Altres

Els filtres actuals son: Any inici = 2012, Any final = 2017
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García-Ladona E. (2017)
Atlas of Bedforms in the Western Mediterranean. Ed. J. Guillén, J. Acosta, F.L. Chiocci, A, Palanques. Springer International Publishing. 41-47. DOI: 10.1007/978-3-319-33940-5_8. ISBN. 978-3-319-33938-2. (BibTeX: garcialadona.2017b)
Resum: Veure
The main circulation patterns in the western Mediterranean are revisited and updated. The schemes are based on the previous literature, adapted and reviewed. The update concerns in particular the circulation at intermediate depths, exemplified by the Levantine Intermediate Water circulation, and includes deep water cascading and recent observations from drifting floats and mooring recordings.
Paraules clau: Ocean currents, Western Mediterranean, circulation patterns
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Pelegrí J.L., Peña-Izquierdo J., Machín F., Meiners C., Presas-Navarro C. (2017)
Deep-Sea Ecosystems Off Mauritania. Ed. Ana Ramos, Fran Ramil, José Luis Sanz. Springer Science+Business Media B.V. 2017. Chap. 3. 119-153. DOI: 10.1007/978-94-024-1023-5_3. ISBN. 978-94-024-1021-1. (BibTeX: pelegri.etal.2017a)
Resum: Veure
TheCapeVerde(CV)Basinisthesiteoffrontsandcurrentsthatfunction as both barriers and connectors between the tropical and subtropical oceans. Here we review former studies and analyze historical, satellite and numerical data in order to portray the oceanography of the CV Basin, with emphasis on its eastern boundary— the Mauritania Slope (MS) Ocean. This is complemented with the analysis of novel hydrographic data from the continental slope. The CV Basin is a dynamic region, forced by seasonally varying winds that drive both coastal and offshore upwelling, the latter linked to the Guinea Dome. Its circulation is controlled by the seasonally changing Dome to the south and southwest, with associated cyclonic currents, and by the CV frontal system to the north, with along-slope flow convergence and offshore export. The MS Ocean is the site of the Poleward Undercurrent, undistin- guishable from the offshore Mauritania Current during winter–spring. The pre- dominant thermocline water–mass is the nutrient-rich South Atlantic Central Water, almost pure in upper layers (100–300 m)—providing for the high primary produc- tion in the entire region—and with substantial North–Atlantic contribution in its lower part (300–550 m)—in what constitutes the poorly–ventilated low oxygen minimum zone; nutrient concentrations keep increasing with depth until the core of the Antarctic Intermediate Waters (700–800 m). The CV Basin holds both the highest primary production and lowest oxygen concentrations for the entire tropical
Paraules clau: Cape Verde Basin Mauritania slope ocean Cape Verde frontal system Guinea dome Poleward undercurrent Upwelling Water masses Oxygen minimum zones Primary production Northwest Africa
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Polverari F., Portabella M., Garcia-Pereda J., Calbet X., Rípodas P. (2017)
Technical Report Numerical Weather Prediction Satellite Application Facilities NWC/CDOP2/SAF/AEMET/SCI/VSP/12, Issue 1, Rev. 2 27 September 2017. (BibTeX: polverari.etal.2017a)
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Ramos A., Sanz J.L., Pelegrí J.L., Fernández-Peralta L., Pascual-Alayón P.J., Ramil F., Castillo S., García-Isarch E., Rocha F., Gil M., Calero B. (2017)
Deep-Sea Ecosystems Off Mauritania. Ed. Ana Ramos, Fran Ramil, José Luis Sanz. Springer Science+Business Media B.V. 2017. Chap. 17. 615-659. DOI: 10.1007/978-94-024-1023-5_17. ISBN. 978-94-024-1021-1. (BibTeX: ramos.etal.2017a)
Resum: Veure
Human activities in continental margins have progressively increased during the last decades, threatening vulnerable marine ecosystems in many conti- nental slopes, such as cold-water coral reefs, seamounts and canyons. In order to protect these ecosystems and ensure the sustainable management of resources, countries and organizations should endorse effective policy actions. However, nowadays about only 0.8% of the oceans and 6% of the territorial seas belong to conservation area systems, a lack of protection that is particularly acute in deep-sea waters. The Mauritanian continental margin is the outcome of exceptional marine features, with abrupt canyon systems, sediment slides and a giant carbonate-mounds barrier occurring together. Mauritanian waters have both tropical and subtropical origins, being affected by coastal and offshore upwelling that leads to elevated productivity and abundant fishery resources. Soft-bottom habitats hold high diversity of species, and hard-bottoms sustain assemblages of suspension- feeders and vulnerable species. Nevertheless, despite the recent increase of ex- tractive activities, the location and characterization of those Mauritanian deep-water areas of biological or ecological interest that require protection remain poorly known. The Maurit surveys have offered the opportunity to perform a first approach to the biodiversity and ecosystems in soft and hard bottoms of the Mauritanian outer shelf and slope. This last chapter provides an integrated overview of the demersal and benthic communities inhabiting Mauritanian deep waters and describes areas of particular ecological and/or biological interest that are vulnerable habitats and should be preserved according to international conventions.
Paraules clau: Geomorphology Water masses Biodiversity Ecosystems Megabenthos Demersal fauna Soft-bottom habitats VMEs EBSAs Coral carbonate mounds Canyons Seamount Deep sea Mauritania Northwest Africa
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Grieco G., Nirchio F., Montuori A., Migliaccio M., Lin W., Portabella M. (2016)
Proceedings of the ESA Living Planet Symposium 2016, 9 - 13 May 2016, Prague, Czech Republic, ESA SP-740 (DVD). (BibTeX: grieco.etal.2016a)
Resum: Veure
The dependency of the azimuth wavelength cut-off on the wind speed has been studied through a dataset of Sentinel-1 multi look SAR images co-located with wind speed measurements, significant wave height and mean wave direction from ECMWF operational output. A Geophysical Model Function (GMF) has been fitted and a retrieval exercise has been done comparing the results to a set of independent wind speed scatterometer measurements of the Chinese mission HY-2A. The preliminary results show that the dependency of the azimuth cut-off on the wind speed is linear only for fully developed sea states and that the agreement between the retrieved values and the measurements is good especially for high wind speed. A similar approach has been used to assess the dependency of the azimuth cut-off also for X-band COSMO-SkyMed data. The dataset is still incomplete but the preliminary results show a similar trend.
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Griego G., Lin W., Migliaccio M., Portabella M. (2016)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China, 11-15 July, 2016. (BibTeX: griego.etal.2016c)
Resum: Veure
The empirical dependence of the azimuth wavelength cut-off on the significant wave height and on the wind speed have been studied. The azimuth cut-off is estimated on the fitting of a Gaussian function to the azimuth autocorrelation function of the radar cross section. The feasibility of estimating the significant wave height and/or the wind speed has been investigated as well. We use SAR images acquired by the European Sentinel 1 from the beginning of November 2014 to the end of April 2015 co-located with the scatterometer winds acquired by the Chinese sensor HSCAT and the significant wave height from ECMWF forecasts. The correlation between the azimuth cut-off and the significant wave height is rather strong. A linear geophysical model function is fitted in order to estimate it. The dependence on the wind speed is secondary and becomes remarkable only when the sea state is fully developed. A significant wave height retrieval exercise is proposed and the results are compared with the buoy measurements of the National Data Buoy Center (NDBC) network
Paraules clau: SAR, significant wave height, Sentinel 1
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Lin W., Chiara G., Portabella M., Stoffelen A., Vogelzang J., Verhoef A. (2016)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China, 11-15 July, 2016. (BibTeX: lin.etal.2016k)
Resum: Veure
In contrast with scatterometer wind data, Numerical Weather Prediction (NWP) models do not well resolve the mesoscale sea surface wind flow under increased wind variability conditions, such as in the vicinity of low-pressure centers, frontal lines, and moist convection. In this paper, several important issues are addressed in order to improve the impact of scatterometer data assimilation into global and regional NWP models, including model error structure functions, situation-dependent Observation/ Background error estimation, and improved scatterometer wind quality control.
