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The Near Real Time (NRT) operational prod- ucts developed from satellite data (AVHRR, Topex/Poseidon, Ers-2) in the framework of the Mediterranean Forecast- ing System Pilot Project (MFSPP, autumn 1998-autumn 2000) are described and compared to delayed time products over the Mediterranean sea. MFSPP SLA and SST data are then discussed in the general context of the Mediter- ranean circulation, showing the interannual variability of the fields and identifying recurrent or anomalous features at mesoscale/sub-basin scales. Finally, MFSPP data are used to test, on a regional (Mediterranean) context, a multi-variate method to identify coupled modes of variability, consisting in the SVD of the covariance between SST and SLA. In the framework of the Mediterranean Forecasting System Pilot Project (MFSPP), a near real time acquisition and pro- cessing system of remote sensing data was set up and tested for the Mediterranean sea. The system was based on existing facilities and could also serve as a prototype for future oper- ational systems. Near real time (NRT) remote sensing data provided unique data sets for the setting up of the operational Mediterranean Forecasting System, being used for the initial- ization of the weekly forecasts. The development and test of algorithms to process NRT altimeter data, the development of a NRT Sea Surface Temperature product, and the analysis of the remotely sensed data collected during MFSPP were thus fundamental steps in the definition of an operational satellite system. a consequence, the aim of this paper is, first of all, to de- scribe the MFSPP near real time satellite data set (AVHRR, TOPEX/Poseidon and ERS-2) and to quantify the quality of NRT products against advanced products, obtainable only in delayed time. Secondly, a scientific analysis of the data will be performed in order to set the dynamical context of the MFSPP period with respect to the "typical" patterns found in the Mediterranean. This analysis will be carried out with the objective of defining the MFSPP period as "climatological" or characterized by anomalous patterns and as support to the

Thermal NOAA/AVHRR satellite images relative to the years 1997–2000 are analyzed in this study, in order to obtain a first systematic identification of the sites of highest frequency in cold filaments in the Mediterranean Sea, as well as their properties. These sites are characterised by upwelling and/or the funnelling of strong cold winds by a somewhat irregular coastal orography. Indeed, intense air–sea interaction in the coastal zone generates a particularly strong input of potential vorticity into the sea. This in turn gives origin to cold filaments and jets. In the Mediterranean Sea, the geographical zones with a higher frequency in these jets are the two lobes of the southern Sicilian coast, the sea off eastern Sardinia, that south of the island of Crete, where a particularly intense mesoscale field is evident, and the Balkan coast of the Adriatic Sea. A chosen subset of the examined images is here used to obtain an estimate of a bulk coefficient M for mass exchange between filaments and ambient water, in order to explain the along-flow warming observed in most of the satellite images, at each filament site.

