Developments in Earth observation for the assessment and monitoring of inland, transitional, coastal and shelf-sea waters

The Earth's surface waters are a fundamental resource and encompass a broad range of ecosystems that are core to global biogeochemical cycling and food and energy production. Despite this, the Earth's surface waters are impacted by multiple natural and anthropogenic pressures and drivers of environmental change. The complex interaction between physical, chemical and biological processes in surface waters poses significant challenges for in situ monitoring and assessment and often limits our ability to adequately capture the dynamics of aquatic systems and our understanding of their status, functioning and response to pressures. Here we explore the opportunities that Earth observation (EO) has to offer to basin-scale monitoring of water quality over the surface water continuum comprising inland, transition and coastal water bodies, with a particular focus on the Danube and Black Sea region. This review summarises the technological advances in EO and the opportunities that the next generation satellites offer for water quality monitoring. We provide an overview of algorithms for the retrieval of water quality parameters and demonstrate how such models have been used for the assessment and monitoring of inland, transitional, coastal and shelf-sea systems. Further, we argue that very few studies have investigated the connectivity between these systems especially in large river-sea systems such as the Danube-Black Sea. Subsequently, we describe current capability in operational processing of archive and near real-time satellite data. We conclude that while the operational use of satellites for the assessment and monitoring of surface waters is still developing for inland and coastal waters and more work is required on the development and validation of remote sensing algorithms for these optically complex waters, the potential that these data streams offer for developing an improved, potentially paradigm-shifting understanding of physical and biogeochemical processes across large scale river-sea continuum including the Danube-Black Sea is considerable

Analyse der Wasserfarbe von Seen mithilfe räumlich hoch und mittel auflösender Satelliten

Remote sensing techniques can assist traditional lake monitoring approaches by supplying spatial information on optically active lake ecology indicators, i.e. chlorophyll-a (CHL), total suspended matter (TSM), coloured dissolved organic matter (CDOM), and, especially in optically shallow waters, water depth and substrate composition. The present thesis provides an overview on the current research status concerning lake remote sensing and the benefit of time series analyses for lake ecology. To investigate the suitability of Sentinel-2 and Landsat 8 for lake monitoring and their combination with other sensors this thesis focused on two study areas with highly different optical characteristics, i.e. the oligotrophic Lake Starnberg (southern Germany) and the mesotrophic-eutrophic Lake Kummerow (northern Germany). Using the bio-optical model WASI-2D, Sentinel-2A turned out to be suited for retrieving low TSM and CDOM values. The high spatial resolution enabled the differentiation between bare ground and areas covered by submerged aquatic vegetation. Water depth estimations performed well until half Secchi disk depth. Cross-sensor comparisons demonstrated high correlation of CHL among timely acquired, spatially high and medium resolved sensors. Evaluations with in situ data showed that most of the sensor-in situ match-ups were within an uncertainty range of in situ measurements. Analysing a 9-year MERIS time series with FUB/WeW revealed unprecedented information on temporal trends and seasonal behaviour of CHL, TSM and CDOM at the study area Lake Kummerow. Combining CHL, retrieved with the Modular Inversion and Processing System, from different satellite sensors (MODIS, Landsat 7/ 8, Sentinel-2A) enabled detailed observations of phytoplankton development. Such combinations are a step forward to future lake analyses which may integrate remote sensing data, in situ measurements and environmental modelling.Fernerkundungstechniken können das Seemonitoring mit räumlichen Informationen über optisch aktive Indikatoren der Gewässerökologie liefern, z.B. Chlorophyll-a (CHL), suspendierte Schwebstoffe (TSM), Gelbstoffe (CDOM) und insbesondere in optisch flachen Gewässern, Wassertiefe und Substratbedeckung. Die vorliegende Arbeit gibt einen Überblick über den aktuellen Forschungsstand zur Seefernerkundung und den Nutzen von Zeitreihenanalysen für die Seeökologie. Um die Eignung von Sentinel-2 und Landsat 8 für ein Seenmonitoring und deren Kombination mit anderen Sensoren zu untersuchen, konzentrierte sich diese Arbeit auf zwei Untersuchungsgebiete mit sehr unterschiedlichen optischen Eigenschaften: den oligotrophen Starnberger See (Süddeutschland) und den mesotroph-eutrophen Kummerower See (Norddeutschland). Mit dem bio-optischen Modell WASI-2D erwies sich Sentinel-2A als geeignet, um niedrige TSM- und CDOM-Werte zu bestimmen. Die hohe räumliche Auflösung ermöglichte eine Unterscheidung zwischen unbewachsenem und mit Makrophyten bewachsenem Untergrund. Die Wassertiefenbestimmung verlief bis zur halben Sichttiefe gut. Sensorübergreifende Vergleiche zeigten eine hohe Korrelation von CHL zwischen zeitnah erfassten, räumlich mittel und hoch aufgelösten Sensoren. Auswertungen mit in-situ-Daten zeigten, dass die meisten Sensor-in-situ-Match-ups innerhalb eines Unsicherheitsbereichs von in-situ-Messungen lagen. Die Analyse einer 9-jährigen MERIS-Zeitreihe mit FUB/WeW ergab neue Informationen über zeitliche Trends und saisonales Verhalten von CHL, TSM und CDOM im Untersuchungsgebiet Kummerow See. Die Kombination von CHL aus verschiedenen Satellitensensoren (MODIS, Landsat 7/ 8, Sentinel-2A) mit dem Modular Inversion and Processing System ermöglichte detaillierte Beobachtungen der Phytoplanktonentwicklung. Solche Kombinationen sind ein Schritt für zukünftigen Gewässeranalysen, die Fernerkundungsdaten, in-situ-Messungen und Umweltmodellierung integrieren sollten