Paraules clau: Scatterometer, data assimilation, ambiguity removal, quality control, singularity analysis
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Lin W., Portabella M., Stoffelen A., Verhoef A., Lang S., Zhang Y., Lin M. (2016)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China, 11-15 July, 2016. (BibTeX: lin.etal.2016j)
Resum: Veure
This paper reviews several wind quality-sensitive parameters derived from HY-2A scatterometer data, such as the windinversion residual (or Maximum Likelihood Estimator, MLE) and its spatially averaged value, and the singularity exponent (SE) derived from an image processing technique, called singularity analysis. Their sensitivity to data quality is evaluated using the collocated European Centre for Medium-range Weather Forecasting (ECMWF) model output and satellite radiometer rain data. It shows that SE is the best quality indicator, followed by the spatially averaged MLE and the conventional MLE. A set of MLE and SE thresholds are derived from the sensitivity analysis in order to optimize the quality control (QC) for the HY-2A scatterometer.
Paraules clau: HY-2A scatterometer, wind, quality control, singularity exponent, rain
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Lin W., Portabella M., Stoffelen A., Vogelzang J., De Chiara G. (2016)
Technical Report Numerical Weather Prediction Satellite Application Facilities NWPSAF-KN-VS-017. (BibTeX: lin.etal.2016n)
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Olmedo E., Turiel A., Ballabrera-Poy J., Martínez J., Portabella M., González-Gambau V., Gabarró C., Pérez F., Hoareau N., Piles M., Font J. (2016)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China, 11-15 July, 2016. (BibTeX: olmedo.etal.2016c)
Resum: Veure
New ocean products from the Soil Moisture and Ocean Salinity (SMOS) mission are being developed at the Barcelona Expert Centre. Besides the already operational 9- day and monthly sea surface salinity (SSS) products, two additional daily SSS products have been recently become operational: a simple user-friendly product containing all swath-based Level 2 data for each day, and a more elaborated product that uses multifractal fusion techniques to increase the spatial and temporal resolution. Finally, experimental BEC products are also presented which provide SSS values in regions strongly affected by radiofrequency interference (RFI). Recent progress on Land-Sea contamination mitigation has been applied to the BEC products.
Paraules clau: Radiometry, SMOS, salinity
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Turiel A., González-Gambau V., Olmedo E., Martínez J., Ballabrera-Poy J., Portabella M. (2016)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS), Beijing, China, 11-15 July, 2016. (BibTeX: turiel.etal.2016g)
Resum: Veure
This work is devoted to describe the new processing techniques that are being conceived, developed and implemented at the Barcelona Expert Centre (BEC) for the generation of sea surface salinity (SSS) maps from the Soil Mooisture and Ocean Salinity (SMOS) mission. Several algorithms to mitigate the ripples and sidelobes present in the SMOS brightness temperature (TB) images, to characterize the spatial correlations in the SMOS antennas, to correct for the systematic SSS-derived biases, and to improve the spatial and temporal resolution of the SSS products, have been recently developed and are presented in this paper.
Paraules clau: Nodal sampling, fusion, bias correction
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Halpern D., Font J., Lagerloef G. (2015)
Proceedings Coordination Group for Meteorological Satellites 43rd annual meeting. NOAA. Boulder, Colorado (USA). (BibTeX: halpern.etal.2015a)
Resum: Veure
The global water balance and the relative magnitudes of its global and regional components are of fundamental importance to society and are largely unmeasured over the ocean. The advent of satellite sea surface salinity (SSS) measurements by the Soil Moisture and Ocean Salinity (SMOS) mission launched in November 2009 and the Aquarius on the fourth Argentine Satélite de Aplicaciones Cientificas (SAC-D) satellite mission launched in June 2011, respectively, opened a new era in ocean sciences. This paper outlines the new measurement systems, including a preliminary assessment on the technological challenges, and provides an overview of results, including the salt budget in the North Atlantic, tropical instability waves, Rossby waves, mesoscale motions, freshening of surface coastal waters from riverine outflow and impact on hurricane forecasting in northwest Atlantic, and SSS response to La Niña. As the SSS time series lengthen with continued mission operations, SSS data will receive additional attention in numerous studies, including the El Niño/La Niña phenomenon, Gulf Stream meanders, and global salt budget of the water balance.
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Lin W., Portabella M., Vogelzang J., Stoffelen A., Verhoef A. (2015)
Associated Scientist report for the EUMETSAT NWP SAF, KN-VS-014. (BibTeX: lin.etal.2015q)
Resum: Veure
Subcell wind variability can be directly characterized using several ASCAT-derived parameters. Triple collocation analysis is useful in the subcell variability study. At 25 km resolution, ASCAT provides the best quality winds in general. The assessment and validation of the quality of satellite scatterometer vector winds is challenging under increased subcell wind variability conditions, since reference wind sources such as buoy winds or model output represent very different spatial scales from those resolved by scatterometers (i.e., increased representativeness error). In this paper, moored buoy wind time series are used to assess the correlation between subcell wind variability and several Advanced Scatterometer (ASCAT)-derived parameters, such as the wind-inversion residual, the backscatter measurement variability factor, and the singularity exponents derived from an image processing technique, called singularity analysis. It is proven that all three ASCAT parameters are sensitive to the subcell wind variability and complementary in flagging the most variable winds, which is useful for further application. A triple collocation (TC) analysis of ASCAT, buoy, and the European Centre for Medium-range Weather Forecasting (ECMWF) model output is then performed to assess the quality of each wind data source under different variability conditions. A novel approach is used to compute the representativeness errors, a key ingredient for the TC analysis. The experimental results show that the estimated errors of each wind source increase as the subcell wind variability increases. When temporally averaged buoy winds are used instead of 10 min buoy winds, the TC analysis results in smaller buoy wind errors (notably at increased wind variability conditions) while ASCAT and ECMWF errors do not significantly change, further validating the proposed TC approach. It is concluded that at 25 km resolution,ASCAT provides the best quality winds in general.
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Olmedo E., Turiel A., Portabella M., González V., Martínez J., Ballabrera J., Font J. (2015)
SMOS BEC Technical Note, BEC-TN.2015.01 v1. (BibTeX: olmedo.etal.2015a)
Resum: Veure
In this tecnical note we analyze two different approaches for salinity retrieval in SMOS: the standard Bayesian approach and a new not-Bayesian approach. In both cases systematic, a bias correction based on SMOS-based climatologies is applied. The performance of both approaches are analysed and discussed.
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Pelegrí J.L., (2015)
Oceanographic and biological features in the Canary Current Large Marine Ecosystem. In: IOC Technical Series. Ed. L. Valdés, I. Déniz-González. IOC-UNESCO. ol. 115, 81-92. (BibTeX: pelegri.2015b)
Resum: Veure
The Cape Verde Front (CVF) separates the North Atlantic subtropical gyre (NASG) from the north‐eastern North Atlantic tropical gyre (NATG). Within the NASG, the Canary Current (CC) and the Canary Upwelling Current (CUC) comprise a relatively shallow (down to about 200‐300 m) flow of North Atlantic Central Waters (NACW): the CC is found far offshore as a wide and poorly defined current while the CUC is a near‐slope intense baroclinic jet linked to the coastal upwelling front. Within the top 300 m of the NATG, the along‐slope Mauritania Current and the Cape Verde Current (CVC, a north‐eastern extension of the North Equatorial Counter Current that broadly rotates around the Guinea Dome) carry South Atlantic Central Waters northwards. As a result, the frontal system is the site of intense along‐slope flow convergence and offshore transport in the top 300 m of the water column. Further deep, down to some 500 m, the interior flow is very weak in both gyres, likely dominated by mesoscale features, except along the continental slope, where the northward Poleward Undercurrent (PUC) feeds through localized inputs from the interior ocean; in particular, within the NATG the CVC appears as responsible for southward transfer of NACW, across the CVF, which eventually reaches the PUC.
