Examining the Potential Impact of SWOT Observations in an Ocean Analysis-Forecasting System

AbstractNASA’s Surface Water and Ocean Topography (SWOT) satellite, scheduled for launch in 2020, will provide observations of sea surface height anomaly (SSHA) at a significantly higher spatial resolution than current satellite altimeters. This new observation type is expected to improve the ocean model mesoscale circulation. The potential improvement that SWOT will provide is investigated in this work by way of twin-data assimilation experiments using the Navy Coastal Ocean Model four-dimensional variational data assimilation (NCOM-4DVAR) system in its weak constraint formulation. Simulated SWOT observations are sampled from an ocean model run (referred to as the “nature” run) using an observation-simulator program provided by the SWOT science team. The SWOT simulator provides realistic spatial coverage, resolution, and noise characteristics based on the expected performance of the actual satellite. Twin-data assimilation experiments are run for a two-month period during which simulated observations are...

[1]  H. Ngodock,et al.  A Weak Constraint 4D-Var Assimilation System for the Navy Coastal Ocean Model Using the Representer Method , 2013 .

[2]  Hyun-chul Lee,et al.  Loop Current, Rings and Related Circulation in the Gulf of Mexico: A Review of Numerical Models and Future Challenges , 2013 .

[3]  H. Ngodock,et al.  Background-error correlation model based on the implicit solution of a diffusion equation , 2010 .

[4]  Remko Scharroo,et al.  One- and Two-Dimensional Wind Speed Models for Ka-Band Altimetry , 2014 .

[5]  Robert Atlas,et al.  Rigorous Evaluation of a Fraternal Twin Ocean OSSE System for the Open Gulf of Mexico , 2014 .

[6]  Rainer Bleck,et al.  An oceanic general circulation model framed in hybrid isopycnic-Cartesian coordinates , 2002 .

[7]  J. Smagorinsky,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS , 1963 .

[8]  J. Sheinbaum,et al.  Geostrophy via potential vorticity inversion in the Yucatan Channel , 2001 .

[9]  Operational Altimeter Sea Level Products , 2002 .

[10]  H. Ngodock,et al.  On the direct assimilation of along‐track sea‐surface height observations into a free‐surface ocean model using a weak constraints four‐dimensional variational (4D‐Var) method , 2016 .

[11]  A. Kara,et al.  Validation Test Report for the 1/8 deg Global Navy Coastal Ocean Model Nowcast/Forecast System , 2007 .

[12]  A. Bennett,et al.  Inverse Modeling of the Ocean and Atmosphere , 2002 .

[13]  Andrew F. Bennett,et al.  Inverse Methods in Physical Oceanography: Bibliography , 1992 .

[14]  H. Hurlburt,et al.  Sea Surface Height Predictions from the Global Navy Coastal Ocean Model During 1998-2001 , 2004 .

[15]  Lee-Lueng Fu,et al.  On the Transition from Profile Altimeter to Swath Altimeter for Observing Global Ocean Surface Topography , 2014 .

[16]  H. Ngodock,et al.  Chapter 15 A Weak Constraint 4 D-Var Assimilation System for the Navy Coastal Ocean Model Using the Representer Method , 2013 .

[17]  A. Wallcraft,et al.  Inferring dynamics from the wavenumber spectra of an eddying global ocean model with embedded tides , 2012 .

[18]  Robert R. Leben,et al.  Altimeter‐Derived Loop Current Metrics , 2013 .

[19]  H. Ngodock,et al.  Impact of Assimilating Ocean Velocity Observations Inferred from Lagrangian Drifter Data Using the NCOM-4DVAR , 2014 .

[20]  Ole Martin Smedstad,et al.  Variational Data Assimilation for the Global Ocean , 2013 .

[21]  H. Ngodock,et al.  Impact of Assimilating Surface Velocity Observations on the Model Sea Surface Height Using the NCOM-4DVAR* , 2016 .

[22]  Andrew F. Bennett,et al.  An inverse ocean modeling system , 2001 .

[23]  Helga S. Huntley,et al.  Ocean Current Estimation Using a Multi-Model Ensemble Kalman Filter During the Grand Lagrangian Deployment Experiment (GLAD) , 2015 .

[24]  Caskey,et al.  GENERAL CIRCULATION EXPERIMENTS WITH THE PRIMITIVE EQUATIONS I . THE BASIC EXPERIMENT , 1962 .

[25]  Lee-Lueng Fu,et al.  Dynamic Interpolation of Sea Surface Height and Potential Applications for Future High-Resolution Altimetry Mapping , 2015 .

[26]  G. Forristall,et al.  Velocity and hydrographic structure of two Gulf of Mexico warm‐core rings , 1990 .

[27]  H. Ngodock,et al.  Do Assimilated Drifter Velocities Improve Lagrangian Predictability in an Operational Ocean Model , 2015 .

[28]  Baptiste Mourre,et al.  Contribution of a Wide-Swath Altimeter in a Shelf Seas Assimilation System: Impact of the Satellite Roll Errors , 2008 .

[29]  Gerald Dibarboure,et al.  Using High-Resolution Altimetry to Observe Mesoscale Signals , 2012 .

[30]  H. Sasaki,et al.  SSH Wavenumber Spectra in the North Pacific from a High-Resolution Realistic Simulation , 2012 .

[31]  Paul J. Martin,et al.  Formulation, implementation and examination of vertical coordinate choices in the Global Navy Coastal Ocean Model (NCOM) , 2006 .

[32]  J. Cummings,et al.  Operational multivariate ocean data assimilation , 2005 .

[33]  Lee,et al.  On the Transition from Profile Altimeter to Swath Altimeter for Observing Global Ocean Surface Topography , 2014 .

[34]  G. Mellor,et al.  Development of a turbulence closure model for geophysical fluid problems , 1982 .

[35]  G. Dibarboure,et al.  Do Altimeter Wavenumber Spectra Agree with the Interior or Surface Quasigeostrophic Theory , 2008 .

[36]  P. Courtier,et al.  Correlation modelling on the sphere using a generalized diffusion equation , 2001 .

[37]  H. Ngodock,et al.  A 4DVAR System for the Navy Coastal Ocean Model. Part 1: System Description and Assimilation of Synthetic Observations in Monterey Bay , 2014 .

[38]  Helga S. Huntley,et al.  Data assimilation considerations for improved ocean predictability during the Gulf of Mexico Grand Lagrangian Deployment (GLAD) , 2014 .