The 1994 Silver Anniversary of APOLLO 11: From the Moon to the Stars

This report summarizes the technology transfer, advanced studies, and research and technology efforts in progress at Marshall Space Flight Center (MSFC) in 1994

The Advanced Compton Telescope Mission

The Advanced Compton Telescope (ACT), the next major step in gamma-ray astronomy, will probe the fires where chemical elements are formed by enabling high-resolution spectroscopy of nuclear emission from supernova explosions. During the past two years, our collaboration has been undertaking a NASA mission concept study for ACT. This study was designed to (1) transform the key scientific objectives into specific instrument requirements, (2) to identify the most promising technologies to meet those requirements, and (3) to design a viable mission concept for this instrument. We present the results of this study, including scientific goals and expected performance, mission design, and technology recommendations.Comment: NASA Vision Mission Concept Study Report, final version. (A condensed version of this report has been submitted to AIAA.

Resolving climate impacts on fish stocks

Evidence is accumulating that the increase in CO2 is affecting the global climate, with far‐reaching implications for biological processes and ecosystem services. Recent studies suggest that there is evidence for a northward shift in the distributional range of fish species, but the mechanisms underlying these changes remain uncertain. Hence, it is largely unknown whether the observed distributional shifts are caused by a relocation of the spawning and feeding grounds, a change in the local survival of fish, or immigration into new habitats

The 1991 Marshall Space Flight Center research and technology

A compilation of 194 articles addressing research and technology activities at the Marshall Space Flight Center (MSFC) is given. Activities are divided into three major areas: advanced studies addressing transportation systems, space systems, and space science activities conducted primarily in the Program Development Directorate; research tasks carried out in the Space Science Laboratory; and technology programs hosted by a wide array of organizations at the Center. The theme for this year's report is 'Building for the Future'

Research and Technology Objectives and Plans Summary (RTOPS)

This publication represents the NASA research and technology program for FY-93. It is a compilation of the Summary portions of each of the RTOP's (Research and Technology Objectives and Plans) used for management review and control of research currently in progress throughout NASA. The RTOP Summary is designed to facilitate communication and coordination among concerned technical personnel in government, in industry, and in universities. The first section containing citations and abstracts of the RTOP's is followed by four indexes: Subject, Technical Monitor, Responsible NASA Organization, and RTOP Number

Characterization of suspended sedimets in the Guadalquivir estuary at modeled scale

