Vertical profile parameters of troposphere refractive index over Northern Atlantic Ocean

Radiometeorological simulation of the troposphere of large regions is urgent. Simulation includes obtaining of the mean vertical profile of the refractive index in the troposphere. On the basis of these data refraction in the troposphere is calculated . The most fundamental of such works is the Radio Climatic Atlas (USA) published in 1966, however, it is based on meteorological data limited in space and time. The relevance of this work is in further research and refinement of the radio climatic regime of the oceans , which due to scarce observations is not studied enough, it is particularly important for the water area of the Atlantic Ocean. We made the calculation and analysis of the mean vertical profile of the refractive index N in the troposphere over the North Atlantic. The calculations were performed at 64 stations located on the coasts of Europe, America, the islands and on the weather ships in the open part of the ocean. To perform the calculations data on the climate of the atmospheres over the countries of the northern hemisphere were used: the mean values of temperature, humidity and atmospheric pressure at stations in Europe, North America and the Atlantic Ocean. Climatic data were calculated for a 10-year period and presented at standard isobaric surfaces. Two parameters of exponential and four parameters of bi-exponential models of the mean vertical profile of the refractive index of the considered territory were calculated. Parameters were defined by the least squares method. The calculations were performed for the four central months of each season: February (winter), May (in spring), August (in summer), and October (autumn). We estimated the restoring of the refractive index profile by the coefficient of determination R . Its numbers are greater than 0.900. In this case, the exponential model reflects profile N more accurately in sub-equatorial and temperate latitudes and the bi-exponential one reflects profile N in subtropical and tropical latitudes. By the results of the calculations using the program ''Surfer'' maps of the spatial distribution of the parameters of the two models were constructed . We analysed the spatial and temporal variations of the model parameters for four months. The extreme values of the calculated parameters were highlighted. The significance of the work lies in the fact that the parameters of the two models for this area were calculated using a large number of data. Its results will be used in the preparation of the Radio-Climate Tropospheric Atlas of the Atlantic Ocean.

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