Oceans cover approximately 70% of the Earth's surface and, with about 60% of the World's ... more Oceans cover approximately 70% of the Earth's surface and, with about 60% of the World's population living within 200 km of the coast, they have an untold impact on all of us. Not surprisingly, for people living close to the coast or those who depend on the ocean for their livelihood, regular forecasts of ocean conditions are just as important as traditional weather forecasts. Therefore, development of the infrastructure needed to support and sustain independent, European operational ocean forecasting, and the associated coastal and marine information services, are key priorities of the joint Global Monitoring for Environment and Security (GMES) initiative by the European Commission and ESA.
ROADMAP FOR A GMES OPERATIONAL OCEANOGRAPHY MISSION Mark Drinkwater~1~' Helge Rebhan... more ROADMAP FOR A GMES OPERATIONAL OCEANOGRAPHY MISSION Mark Drinkwater~1~' Helge Rebhan~1~, Pierre-Yves Le Traon~2~, Laurent Pha1ippou~3~ David Cotton~4~, Johnny Johannessen~5~, Giulio Ruffini~6~, Pierre Bahure1~7~ Mike ...
ABSTRACT A new method to estimate radiation budgets at air-sea interface by means of AVHRR data h... more ABSTRACT A new method to estimate radiation budgets at air-sea interface by means of AVHRR data has been developed and tested in the framework of the Arctic Radiation and Turbulence Interaction Study (ARTIST). Main goal of the ARTIST project is assess the effects of clouds and of Arctic Haze on the radiative fluxes at the surface and in the atmospheric column in the European Arctic. One month of Advanced Very High Resolution Radiometer (AVHRR) data relative to the period March - April 1998 has been processed and analyzed in order to evaluate short and long wave radiation budgets in the Arctic Sea during the experiment. Remote sensing data (NOAA 14 satellite) have been acquired at the Tromso station and then processed at the Istituto Fisica dell'Atmosfera (IFA) to produce maps of surface albedo and brightness temperature of the experiment's zone. These maps were used to develop a new cloud detection algorithm for the region. Image pixels then have been classified as ice, clouds or water. The method was applied to 151 available AVHRR scenes. The pixels classification performance was verified against the analysis of an expert in satellite image. The cloud classification results to be quite accurate. In fact 99 images are classified as 'very good' by the expert and 37 images the accuracy is a little lower. The radiation budgets are then estimated using several available empirical formulae for clear sky and overcast conditions. The results were compared with in situ measurements made during the ARTIST experiment in order to define the best parameterization of the fluxes. The best estimates of shortwave incoming radiation results from the Bennet (1982) formula for clear sky condition with the Laevastu (1960) correction for overcast condition. The more accurate estimate of incoming long wave radiation in clear sky has been obtained using the Swinbank (1963) parameterization. Finally, averaged map of total radiation budget are calculated for the time period of the ARTIST experiment in the Arctic region.
ABSTRACT Many studies indicate that the atmosphere is a significant and in some cases the dominan... more ABSTRACT Many studies indicate that the atmosphere is a significant and in some cases the dominant pathway by which specific elements are transported from the land to the open sea. The Mediterranean Sea is a semi-enclosed basin, that continuously receives anthropogenic substances from the industrialized European country, and sporadically, from the arid region of the Sahara desert, nearly the 90% of the total amount of aerosols that reach the sea surface. The Mediterranean is a predominantly oligotrophic basin with areas of high productivity limited to areas influenced by runoff, rivers or upwelling. In situ biogeochemical measurements indicate that atmospheric deposition can induce significant productivity changes. The present work aims to use SeaWiFS satellite data and the SKIRON atmospheric model to provide an estimate of the temporal and spatial variability in the atmospheric forcing (dust events) and in the marine biological response (blooms), and to evaluate the overall contribution of these Saharan dust events to the fertility of the Mediterranean Sea. Although biological dynamic is meanly driven by the circulation features of the basin, results show that the atmospheric nutrient deposition gives some evident response in the biological activity.
Large amplitude internal waves were observed north and south of the Strait of Messina during two ... more Large amplitude internal waves were observed north and south of the Strait of Messina during two different periods. A comparison between the two sets of data is made. The behaviour of the shape of the waves is analysed from the physical parameters and two possible interpretations of these waves are given. The mechanism of formation related to the tide in
This work is aimed at studying the variability of Rhodes and Ierapetra Gyres during the Levantine... more This work is aimed at studying the variability of Rhodes and Ierapetra Gyres during the Levantine Intermediate Water Experiment. Sea surface temperature maps, derived from Global Area Coverage advanced very high resolution radiometer (AVHRR) data in the framework of the Pathfinder Project and sea level anomalies, derived from TOPEX/Poseidon altimeter, were used to track the evolution, both in terms of dimension and position, of the cyclonic Rhode Gyre and Ierapetra anticyclone. The analysis was performed for the period from October 1994 to the end of April 1995, i.e., from the preconditioning to the spreading phase of Levantine Intermediate Water. The description of the surface fields was complemented by a temporal evolution study of the Rhodes and Ierapetra Gyres hydrological vertical structure. European Centre for Medium-Range Weather Forecasts AVHRR-derived fluxes have been used as forcing for a numerical model to study the variability of the mixed layer in both gyres. The simula...