Paraules clau: Eastern boundary currents, Cape Verde Front, Canary Upwelling Current, Poleward Undercurrent, Guinea Dome, Canary Current Large Marine Ecosystem, Northwest Africa
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Pelegrí J.L., Benazzouz A. (2015)
Oceanographic and biological features in the Canary Current Large Marine Ecosystem. In: IOC Technical Series. Ed. L. Valdés, I. Déniz-González. IOC-UNESCO. ol. 115, 93-103. (BibTeX: pelegri.benazzouz.2015b)
Resum: Veure
North of Cape Blanc, the north‐easterly winds cause offshore flow of surface waters that are replaced by subsurface inflow of relatively cold and nutrient‐rich waters, driving the vertical cell of coastal upwelling. This vertical circulation, together with surface heating and horizontal mixing, causes the coastal upwelling front (typically about 200 m deep) that separates cold onshore from warm offshore waters. A southward baroclinic coastal jet is associated to this front, which causes vertical shear and mixing that contribute to the intensity of the vertical cell. Very importantly, this jet feeds from upstream waters, resulting in an along‐slope coherent flow, or the horizontal cell of coastal upwelling - this is the Canary Upwelling Current (CUC) that connects all surface coastal African waters north of Cape Blanc. Further south, because of the northward offshore flow and the seasonality of the winds, the connection remains only during winter and spring, very close to shelf break and in the top 100 m. North of Cape Blanc, a Poleward Undercurrent (PUC) flows in the relatively homogenous upwelled waters that found over the continental slope. South of Cape Blanc the PUC appears as a nearshore expression of the Mauritania Current. Both the southward CUC and the northward PUC constitute the true skeleton of the Canary Current Large Marine Ecosystem.
Paraules clau: Coastal upwelling, Ekman transport, Recirculation cells, Canary Upwelling Current, Poleward Undercurrent, Canary Current Large Marine Ecosystem, Northwest Africa
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Pelegrí J.L., Peña‐Izquierdo  J. (2015)
Oceanographic and biological features in the Canary Current Large Marine Ecosystem. In: IOC Technical Series. Ed. L. Valdés, I. Déniz-González. IOC-UNESCO. ol. 115, 133-142. (BibTeX: pelegri.penaizquierdo.2015b)
Resum: Veure
Inorganic nutrients increase with depth as a result of the enhanced remineralization of organic matter with aging waters (the time since they were last near the sea surface), and the opposite happens with dissolved oxygen (except within the saturated surface mixed layer). In the Canary Current Large Marine Ecosystem there is also a marked latitudinal gradient, with the Cape Verde Front separating relatively nutrient‐poor and oxygen‐rich subtropical waters from the nutrient‐rich and oxygen‐poor tropical waters. Along a latitudinal band off North‐West Africa, coastal upwelling brings the subsurface waters towards the sea surface, locally raising the inorganic nutrient levels. This becomes an important lateral source to both gyre especially to the nutrient‐poor subtropical one, taking place through lateral mixing (mainly as a result of the instability of the coastal‐upwelling baroclinic jet) and localized coastal filaments (in those regions, typically capes, where the coastal flow converges and offshore advection takes place). In the southernmost portion of our domain, within tropical waters, there is also high (wind‐induced) offshore primary production. This, together with the slow ventilation of the subsurface waters, leads to much enhanced remineralization, producing a region with very low oxygen and high inorganic nutrient levels, the oxygen minimum zone of the North Atlantic Ocean.
Paraules clau: Cape Verde Front, Inorganic nutrient supply, Biogeochemical processes, Spatial distributions, Oxygen minimum zone, Canary Current Large Marine Ecosystem, Northwest Africa
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Stoffelen A., Vogelzang J., Lin W. (2015)
EUMETSAT NWP SAF Technical Report, KN-TR-024-1.0. (BibTeX: stoffelen.etal.2015d)
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Barrado C., Fuentes J.A., Salamí E., Royo P., Olariaga A.D., López J., Fuentes V.L., Gili J.M., Pastor E. (2014)
35th International Symposium on Remote Sensing of Environment (ISRSE35) 22–26 April 2013, Beijing, China. In: IOP Conference Series: Earth and Environmental Science, 17. Ed. GUO Huadong. IOP Science. 012195. DOI: 10.1088/1755-1315/17/1/012195. (BibTeX: barrado.etal.2014a)
Resum: Veure
In the last 10 years the number of jellyfish shoals that reach the swimming area of the Mediterranean Sea are increasing constantly. The term \"Jellyfish\" refers to animals from different taxonomic groups but the Scyphomedusae are within the most significant one. Four species of Scyphomedusae are the most conspicuous ones inhabiting the studied area, the Barcelona metropolitan area. Jellyfish are usually found at the surface waters, forming big swarms. This feature makes possible to detect them remotely, using a visual camera and image processing algorithms. In this paper we present the characteristics of a remote piloted aircraft capable to perform monitoring flights during the whole summer season. The requirements of the aircraft are to be easy to operate, to be able to flight at low altitude (100 m) following the buoy line (200 m from the beach line) and to be save for other users of the seaside. The remote piloted aircraft will carry a vision system and a processing board able to obtain useful information on real-time.
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Berdalet E., Artigas M.L., Llebot C., Ross O.N., Hoyer A.B., Neszi N.Z., Piera J., Rueda F., Estrada M. (2014)
Harmful Algae 2012, Proceedings of the 15th International Conference on Harmful Algae. Ed. H.G. Kim, B. Reguera, G.M. Hallegraeff, C.K. Lee, M.S. Han, J.K. Choi. International Society for the Study of Harmful Algae. 55-58. ISBN. 978-87-990827-4-2. (BibTeX: berdalet.etal.2014c)
Resum: Veure
Understanding the spatio-temporal variability of phytoplankton in aquaculture areas is necessary for the appropriate management of natural resources and the prevention of toxic outbreaks. With this objective, we combined synoptic cruises, time series of physical parameters, and modeling, to study the ecosystem of Alfacs Bay, an important shellfish and fish production area commonly affected by toxic outbreaks.Synoptic cruises performed during relevant harmful species proliferations, such as a Karlodinium spp. outbreak in 2007, showed the existence of a preferential phytoplankton accumulation area in the inner NE side of the Bay. We explored the role of nutrient supply (which takes place mainly through the irrigation channels discharging into the northern coast) and the hydrodynamic regime in explaining the observed phytoplankton distribution patterns. Based on a 3D hydrodynamic model combined with a particle-tracking module, we suggest that the phytoplankton confinement in that area could be fostered by the estuarine circulation dynamics taking place in the bay.
