ESSO-INCOIS-Indian National Centre for Ocean Information Services

ESSO - Indian National Centre for Ocean Information Services

(An Autonomous Body under the Ministry of Earth Sciences, Govt. of India)
Home Modelling & Research INCOIS-GODAS


The INCOIS-GODAS (Indian National Centre for Ocean Information Services-Global Ocean Data Assimilation System), a modified version of NCEP-GODAS (National Centre for Environmental Prediction-Global Ocean Data Assimilation System), is an Ocean General Circulation Model (OGCM) with assimilation capabilities. The OGCM is Modular Ocean Model-4.0 (MOM-4.0). The assimilation schemes used in INCOIS-GODAS is 3DVAR and Newtonian relaxation (Nudging). The 3DVAR assimilation scheme is used to assimilate observed temperature and salinity profiles, in the top 700m, from observational platforms like Argo, Moored buoys (RAMA, PIRATA/TRITON, TAO, NIOT buoys etc.), and ship-based (XBT, CTD, XCTD, etc.). Using the Newtonian relaxation scheme the model SST is nudged towards satellite blended gridded fields of SST.

Major differences between NCEP-GODAS and INCOIS-GODAS

OGCMModular Ocean Model 3 Modular Ocean Model 4.0
DomainQuasi-Global Global
AssimilationObserved In-situ Temperature and Synthetic Salinity Observed In-Situ Temperature and observed In-situ salinity
T&S profiles for assimilation GTSGTS + NDBP moorings
River Annual Climatology Inter-annual monthly river discharge (derived from datasets provided by Dai et al. 2009 and Papa et al. 2010)
Radiation, momentum, and Freshwater Fluxes Daily averaged NCEP-R2 fluxes on coarse resolution (1.8º X 1.8º near equator) 4 times daily NCMRWF-T574L64 fluxes on high spatial resolution (0.25º X 0.25º)
LATEST ANALYSIS 10-15 day delayed pentadal averaged ocean analysis 1 day delayed daily averaged ocean analysis

Figure Schematic diagram of INCOIS-GODAS

Data Products:

The INCOIS-GODAS runs every day to provide global ocean analysis of temperature, salinity, sea surface height, and currents from the surface to the bottom of the ocean on real time basis (products are available with just 1-day delay). Various tailor made products (ElNino indices, Global maps of monthly SST anomalies, depth-wise distribution of temperature anomalies, TCHP, etc.) are also being made available using these INCOIS-GODAS ocean analysis.Ocean analysis data from INCOIS-GODAS is available for free from 2003 to till date on INCOIS ftp server ( and also on INCOIS Live Access Server ( ; under ocean analysis folder). For data access, users are requested to contact

S Sivareddy, Scientist, INCOIS


In case of utilizing the products of INCOIS-GODAS we ask you to kindly cite the following paper

Sivareddy, S., 2015, A study on global ocean analysis from an ocean data assimilation system and its sensitivity to observations and forcing fields. Ph.D. thesis, Andhra University

Ravichandran, M., D. Behringer, S. Sivareddy, M. Girishkumar, N. Chacko, and R. Harikumar, 2013: Evaluation of the global ocean data assimilation system at INCOIS: The tropical Indian Ocean. Ocean Modelling, 69, 123-135.