Spatio-temporal analysis of prodelta dynamics by means of new satellite generation: the case of Po river by Landsat-8 data

Abstract This paper describes a procedure to perform spatio-temporal analysis of river plume dispersion in prodelta areas by multi-temporal Landsat-8-derived products for identifying zones sensitive to water discharge and for providing geostatistical patterns of turbidity linked to different meteo-marine forcings. In particular, we characterized the temporal and spatial variability of turbidity and sea surface temperature (SST) in the Po River prodelta (Northern Adriatic Sea, Italy) during the period 2013–2016. To perform this analysis, a two-pronged processing methodology was implemented and the resulting outputs were analysed through a series of statistical tools. A pixel-based spatial correlation analysis was carried out by comparing temporal curves of turbidity and SST hypercubes with in situ time series of wind speed and water discharge, providing correlation coefficient maps. A geostatistical analysis was performed to determine the spatial dependency of the turbidity datasets per each satellite image, providing maps of correlation and variograms. The results show a linear correlation between water discharge and turbidity variations in the points more affected by the buoyant plumes and along the southern coast of Po River delta. Better inverse correlation was found between turbidity and SST during floods rather than other periods. The correlation maps of wind speed with turbidity show different spatial patterns depending on local or basin-scale wind effects. Variogram maps identify different spatial anisotropy structures of turbidity in response to ambient conditions (i.e. strong Bora or Scirocco winds, floods). Since the implemented processing methodology is based on open source software and free satellite data, it represents a promising tool for the monitoring of maritime ecosystems and to address water quality analyses and the investigations of sediment dynamics in estuarine and coastal waters

Remote sensing data as a tool to monitor and mitigate natural catastrophes resulting from anthropogenic activities