Paraules clau: Alfacs bay, NW Mediterranean, phytoplankton dynamics, estuarine circulation
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García-Olivares A., García-Ladona E., A. Jiménez Madrid J. (2014)
Marine Pollution: Types, Environmental Significance and Management Strategies. In: Air, Water and Soil Pollution Science and Technology. Ed. D. E. Jefferson. Nova Science Publishers. Chap. 2. 55-110. Nova York, Estados Unidos. ISBN. 978-1-63321-520-7. (BibTeX: garciaolivares.etal.2014a)
Resum: Veure
Despite the fact that water covers two-thirds of the Earth’s surface, it is surprisingly vulnerable to human influence and activity. Marine ecosystems receive large amounts of a variety of pollutants from either treated or untreated wastewater. The extensive use of chemicals and their introduction into the environment has resulted in increased public concern for the potential threats to ecosystems, human health and safety. Persistent organic pollutants such as polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers and pesticides, as well as heavy metals, surfactants; endocrine disrupting chemicals or personal care products and pharmaceuticals are pollutants usually present in marine environments. This book focuses on discussing the types of marine pollutants. It provides topics on the environmental significance and management strategies available. (Imprint: Nova)
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Garçon V.C., G. Bell T., Wallace D., Arnold S.R., Baker A., Bakker D.C.E., W. Bange H., Bates N.R., Bopp L., Boutin J., W. Boyd P., Bracher A., P. Burrows J., J. Carpenter L., de Leeuw G., Fennel K., Font J., Friedrich T., Garbe C.S., Gruber N., Jaeglé L., Lana A., D. Lee J., S. Liss P., A. Miller L., Olgun N., Olsen A., Pfeil B., Quack B., A. Read K., Reul N., Rödenbeck C., S. Rohekar S., Saiz-Lopez A., S. Saltzman E., Schneising O., Schuster U., Seferian R., Steinhoff T., Le Traon P.-Y., Ziska F. (2014)
Ocean-Atmosphere Interactions of Gases and Particles. Ed. P. Liss, M.T. Johnson. Springer Earth System Sciences. Chap. 5. 247-306. DOI: 10.1007/978-3-642-25643-1_5. ISBN. 9783642256424. (BibTeX: garcon.etal.2014a)
Resum: Veure
Why a chapter on Perspectives and Integration in SOLAS Science in this book? SOLAS science by its nature deals with interactions that occur: across a wide spectrum of time and space scales, involve gases and particles, between the ocean and the atmosphere, across many disciplines including chemistry, biology, optics, physics, mathematics, computing, socio-economics and consequently interactions between many different scientists and across scientific generations. This chapter provides a guide through the remarkable diversity of cross-cutting approaches and tools in the gigantic puzzle of the SOLAS realm. Here we overview the existing prime components of atmospheric and oceanic observing systems, with the acquisition of ocean–atmosphere observables either from in situ or from satellites, the rich hierarchy of models to test our knowledge of Earth System functioning, and the tremendous efforts accomplished over the last decade within the COST Action 735 and SOLAS Integration project frameworks to understand, as best we can, the current physical and biogeochemical state of the atmosphere and ocean commons. A few SOLAS integrative studie illustrate the full meaning of interactions, paving the way for even tighter connections between thematic fields. Ultimately, SOLAS research will also develop with an enhanced consideration of societal demand while preserving fundamental research coherency. The exchange of energy, gases and particles across the air-sea interface is controlled by a variety of biological, chemical and physical processes that operate across broad spatial and temporal scales. These processes influence the composition, biogeochemical and chemical properties of both the oceanic and atmospheric boundary layers and ultimately shape the Earth system response to climate and environmental change, as detailed in the previous four chapters. In this crosscutting chapter we present some of the SOLAS achievements over the last decade in terms of integration, upscaling observational information from processoriented studies and expeditionary research with key tools such as remote sensing and modelling. Here we do not pretend to encompass the entire legacy of SOLAS efforts but rather offer a selective view of some of the major integrative SOLAS studies that combined available pieces of the immense jigsaw puzzle. These include, for instance, COST efforts to build up global climatologies of SOLAS relevant parameters such as dimethyl sulphide, interconnection between volcanic ash and ecosystem response in the eastern subarctic North Pacific, optimal strategy to derive basin-scale CO2 uptake with good precision, or significant reduction of the uncertainties in sea-salt aerosol source functions. Predicting the future trajectory of Earth’s climate and habitability is the main task ahead. Some possible routes for the SOLAS scientific community to reach this overarching goal conclude the chapter
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González-Gambau V., Corbella I., Torres F., Duffo N., Turiel A. (2014)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS). IEEE. 1917,1920. Quebec, Canada. DOI: 10.1109/IGARSS.2014.6946833. (BibTeX: gonzalezgambau.etal.2014)
Resum: Veure
The consistency of MIRAS amplitude calibration along the mission is a key issue to ensure a stable and accurate longterm dataset of ESA’s SMOS soil moisture and ocean salinity data. Recent studies have revealed latitudinal and seasonal drifts in some receivers of the instrument. This paper focuses on the assessment of MIRAS amplitude calibration consistency using the available long-term dataset. A methodology is presented to evaluate residual amplitude calibration errors and to investigate the origin of these deviations.
Paraules clau: SMOS, MIRAS, interferometric radiometer, amplitude calibration
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Herrero C., García-Olivares A. (2014)
Proceedings ITISE 2014 International work-conference On Time Series. ol. 2, 1068 -1080. ISBN. 978-84-15814-97-4. (BibTeX: herrero.garciaolivares.2014)
Resum: Veure
The results of a simulated CO2 (C) and a global ice volume (V ) time series, derived from a simple relaxation model of the glacialinterglacial cycles[1], have been analyzed using non-linear techniques. On a first approximation, we have compared simulated time series with the corresponding observational time series, obtaining correlations of 0.88 between the proxy-record !18O([2]) and simulated V , and 0.79 between the reconstructed atmospheric CO2 concentration([2–7]) and simulated C, used to quantify the maximum observational variance that this simple model is able to explain. Fourier transform, wavelet transform, cross-wavelet transform, wavelet coherence and cross-recurrence analysis are useful tools to quantify the performance of a model at reproducing the dynamics embedded in observational time series. The analysis shows that the model reproduces closely the dynamics embedded in the ice volume time series, but for the CO2 case the coherence between simulated and observational CO2 is only sporadic, indicating that both time series do not follow the same dynamical behavior, although, in the deglacial periods the two carbon series become dynamically close. The analysis reinforces the hypothesis that some specific mechanisms included in the model are able to closely reproduce the glacial-interglacial oscillations and thus suggests which specific mechanisms should be more seriously investigated in the climate system. These techniques may be applied to other climatic time series to quantify the performance of a model simulating the dynamics of the climate system
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Lin W., Portabella M., Stoffelen A., Vogelzang J., Verhoef A., Turiel A., González V. (2014)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS). IEEE. Quebec, Canada. (BibTeX: lin.etal.2014b)
Resum: Veure
The current ASCAT Wind Data Processor (AWDP) uses the 2D variational ambiguity removal (2DVAR) scheme to select a unique wind field from a set of retrieved ambiguities. This has led to spatially consistent and accurate ASCAT Level 2 wind products. Nevertheless, recent research shows that 2DVAR picks up the wrong wind direction ambiguities in regions where the background field shows mislocation of fronts (convergence) or misses convective systems. In this paper, the exploitation of complementary information derived from the inversion and from an image processing technique is proposed to improve the current 2DVAR for ASCAT in mesoscale conditions.
Paraules clau: ASCAT, ambiguity removal, MLE, singularity analisys, rain effects
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Pablos M., Piles M., Sánchez N., González-Gambau V., Vall-llossera M., Camps A., Martínez-Fernández J. (2014)
Proc. of the International Geoscience and Remote Sensing Symposium (IGARSS). IEEE. 3267- 3269. Quebec, Canada. DOI: 10.1109/IGARSS.2014.6947176. (BibTeX: pablos.etal.2014)
Resum: Veure
Surface Soil Moisture (SSM) affects the soil surface energy balance and thus affects the Land Surface Temperature (LST), and viceversa. Currently, LST and SSMare remotely sensed using TIR sensors and L-band radiometers, respectively. The NASA’s Terra/Aqua missions provide full coverage of LST measurements under clear sky conditions using MODIS. The ESA’s SMOS mission is the first satellite providing frequent SSM and ocean salinity observations at global scale. In this paper, a sensitivity study about the relationship of the LST and SSM is performed using in-situ measurements from the REMEDHUS network and spaceborne observations from MODIS and SMOS. Results show that the correlation between SSM and LST (both in-situ and remotely sensed) is highest using the daily maximum LST. This could help improving SSM algorithms and deriving new SSM products at higher resolution from the synergy of microwave and TIR observations.
