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Projects
Dr. Gade has been participating in various national and international projects:
ongoing:
DeMARINE-U (nation.; 2008-2011/2012-2015).UHH's contribution to the German national project DeMarine, in the second project phase called Satellitendaten für ein Monitoring im Watt (SAMOWatt), is focussing on the inclusion of SAR data into an existing monitoring system of the Wadden Sea on the German North Sea coast. DeMarine is the German contribution to the European Earth Observing program Copernicus and is aiming at providing operational services for the sustainable use of remote sensing data. The role of UHH within this sub-project is to investigate, and to demonstrate, the potential of high-resolution SAR data (from TerraSAR-X and Radarsat-2, along with older data from ERS-2, ENVISAT and ALOS) for the routine monitoring of exposed intertidal flats. In this frame, special emphasis is being put on the imaging of mussel beds (blue mussels and oysters) and macrophytes, as well as on SAR signatures of different sediment classes (sand and mud).
SOPRAN (nation.; 2007-2010/2010-2013/2013-2016). The German national Project Surface Ocean Processes in the Anthropocene (SOPRAN) is a joint national project (Verbundprojekt) as well as a German national contribution to the International SOLAS programme. SOPRAN’s focus is on processes operating within and close to the surface ocean, and their potential changes over the next century. The project is an integrated study of surface ocean response to global atmospheric change, combining the insights gained from different disciplines (marine and atmospheric chemistry, biological and physical oceanography) and methods (observations and modelling). SOPRAN aims to deliver an improved description of the effects of global atmospheric change on the sensitive marine ecosystems. The goal of this sub-project is to provide an improved methodology for the determination of global gas transfer rates derived from satellite data. Measurements on the research platform FINO 2, of radar backscatter and of gas fluxes, will provide an in-depth knowledge of the mechanisms responsible for the gas transfer under various environmental conditions and are being used to derive an algorithm which relates air-sea CO2 fluxes directly to surface roughness parameters. To reach this goal, time series of the radar cross section, obtained on the FINO-2 platform using a multi-frequency scatterometer (L-Ku MW Bands), are being analyzed at all frequencies and polarizations and correlated with CO2 fluxes, CO2 transfer velocities, wind speed and direction, wave state, and air and water temperatures. The goal of the analysis is a thorough understanding of the dependencies of all measured parameters on the seasonal changes and in particular un improved understanding of the relation between radar backscatter and air-sea fluxes of CO2. Results of the analyses of global scatterometer data as well as high-resolution synthetic aperture radar (SAR) data on a regional scale are aiding our joint investigation.
EO data projects:
Using RADARSAT-2 and ESA EO Data for an Improved Classification of Wadden Sea Surface Types (REDIWaSST) (CSA, ESA; partners Brockmann Consult and German National Park Agency) REDIWaSST builds upon previous projects (SOAR 5077, ESA 5849, ESA 3584), which aimed at the use of Synthetic Aperture Radar (SAR) data for an improved classification of surface types on dry-fallen intertidal flats in the German Wadden Sea. While those projects used SAR data acquired at different radar bands, the aim of this effort will be to systematically analyse C-Band SAR data, both historical
and newly acquired. Taking benefit of the knowledge gained so far, high-resolution RADARSAT-2 data will be used to derive surface roughness parameters through an inversion of the updated Integral Equation Model (IEM). Those parameters will be used as input into an improved classification system based on optical EO data. Moreover, the comparison of historical and new SAR data of exposed intertidal flats will allow for the detection and quantification of changes in the highly morpho-dynamical Wadden Sea, that have been taken place during the past two decades. By comparing and combining the two remote sensing technologies (SAR and optical) it is hoped that new insights will be gained into the potential of classifying tidal flat surface structures for monitoring purposes.
