Research involving a yearlong drift with the ice pack in the Arctic Ocean witnessed surprisingly thin ice at the start and even thinner ice at the end. Also, the extent of open water during the summer of 1998 in the Beaufort and Chukchi Seas was the greatest of the past 2 decades. As the ice is melting from under your feet there is an understandable tendency to blame global warming. But the project, known as the Surface Heat Budget of the Arctic Ocean (SHEBA), though motivated by climate change, was not designed to detect global warming. Definitive climate change pronouncements can not be made based on a single experiment.

Satellite-based datasets of surface turbulent fluxes over the global oceans are being evaluated and improved.O cean surface fluxes of heat, moisture, and momentum observed during field experiments show strong variability on temporal scales that range from the diurnal cycle to the life cycle of storms, and on spatial scales as small as that of an individual convective cloud. High-frequency variability (e.g., diurnal, storm scale) in tropical air-sea fluxes has been hypothesized to influence intraseasonal and interannual variability of the monsoon (e.g., Webster et al. 1998) and the Pacific Ocean warm pool and El Nino (e.g., Sui and Lau 1997;Fasullo and Webster 2000). At high latitudes, large variations in surface fluxes and sea surface temperature are seen in response to storms, which impact the temperature, density, and mixing in the upper ocean, further influencing the atmospheric dynamics and thermodynamics. Storm-scale events have been hypothesized (e.g., Marshall et al. 1998;Nardelli and Salusti 2000) to be associated with ocean convection in the high-latitude water mass formation regions, contributing to deep water formation and the global ocean thermohaline circulation. Ocean mixing induced by tropical cyclones might play an important role in driving the global ocean thermohaline circulation and, thereby,

Satellite retrievals of surface evaporation and precipitation from the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3) dataset are used to document the distribution of evaporation, precipitation, and freshwater flux over the Mediterranean and Black Seas. An analysis is provided of the major scales of temporal and spatial variability of the freshwater budget and the atmospheric processes responsible for the water flux changes. The satellite evaporation fluxes are compared with fields from three different reanalysis datasets [40-yr ECMWF Re-Analysis (ERA-40), ERA-Interim, and NCEP].The results show a water deficit in the Mediterranean region that averages to about 2.4 mm day 21 but with a significant east-west asymmetry ranging from 3.5 mm day 21 in the eastern part to about 1.1 mm day 21 in the western part of the basin. The zonal asymmetry in the water deficit is driven by evaporation differences that are in turn determined by variability in the air-sea humidity difference in the different parts of the Mediterranean basin. The Black Sea freshwater deficit is 0.5 mm day 21 , with maxima off the northern coast (0.9 mm day 21 ) that are attributed to both evaporation maxima and precipitation minima there.The trend analysis of the freshwater budget shows that the freshwater deficit increases in the 1988-2005 period. The prominent increase in the eastern part of the basin is present in the satellite and all three reanalysis datasets. The water deficit is due to increases in evaporation driven by increasing sea surface temperature, while precipitation does not show any consistent trends in the period. Similarly, in the Black Sea, trends in the freshwater deficit are mainly due to evaporation, although year-to-year variability is due to precipitation patterns.

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Simulations of eight different regional climate models (RCMs) have been performed for the period September 1997–September 1998, which coincides with the Surface Heat Budget of the Arctic Ocean (SHEBA) project period. Each of the models employed approximately the same domain covering the western Arctic, the same horizontal resolution of 50 km, and the same boundary forcing. The models differ in their vertical resolution as well as in the treatments of dynamics and physical parameterizations. Both the common features and differences of the simulated spatiotemporal patterns of geopotential, temperature, cloud cover, and long-/shortwave downward radiation between the individual model simulations are investigated. With this work, we quantify the scatter among the models and therefore the magnitude of disagreement and unreliability of current Arctic RCM simulations. Even with the relatively constrained experimental design we notice a considerable scatter among the different RCMs. We found the largest across-model scatter in the 2 m temperature over land, in the surface radiation fluxes, and in the cloud cover which implies a reduced confidence level for these variables