West Coast Operational Forecast System
Project Lead: Alex Kurapov, Oregon State University
CO-PIs: Christopher Edwards (UCSC), Yi Chao (Remote Sensing Solutions), Parker MacCready (UW), Andrew Moore (UCSC)
Other Collaborators: Bruce Cornuelle (UCSD), Fei Chai (U Maine)
NOAA-CSDL: Edward Meyers
NOAA-JCSDA: Eric Bayler
NOAA NWS NCEP: Avichal Mehra
NRL: Igor Shulman
Project Overview and Results
Accurate forecasts of oceanic physical and biochemical variables along the US West Coast will provide information in support of safe navigation, environmental hazard response, search and rescue, fishery management, and public health. This project is part of a larger NOAA cross-line office project to develop a new west coast basin wide operational forecast system, the West Coast Ocean Forecast System (WCOFS). The larger project is being coordinated by several offices including CO-OPS, CSDL, NESDIS/STAR, and NCEP. The COMT project is a subset of the larger project brings together researchers involved in coastal ocean modeling, data assimilation, and prediction with the goal to improve existing prediction systems and compare performance of different models and data assimilation approaches. The existing real-time forecast systems, supported by NOAA IOOS regional observing systems, include the OR-WA system (run by OSU/NANOOS), the CA system (run by RSSI/CeNCOOS, SCCOOS), and the regional West Coast system run by UCSC/CeNCCOOS. All three models are based on the Regional Ocean Modeling System (ROMS), which has demonstrated realistic reproduction of ocean variability on temporal scales from a few days to inter-annual along the entire US west coast. The three models being evaluated differ in complexity allowing identification of advantages and limitations of the varying model formulations and assessment of associated rate processes. Approaches to data assimilation in ROMS are being evaluated using new metrics for model and assimilation system skill and have shown that existing observational data are reasonably effective for correcting model representations of circulation associated with the California Current System. Specific system evaluations, comparisons, and improvements include:
(i) Comparisons of forecasts to available in-situ and satellite observations. Inter-model comparisons will be conducted for all three models and then extended to global and regional operational NOAA and Navy forecast products, including Navy HYCOM (Bub) and NOAA NCEP RTOFS (Mehra), as well as regional Navy products.
(ii) Three existing NPZ-type biogeochemical models (already integrated in ROMS), including the 6-component NPZDO (Banas; Banas et al., 2009), the 11-component NEMURO (Edwards, Moore; Kishi et al. 2007), and the 31-component CoSiNe (Chai et al., 2002; Dugdale et al., 2002) will be compared to each other and to available data, using the COMT testbed tools. The practicality of developing a unified biogeochemical model across all three regions and a multi-model ensemble will be evaluated.
(iii) Effects of different boundary conditions (climatology, Navy HYCOM, RTOFS) on accuracy of coastal ocean forecasts (CA and OR-WA) will be evaluated.
(iv) The OR-WA 4DVAR system will be tested with a new (ensemble-based) model error covariance suitable for anisotropic ocean conditions in the presence of the Columbia River (Kurapov).
(v) The Ensemble Kalman Filter assimilation method will be implemented into the CA model and results will be compared to 3DVAR (Cornuelle).
(vi) Observing system simulation experiments (OSSE) will be performed for the regional UCSC model using observation sensitivity and observation impact tools developed for ROMS (Moore).
Additional detail on the methodology and results of this project are available from the 2016 COMT Annual Meeting: West Coast Operational Forecast System Report; the 2016 COMT Annual Meeting: West Coast California Current Obs System Report, the 2016 COMT Annual Meeting: West Coast BioPhysical Report, and the 2016 Semi-Annual Report.
Regional West Coast