196,132 research outputs found
An intercomparison of global oceanic precipitation climatologies
No full textLarge-scale patterns of precipitation are important for the changes they may effect upon the circulation of the ocean. However, marine precipitation is very hard to quantify accurately. Four independent climatologies are examined to compare their estimates of the annual mean precipitation, and the seasonal and interannual variations. One data set, Global Precipitation Climatology Project (GPCP), is based upon satellite data, the other three on output of weather forecast reanalyses from the National Centers for Environmental Prediction (NCEP) and the European Centre for Medium-range Weather Forecasts (ECMWF). Although all datasets have their errors, there is general agreement on the geographical patterns of precipitation. All the models had higher rain rates in the tropics than shown by the satellite data, and also greater seasonal ranges. However, GPCP has 10-25% more precipitation than NCEP and ECMWF in most of the southern regions, because of their weak representation of convergence zones; NCEP2, a more recent version of the NCEP reanalysis, shows a marked improvement in this area. However, in most regions NCEP2 exhibits a larger seasonal range than shown by other datasets, particularly for the tropical Pacific. Both NCEP and NCEP2 often show a seasonal cycle lagging two months or more behind GPCP. Of the three reanalysis climatologies, ECMWF appears best at realising the position and migration of rain features. The interannual variations are correlated between all four datasets, however the correlation coefficient is only large for regions that have a strong response to El Niño and La Niña event, or for comparisons of the two NCEP reanalyses. Of the datasets evaluated, GPCP has the most internal consistency, with no long-term trend in its regional averages, and it alone shows the deficit in Mediterranean precipitation coincident with the Eastern Mediterranean Transient
The Bunker Pollution Convention 2001: completing and harmonising the liability regime for oil pollution from ships?
No full textLiability and compensation in international transport of hazardous wastes by sea: the 1999 protocol of the Basel Convention plus appendix "Basel Protocol on Liability and Compensation for Damage Resulting from Transboundary Movements of Hazardous Wastes and Their Disposal"
No full textVariations of the seasonal sea level cycle in southern Europe
No full textThe temporal and spatial variability of the seasonal signals in the Mediterranean Sea and the Atlantic Iberian coast is explored on the basis of tide gauge data. Mean amplitudes range in the various stations between 3 and 7 cm for the mean annual component and between 1 and 3 cm for the semiannual component. On average, seasonal signals account for approximately 20% of the total variance of monthly records. The seasonal cycle is unsteady in time, with large variations in amplitudes and phases in some stations reaching up to 8 cm and 40 d, respectively. The contribution of the direct atmospheric effects to the seasonal cycle has been estimated by means of the output of a barotropic model forced with wind and atmospheric pressure. This contribution is regionally coherent, albeit variable in time. The annual cycle of the residuals (observations minus atmospherically induced sea level) is larger than that of the observations by about 2–3 cm. The residual semiannual cycle is smaller than that of the observations by about 25%. The temporal variability of the seasonal cycle of the residual series is also explored. Changes in water temperatures at the upper layers is the only parameter that appears connected with the observed variations
Sea level in the Mediterranean Sea: the contribution of temperature and salinity changes
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Forcing of coastal sea level rise patterns in the North Atlantic and the Mediterranean Sea
No full textSea level trends derived from North Atlantic and the Mediterranean Sea tide gauges have been re-evaluated with a common reference period (1960–2000) and with the atmospheric component of the observed sea level variability quantified and removed by means of regional barotropic ocean models forced by wind and atmospheric pressure. The atmospherically forced trends are important and have values of ?0.2 ± 0.1 mm/yr in the North Atlantic (west coast), ?0.2 ± 0.2 mm/yr in the NE Atlantic, 0.3 ± 0.4 mm/yr in North Sea and ?0.7 ± 0.1 mm/yr in the Mediterranean. The residual sea level trends corrected for post-glacial rebound processes are 0.9 ± 0.4 mm/yr in the Mediterranean, 1.1 ± 0.6 mm/yr in the NW Atlantic, 1.3 ± 1.0 mm/yr in the NE Atlantic and 1.3 ± 0.8 mm/yr in the North Sea. Atmospheric forcing is partly responsible for the observed patterns of sea level rise and for part of the observed sea level acceleration during the 1990s. The residual trends have further been corrected for the influence of the steric effects. In the Mediterranean removing the steric component increases the trends by 40% and makes them consistent with the Atlantic trends. The remaining sea level rise rates are due to mass addition and their spatial pattern in the region can be related to Greenland ice-melting rates
The influence of the North Atlantic Oscillation on sea level in the Mediterranean and the Black Sea derived from satellite altimetry
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