The Simple Ocean Data Assimilation (SODA) analysis is an oceanic reanalysis data set consisting of gridded

state variable A state variable is one of the set of variables that are used to describe the mathematical "state" of a dynamical system. Intuitively, the state of a system describes enough about the system to determine its future behaviour in the absence of a ...

s for the global ocean, as well as several derived fields. SODA was developed in the 1990s as a collaborative project between the Department of Atmospheric and Oceanic Science at the University of Maryland and the Department of Oceanography at Texas A&M University with the goal of providing an improved estimate of ocean state from those based solely on observations or numerical simulations. Since its first release there have been several updates, the most recent of which extends from 1958-2008, as well as a “beta release” of a long-term reanalysis for 1871-2008.

Initial release

Initially released in 2000, SODA included data from the 1994

World Ocean Atlas The World Ocean Atlas (WOA) is a data product of the Ocean Climate Laboratory of the National Oceanographic Data Center (U.S.). The WOA consists of a climatology of fields of ''in situ'' ocean properties for the World Ocean. It was first produced ...

(WOA-94) such as MBT, XBT, CTD and station data; hydrography, SST, and altimeter measured sea level; as well as data from NODC, NCEP, and

TOGA The toga (, ), a distinctive garment of ancient Rome, was a roughly semicircular cloth, between in length, draped over the shoulders and around the body. It was usually woven from white wool, and was worn over a tunic. In Roman historical tra ...

TAO ''Tao'' or ''Dao'' is the natural order of the universe, whose character one's intuition must discern to realize the potential for individual wisdom, as conceived in the context of East Asian philosophy, East Asian religions, or any other philo ...

. The spatial extend of the first release was more limited than subsequent releases, extending from 62°S to 62°N, and covering the time period from January 1950 through December 1995.Carton, J.A., G. Chepurin, X. Cao, B. Giese, 2000: A Simple Ocean Data Assimilation Analysis of the Global Upper Ocean 1950–95. Part I: Methodology. ''J. Phys. Oceanogr. '', 30, 294–309.

Current release

The latest release of SODA (SODA 2.1.6) covers the time period from January 1958 to December 2008. As part of the

data assimilation Data assimilation is a mathematical discipline that seeks to optimally combine theory (usually in the form of a numerical model) with observations. There may be a number of different goals sought – for example, to determine the optimal state es ...

scheme, the system ingests a wide variety of observations including hydrographic profiles, ocean station data, moored temperature and salinity measurements, surface temperature and salinity observations from a variety of instruments (e.g., MBT, XBT, CTD), sea surface temperature (SST) from nighttime infrared observations from satellites, and satellite based sea level altimetry. Additionally, the numerical model used for forecasts is driven by surface winds from the European Center for Medium-Range Weather Forecasts

ERA-40 The ECMWF reanalysis project is a meteorological reanalysis project carried out by the European Centre for Medium-Range Weather Forecasts (ECMWF). The first reanalysis product, ERA-15, generated reanalyses for approximately 15 years, from December ...

reanalysis data set during the period between 1958-2001,Carton, J.A. and B. Giese, 2008: A Reanalysis of Ocean Climate Using Simple Ocean Data Assimilation (SODA). ''Mon. Weath. Rev. '', 136, 2999-3017. and from the QuickSCAT scatterometer for 2002-2008.Carton, J.A. and B. Giese, 2005: SODA: A Reanalysis of Ocean Climate. nlineAvailable at: ccessed 26 November 2012 The state variable forecasts used in the assimilation are calculated using a general circulation model based on

Parallel Ocean Program The Parallel Ocean Program (POP) is a three-dimensional ocean circulation model designed primarily for studying the ocean climate system. The model is developed and supported primarily by researchers at LANL Los Alamos National Laboratory (oft ...

numerics with an average horizontal resolution of 0.25°x0.4°, and 40 vertical layers, which have 10-meter vertical resolution near the surface. Starting with version 1.4.2, the ocean model is run using a displaced pole grid configuration, allowing for the representation of

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, a ...

processes. The data assimilation method used is based on a sequential analysis with a 10-day update cycle. The reanalysis data is packaged into monthly means from January 1958 to December 2008 (although five-day means are also available) and stored in

NetCDF NetCDF (Network Common Data Form) is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata ...

format. Standard state variables were calculated including temperature, salinity, zonal and meridional velocities, and sea level, as well as several derived fields such as heat content. Finalized data was remapped from the displaced pole grid to a uniform horizontal grid with 0.5°x0.5° horizontal resolution and 40 vertical layers with 10-meter vertical resolution near the surface. In addition to the 61-year reanalysis data set, a “beta” version (i.e., currently being evaluated), SODA 2.2.4, was released in 2010 and extends from 1871 to 2008 with monthly temporal resolution. This extended analysis is identical in horizontal and vertical spatial resolution as the standard reanalysis data set (SODA 2.1.6), and includes similar output variables.IRI Data Library, 2012. ''Carton-Giese SODA SODA 2.2.4, 1871-2008 Assimilation Run''. nlineAvailable at: ccessed 26 November 2012

References

{{reflist

External links

University of Maryland SODA Webpage

SODA Description for CLIVAR

List of SODA experiments

Texas A&M University SODA Webpage

Data access via the IRI Data Library Oceanography

Initial release

Current release

See also

References

External links