Comparative Study on Assimilating Remote Sensing High Frequency Radar Surface Currents at an Atlantic Marine Renewable Energy Test Site

Abstract

A variety of data assimilation approaches have been applied to enhance modelling capability and accuracy using observations from different sources. The algorithms have varying degrees of complexity of implementation, and they improve model results with varying degrees of success. Very little work has been carried out on comparing the implementation of different data assimilation algorithms using High Frequency radar (HFR) data into models of complex inshore waters strongly influenced by both tides and wind dynamics, such as Galway Bay. This research entailed implementing four different data assimilation algorithms: Direct Insertion (DI), Optimal Interpolation (OI), Nudging and indirect data assimilation via correcting model forcing into a three-dimensional hydrodynamic model and carrying out detailed comparisons of model performances. This work will allow researchers to directly compare four of the most common data assimilation algorithms being used in operational coastal hydrodynamics. The suitability of practical data assimilation algorithms for hindcasting and forecasting in shallow coastal waters subjected to alternate wetting and drying using data collected from radars was assessed. Results indicated that a forecasting system of surface currents based on the three-dimensional model EFDC (Environmental Fluid Dynamics Code) and the HFR data using a Nudging or DI algorithm was considered the most appropriate for Galway Bay. The largest averaged Data Assimilation Skill Score (DASS) over the ≥6 h forecasting period from the best model NDA attained 26% and 31% for east-west and north-south surface velocity components respectively. Because of its ease of implementation and its accuracy, this data assimilation system can provide timely and useful information for various practical coastal hindcast and forecast operations.

Seasonal Variation Characteristics Of Winds At The West Coast Of Ireland

“…In this research, we are interested in exploring wind variation characteristics in the domain as shown in Figure 1. Moreover, a 1/4-scale wave energy test site was selected in this area [7]. different periods, the full dataset was divided into four categories: winter (December, 2013-February, 2014), spring (March-May, 2014), Summer (June-August, 2014) and Autumn (September-November, 2014).…”

“…The wind energy resources on the earth are very rich. According to the World Meteorological Organization (WMO), the global wind energies are about 2.79x10 9 MW, and the total amount of wind energy that can be exploited is approximately 2x10 7 MW, which is 10 times larger than the total amount of hydropower that can be exploited and used in the world. In the twentyfirst century, wind energy has been attached more importance to various governments, and the development of wind power technology is accelerating, especially in recent years [1,2].…”

Estimation of Coastal Currents Using a Soft Computing Method: A Case Study in Galway Bay, Ireland

“…Model prediction accuracy over the long term is hard to guarantee. Oceanic observation tools such as satellites and radars based on electro communication technologies are useful means to record surface flow information over a large coastal domain [2]. However, these observation tools cannot provide forecasts.…”