Paraules clau: Land surface temperature, surface soil moisture, passive microwave remote sensing, L-band radiometer, TIR sensors, REMEDHUS network, MODIS, Terra/Aqua mission, SMOS mission.
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Portabella M., Lin W., Stoffelen A., Verhoef A., Turiel A. (2014)
Associated Scientist report for the EUMETSAT OSI SAF/OSI/CDOP2/KNMI/SCI/RP/213. (BibTeX: portabella.etal.2014b)
Resum: Veure
The Advanced Scatterometer (ASCAT) onboard the Me top satellite series is designed to measure the ocean surface wind vectors globally. Generally, ASCAT provides wind products at excellent quality. The quality of the Advanced Scatterometer (ASCAT) derived winds is known to be generally degraded with increasing values of the inversion residual or maximum likelihood estimator (MLE). In the current ASCAT Wind Data Processor (AWDP), an MLE-based Quality control (QC) is adopted to filter poor-quality winds, which has proven to be effective in screening artifacts in the ASCAT winds, associated with increased sub-cell wind variability, notably under rain conditions. However, some poorly verifying winds, which appear in areas with convection, are not screened by the operational QC.
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Verspeek J., Stoffelen A., Verhoef A., Portabella M. (2014)
Proc. 2014 EUMETSAT Satellite Conference. EUMETSAT. 64. Geneva, Suiza. (BibTeX: verspeek.etal.2014)
Resum: Veure
An ocean calibration method for scatterometer wind data is developed at KNMI. The method is based on a direct comparison of measured backscatter data with simulated backscatter data from Numerical Weather Prediction (NWP) winds. This NWP Ocean Calibration tool (NOC) is used to improve the scatterometer wind products and can be used to eliminate systematic interbeam biases and across-swath dependencies (when present) in the wind product. Monte Carlo simulations are useful to assess the accuracy of the NOC method and to determine the sensitivity with respect to binning and sampling errors. As such, simulation runs with realistic “true” wind distribution and realistic measurement and NWP wind-component error values are performed. A reprocessing of QuikSCAT data over its whole lifespan (1999-2009) is being performed by KNMI. The averaged NOC residuals over a longer period are used to calculate correction factors and used to improve the wind retrieval.
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Bardají R., Zafra E., Piera J. (2013)
Instrumentation Viewpoint. ol. 15, 13. (BibTeX: bardaji.etal.2013c)
Resum: Veure
The Citclops European Project aims to develop low-cost technologies to estimate parameters related to water optical properties. The light diffuse attenuation coefficient (Kd) is one of those parameters, which provide information related to water transparency. As a potential low-cost solution for Kd estimation, a moored instrument has been designed based on the open-hardware Arduino platform and quasidigital (light-frequency) sensors. The present contribution analyses, using a model based approach, the configuration of the light sensors of this system (sensitivity and vertical position) to assure the optimal Kd estimation.
Paraules clau: Buoy technology; Low cost sensors; Do it yourself; Oceanographic instrumentation and sensors
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Emelianov M., Font J., Puig P., Martín J., García Ladona E., Salat J., Ostrovskii A., Zatsepin A., Kremenetskiy V., Soloviev V., Tsibulskiy A., Shvoev D. (2013)
Rapports et Proces-verbaux des Réunions. Com. Int. Explor. Sci. Mer Mediterranée, CIESM.. ol. 40, (BibTeX: emelianov.etal.2013a)
Resum: Veure
A pilot experiment aiming at investigating the small scale dynamics and variability of the seawater fine thermohaline structure, the processes of vertical exchange of momentum and mass, and mechanisms of the nepheloid layer formation in the Besòs submarine canyon, situated in the continental slope close to Barcelona, was carried out by using the prototype moored profiler “Aqualog”.
Paraules clau: Instruments and techniques, North-Western Mediterranean
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1.69 Mb
Fernández P., Salvador J., Font J., Pelegrí J.L., García Ladona E. (2013)
Instrumentation Viewpoint. ol. 15, 27. (BibTeX: fernandez.etal.2013d)
Resum: Veure
Since2005 the ICM-CSIC has designed, built and tested surface drifting buoys for the measurement of several oceanographic parameters, mainly temperature and salinity. These prototypes have evolved and been adapted to different sampling needs and strategies. We present here the main characteristics and capabilities of these last developments
Paraules clau: Oceanographic instrumentation, Lagrangian buoys, surface drifters, salinity, temperature
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2.46 Mb
García-Ladona E., Salat J., Ballabrera J. (2013)
El Agua y la Vida. Cooperación en la Esfera del Agua. Ed. M. Boada, R. Maneja. Lunwerg. 68-71. ISBN. 978-84-15888-08-6. (BibTeX: garcialadona.etal.2013a)
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García-Olivares A., Turiel A. (2013)
Fossil Fuels, Sources, Environmental Concerns and Waste Management Practices. Ed. Kumar, R. Nova Science Publishers. Chap. 10. 271-290. Nova York, Estados Unidos. ISBN. 978-162808-412-2. (BibTeX: garciaolivares.turiel.2013b)
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7.42 Mb
Johannessen J.A., Chapron B., Alpers W., Collard F., Cipollini P., Liu A., Horstmann J., Da Silva J.C.B., Portabella M., Robinson I.S., Holt B., Wackerman C., Vachon P. (2013)
ERS Missions: 20 Years of Observing Earth. In: ESA SP-1326. Ed. K. Fletcher. European Space Agency. Chap. 6. 201-224. ISBN. 978-92-9221-424-1. (BibTeX: johannessen.etal.2013b)
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2.34 Mb
Olivé J., Piera J., Sorribas J., Bardají R. (2013)
Instrumentation Viewpoint. ol. 15, 26. (BibTeX: olive.etal.2013c)
Resum: Veure
The Citclops European Project aims to develop low-cost technologies to estimate parameters related to water optical properties. The wide variety of sensors involved makes it desirable to have a standardized description of the sensor itself and the data acquired by the sensor. This project presents a practical approach to modeling thess descriptions and the graphical representation of this information.
Paraules clau: SOS, SensorML, O&M, marine, Android, IoT, XML
Pablos M., Piles M., González V., Vall-llossera M., Camps A. (2013)
Proceedings Geoscience and Remote Sensing Symposium (IGARSS), 2013. Ed. IEEE. 386-389. Melbourne, VIC. DOI: 10.1109/IGARSS.2013.6721173. ISBN. 978-1-4799-1114-1. (BibTeX: pablos.etal.2013e)
Resum: Veure
The spectral window at L-band (1.400 - 1.427 GHz) is reserved for passive microwave remote sensing. This band is well-suited to retrieve soil moisture and ocean salinity due to emissivity of soil and seawater decreases with moisture and salinity, respectively, affecting microwave radiation of the Earth\'s surface. Nowadays, there are two space missions devoted to Earth observation with L-band radiometers on-board: the SMOS mission from the ESA and the Aquarius/SAC-D mission from the NASA and CONAE. Both missions are providing the first TB measurements of the Earth\'s surface at 1.413 GHz. Thus, it is a great opportunity to compare SMOS and Aquarius TBs and verify the continuity and consistency of the data. This inter-comparison is a key requirement needed to use data of both radiometers for meteorological, hydrological and climatological studies on a long term.
