Assessment of Skill for Coastal Ocean Transients
ASCOT-01
Massachusetts Bay / Gulf of Maine
June 2001
An Experiment for Ocean Coastal Prediction and
NATO Rapid Environmental Assessment Skills Evaluation
NATO NRV Alliance
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A.R. Robinson, J. Sellschopp, |
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Participating Institutions
Harvard University
SACLANT Undersea Research Centre
University of Massachusetts - Boston
University of Massachusetts - Dartmouth
1. Introduction
Coastal Predictive Skill Experimentation (CPSE) measures the ability of a forecast system to combine model results and observations in coastal domains or regimes and to accurately define the present state and predict the future state. Rapid Environmental Assessment (REA) is defined in the military environment as "the acquisition, compilation and release of tactically relevant environmental information in a tactically relevant time frame". Ocean forecasting is essential for effective and efficient REA operations. A REA CPSE must be designed to determine forecast skill on the basis of minimal and covertly attainable observations and thus may be most efficiently carried out in the context of the definitive over-sampling provided by a CPSE.
Environmental observations are a necessity for initialization and updating of ocean forecasts. Numerical ocean forecast capabilities in general consist of observational networks, data assimilation schemes and dynamic forecast models. Since observations are the most expensive part of the forecast and are often difficult to achieve, methods that would reduce the requirements are highly desirable. Knowledge of features, structures and the dynamics which evolves them is necessary for successful forecasting. Adaptive sampling of the observations of greatest impact increases efficiency and can drastically reduce the observational requirements, i.e. by one or two orders of magnitude. This project will develop methodology for ocean forecasting using minimum input.
The Assessment of Skill for Coastal Ocean Transients (ASCOT) project is a series of real-time CPSE/REA experiments and simulations focused on quantitative skill evaluation and cost-effective forecast system development. ASCOT-01, being carried out in Massachusetts Bay/Gulf of Maine in June 2001, is the first such experiment.
2. Goals and Objectives
ASCOT Overall Goal: to enhance the efficiency, improve the accuracy and extend the scope of nowcasting and forecasting of oceanic fields for Coastal Predictive Skill Experimentation and for Rapid Environmental Assessment in the coastal ocean and to quantify such CPSE and REA capabilities.
ASCOT General Objectives:
ASCOT-01 Objectives:
REA requires multiscale capabilities for different kinds of warfare (e.g. anti-submarine (ASW), mine warfare (MW), etc.). An experiment which is to assess the predictive skill of a forecast system must therefore measure and evaluate on multiple scales. Knowledge of the multiscale dynamics is essential. For ASCOT-01, the coupling extends from Massachusetts Bay, through the Gulf of Maine, out to the northwest Atlantic. Skill metrics will be designed to take the coupling of scales into account. All coastal regions require both generic and regional-specific metrics for the dominant variabilities. For example, upwelling is a generic process, however, the location and time of occurrence of upwelling is specific to the region.
As a predictive skill experiment, ASCOT-01 will include oversampling, in order that sources of error can be tracked. During the verification survey a significant fraction of the initialization survey will be repeated. Adaptive sampling survey patterns will be designed to address: 1) the interactions of Massachusetts Bay and the Gulf of Maine (inflow updates, exchanges, etc.); 2) response to storms or air-sea exchanges (upwelling, structures of currents and gyres, bifurcation structures in the Gulf of Maine, etc.); coupling of wind-response and buoyancy currents; reduction of multi-variate forecast errors; and, update of information for feature model parameters. Such scenarios will be designed in advance through OSSEs.
Nowcast and Forecast Products | Massachusetts Bay | Gulf of Maine | |
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Physics | Biology | Physics |
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The real-time analyses and forecasts are being produced by the Harvard Ocean Prediction System under the guidance of Prof. Allan R. Robinson. The forecasts of physics are being carried out at sea on the NRV Alliance by Dr. Patrick J. Haley, Jr. The forecasts of biology are being carried out at Harvard University by Dr. Pierre F.J. Lermusiaux. Data processing, analysis and web pages are the responsibility of Wayne G. Leslie