In the framework of the ADRICOSM project, the Satellite Oceanography Group (GOS) of Rome developed a Fast Delivery System (FDS) for providing the partner modeling centres with remotelysensed ocean colour and sea surface temperature (SST) data. Data are processed, mapped and binned on the Adriatic Sea area in order to be assimilated into both ecosystem models and circulation models for ocean forecasting. Further technological improvements permitted the building and optimization of a system suitable for meeting the increasing demand for near-real-time ocean colour and SST products for applications in operational oceanography. Real-Time Images of SeaWiFS chlorophyll concentration, clouds/case I/case II water flags and true colour images are obtained by processing the satellite passes using climatological ancillary data. These images are provided daily through an ad hoc automatic system that processes the raw satellite data and makes it available on the web within an hour of satellite overpass acquisition. All of the images are stored in a gallery web archive organized in a calendar chart. Accurate chlorophyll maps for assimilation are produced in near real time (typically after 4 days) as soon as daily meteorological ancillary data are made available on the NASA website. Each chlorophyll map is flagged for clouds or other contamination factors using the corresponding 24 quality flag maps. This implies that case-2 waters and spurious atmospheric effects have been removed from the pigment data set. This final product is binned on the Adriatic model grid and made available for the ADRICOSM project on the GOS web site. NOAA/AVHRR data are also acquired by the GOS ground station in Rome and managed by the FDS from their reception up to their distribution. Daily SST maps of the Adriatic Sea binned over the AREG model grid at 1/16° resolution are distributed weekly in Near-Real-Time along with the daily SST maps of the eastern Mediterranean Sea delivered at 1/8° resolution to the MFSTEP project. Real-Time SST maps of the Adriatic Sea at 1km resolution are posted daily in GIF format on the GOS website., U okviru projekta ADRISOSM, GOS (Grupa za satelitsku oceanografiju) iz Rima razvila je Sustav za brzu isporuku FDS, snabdijevanje partnerskih centara za modeliranje satelitskim snimcima boje mora i tem-peraturnim podacima površine mora (SST). Podaci za Jadran su obrađeni, pretvoreni u grafičke produkte i digitalizirani kako bi se mogli asimilirati u model strujanja i model ekosistema, te koristiti oceanografskoj prognozi. Daljnja tehnološka poboljšanja su omogućila izgradnju i optimalizaciju sustava, zbog rastućih potreba za produktima boje mora i površinske temperature za različite primjene u operativnoj oceanografiji. Slike koncentracije klorofila od senzora SeaWiFS, slike oblaka te Case1 i Case2 oznake, kao i slike prave boje dobivaju se procesiranjem satelitskih scena uz popratne klimatološke podatke. Slike se procesiraju dnevno kroz ad-hoc automatski sustav koji obrađuje sirove satelitske podatke i omogućuje njihovu isporuku na mrežu, sat vremena nakon prikupljanja satelitskih podataka tj. nakon prolaska satelita. Sve se slike spremaju u arihvu na mreži koja je organizirana prema datumima. Korigirane slike koncentracije klorofila za asimilaciju u model proizvode se u skoro realnom vremenu (tipično 4 dana kasnije) čim se dobiju popratni meteorološki podaci s mreže NASA-e. Na svakoj slici klorofila su označeni oblaci ili drugi kontaminirajući faktori, prema 24 kategorije kvalitete slika. To znači da su Case 2 slučajevi piksela uklonjeni iz snimaka kao i atmosferske sme-tnje. Konačni produkt se usklađuje s koordinatnom mrežom Jadrana i stavlja na raspolaganje na stranicama ADRICOSM-a preko GOS-ove Internet stranice. GOS zemaljska stanica u Rimu prikuplja i podatke NOAA/ AVHRR koji se procesiraju kroz FDS sustav, od prijema do konačne distribucije podataka. Dnevne se slike površinske temperature mora (SST), usklađene preko koordinatne mreže AREG-a pri prostornom razlučivanju od 1/16 stupnja, distribuiraju tjedno u skoro realnom vremenu, zajedno sa slikama istočnog Sredozemlja koje imaju razlučivanje od 1/8 stupnja prema MFSTEP projektu. Dnevno, u skoro realnom vremenu, isporučuju se slike SST za Jadran uz prostorno razlučivanje od 1 km u GIF formatu na Internet stranici GOS-a.

Operational oceanography requires availability of remotely sensed data, for example sea surface temperature (SST), in near realtime (NRT). A system is presented that makes use of a combination of state of the art NASA Pathfinder SST (PFSST) algorithm and cloud detection procedures both adapted to operate in NRT. A novel cloud detection algorithm that makes use of a reference image based upon recent SST fields recovers data over coastal areas affected by sharp SST fronts that are discarded by the standard PFSST quality flag. The resulting increased SST coverage is visually checked, to remove residual cloud contamination, by a trained analyst prior to input to the objective analysis package in turn adapted for satellite-derived SST observations. The output daily gridded data in which the gaps due to clouds have been filled by the optimal interpolation module are assimilated into the Mediterranean Forecasting System Toward Environmental prediction (MFSTEP) ocean forecasting system on a weekly basis.