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1.86 Mb
Pujol N., Piera J. (2013)
Instrumentation Viewpoint. ol. 15, 25. (BibTeX: pujol.piera.2013b)
Resum: Veure
ANERIS is a multidisciplinary project focused on the design and development of an innovative profiler. As main innovation, the vertical profiler has the capability to obtain microstructure profiles and spectrometric data simultaneously with high resolution in a totally autonomous way.
Paraules clau: vertical profiler, innovation, autonomous, hyperspectral, CMIMA-CSIC
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1.72 Mb
Ramírez-Pérez M., Torrecilla E., Guillén J., Piera J. (2013)
Instrumentation Viewpoint. ol. 15, 14. (BibTeX: ramirezperez.etal.2013b)
Resum: Veure
A method is described for discriminating the size of inorganic suspended particles based on hyperspectral attenuation spectra. In this study, the beam attenuation spectra of different samples with different suspended sediment sizes (i.e., from mud, <5 μm, to fine sand, 125-250 μm), were measured in the laboratory using a hyperspectral attenuation meter (VIPER instrument with a 5 cm path length and 1.7 nm spectral resolution). In order to classify the measured spectra according to their relative similarity, a hierarchical cluster analysis has been applied and the results have been represented in a Multi-dimensional scaling graphic. Our results show that the changes in the attenuation spectral signature are according to the particle size. The applied methodology clearly allows discriminating samples with different particle size ranges. The hyperspectral attenuation meter can therefore be considered a powerful instrument for these purposes, because of the high spectral resolution and relative lower cost compared to other commercial instruments. Furthermore, it is possible to design hyperspectral attenuation meters with smaller size and relatively low-consumption that could be incorporated into different observing autonomous platforms, such as gliders, profilers and autonomous underwater vehicles.
Paraules clau: hyperspectral attenuation spectra, particle size distribution, hierarchical cluster analysis, multidimensional scaling
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Sabia R., Marconcini M., Katagis T., Fernández-Prieto D., Portabella M. (2013)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS) 2013. IEEE. Ed. IEEE. 1555-1558. Melbourne, VIC. DOI: 10.1109/IGARSS.2013.6723085. ISBN. 978-1-4799-1114-1. (BibTeX: sabia.etal.2013d)
Resum: Veure
A sounding of the capabilities of a novel salinity retrieval strategy by means of Support Vector Regression (SVR) has been performed. SMOS brightness temperatures measurements and additional auxiliary parameters have been co-located with salinity data collected by ARGO buoys, which represented the ground-truth to be matched by the algorithm. Salinity fields estimated by the SVR are in good agreement with the ground-truth, suggesting that the chosen approach can be promising, despite its robustness and versatility are under further assessment over wider areas and time lags, and in various combinations of SMOS features
Paraules clau: SMOS, Ocean Salinity, Regression, Support Vector Machines.
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2.17 Mb
Simon C., Piera J. (2013)
Instrumentation Viewpoint. ol. 15, 12-15. (BibTeX: simon.piera.2013c)
Resum: Veure
Based on crowdsourcing data, the study aims at developing a simple method to automatically compute the water transparency. With underwater camera pictures, an image processing technique should provide robust estimations of parameters re- lated to water transparency. We will mainly see the first step: estimating the distance from the image to the camera and the optimal choice of a pattern to photograph.
Paraules clau: Image processing, Distance estimation, Crowdsourcing, Underwater imaging
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Stoffelen A., Verhoef A., Verpeek J., Vogelzang J., Driesenaar T., Risheng Y., De Chiara G., Payan C., Cotton J., Bentamy A., Portabella M. (2013)
44 pp. (BibTeX: stoffelen.etal.2013b)
Resum: Veure
Final report of the project initiated in response to the Indian Space Research Organisation (ISRO) Announcement of Opportunity (AO) call for the calibration and validation of the OceanSat-2 mission instruments by the Royal Netherlands Meteorological Institute (KNMI) within the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). Satellite Application Facility (SAF) Network under responsibility of the Numerical Weather Prediction (NWP) SAF and the Ocean and Sea Ice (OSI) SAF. NWP SAF report number: NWPSAF-KN-TR-022 OSI SAF report number: SAF/OSI/CDOP2/KNMI/TEC/RP/196
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Turiel A. (2013)
Quaderns de Medi Ambient. Governança de la sostenibilitat i el canvi climàtic en l'àmbit local. Ed. Mita Castañer, Sergi Nuss. Documenta Universitaria. ol. 3, 27-44. ISBN. 978-84-9984-168-7. (BibTeX: turiel.2013c)
Resum: Veure
Alguns autors, i fins i tot poders públics, reconeixen el paper de la crisi energètica que s'està desenvolupant com una de les claus de la present crisi econòmica i financera, i particularment de la seva durada. Tot i això, les polítiques que s'intenten promoure des de les institucions públiques posen l'accent en els aspectes merament energètics del problema, promovent mesures com ara l’estalvi o l'eficàcia, sense tenir en compte la forta interacció d'aquestes mesures amb el sector productiu i els seus efectes indesitjables. En realitat, la crisi energètica no és res més que un altre símptoma d'una crisi global i holística. En aquest sentit, les entitats locals estan cridades a exercir un paper clau, tota vegada que un dels efectes secundaris de la crisi energètica és la desglobalització o relocalització.
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Verspeek J., Stoffelen A., Verhoef A., Portabella M., Vogelzang J. (2013)
2013 EUMETSAT Meteorological Satellite Conference. 62. Viena, Austria. (BibTeX: verspeek.etal.2013a)
Resum: Veure
The EUMETSAT Metop-B satellite with onboard the Advanced Scatterometer (ASCAT) has been successfully launched on September 17, 2012. ASCAT-B onboard Metop-B is identical to the already operational scatterometer ASCAT-A onboard Metop-A which was launched in 2006. KNMI has further developed an ocean calibration method for ASCAT-A, based on Numerical Weather Prediction (NWP) wind inputs, the so-called NWP Ocean Calibration (NOC). When the corrections based on NOC are applied to MetOp-B backscatter data, also the MetOp-B wind retrieval quality improves to a level very similar to the ASCAT-A wind quality.
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Weissman D., Johnson T., Wolf J., Portabella M., Lin W., Stoffelen A., Verhoef A. (2013)
Procceedings OCEANS’13 Conference. (BibTeX: weissman.etal.2013a)
Resum: Veure
Improving the quality of Advanced Scatterometer (ASCAT) derived winds in the presence of rain has been challenging due to the coarse spatial and time resolution of available rain information. A new effort is in progress that which will provide high spatial and time resolution surface rain rates coincident with ASCAT data collection off the coastlines in the Gulf of Mexico and Florida, using groundbased radar sensors. Preliminary results show that the NRCS is appreciable affected by the surface rainrate due to splash effects and also due the variation of wind speeds within and surrounding region. There are also indications that the ECMWF winds are not able to incorporate rain events and their air-sea interaction propererties.
