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In this study the performance of Medium Resolution Imaging Spectrometer (MERIS) geophysical products were evaluated using in situ measurements in northwestern part of the Black Sea. The in situ chlorophyll a (Chl-a), total suspended matter (TSM) and Scechi disk depth (SDD) were collected from two Institute of Oceanology, BAS cruises during spring season of 2006 and 2009. A strict comparison method between two data sets was adopted resulting in 27 and 33 match ups for TSM and Chl a respectively. The method comprised the arithmetic average of valid MERIS values calculated over the 3 × 3 - pixels square found within time difference of ± 3 h from the in situ measurement. Additionally, classification of the in situ data was performed, in order to assess accuracy of MERIS algal_2 and TSM products in respect to the sea water with different optical properties. The in situ data were subdivided into three groups to represent clear, moderate turbid and turbid waters by applying K - mean clustering method on the measured concentrations of Chl-a, TSM and transparency. Statistical analysis of MERIS derived TSM and Chl-a and in situ data were carried out for the different water types. In the case of TSM concentrations, was found a reasonably good agreement between two data sets in clear and moderate turbid waters. The estimated R2 are greater than or equal to 0.66 and log_RMS differences for clear and moderate turbid waters ranging between 0.09 g/m3 and 0.19 g/m3. The similar correlations were estimated for Chl-a concentrations, but the value for log_RMS in turbid waters is higher to those obtained for TSM. For both variables, the best results of comparison were found for the moderate turbid waters, that corresponding to high coefficients of determination (R2>0.75) and small log_RMS differences of 0.1 mg/m3 for Chl-a and 0.09 g/m3 for TSM. The present study suggested that MERIS Case 2 products are reasonably accurate in moderate turbid shelf waters, but not yet reliable in turbid coastal waters of the northwestern Black Sea.

Winds over the ocean play an important role in meteorology, oceanography and climatology. They affect air-sea variations in heat, humidity, gases and particles, regulating the crucial relation between the ocean and the atmosphere that establishes and supports the climate on regional and global scale. Therefore, the knowledge of wind fields over the oceans is essential for global weather forecast purposes. Furthermore, the accurate forecasting of ocean surface winds contribute to good wave forecasts, which provide informativeness and safety in marine industry, navigation and other human activities in open and off-shore seas. The sources of surface observations that are generally used to make analyses of winds over the oceans not always can provide data with temporal and spatial regularity. These gaps can be filled in with wind data registered by satellite sensors like NASA's QuikSCAT satellite radar scatterometer. It provides on operational basis wind vector measurements over global oceans with considerable reliability and sufficient time frequency. The standard operational QuikSCAT wind vector product has a spatial resolution of 25km × 25km. However, the recent measurement methodology of QuikSCAT allows for wind vector retrievals at better spatial resolution of 12.5 km.