This thesis demonstrates how remotely sensed satellite acquisitions can be used to addresses some of the natural catastrophes resulting from anthropogenic activities. Examples from both land and water systems are used to illustrate the breath of this toolbox. The effects of global climate change on biological systems and the wellbeing of everyday people are becoming less easy to ignore. In addition, our oceans are facing multiple large-scale stressors, including microplastics as a recently recognized threat, which place at risk the resources which a large percentage of the world’s population depends on for their livelihood. The cause of many of these changes stem from anthropogenic activities, but lacking understanding of complex ecosystems limits our ability to make definite conclusions as to cause and effect. The difficulty to collect on-the-ground data sufficient enough to capture processes working over scales of hundred of kilometers up to the entire globe is often a limitation to research. Remote sensing systems help ameliorate this issue through providing tools to better monitor environmental changes over large areas. The examples provided in this thesis focus on (Section I) tropical peatland fire characteristics and burning in Southeast Asia as a significant contributor to greenhouse gas emissions and (Section II) spread of river-based plastic pollution in coastal ocean systems. Section I specifically focuses on fires within Indonesia, which holds more than half of all known peatlands in the tropical zone and are estimated to represent a carbon pool of 82–92 gigatons. A brief description of recent development activities within Indonesia is presented in Section I of the Introduction, followed by meteorological processes responsible for extended drought periods in the region, and the situation of current fire control within the country. Chapter 1 presents an example of the large improvement in fire detection, as well as measurement of fire front characteristics, provided by a state-of-the-art thermal remote sensing. Chapter 2 goes into detail describing how an active satellite sensor system is able to provide much quicker and more accurate estimates of burned area for the tropics than other existing methods dependent on passive satellite sensor systems. Both these methods provide powerful tools for development of an improved system to monitor fire over Indonesia. The goal of such a monitoring system would be to reduce fire emissions from this large country, which according to global climate models play an important role in global climate change. Section II focuses on aquatic plastic pollution flowing from a freshwater system into the coastal oceans. A background of the issue of plastic pollution along with the current status of plastic debris in both oceans and inland river systems is presented in Section II of the Introduction. Chapter 3 describes development and comparison of two different modelling efforts to display how plastic particles being emitted from a major river are accumulating along the nearby coastline. The goal of this work is to present how remote sensing data could be used to in conjunction with ocean current modelling to create a comprehensive particle tracking monitoring system.Diese Arbeit zeigt, wie aus der Ferne wahrgenommene Satellitenaufnahmen dazu verwendet werden können, sich einigen Naturkatastrophen, die aus anthropogenen Aktivitäten resultieren, zu widmen. Anhand von Beispielen aus Land- und Wassersystemen wird der Umfang dieses technischen Werkzeugkastens dargestellt. Die Auswirkungen des globalen Klimawandels auf biologische Systeme und das Wohlbefinden des Menschen lassen sich nicht mehr ignorieren. Darüber hinaus sind unsere Ozeane mehreren großen Stressfaktoren ausgesetzt, einschließlich Mikroplastik als eine seit kurzem anerkennte Bedrohung, welche die Ressourcen gefährden, von denen der Lebensunterhalt eines großen Teils der Weltbevölkerung abhängt. Die Ursache vieler dieser Veränderungen liegt in anthropogenen Aktivitäten, aber mangelndes Verständnis für komplexe Ökosysteme begrenzt unsere Fähigkeit, eindeutige Rückschlüsse auf Ursache und Wirkung zu treffen. Die Schwierigkeit, Daten vor Ort zu sammeln, die ausreichen, um Prozesse zu erfassen, die über Hunderte von Kilometern bis hin zum gesamten Globus arbeiten, ist oft eine Einschränkung der Forschung. Fernerkundungssysteme tragen dazu bei, dieses Problem zu beheben, indem sie Werkzeuge zur besseren Überwachung von Umweltveränderungen in großen Gebieten bereitstellen. Die Beispiele in dieser Arbeit konzentrieren sich auf („Section I“) Feuermerkmale und Brandflächen der tropischen Torfgebiete in Südostasien als signifikanter Beitrag zu Treibhausgasemissionen und („Section II“) Ausbreitung von Fluss-basiertem Plastikmüll in küstennahen Meeressystemen. Section I konzentriert sich speziell auf die Brände in Indonesien, welches mehr als die Hälfte aller bekannten Torfgebiete in der tropischen Zone besitzt und auf einen Kohlenstoffpool von 82-92 Gigatonnen geschätzt wird. Eine kurze Beschreibung der jüngsten Entwicklungstätigkeiten in Indonesien wird in Section I der Einleitung vorgestellt, gefolgt von meteorologischen Prozessen, die für ausgedehnte Dürreperioden in der Region verantwortlich sind, und der Situation der aktuellen Feuerkontrolle innerhalb des Landes. Chapter 1 zeigt ein Beispiel für die große Verbesserung der Branddetektion sowie die Messung der Brandfronteigenschaften, die durch eine moderne thermische Fernerkundung erreicht werden können. In Chapter 2 wird ausführlich beschrieben, wie ein aktives Satellitensensorsystem in der Lage ist, schnellere und genauere Schätzungen der verbrannten Fläche für die Tropen zu liefern als andere existierende Methoden, die von passiven Satellitensensorsystemen abhängen. Beide Methoden bieten leistungsstarke Werkzeuge für die Entwicklung eines verbesserten Systems zur Brandüberwachung von Indonesien. Ziel eines solchen Überwachungssystems wäre es, Brandemissionen aus diesem großen Land zu reduzieren, das nach globalen Klimamodellen eine wichtige Rolle im globalen Klimawandel spielt. Section II konzentriert sich auf die Verschmutzung von Wasserplastik, die von einem Süßwassersystem in die Küstenmeere fließt. Ein Hintergrund des Problems der Plastikverschmutzung zusammen mit dem gegenwärtigen Status von Plastiktrümmern sowohl in Ozeanen als auch Binnenflusssystemen wird in Section II der Einleitung dargestellt. Chapter 3 beschreibt die Entwicklung und den Vergleich von zwei verschiedenen Modellierungsbemühungen, um zu zeigen, wie sich Kunststoffpartikel, die von einem großen Fluss emittiert werden, entlang der nahen Küstenlinie ansammeln. Das Ziel dieser Arbeit ist zu zeigen, wie Fernerkundungsdaten in Verbindung mit Meeresströmungsmodellierung verwendet werden können, um ein umfassendes Teilchenverfolgungsüberwachungssystem zu schaffen

