No abstract

The objective of this work is to gain new insight on the variability and offshore export of turbid coastal waters in the Adriatic Sea, which are optically classified as Case 2 waters. This is done by means of the 1998–2004 SeaWiFS ocean color products (chlorophyll, Case 2 flags and light attenuation coefficient at 490 nm, k490) and NOAA AVHRR sea surface temperature. The role of wind‐driven circulation in the redistribution of the above ocean color features is also analyzed both at seasonal and interannual time scales and in the light of particular wind and current situations occurring in 2003, via scatterometer wind data as well as atmospheric and marine circulation medium and high resolution model output. Results indicate that turbid (Case 2) waters are exported offshore at the Po delta and Ancona headland during the colder months, in concomitance of Bora wind events and when the 2003 daily Po river discharge is above about 500 m3 s−1 and 1000 m3 s−1, respectively. Southeasterly Sirocco events do not to originate extensive offshore transport, but only locally modify the shape of the WAC front. Mistral episodes enhance the WAC flow into the Ionian Sea. Finally, estimates of coastal current width and length from Case 2 flag distribution follow the Po discharge pattern, confirming this forcing to be the main responsible for WAC width seasonal modulation. Experimental WAC widths agree reasonably with theoretical analyses, while underestimation of WAC length suggests the necessity to include the other Italian rivers in the freshwater discharge evaluation.

[1] The coupling between dust aerosols and phytoplankton concentrations in the Mediterranean Sea, a low-nutrient, low-chlorophyll region, is examined at different timescales using Sea-viewing Wide Field-of-view Sensor observations (1998. Aerosol optical thickness (AOT) and chlorophyll (MCHL) were used as proxies for dust aerosol and phytoplankton biomass, respectively. The AOT data was qualified using quasi-true color images in order to ascertain the presence of dust. Strong positive correlations were found between AOT and MCHL on weekly but not on seasonal timescales. However, weekly analyses cannot distinguish between real phytoplankton response and artifacts due to residual dust in the atmosphere or water. Daily time series of AOT and MCHL, for single-dust events, and their temporal cross-correlation function were analyzed. Apparent AOT-driven MCHL increases principally occurred within 0-2 days and most cross correlations were significant at zero lag. In contrast, significant negative or positive correlations at lag greater than 2 days were very few, indicating no compelling evidence that dust enhancement of phytoplankton growth is significant and that the response at near-zero lags is an artifact of the satellite data processing. Our analysis demonstrates that the dust fertilization does not play a significant role in the sustainment of the phytoplankton dynamics in the Mediterranean Sea.

The series of Global Monitoring for Environment and Security (GMES) Sentinel satellites will continue and extend the European heritage of ENVISAT to provide data to numerous user communities. Sentinel-3 is being developed to support GMES Ocean and global Land monitoring services. Two Sentinel-3 satellites are in development with a first launch in 2014 and the second satellite expected approximately 18 months after the first. This paper provides an overview of the Sentinel-3 Mission.

The present work develops in the framework of the EU-ADIOS project for providing an estimate of the seasonal occurrence of Saharan dust events over the Mediterranean Sea. SeaDAS True Color (TC) images are used for monitoring dust. Dust identification has been carried out by visual inspection of TC images from 1998 up to 2002. The presence of dust, easily recognizable because of its color, is catalogued day by day. A grid representing a schematic division of the Mediterranean basin is overlaid to the TC images for a better identification and localization. The information retrieved by the cataloguing concerns space-time distribution of dust throughout the years examined. It is not possible to retrieve the intensity of the event by looking only at the TC images. Monthly values of Saharan dust load observed for each sector of the Mediterranean Basin for the period 2001 to 2002 have been retrieved from the Aerosol Optical Thickness maps for each dust day identified by the previous analysis. This is given in order to describe a spatial-temporal variability of the aerosol content. A brief description of the dataset, of the processing methodology and of the geophysical atmospheric products is also given.