Los estuarios son complejas zonas de transición e intercambios de agua, energía, sólidos en suspensión y nutrientes, con variaciones estacionales y espaciales de la materia suspendida (SPM), materia orgánica (MO) y salinidad a lo largo del mismo asociadas a ciclos de marea y descargas fluviales, especialmente en régimen de avenidas. Las características morfológicas de estas áreas de transición (semiconfinamiento, escaso calado, bajos regímenes de velocidad) unidas a que son tramos finales de los ríos, favorece la presencia de elevadas concentraciones de sólidos en suspensión de naturaleza fina o muy fina, que han superado las barreras de regulación aguas arriba, y que inducen una mayor capacidad de suspensión y resuspensión. La presencia de eventos de elevada concentración de sólidos en suspensión, afecta a las propiedades físicas del agua: densidad, viscosidad cinemática y transparencia del agua, su turbidez, generando daños ecológicos y económicos, que pueden persistir durante días o semanas y la convierte en motivo de estudio y seguimiento. Las redes de control de calidad de agua superficial miden su turbidez; no obstante, no siempre existen puntos de control con la suficiente densidad en la red y, sobre todo, alta frecuencia de registro, para poder analizar los efectos transitorios de los múltiples procesos que coexisten en un estuario. En ese sentido, las medidas de reflectancia proporcionada por sensores remotos añaden información de la cual derivar medidas indirectas de turbidez y, con ello, estimar concentraciones de sólidos en suspensión a lo largo de la masa de agua. En las últimas décadas, su uso se ha convertido en una herramienta rápida y de bajo coste, que permite obtener mapas de distribución espacial de la concentración de sólidos en suspensión y turbidez, con la resolución temporal de los sensores empleados. Este trabajo aborda el análisis de los efectos de los sólidos en suspensión en aguas hiperconcentradas a ambas escalas del modelado: global, con fines de seguimiento y calibrado de modelos a escala de estuario, y de detalle, con fines de corrección de variables de estado significativas de la mezcla agua-sales-sedimentos en la columna de agua característica del estuario del Guadalquivir. Este estuario es un claro ejemplo de un sistema muy regulado en el que han disminuido los caudales aportados al mismo y que ha sufrido importantes cambios de uso en la cuenca vertiente. El estudio de la influencia de los sólidos en suspensión en las mezclas agua-salessedientos con la temperatura permite cuantificar los cambios que estos factores implican en las variables físicas de densidad y viscosidad cinemática. Dichas modificaciones condicionan los procesos de advección- difusión en la masa de agua, así como la dinámica del transporte de sólidos afectando a su sedimentación y resuspensión. La obtención de curvas trivariadas densidad-salinidad-temperatura para distintas concentraciones de sólidos en suspensión, permite obtener valores de densidad en masas...Estuaries are complex areas of transition and exchanges of water, energy, suspended solids and nutrients. There are seasonal and spatial variations in suspended matter (SPM), organic matter (MO) and salinity throughout them, which are associated with tidal cycles and fluvial discharges, especially under flood regimes. The morphological characteristics of these transition areas (semi-confinement, small depth, low velocity regimes) as well as being final stretches of rivers, favours the presence of high suspended solid concentrations of a fine or very fine nature. The latter have passed through the regulation barriers upstream, which has induced a greater suspension and resuspension capacity. The presence of these suspended solid events affects the physical properties of the water: density, kinematic viscosity and water transparency, its turbidity, thus generating ecological and economic damage, which may persist for days or weeks and converts them into a reason for study and monitoring. The quality control networks of surface water measure its turbidity although there are not always control points with a sufficient density in the network and, especially, a recording frequency to enable the analysis of the transitory effects of the multiple processes which co-exist in an estuary. In this sense, the reflectance measurements supplied by remote sensors add information from which indirect measurements of turbidity can be derived and, thus, concentrations of suspended solids throughout the mass of water can be estimated. In the last few decades, their employment has become a fast and low-cost tool, which permits the obtaining of maps of the spatial distribution of suspended solid concentrations and turbidity, with the temporal resolution of the sensors used. This work deals with the analysis of the effects of suspended solids in hyperconcentrated water at both scales of the modelling: global, with monitoring and model calibration objectives at an estuary scale; and detailed, with the purpose of correcting variables of the significant state of the water-salts-sediments mix in the column of water which is characteristic of the Guadalquivir estuary. This is a clear example of a highly regulated system, in which the discharges supplied to it have diminished, and which has undergone important use changes in its catchment. Studying the influence of the suspended solids on the water-salts-sediments mixes with the temperature permits one to quantify the changes implied by these factors in the physical variables of density and kinematic viscosity. Those modification condition the advection-diffusion processes in the water mass, as well as the dynamics of the transport of solids affecting its sedimentation and resuspension. The obtaining of trivariate curves of density-salinity-temperature for different suspended solids permits the finding out of density values in characteristic water masses in estuarine environments similar to the Guadalquivir estuary conditions..