Paraules clau: ASCAT, NEXRAD, ocean winds, scatterometer
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Company J.B., Ramirez-Llodra E., Sardà F., Aguzzi J., Puig P., Canals M., Calafat A., Palanques A., Solé M., Sanchez-Vidal A., Martín J., Lastras G., Tecchio S., Koenig S., Fernandez-Arcaya U., Mechó A., Fernández P. (2012)
Mediterranean Submarine Canyons: Ecology and Governance. Ed. Würtz M. (Ed.). IUCN. Chap. 3.8. 133-144. ISBN. 978-2-8317-1469-1. (BibTeX: company.etal.2012b)
Resum: Veure
IUCN, Centre for Mediterranean Cooperation; UNEP, Mediterranean Action Plan for the Barcelona Convention (MAP); Regional Activity Center for Specially Protected Areas (RAC/SPA); IUCN, Global Marine Programme; France, Ministère de l\'Ecologie, de l\'Energie, du Développement Durable, des Transports et du Logement; France, Ministère des Affaires Etrangères et Européennes; France, Agence des aires marines protégées; Fondation MAVA pour la nature; Total Foundation; Musée océanographique de Monaco, MC; Musée océanographique; Institut océanographique, Fondation Albert 1er, Prince de Monaco, MC Although there is a common agreement on the importance of conservation of Mediterranean submarine canyons amongst international organizations, their governance is complex: the canyons\' extension covers waters and seabeds under various types of jurisdictions (territorial waters, Fisheries Protection Zone, Ecological Protection Zone, including delimitation issues). Conservation of deep-sea features, such as canyons, requires improving our understanding of the biological and ecological role of these ecosystems, threats and conservation issues, limits and chances of national and international jurisdictions. This report has been written with the intention of meeting this need by reviewing interdisciplinary contributions of experts from various Mediterranean countries.
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Corral A., Turiel A. (2012)
Extreme Events and Natural Hazards: The Complexity Perspective. Ed. A. S. Sharma, A. Bunde, V. P. Dimri, and D. N. Baker. American Geophysical Union. ol. 196, 111-125. Washington D.C. (USA). ISBN. 978-0-87590-486-3. (BibTeX: corral.turiel.2012)
Resum: Veure
Tropical cyclones are affected by a large number of climatic factors, which translates into complex patterns of occurrence. The variability of annual metrics of tropical cyclone activity has been intensively studied since the sudden activation of the North Atlantic in the mid-1990s.We provide an overview of work by diverse authors about these annual metrics for the North Atlantic basin, where the natural variability of the phenomenon, the existence of trends, the drawbacks of the records, and the influence of global warming have been the subject of interesting debates. Next, we present an alternative approach that does not focus on seasonal features but on the characteristics of single events. Thus, the individual-storm power dissipation index (PDI) constitutes a natural way to describe each event, with its statistics yielding a robust law for the occurrence of tropical cyclones in terms of a power law distribution. As an important extension, we model the whole range of the PDI density (excluding incompleteness effects at the smallest values) with the gamma distribution, consisting of a power law with an exponential tail. The characteristic scale of this decay, represented by the cutoff parameter, provides very valuable information on the finite size of the basin via the largest values of the PDIs that the basin can sustain. We use the gamma fit to evaluate the positive influence on the occurrence of extreme PDI values of sea surface temperature, the positive phase of the Atlantic multidecadal oscillation, the number of hurricanes in a season, and extreme negative values of the multivariate El Niño–Southern Oscillation index.
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Cristo A., Sabia R., Talone M., Fernández-Prieto D., Portabella M. (2012)
Proceedings IEEE GOLD Remote Sensing Conference 4-5 June. 3 p. Rome, Italy. (BibTeX: cristo.etal.2012b)
Resum: Veure
The ESA Soil Moisture and Ocean Salinity (SMOS) mission aims at providing, over the oceans, Sea Surface Salinity (SSS) maps with spatial and temporal coverage adequate for large scale oceanography. The MIRAS payload provides the brightness temperature measurements (TB, Level 1 data) to be ingested in the inversion scheme to retrieve SSS in a single satellite overpass (Level 2 product). Besides, in order to reduce measurements’ noise, spatio-temporal averaging of the retrieved L2 SSS has to be properly performed (Level 3 product) to meet the challenging mission requirements. At high geographical latitudes Sea Surface Temperature (SST) is generally low and it is known that the TB sensitivity to SSS decreases at colder SSTs. Conversely, at those latitudes, an improvement in the Level 3 retrieved SSS performances should be expected, due to the increased sampling of pixels at the same longitude in successive latitudes. In this study, an extension of previous work on this topic has been performed, in various retrieval configurations and settings, once a tight data filtering strategy is applied. Quantitative rate of changes with the SST variability are provided together with the net oversampling contribution to the L3 SSS accuracy.
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Font J., Vaqué D. (2012)
Scientia Marina. Ed. D. Vaqué. ICM-CSIC. ol. 76, Chap. 3. 423-423. Barcelona. DOI: 10.3989/scimar.03734.12B. (BibTeX: font.vaque.2012c)
Resum: Veure
The Mediterranean Sea is an unusual basin that has interesting characteristics for ocean dynamics studies. As it is a semi-enclosed sea under a semi-arid climate, it appears to behave as a negative estuary: the water loss by evaporation over the year exceeds the water input from precipitation and river runoff. This generates an increase in salinity that is compensated by an intense exchange at the strait of Gibraltar, through which it exports salty water to the Atlantic at depth and imports fresher water at the surface. This feature is linked to the strong seasonality observed in the Mediterranean water mass structure, with a vertical temperature stratification of the surface layer that is enhanced in summer and destroyed in winter, and a great impact on sea level variability due to seasonal density changes. Even sea level does not display great tidal amplitudes as in other ocean basins: its temporal evolution at different scales reflects the consequences of the climatic variability in the region. The featured article in this issue of Scientia Marina is “Comparison of satellite altimetry sea level anomalies and hydrographic observations in the Mediterranean Sea”, written by F.M. Calafat and M. Marcos. The authors use two complementary sources of data to obtain information on the characteristics of sea level variability over a period of 15 years. In situ measurements of temperature and salinity allow the changes in water height linked to variable density conditions to be computed. Also, the satellite observations of sea level that are now available through radar altimetry and—in the most recent last period—through mass determination by gravimetric space missions provide a different way of estimating the steric sea level that can then be compared with in situ determinations. An analysis of these data sets provides the opportunity to examine the representativeness and limitations of the existing hydrographic information and to determine the best way to use it for sea level variability studies. This issue also includes the obituary of Dr. Miquel Massutí Oliver (1930-2012), a renowned fisheries oceanographer from the Spanish Institute of Oceanography in the Balearic Islands, and the biography of Dr. Carles Bas, the fourth director (1983-1987) of the Spanish National Research Council’s Institute of Fisheries Research (Instituto de Investigaciones Pesqueras, IIP).
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Font J., Gabarró C., Piles M., Ballabrera J., Turiel A., Martínez J., Portabella M., Camps A., Vall-llosera M., Gourrion J., Hoareau N., Umbert M. (2012)
Microwave Radiometry and Remote Sensing of the Environment (MicroRad), 2012 12th Specialist Meeting on. DOI: 10.1109/MicroRad.2012.6185236. ISBN. 978-1-4673-1468-8. (BibTeX: font.etal.2012o)
Resum: Veure
This paper presents the soil moisture and ocean salinity maps from the SMOS mission generated operationally by the Spanish SMOS Level 3 and 4 data processing center (CP34) and experimentally by the SMOS Barcelona Expert Center (SMOS-BEC).
Paraules clau: SMOS mission; soil moisture; ocean salinity; level 3 and 4 products; CP34; SMOS-BEC
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Gabarró C., González V., Martínez J., Guimbard S., Gourrion J., Piles M., Portabella M., Font J. (2012)
IEEE International Geoscience and Remote Sensing Symposium (IGARSS 2012). 2613 - 2616. Munich, Germany. DOI: 10.1109/IGARSS.2012.6350940. ISBN. 978-1-4673-1160-1. (BibTeX: gabarro.etal.2012c)
Resum: Veure
Radiometer using Aperture Synthesis (MIRAS) onboard the Soil Moisture and Ocean Salinity (SMOS) satellite are used to maintain the operating frequency of the 69 receivers. The phase of the LO drifts over time, in turn blurring the MIRAS brightness temperature (TB) measurements. After a pre-launch assessment, it was decided to calibrate the LO every 10 minutes to reduce the phase drifts. During short periods of the first 2.5 years of SMOS mission, the LO calibration has been performed every 2 minutes to assess the impact of a higher calibration frequency on the quality of the data. In this study, relative differences (10-min TBs versus 2-min TBs) of about 0.3 K are shown, which lead to non-negligible relative differences of about 0.2-0.3 practical salinity units (psu) in the retrieved sea surface salinity (SSS). However, when performing independent validation against Argo float SSS data at Level 3 (spatio-temporally averaged SSS products), no significant differences are found between 10-min and 2-min data. This is due to the fact that current SMOS SSS accuracy (relative to Argo) is about 0.6-0.8 psu, thus masking the relatively smaller LO calibration frequency effect.