Thermal satellite images relative to the years 1997-2000 are analyzed in this study, in order to infer cold filament and surface jet dynamics in the Mediterranean Sea. The main zones in which these phenomena are seen to occur, are characterised by upwelling and/or the funnelling of strong cold winds by a somewhat irregular coastal orography. Indeed, intense air-sea interaction in the coastal zone is known to generate a particularly strong input of potential vorticity into the sea, and this in turn gives origin to upwellings, cold filaments and jets. In the Mediterranean Sea the geographical zones with a higher frequency in these jets are the two lobes of the southern Sicilian coast, the sea off Olbia in Eastern Sardinia, that south of the island of Crete where a particularly intense large scale turbulence field is evident, and the Balkanic coast of the Adriatic Sea. In addition the theoretical analysis of these jets' evolution using a modern version of the potential vorticity conservation, valid even if friction and entrainment are considered, gives further insight into these systems’ dynamics.

Two years and six months of night-time Advanced Very High Resolution Radiometer (AVHRR) sea surface temperature (SST) and daytime Sea viewing Wide Field of view Sensor (SeaWiFS) data collected during the MFSPP have been used to examine spatial and temporal variability of SST and chlorophyll (Chl) in the Adriatic Sea. Flows along the Albanian and the Italian coasts can be distinguished year-round in the monthly averaged Chl but only in the colder months in the monthly averaged SST’s. The Chl monthly-averaged fields supply less information on circulation features away from coastal boundaries and where conditions are generally oligotrophic, except for the early spring bloom in the Southern Adriatic Gyre. To better characterise the year-to-year and seasonal variability, exploratory data analysis techniques, particularly the plotting of multiple Chl-SST histograms, are employed to make joint quantitative use of monthly-averaged fields. Modal water mass (MW), corresponding to the Chl-SST pairs in the neighbourhood of the maximum of each monthly histogram, are chosen to represent the temporal and spatial evolution of the prevalent processes and their variability in the Adriatic Sea. Over an annual cycle, the MW followed a triangular path with the most pronounced seasonal and interannual variations in both Chl-SST properties and spatial distributions of the MW in the colder part of the year. The winter of 1999 is the colder (by at least 0.5°C) and most eutrophic (by 0.2 mg/m 3). The fall of the year 2000 is characterised by the lack of cooling in the month of November that was observed in the previous year. In addition to characterising the MW, the two-dimensional histogram technique allows a distinction to be made between different months in terms of the spread of SST values at a given Chl concentration. During spring and summer, the spread is minimal indicating surface homothermal conditions. In fall and winter, on the other hand, a spread of points suggesting a linear negative correlation between SST and Chl is found. This behaviour is related to the high nutrient content of cooler water associated with upwelling or the Po River fresh water outflow. Key words. Oceanography: general (diurnal, seasonal and annual cycles; marginal and semi-enclosed seas; water masses)

