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This paper examines monthly variability of climatological mean sea surface temperature (SST) in the Black Sea. A total of eight products, including observation- and model-based SST climatologies, are formed and compared with each other. Some of the observation-based SST data sets include only satellite measurements, while others combine in situ temperatures, such as those from moored and drifter buoys, with satellite data. Climatologies for numerical weather prediction (NWP) model-based data sets are formed using high temporal resolution (6 hourly) surface temperatures. Spatial resolution of these SST products varies greatly (approx. = 4 km to 280 km), with the observation-based climatologies typically finer than the NWP-based climatologies. In the interior, all data sets are in general agreement, with annual mean SST biases typically within + or - 0.2 deg C in comparison to the finest resolution (4 km) satellite-based Pathfinder climatology. Major differences are near the land-sea boundaries where model-based SSTs pose serious biases (as much as >5 deg C). Such errors are due to improper contamination of surface temperatures over land since coarse resolution model-based products cannot distinguish land and sea near the coastal boundaries. A creeping sea-fill interpolation improves accuracy of coastal SSTs from NWP climatologies, such as European Centre for Medium-Range Weather Forecast. All climatologies are also evaluated against historical in situ SSTs during 1942-2007. These comparisons confirm the relatively better accuracy of the observation-based climatologies

Individual sea surface temperature (SST) anomalies are calculated using a satellite-based climatology and observations from the World Ocean Atlas 1994 (WOA94) and the Comprehensive Ocean-Atmosphere Data Set (COADS) to characterize global and regional changes in ocean surface temperature since 1942. For each of these datasets, anomaly trends are computed using a new method that groups individual anomalies into climatological temperature classes. These temperature class anomaly trends are compared with trends estimated using a technique representative of previous studies based on 5° latitude-longitude bins. Global linear trends in the data-rich period between 1960 and 1990 calculated from the WOA94 data are found to be 0.14° ± 0.04°C decade-1 for the temperature class approach and 0.13° ± 0.04°C decade-1 for the 5° bin approach. The corresponding results for the COADS data are 0.10° ± 0.03°C and 0.09° ± 0.03°C decade-1. These trends are not statistically different at the 95% confidence level. Additionally, they agree closely with both SST and land-air temperature trends estimated from results reported by the Intergovernmental Panel on Climate Change. The similarity between the COADS trends and the trends calculated from the WOA94 dataset provides confirmation of previous SST trend studies, which are based almost exclusively on volunteer observing ship datasets like COADS. Regional linear trends reveal a nonuniformity in the SST rates between 1945-70 and 1970-95. Intensified warming during the later period is observed in the eastern equatorial Pacific, the North Atlantic subtropical convergence, and in the vicinity of the Kuroshio extension. Also, despite close agreement globally, localized differences between COADS and WOA94 trends are observed.