Paraules clau: SMOS, local oscillator calibration, brightness temperature, sea surface salinity retrievals.
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Lin W., Portabella M., Stoffelen A., , Verhoef A., Verspeek J., Ballabrera J., Vogelzang J. (2012)
Proccedings International Geoscience and Remote Sensing Symposium (IGARSS) 22-27 July. IEEE. 4 p. Munich, Germany. (BibTeX: lin.etal.2012a)
Resum: Veure
In this study, the rain impact on the ASCAT operational Level 2 retrieved wind quality and the effectiveness of the quality control (QC) are investigated. It is shown that ASCAT is much less affected by direct rain effects, such as ocean splashing, but effects of increased wind variability appear to dominate. The operational QC proves to be effective in screening these artifacts, but at the expense of valuable winds. An image processing method, known as the singularity analysis, is proposed in this study to complement the current QC, and its potential is illustrated.
Paraules clau: ASCAT, rain effects, quality control, MLE, singularity analysis
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Malanotte-Rizzoli P., Pan-Med Group (J. Font the, García-Ladona ...) E. (2012)
Report of the Workshop. Ed. UNESCO, IOC, CIESM. 48 pp. (BibTeX: malanotterizzoli.etal.2012d)
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Portabella M., Stoffelen A., Lin W., Verhoef A., Verspeek J. (2012)
pp. 37. (BibTeX: portabella.etal.2012i)
Resum: Veure
An important part of the scatterometer wind data processing is the quality control (QC). This report shows the implementation of a new scatterometer QC procedure, based on a comprehensive analysis of the wind inversion residual, which significantly improves the effectiveness of the wind data QC. The method is applied on the Advanced Scatterometer (ASCAT) onboard Metop-A, but is generic and can therefore be applied to any scatterometer system. The method is also used to analyse the C-band geophysical model function (CMOD5n). It turns out that for winds around 4 m/s, the GMF does not match the ASCAT measurements, therefore indicating a GMF misfit or error. In this study, the rain impact on the ASCAT QC and retrieved winds is thoroughly investigated using the European Centre for Medium-range Weather Forecasts (ECMWF) model winds, the Tropical Rainfall Measuring Mission’s (TRMM) Microwave Imager (TMI) rain data, and tropical buoy wind and precipitation data as reference. In contrast to Ku-band, it is shown that C-band is much less affected by direct rain effects, such as ocean splash, but effects of increased wind variability appear to dominate ASCAT wind retrieval. ECMWF winds do not well resolve the air flow under rainy conditions. ASCAT winds do, but also show artefacts in both the wind speed and the wind direction distributions for high rain rates. The operational QC proves to be effective in screening these artefacts, but at the expense of many valuable winds.
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Sabia R., Marconcini M., Katagis T., Fernández-Prieto D., Martinez J., Portabella M. (2012)
Proceedings International Geoscience and Remote Sensing Symposium (IGARSS) 22-27 July. IEEE. 4 p. Munich, Germany. (BibTeX: sabia.etal.2012c)
Resum: Veure
A prospective sounding of the capabilities of a novel salinity retrieval by means of Support Vector Regression has been performed. Co-located SMOS measurements and additional auxiliary parameters have been considered, whilst salinity data collected by ARGO buoys represented the ground-truth to be matched by the algorithm. Salinity fields estimated by the SVR are in good agreement with the ground-truth, suggesting that the chosen approach can be promising, despite its robustness and versatility needs to be assessed over wider areas and time lags, and in various combinations of SMOS features.
Paraules clau: SMOS, Ocean Salinity, Regression, Support Vector Machines.
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Sabia R., Talone M., Portabella M., Fernández-Prieto D., Gourrion J., Camps A., Font J. (2012)
Microwave Radiometry and Remote Sensing of the Environment (MicroRad), 2012 12th Specialist Meeting on. DOI: 10.1109/MicroRad.2012.6185232. ISBN. 978-1-4673-1468-8. (BibTeX: sabia.etal.2012b)
Resum: Veure
A study of the latitudinal trend of the retrieved salinity performances along a Southwards transect has been performed, analyzing the trade-off between geophysical effects in cold seawater and the concomitant temporal oversampling under various processing configurations. Quantitative sensitivity with respect to sea surface temperature gradient has been evaluated
Paraules clau: SMOS, Radiometry, Sea Surface Salinity, Sea Surface Temperature, Spatial averaging, Temporal sampling
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Turiel A., Portabella M., Lin W., Ballabrera J. (2012)
SMOS BEC Technical Note, BEC-TN.2012.02 v1. (BibTeX: turiel.etal.2012a)
Resum: Veure
New image processing techniques derived from the study of turbulent ows have demon- strated a great potential in geophysical studies. For instance, the singularity analysis allows to derive instantaneous information on sea surface currents from remote sensing maps of scalars. However, such techniques can also be used to detect acquisition and/or processing errors in remote sensing maps, therefore opening the way to improve their quality control procedure. In this paper singularity analysis is applied to the Advanced scatterometer (AS- CAT) retrieved sea-surface wind eld maps. Retrieval errors, notably wind direction errors as induced by e.g., presence of wind fronts, lead to spurious singularity fronts. The location of such spurious singularities is generally in good correspondence with the location of the ASCAT operational QC'ed data. Singularity analysis can hence be applied as a comple-mentary tool to existing scatterometer QC procedures. The tool is generic and therefore has great potential for assessing other types of geophysical data
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Verspeek J., Stoffelen A., Verhoef A., Portabella M., Vogelzang J., (2012)
Proceedings EUMETSAT Meteorological Satellite Conference, , 3-7 September. 8 p. Sopot, Poland. (BibTeX: verspeek.etal.2012b)
Resum: Veure
The Metop-B satellite with onboard the Advanced Scatterometer (ASCAT) has been successfully launched on September 17, 2012. The ASCAT instrument is a C-band vertically-polarized fan antennae beam system. ASCAT-B onboard Metop-B is identical to the already operational scatterometer ASCAT-A onboard Metop-A which was launched in 2006. Within the framework of the Ocean & Sea Ice (OSI) Satellite Application Facility (SAF), KNMI has developed an ocean calibration method, based on Numerical Weather Prediction (NWP) wind inputs, the so-called NWP Ocean Calibration (NOC). The NOC method resides in direct comparison of measured backscatter data with simulated backscatter data from NWP winds using a forward model or Geophysical Model Function (GMF). For ASCAT, the CMOD5.n GMF is used, which is compliant with the GMF of its predecessor, the European Remote-sensing Satellite (ERS) scatterometer. The radar backscatter triplets can be visualized in a 3-dimensional measurement space. For a given Wind Vector Cell (WVC), i.e., position across the swath, the measured triplets are distributed around the GMF, which constitutes a well-defined conical surface that depends on wind speed and wind direction only. Systematic displacements of the cloud of triplets in any direction of the 3D space are mainly due to absolute beam biases, which are adequately removed by the results of the NOC. The NOC corrections are furthermore split into a smooth incidence angle dependent part, which is to be included in the GMF, and a remaining antenna-dependent part (NOCa). The averaged NOC residuals over a longer period are used to calculate correction factors that are shown to improve the wind retrieval.