Synchronous and asynchronous relations between the North Atlantic SSTA and the Northern Hemisphere large-scale circulation features

The spatial and temporal relationships between sea surface temperature anomalies (SSTA) in the North Atlantic and the large-scale mid-troposphere circulation features in the Northern Hemisphere during the summer and the winter seasons are investigated. Results are based on atmospheric circulation indices (CI), introduced by Wallace and Gutzler for physical reasoning the low frequency atmospheric oscillations. Extreme levels and extreme situations in the mid-troposphere were defined and the SSTA composite charts were constructed with backward lags from 0 to 3 months. Analysis shows that several CI extreme phases of different signs are associated with synchronous and asynchronous SSTA composites of statistically separable types, or even antipodes, which may be interpreted as the intraseasonal influence of the ocean on the large-scale mid-troposphere anomaly features. Noteworthy is the role of the North Atlantic tropical zone in formation of ridges and blocking situations both in synchronous and asynchronous aspects. The North Atlantic SSTA relations to the West Atlantic Oscillation are shown to be significantly weaker that the same to the East Atlantic Oscillation.     

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...     

Modeling the response of microwave self-radiation of the ocean-atmosphere system to horizontal heat transfer in the atmospheric boundary layer

Carried out is the study of the response of microwave radiation of the ocean-atmosphere system to the horizontal heat transfer in the atmospheric boundary layer (ABL). Model estimates are obtained for the radiation on the wave lengths of 0.6, 0.8, 1, 1.35, and 1.6 cm. It is demonstrated that the value and sign of bright ness temperature contrasts induced by the horizontal transfer depend on the ABL density stratification and transfer direction relative to the orientation of horizontal gradients of air temperature and air humidity. Variations of brightness temperature in the ABL at the wave length of 1.35 cm reach 30–40 K. Ob served is the high correlation between the variations of brightness temperature in the ABL at the wave length of 1.35 cm and the vertical fluxes of sensible and la tent heat for different types of the ABL stratification and for different conditions of advective transport.     

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.     

Marine Observational Systems as an Integral Part of Operational Oceanology: A Review

The paper presents an overview of the current marine observational systems which provide primary information for operational monitoring and predicting the variability of the main hydrophysical fields on the scales from several tens to several thousand kilometers (of the order of the Rossby baroclinic deformation radius and higher). Such systems provide the regular implementation of oceanographic and marine meteorological observations, their rapid interpretation and delivery to users; this is a subject of a relatively new discipline, operational oceanology. The active development of this discipline during the recent two decades suggests that the forecasting of the marine environment state will eventually reach the same level of accuracy and reliability as in operational meteorology, a more successful and older discipline.     

Interrelation of the intraseasonal precipitation variability over Eurasia to the Eliassen-Palm flux characteristics over the Northern Hemisphere

Conditional averages of principal components of the Eliassen-Palm flux divergence variability are projected onto the daily precipitation amounts chart. The conditions of calculating the average values are determined by the dates classified in three equiprobable precipitation categories. The classification and calculation of characteristics are performed for the summer and winter seasons. Using the rotated principal component analysis, several regions are revealed of statistically significant interrelation between extreme precipitation and the first EP flux divergence variability modes, a simplified exploratory interpretation of interrelations is given and several recommendations are formulated for correcting seasonal forecasts of meteorological conditions with the use of results obtained.