Space and Time Occurrence of Algal Blooms in the Mediterranean: their Significance for the Trophic Regime of the Basin

The Mediterranean Sea is generally classified as an oligotrophic basin with a dominant subtropical regime. The coarse temporal resolution of the Coastal Zone Color Scanner data did not allow to properly reconstruct the dynamics of the regional events which could support or falsify that view. In this thesis, five years of the SeaWiFS Mediterranean data were analyzed to depict the trophic regime of the basin and to quantify the impact of periodic or episodic phytoplankton blooms occurring there. The retrieval of chlorophyll a concentration was based on a new empirical regional algorithm (DORMA) developed and tested in the frame of this study. While confirming the low standing stock of phytoplankton biomass evidenced by the CZCS time series, the SeaWiFS imageries allowed to discriminate among two distinct regimes, which were classified as the ‘bloom areas’ and ‘non-bloom areas’. The former are mostly driven by the coupling of local atmospheric forcing and cyclonic circulation and, therefore, are often sites of dense water formation whereas the latter do follow a typical sub-tropical seasonal cycle without a pronounced maximum of biomass over the year. Surprisingly, the second regime not only pertains to most of the Eastern basin, as previously assumed, but also to the southern part of the Western one. The ‘bloom areas’ contribute to no more than 10-15% of the primary production in the basin, but account for the relevant part of the interannual variability in the standing stock of autotrophic biomass and display a seasonal cycle close to the North Atlantic Drift Region (sensu Longhurst). The merge of atmospheric data, 1D modeling and remote sensed SST as well as color water leaving radiances also allowed a detailed reconstruction of the dynamics of each bloom site and of the impact of the climatic fluctuation, usually referred as the eastern Mediterranean Transect, which took place at the beginning of the nineties in the basin

Physical forcing and physical/biochemical variability of the Mediterranean Sea: a review of unresolved issues and directions for future research

This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper. Three major topics were identified, each of them being the object of a section divided into a number of different sub-sections, each addressing a specific physical, chemical or biological issue: 1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions. 2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability. 3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution. Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries

Report of the Croatian Committee of Geodesy and Geophysics on activities carried out between 2015 and 2018

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Geodesy in Croatia, 2015–2018 . . . . . . . . . . . . . . . . . . . . . . . . . . 173 Geomagnetism and aeronomy in Croatia, 2015–2018 . . . . . . . . ... 181 Hydrology and physical limnology in Croatia, 2015–2018 . . . . . ... 185 Meteorology in Croatia, 2015–2018 . . . . . . . . . . . . . . . . . . . . . . . . 195 Physical oceanography in Croatia, 2015–2018 . . . . . . . . . . . . . . . . 203 Seismology in Croatia, 2015–2018 . . . . . . . . . . . . . . . . . . . . . . . . . 21

Remote sensing data as a tool to monitor and mitigate natural catastrophes resulting from anthropogenic activities

