Coupled Ocean/Wav/Air/Ice Prediction System

Richard Allard, T. Campbell, T. Smith, P. Chu, J. Dykes, J. Veeramony, M. Orzech, and E. Rogers

U.S. Naval Research Laboratory,
Stennis Space Center, MS

CTA: CWO | Resources: IBM iDataPlex [NAVY, MS]; Cray XC30 [NAVY, MS]

DoD Impact/Significance

Coupled air/ocean/wave prediction systems can improve Navy forecasting via ASW performance, tropical cyclone prediction, search and rescue, and mission planning. Relocatable COAMPS-CICE systems to provide high-resolution Arctic forecasting of ice thickness, drift, and concentration for navigation.

Research Objectives

Validation testing of COAMPS, which is six-way coupled with the Navy Coastal Ocean Model (NCOM), Simulating Waves Nearshore (SWAN) model and WaveWatch-III model via the Earth System Modeling Framework (ESMF).

Methodology

Validation testing of the air/ocean/wave system continued in FY15 with three test areas: Madden Julian Oscillation (MJO) part of the DYNAMO/CINDY experiment - October 2011, Trident Warrior 2013 July 1-October 31, 2013 off the Virginia coast, and Hawaii domain. All cases had observational data for atmosphere and ocean (including waves). The six-way coupled system was spun up for 14 days; 48-hour forecasts were generated. Initial/boundary conditions for the ocean/wave components provided by HYCOM and WaveWatch-III. NOGAPS and NAVGEM atmospheric forcing used for COAMPS.

Results

Trident Warrior 2013 validation studies include a 2km NCOM-SWAN nest coupled with a 6km COAMPS atmospheric nest. Models run coupled and atmosphere, wave and ocean only. Model/data comparisons at NDBC wave buoys at Cape Henry, VA and Duck, NC show improvement in wave height, period, and direction; higher correlations and lower RMSE compared to wave-only cases. A 2km regional CICE forecasting system was developed, tested, and implemented to support USCG Healy Arctic operations in summer/fall 2015. Model/data comparisons agree with ice thickness and drift compared to Cold Regions Research Engineering Laboratory (CRREL) Ice Mass Balance Buoys.

Figure/Image Description

Daily averaged COAMPS (NCOM) sections on 18 Dec, 2013 of meridional velocity and salinity show near-surface flow of relative fresh water along the coast of Indian, past Sri Lanka, reaching the equatorial region. Southward flow is balanced by northward subsurface flow of high-salinity foundto the east. Salinity along the 1024 kg/m3 density iso-surface on 24 Dec, 2013 show sharp gradients where relative fresh water can mix with relative high-salinity water.

Daily averaged COAMPS (NCOM) sections on 18 Dec, 2013 of meridional velocity
          and salinity show near-surface flow of relative fresh water along the coast of
          Indian, past Sri Lanka, reaching the equatorial region. Southward flow is balanced
          by northward subsurface flow of high-salinity foundto the east. Salinity along the
          1024 kg/m3 density iso-surface on 24 Dec, 2013 show sharp gradients where relative
          fresh water can mix with relative high-salinity water.