ROMS Monterey Bay

ROMS Monterey Bay

Model Summary

A 1.5 km resolution ROMS model that encompassed Monterey Bay was operational from October 2010 to January 2013. The model was operated by JPL, a CeNCOOS partner intitution. Access and visualization to the data are available through the JPL Monterey Bay ROMS website and our THREDDS catalog. Available data includes sea surface height, water temperature, salinity and currents data from forecasts and nowcasts.

Model Description

ROMS nowcast (also known as analysis) is issued every six hours at 03, 09, 15, and 21 GMT hours. This six-hour block is also known as the data assimilation window, where all the data collected within this six-hour window are assimilated into ROMS using the 3DVAR data assimilation scheme.

Monterey Bay ROMS Real-Time Forecasting

The Monterey Bay (MB) ocean forecasting system is based on the Regional Ocean Modeling System (ROMS). The ROMS configuration consists of three-level nested domains covering the U.S. West coast, central California coast, and Monterey Bay at 15-km, 5-km and 1.6-km, respectively. The atmospheric forcing is derived from the COAMPS atmospheric model. The tidal forcing is specified at the three lateral boundaries of the outer most domain using information from the global tidal model.

Both in situ and satellite measurements that are available in real-time are assimilated into ROMS using the multi-scale 3-dimensional variational (3DVAR) data assimilation scheme. An incremental 3DVAR data assimilation scheme is implemented in ROMS using an assimilation window of six hours. The ROMS nowcast (also known as analysis) is issued every six hours at 03, 09, 15, and 21 GMT hours. The first guess is first obtained from the 6-hour forecast starting from the ROMS nowcast six hours before. During this six-hour data assimilation window, all the available data (e.g., Satellite SST, HF radar surface current, vertical profiles of temperature and salinity from moorings and gliders) are assimilated into ROMS-3DVAR system. The data assimilation produces a data correction term that corresponds to the minimal model and data misfit averaged over the entire model domain. The ROMS nowcast is simply the addition of the first guess and data correction. A 48-hour forecast is issued daily and this forecast run usually takes place overnight.

ROMS 3DVAR Schematic Diagram

The MB ROMS ocean forecasting system was developed during the 2003 AOSN (Autonomous Sampling Ocean Network) and the MB 2006 ASAP (Adaptive Sampling and Prediction) field experiments. The ROMS model configuration was originally developed by the UCLA ROMS group led by Professor Jim McWilliams. This project is jointly funded by NASA and the Office of Naval Research (ONR). Since August 2010, CeNCOOS/IOOS has been funding the transition of this R&D forecasting system to 24/7 operational status.

Peer-Reviewed Publications related to this forecasting system:

  • Chao, Y., Z. Li, J. Farrara, J. C. McWilliams, J. Bellingham, X. Capet, F. Chavez, J.-K. Choi, R. Davis, J. Doyle, D. Frantaoni, P. P. Li, P. Marchesiello, M. A. Moline, J. Paduan, S. Ramp: Development, implementation and evaluation of a data-assimilative ocean forecasting system off the central California coast. Deep-Sea Research II, 56, 100-126, doi:10.1016/j.dsr2.2008.08.011, 2009.
  • Chao, Y., Z. Li, J. D. Farrara, and P. Huang: Blended sea surface temperatures from multiple satellites and in-situ observations for coastal oceans. Journal of Atmospheric and Oceanic Technology, 26 (7), 1435-1446, 10.1175/2009JTECHO592.1, 2009.
  • Wang, X., Y. Chao, C. Dong, J. Farrara, Z. Li, J. C. McWilliams, J. D. Paduan, L. K. Rosenfeld: Modeling tides in Monterey Bay, California. Deep-Sea Research II, 56, 219-231, doi:10.1016/j.dsr2.2008.08.012, 2009.
  • Li, Z., Y. Chao, J.C. McWilliams, and K. Ide: A Three-Dimensional Variational Data Assimilation Scheme for the Regional Ocean Modeling System. Journal of Atmospheric and Oceanic Technology, 25, 2074-2090, 2009.
  • Li, Z., Y. Chao, J. C. McWilliams, and K. Ide: A three-dimensional variational data assimilation scheme for the Regional Ocean Modeling System: Implementation and basic experiments. Journal of Geophysical Research (Oceans), 113, C05002, doi:10.1029/2006JC004042, 2008.
  • Chao, Yi, Zhijin Li, John D. Farrara, Mark A. Moline, Oscar M. E. Schofield, and Sharanya J. Majumdar: Synergistic applications of autonomous underwater vehicles and the regional ocean modeling system in coastal ocean forecasting. Limnology and Oceanography, 53, 2251-2263, 2008.