This thesis demonstrates how remotely sensed satellite acquisitions can be used to addresses some of the natural catastrophes resulting from anthropogenic activities. Examples from both land and water systems are used to illustrate the breath of this toolbox. The effects of global climate change on biological systems and the wellbeing of everyday people are becoming less easy to ignore. In addition, our oceans are facing multiple large-scale stressors, including microplastics as a recently recognized threat, which place at risk the resources which a large percentage of the world’s population depends on for their livelihood. The cause of many of these changes stem from anthropogenic activities, but lacking understanding of complex ecosystems limits our ability to make definite conclusions as to cause and effect. The difficulty to collect on-the-ground data sufficient enough to capture processes working over scales of hundred of kilometers up to the entire globe is often a limitation to research. Remote sensing systems help ameliorate this issue through providing tools to better monitor environmental changes over large areas. The examples provided in this thesis focus on (Section I) tropical peatland fire characteristics and burning in Southeast Asia as a significant contributor to greenhouse gas emissions and (Section II) spread of river-based plastic pollution in coastal ocean systems. Section I specifically focuses on fires within Indonesia, which holds more than half of all known peatlands in the tropical zone and are estimated to represent a carbon pool of 82–92 gigatons. A brief description of recent development activities within Indonesia is presented in Section I of the Introduction, followed by meteorological processes responsible for extended drought periods in the region, and the situation of current fire control within the country. Chapter 1 presents an example of the large improvement in fire detection, as well as measurement of fire front characteristics, provided by a state-of-the-art thermal remote sensing. Chapter 2 goes into detail describing how an active satellite sensor system is able to provide much quicker and more accurate estimates of burned area for the tropics than other existing methods dependent on passive satellite sensor systems. Both these methods provide powerful tools for development of an improved system to monitor fire over Indonesia. The goal of such a monitoring system would be to reduce fire emissions from this large country, which according to global climate models play an important role in global climate change. Section II focuses on aquatic plastic pollution flowing from a freshwater system into the coastal oceans. A background of the issue of plastic pollution along with the current status of plastic debris in both oceans and inland river systems is presented in Section II of the Introduction. Chapter 3 describes development and comparison of two different modelling efforts to display how plastic particles being emitted from a major river are accumulating along the nearby coastline. The goal of this work is to present how remote sensing data could be used to in conjunction with ocean current modelling to create a comprehensive particle tracking monitoring system.Diese Arbeit zeigt, wie aus der Ferne wahrgenommene Satellitenaufnahmen dazu verwendet werden können, sich einigen Naturkatastrophen, die aus anthropogenen Aktivitäten resultieren, zu widmen. Anhand von Beispielen aus Land- und Wassersystemen wird der Umfang dieses technischen Werkzeugkastens dargestellt. Die Auswirkungen des globalen Klimawandels auf biologische Systeme und das Wohlbefinden des Menschen lassen sich nicht mehr ignorieren. Darüber hinaus sind unsere Ozeane mehreren großen Stressfaktoren ausgesetzt, einschließlich Mikroplastik als eine seit kurzem anerkennte Bedrohung, welche die Ressourcen gefährden, von denen der Lebensunterhalt eines großen Teils der Weltbevölkerung abhängt. Die Ursache vieler dieser Veränderungen liegt in anthropogenen Aktivitäten, aber mangelndes Verständnis für komplexe Ökosysteme begrenzt unsere Fähigkeit, eindeutige Rückschlüsse auf Ursache und Wirkung zu treffen. Die Schwierigkeit, Daten vor Ort zu sammeln, die ausreichen, um Prozesse zu erfassen, die über Hunderte von Kilometern bis hin zum gesamten Globus arbeiten, ist oft eine Einschränkung der Forschung. Fernerkundungssysteme tragen dazu bei, dieses Problem zu beheben, indem sie Werkzeuge zur besseren Überwachung von Umweltveränderungen in großen Gebieten bereitstellen. Die Beispiele in dieser Arbeit konzentrieren sich auf („Section I“) Feuermerkmale und Brandflächen der tropischen Torfgebiete in Südostasien als signifikanter Beitrag zu Treibhausgasemissionen und („Section II“) Ausbreitung von Fluss-basiertem Plastikmüll in küstennahen Meeressystemen. Section I konzentriert sich speziell auf die Brände in Indonesien, welches mehr als die Hälfte aller bekannten Torfgebiete in der tropischen Zone besitzt und auf einen Kohlenstoffpool von 82-92 Gigatonnen geschätzt wird. Eine kurze Beschreibung der jüngsten Entwicklungstätigkeiten in Indonesien wird in Section I der Einleitung vorgestellt, gefolgt von meteorologischen Prozessen, die für ausgedehnte Dürreperioden in der Region verantwortlich sind, und der Situation der aktuellen Feuerkontrolle innerhalb des Landes. Chapter 1 zeigt ein Beispiel für die große Verbesserung der Branddetektion sowie die Messung der Brandfronteigenschaften, die durch eine moderne thermische Fernerkundung erreicht werden können. In Chapter 2 wird ausführlich beschrieben, wie ein aktives Satellitensensorsystem in der Lage ist, schnellere und genauere Schätzungen der verbrannten Fläche für die Tropen zu liefern als andere existierende Methoden, die von passiven Satellitensensorsystemen abhängen. Beide Methoden bieten leistungsstarke Werkzeuge für die Entwicklung eines verbesserten Systems zur Brandüberwachung von Indonesien. Ziel eines solchen Überwachungssystems wäre es, Brandemissionen aus diesem großen Land zu reduzieren, das nach globalen Klimamodellen eine wichtige Rolle im globalen Klimawandel spielt. Section II konzentriert sich auf die Verschmutzung von Wasserplastik, die von einem Süßwassersystem in die Küstenmeere fließt. Ein Hintergrund des Problems der Plastikverschmutzung zusammen mit dem gegenwärtigen Status von Plastiktrümmern sowohl in Ozeanen als auch Binnenflusssystemen wird in Section II der Einleitung dargestellt. Chapter 3 beschreibt die Entwicklung und den Vergleich von zwei verschiedenen Modellierungsbemühungen, um zu zeigen, wie sich Kunststoffpartikel, die von einem großen Fluss emittiert werden, entlang der nahen Küstenlinie ansammeln. Das Ziel dieser Arbeit ist zu zeigen, wie Fernerkundungsdaten in Verbindung mit Meeresströmungsmodellierung verwendet werden können, um ein umfassendes Teilchenverfolgungsüberwachungssystem zu schaffen