Remote sensing instruments provide a huge volume of measurements of sea surface parameters which are of fundamental interest to the oceanographic community, mainly because of the high spatial and temporal coverage of satellite sensors respect to traditional techniques. In fact, the whole ocean circulation is actually driven by processes occurring at the air-sea interface, as the energy is mainly supplied to the ocean by atmosphere-ocean interactions. Consequently, altimeter derived SSH and SST obtained from AVHRR, that have already proved to be quit useful to evaluate the sea surface variability, can be though t as possible tools to investigate the ocean dynamics and atmosphere-ocean interaction more deeply. In this work, 2 years of Mediterranean Forecasting System Pilot Project dat over the Mediterranean basin are analyzed. The relationship between SST and SLA is investigated applying an objective method for coupled pattern detection, based on the singular value decomposition of the covariance of the two data-sets.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Satellite data have revealed the presence of an intens4e mesoscale anticyclonic eddy at the northern boundary of the Balearic Sea, which appeared in September 1998 and remained almost stationary until March 1999. Sea Surface Temperature (SST) images have allowed to investigate the formation of the eddy indicating an entrance of Atlantic Water through the Ibiza and Mallorca channels much stronger than normal conditions and following an anomalous path. Additional data form an oceanographic cruise on February 1999 confirmed the signature of Atlantic Water in the region. This structure produced a relevant inversion in the usual cyclonic circulation of the basis. The observed strong anticyclonic eddy induced anomalous northeastwards geostrophic velocities near the Catalan Coast reaching the maximums of about 50 cm/s, by contrast of the typical 20 cm/s in opposite sense. The three data-sets examined in this work are in good agreement in terms of the dimensions and intensity of the eddy. This suggests that remote sensing would be able to detect such kind of events in the future constituting a powerful tool providing a real-time monitoring of the Basin.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Upper ocean dynamics is characterized by a strong variability, at different scales, both in direction and structure of the flow. Mesoscale variability, which is ubiquitous in the world ocean, is often the dominant component in the variance spectrum of velocity with relevant implications on water mass mixing and transformation and on the carbon transfer in the marine food web. Mesoscale activity is manifested through the formation of instabilities, meanders and eddies. Eddies generate either a doming of isopycnals (cyclones) or a central depression (anticyclones). This in turn modifies, among the others, nutrient and organism distributions in the photic zone eventually enhancing or depressing photosynthetic activity and other connected biological responses. The mechanism is similar to what has been thoroughly studied for the warm and cold core rings but at different spatial and temporal scales. The enhancement of phytoplankton growth and the modification of photosynthetic parameters has been shown to occur in situ by means of a modulated fluorescence probe. More recently, an attempt to estimate the magnitude of this specific forcing on nutrient fluxes and primary production has also been conducted at different scales by modeling exercises, though with contrasting estimates the relative importance concerns. Because phytoplankton growth takes place when light, nutrients and cells are found at the same place, the increase in primary production favored by mesoscale eddies cannot be easily predicted. The incident light, the seasonality, the life-time of the structure, its intensity etc. can all influence the final yield. In addition, it has still to be determined which component of the community reacts faster and takes advantage of the new nutrients and how efficiently the new carbon is channeled in the food web. For what remote sensing is concerned, the detectability form the space of such structures is certainly dependent on the depth at which the upward distortion of isopycnals takes places. It can be supposed that a change in bio-optical signature of the whole structure could occur because of the 3-D dynamics of the eddy. If this holds true, then color remote sensing coupled with sea level topography and sea surface temperature should be a powerful tool to track such transient structures. The ALT-SYMPLEX program has been designed to better understand the relationship between short living eddies and carbon transfer in the food web. This is based on several experiments aimed to integrate remote sensing data (ocean color and surface topography) and in situ data in order to evaluate the relationship between surface and sub-surface physical dynamics and its relations on chemical and biological aspects in presence of mesoscale features.

Advanced Very High Resolution Radiometer (AVHRR) and Sea viewing Wide Field of view Sensor (SeaWiFS) data from January 1998 to June 1999 are used to examine spatial and temporal variability of sea surface temperature (SST) and apparent chlorophyll (AChl) in the Adriatic Sea. Flows long the Albanian coast and the Italian can be distinguished year-round in the monthly averaged AChl, but only in the colder months in the monthly averaged SST's. The AChl averaged fields supply less information on circulation features away from coastal boundaries and where conditions are generally oligotrophic except for the early spring bloom in the Southern Adriatic Gyre. The winter-spring SST and chlorophyll distributions are very different between the two years, particularly in the Northern Adriatic shelf and the Southern Adriatic Gyre. It is hypothesized that this difference may be related to dense water formation that occurs only in the northern and southern Adriatic Seas. The time series of daily SST indicate that dense water formation was favored in 1999 by episodes of cooler winter temperatures in the southern gyre (less than 13.5 degrees Celsius) and on the northern Adriatic shelf. Blooms in 1999 may have been delayed due to surface replacement flows driven by sinking of dense water.