Operational oceanography requires availability of remotely sensed data, for example sea surface t... more 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
Oceans cover approximately 70% of the Earth's surface and, with about 60% of the World's ... more Oceans cover approximately 70% of the Earth's surface and, with about 60% of the World's population living within 200 km of the coast, they have an untold impact on all of us. Not surprisingly, for people living close to the coast or those who depend on the ocean for their livelihood, regular forecasts of ocean conditions are just as important as traditional weather forecasts. Therefore, development of the infrastructure needed to support and sustain independent, European operational ocean forecasting, and the associated coastal and marine information services, are key priorities of the joint Global Monitoring for Environment and Security (GMES) initiative by the European Commission and ESA.
ROADMAP FOR A GMES OPERATIONAL OCEANOGRAPHY MISSION Mark Drinkwater~1~' Helge Rebhan... more ROADMAP FOR A GMES OPERATIONAL OCEANOGRAPHY MISSION Mark Drinkwater~1~' Helge Rebhan~1~, Pierre-Yves Le Traon~2~, Laurent Pha1ippou~3~ David Cotton~4~, Johnny Johannessen~5~, Giulio Ruffini~6~, Pierre Bahure1~7~ Mike ...
ABSTRACT A new method to estimate radiation budgets at air-sea interface by means of AVHRR data h... more ABSTRACT A new method to estimate radiation budgets at air-sea interface by means of AVHRR data has been developed and tested in the framework of the Arctic Radiation and Turbulence Interaction Study (ARTIST). Main goal of the ARTIST project is assess the effects of clouds and of Arctic Haze on the radiative fluxes at the surface and in the atmospheric column in the European Arctic. One month of Advanced Very High Resolution Radiometer (AVHRR) data relative to the period March - April 1998 has been processed and analyzed in order to evaluate short and long wave radiation budgets in the Arctic Sea during the experiment. Remote sensing data (NOAA 14 satellite) have been acquired at the Tromso station and then processed at the Istituto Fisica dell'Atmosfera (IFA) to produce maps of surface albedo and brightness temperature of the experiment's zone. These maps were used to develop a new cloud detection algorithm for the region. Image pixels then have been classified as ice, clouds or water. The method was applied to 151 available AVHRR scenes. The pixels classification performance was verified against the analysis of an expert in satellite image. The cloud classification results to be quite accurate. In fact 99 images are classified as 'very good' by the expert and 37 images the accuracy is a little lower. The radiation budgets are then estimated using several available empirical formulae for clear sky and overcast conditions. The results were compared with in situ measurements made during the ARTIST experiment in order to define the best parameterization of the fluxes. The best estimates of shortwave incoming radiation results from the Bennet (1982) formula for clear sky condition with the Laevastu (1960) correction for overcast condition. The more accurate estimate of incoming long wave radiation in clear sky has been obtained using the Swinbank (1963) parameterization. Finally, averaged map of total radiation budget are calculated for the time period of the ARTIST experiment in the Arctic region.
ABSTRACT Many studies indicate that the atmosphere is a significant and in some cases the dominan... more ABSTRACT Many studies indicate that the atmosphere is a significant and in some cases the dominant pathway by which specific elements are transported from the land to the open sea. The Mediterranean Sea is a semi-enclosed basin, that continuously receives anthropogenic substances from the industrialized European country, and sporadically, from the arid region of the Sahara desert, nearly the 90% of the total amount of aerosols that reach the sea surface. The Mediterranean is a predominantly oligotrophic basin with areas of high productivity limited to areas influenced by runoff, rivers or upwelling. In situ biogeochemical measurements indicate that atmospheric deposition can induce significant productivity changes. The present work aims to use SeaWiFS satellite data and the SKIRON atmospheric model to provide an estimate of the temporal and spatial variability in the atmospheric forcing (dust events) and in the marine biological response (blooms), and to evaluate the overall contribution of these Saharan dust events to the fertility of the Mediterranean Sea. Although biological dynamic is meanly driven by the circulation features of the basin, results show that the atmospheric nutrient deposition gives some evident response in the biological activity.
Large amplitude internal waves were observed north and south of the Strait of Messina during two ... more Large amplitude internal waves were observed north and south of the Strait of Messina during two different periods. A comparison between the two sets of data is made. The behaviour of the shape of the waves is analysed from the physical parameters and two possible interpretations of these waves are given. The mechanism of formation related to the tide in
This work is aimed at studying the variability of Rhodes and Ierapetra Gyres during the Levantine... more This work is aimed at studying the variability of Rhodes and Ierapetra Gyres during the Levantine Intermediate Water Experiment. Sea surface temperature maps, derived from Global Area Coverage advanced very high resolution radiometer (AVHRR) data in the framework of the Pathfinder Project and sea level anomalies, derived from TOPEX/Poseidon altimeter, were used to track the evolution, both in terms of dimension and position, of the cyclonic Rhode Gyre and Ierapetra anticyclone. The analysis was performed for the period from October 1994 to the end of April 1995, i.e., from the preconditioning to the spreading phase of Levantine Intermediate Water. The description of the surface fields was complemented by a temporal evolution study of the Rhodes and Ierapetra Gyres hydrological vertical structure. European Centre for Medium-Range Weather Forecasts AVHRR-derived fluxes have been used as forcing for a numerical model to study the variability of the mixed layer in both gyres. The simula...
Operational oceanography requires availability of remotely sensed data, for example sea surface t... more 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
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