A SWOT analysis for offshore wind energy assessment using remote-sensing potential

The elaboration of a methodology for accurately assessing the potentialities of blue renewable energy sources is a key challenge among the current energy sustainability strategies all over the world. Consequentially, many researchers are currently working to improve the accuracy of marine renewable assessment methods. Nowadays, remote sensing (RSs) satellites are used to observe the environment in many fields and applications. These could also be used to identify regions of interest for future energy converter installations and to accurately identify areas with interesting potentials. Therefore, researchers can dramatically reduce the possibility of significant error. In this paper, a comprehensive SWOT (strengths, weaknesses, opportunities and threats) analysis is elaborated to assess RS satellite potentialities for offshore wind (OW) estimation. Sicily and Sardinia-the two biggest Italian islands with the highest potential for offshore wind energy generation-were selected as pilot areas. Since there is a lack of measuring instruments, such as cup anemometers and buoys in these areas (mainly due to their high economic costs), an accurate analysis was carried out to assess the marine energy potential from offshore wind. Since there are only limited options for further expanding the measurement over large areas, the use of satellites makes it easier to overcome this limitation. Undoubtedly, with the advent of new technologies for measuring renewable energy sources (RESs), there could be a significant energy transition in this area that requires a proper orientation of plans to examine the factors influencing these new technologies that can negatively affect most of the available potential. Satellite technology for identifying suitable areas of wind power plants could be a powerful tool that is constantly increasing in its applications but requires good planning to apply it in various projects. Proper planning is only possible with a better understanding of satellite capabilities and different methods for measuring available wind resources. To this end, a better understanding in interdisciplinary fields with the exchange of updated information between different sectors of development, such as universities and companies, will be most effective. In this context, by reviewing the available satellite technologies, the ability of this tool to measure the marine renewable energies (MREs) sector in large and small areas is considered. Secondly, an attempt is made to identify the strengths and weaknesses of using these types of tools and techniques that can help in various projects. Lastly, specific scenarios related to the application of such systems in existing and new developments are reviewed and discussed