter availability and comparisons with the Met Office wave model products. The trial confirmed the need for a dual-radar configuration for accurate wave measurements.

Meeting the challenge: Real-time sea-state forecast modelling for the atlantic at the met office

Abstract To predict the detailed sea state in the North Atlantic, the UK Met Office runs a suite of numerical wave models. The global wave model runs twice daily, forecasting to 5 days ahead, driven by surface winds from the Met Office global weather prediction model. Each run starts with a 12-hour analysis, assimilating radar altimeter wave heights from ERS-2. In addition to forecasts of wave height and period, the full model wave energy spectrum can be applied to predict the heave of a rig. Observations of waves from the synthetic aperture radar on ERS-2 require processing to provide a wave energy spectrum. Algorithms developed by MPI(Hamburg) are routinely applied at the Met Office to retrieve wave energy spectra over the N Atlantic. For detailed forecasts in coastal waters a nested wave model is run, covering the NW European shelf, Baltic, Mediterranean and Black Sea. A high resolution model for UK waters is being developed.

Real-time ocean forecast modelling for the Global Ocean and the Atlantic

Abstract The circulation of the Atlantic poses a challenge to prediction on all time scales, from changes in the surface mixed layer depth over several days, to SST anomalies influencing seasonal weather prediction, with variations over decades. To analyse and predict the state of the ocean the UK Met Office has developed the Forecast Ocean Atmosphere Model (FOAM). At the heart of FOAM is an ocean circulation model, of the same basic formulation as that used by the Hadley Centre at the UK Met Office to predict climate change. Global FOAM runs on a one-degree grid, with twenty levels, ten of which are in the top 300m. A sea-ice model and surface mixed layer scheme are also included. FOAM runs once a day, driven by surface fluxes from the global prediction model. A 24-hour analysis, assimilating temperature profiles and SST observations, is followed by a 5-day forecast. Verification shows that FOAM improves on climatology, down to 300m depth. Examples will be presented from FOAM, and from nested high resolution. Atlantic models, currently being developed. The data assimilation component of FOAM is being applied for seasonal and decadal prediction studies, examples from which will also be presented.