Relaxation Method for Assimilation of Sea Ice Concentration Data in the NEMO—LIM3 Multicategory Sea Ice Model

Russian Meteorology and Hydrology - A method for the assimilation of data on sea ice concentration in the NEMO—LIM3 multicategory sea ice model is presented for application in the operational...     

An ocean data assimilation system and reanalysis of the World Ocean hydrophysical fields

A new version of the ocean data assimilation system (ODAS) developed at the Hydrometcentre of Russia is presented. The assimilation is performed following the sequential scheme analysis–forecast–analysis. The main components of the ODAS are procedures for operational observation data processing, a variational analysis scheme, and an ocean general circulation model used to estimate the first guess fields involved in the analysis. In situ observations of temperature and salinity in the upper 1400-m ocean layer obtained from various observational platforms are used as input data. In the new ODAS version, the horizontal resolution of the assimilating model and of the output products is increased, the previous 2D-Var analysis scheme is replaced by a more general 3D-Var scheme, and a more flexible incremental analysis updating procedure is introduced to correct the model calculations. A reanalysis of the main World Ocean hydrophysical fields over the 2005–2015 period has been performed using the updated ODAS. The reanalysis results are compared with data from independent sources.     

Statistical structure of spatial variability of the ocean thermohaline fields from argo profiling data, 2005–2007

The means, variances, and three-dimensional spatial covariances of the ocean temperature and salinity anomalies in the upper 1400 m layer have been estimated using data of the Argo profiling floats from 2005 to 2007. The results of data processing suggest the continuation of general warming of the ocean waters noted in a number of papers based on earlier data. A pronounced geographical and vertical nonuniformity characterizes this warming but, as a whole, it is mostly distinct in the upper 100 m layer both in the tropics and midlatitudes. For the first time, the unique characteristics of the Argo observing system allowed us to obtain previously unfeasible estimates of the spatial statistics for salinity field. In particular, it has been demonstrated that the spatial structure of salinity anomalies is similar to those of temperature, excluding the case of the near-surface layer.