A Simple Ocean Data Assimilation Analysis of the Global Upper Ocean 1950–95. Part I: Methodology

Abstract The authors describe a 46-year global retrospective analysis of upper-ocean temperature, salinity, and currents. The analysis is an application of the Simple Ocean Data Assimilation (SODA) package. SODA uses an ocean model based on Geophysical Fluid Dynamics Laboratory MOM2 physics. Assimilated data includes temperature and salinity profiles from the World Ocean Atlas-94 (MBT, XBT, CTD, and station data), as well as additional hydrography, sea surface temperature, and altimeter sea level. After reviewing the basic methodology the authors present experiments to examine the impact of trends in the wind field and model forecast bias (referred to in the engineering literature as “colored noise”). The authors believe these to be the major sources of error in the retrospective analysis. With detrended winds the analysis shows a pattern of warming in the subtropics and cooling in the Tropics and at high latitudes. Model forecast bias results partly from errors in surface forcing and partly from limitati...

[1]  S. Levitus.  Interpentadal variability of salinity in the upper 150 m of the North Atlantic Ocean, 1970–1974 versus 1955–1959 , 1989 .

[2]  A. Bennett.  Inverse Methods in Physical Oceanography , 1992 .

[3]  R. Daley.  Atmospheric Data Analysis , 1991 .

[4]  Anthony Rosati,et al.  Decadal Analysis Produced from an Ocean Data Assimilation System , 1995 .

[5]  James A. Carton,et al.  Impact of altimeter, thermistor, and expendable bathythermograph data on retrospective analyses of the tropical Pacific Ocean , 1996 .

[6]  P. Malanotte‐Rizzoli.  Modern approaches to data assimilation in ocean modeling , 1996 .

[7]  John Derber,et al.  An Ocean Analysis System for Seasonal to Interannual Climate Studies , 1995 .

[8]  C. Wunsch.  The Ocean Circulation Inverse Problem , 1996 .

[9]  T. Joyce,et al.  The Long-Term Hydrographic Record at Bermuda , 1996 .

[10]  S. Gorshkov,et al.  World ocean atlas , 1976 .

[11]  Lawrence L. Takacs,et al.  Data Assimilation Using Incremental Analysis Updates , 1996 .

[12]  J. Carton,et al.  Comparison of retrospective analyses of the global ocean heat content , 1999 .

[13]  H. Jean Thiébaux,et al.  Short‐term systematic errors in global forecasts: their estimation and removal , 1990 .

[14]  R. Newell,et al.  The annual cycle of oceanic heat storage and oceanic meridional heat transport , 1989 .

[15]  James A. Carton,et al.  A Simple Ocean Data Assimilation Analysis of the Global Upper Ocean 1950-95. Part II: Results , 2000 .

[16]  Anthony H. Knap,et al.  Overview of the U.S. JGOFS Bermuda Atlantic Time-series Study and the Hydrostation S program , 1996 .

[17]  N. Smith,et al.  An Improved System for Tropical Ocean Subsurface Temperature Analyses , 1995 .

[18]  R. Daley.  The Lagged Innovation Covariance: A Performance Diagnostic for Atmospheric Data Assimilation , 1992 .

[19]  Thomas M. Smith,et al.  Improved Global Sea Surface Temperature Analyses Using Optimum Interpolation , 1994 .

[20]  D. Hansen,et al.  Evaluation and diagnosis of surface currents in the National Centers for Environmental Prediction's ocean analyses , 1997 .

[21]  Eric C. Hackert,et al.  Data Assimilation Applied to the Temperature and Circulation in the Tropical Atlantic, 1983–84 , 1990 .

[22]  Janet Sprintall,et al.  Space and time scales for optimal interpolation of temperature — Tropical Pacific Ocean , 1991 .

[23]  Calculation of New Depth Equations for Expendable Bathythermographs Using a Temperature-Error-Free Method (Application to Sippican/TSK T-7, T-6 and T-4 XBTS) , 1994 .

[24]  A. Hollingsworth,et al.  The verification of objective analyses: Diagnostics of analysis system performance , 1989 .

[25]  James Churgin.  Proceedings of the Ocean Climate Data Workshop , 1992 .