High-Resolution TerraSAR-X Data for an Improved Monitoring of Exposed Intertidal Flats (HiTIME) (DLR; partners Brockmann Consult and German National Park Agency) Optical remote sensing techniques are at a pre-operational stage in terms of their use in the classification and quantification of Wadden Sea surface types. In particular, government agencies responsible for monitoring this area and others responsible for implementing the Water Framework Directive are particularly interested in employing such techniques on a routine basis. Within the last five years, methods have been developed to integrate optical and SAR data into an optimized classification system of intertidal flats. Though promising results have been achieved, those methods are still under development and need further improvement, particularly with respect to the SAR imaging of small-scale features such as bivalve beds, residuals of historical landuse, and groyne fields. In this respect, the New Modes of TerraSAR-X will provide the unique opportunity to study small-scale SAR signatures with an unsurpassed accuracy. The innovative character, and the long-term goal, of the proposed effort will therefore be an advancement of current monitoring methodologies. A study will be performed how the data and results can be integrated into the operational monitoring program and which data fulfil the requirements of the users – also in terms of cost-benefit – for an operational application.
Spiral Eddy Statistical Analyses for the Mediterranean Sea using Envisat ASAR Imagery (SESAMeSEA) (ESA; partners UHH and IKI Moscow) In this study Envisat ASAR WSM imagery is used to produce statistics of the spatial and temporal distribution of spiral, sub-mesoscale eddies in the entire Mediterranean Sea. SAR images will be systematically analysed with respect to manifestations of those eddies, i.e. spiral bright or dark signatures. In order to provide a basis for robust statistics more than 3000 medium-resolution images obtained in 2009-2011 are being used. The data processing chain starts with a visual inspection of all SAR images and a detection of sub-mesoscale eddies, followed by statistical analyses of the detected eddies’ locations, sizes, shapes, and visualization mechanisms. Wind speed information gained from the SAR images themselves as well as from other sources (e.g. wind scatterometers) will be used to improve those statistics in terms of the effect of the local wind speed on the SAR visibility of eddies. This will allow for the generation of so-called eddy density maps, which will show the mean spatial and temporal eddy density (or the likelihood of their appearance) for the entire basin.
Detecting and Tracking Small-Scale Eddies in the Black Sea and the Baltic Sea Using High-Resolution RADARSAT-2 and TerraSAR-X Imagery (DTeddie) (CSA, DLR; leading partner UHH's Informatics Dept., partner IKI Moscow) This project aims at developing algorithms to detect, track and measure small scale eddies using high resolution SAR-Data from both RADARSAT-2 and TerraSAR-X. The principle areas to be investigated are the Black Sea and the Baltic Sea, where mesoscale surface currents may be detected and measured by tracking surface films (natural surface films, oil spills) using SAR- or optical images and applying a combination of maximum-cross-correlation and optical flow techniques. In the frame of this effort, our promising results will be extended to the region of the Black Sea and to the study of small-scale eddies. Special attention is being paid to dynamics of small-scale fronts in those semi-enclosed seas. The input of frontal instabilities in the structure formation process will be highlighted. High resolution radar data provides valuable information on the position of fronts, their origin, peaking, transition and destruction. They will be used to receive statistical and other information about their variability, to observe the formation of meanders along the fronts and their departure with the formation of vortices. Type, form and dynamic characteristics of the phenomena stipulated by a front and observed in its immediate proximity: jets, spiral eddies; vortical dipoles, internal waves etc. will be analyzed. With the high resolution data provided by RADARSAT-2 and TerraSAR-X it will be possible even to study small scale eddies with sizes of less than 1 Km. Using data from both satellites we will benefit from the high spatial resolution, the multiple modes of polarisation (more robust feature detection) and the higher temporal resolution.
Using TerraSAR-X and RADARSAT-2 Data for an Improved Classification of Wadden Sea Surface Types (UTRICS) (CSA, DLR; partners Brockmann Consult and German National Park Agency) Optical remote sensing techniques are at a pre-operational stage in terms of their use in the classification and quantification of Wadden Sea surface types. In particular, government agencies responsible for monitoring this area and others responsible for implementing the Water Framework Directive are particularly interested in employing such techniques on a routine basis. Within the last 3 years, methods have been developed to integrate optical and SAR for an optimized classification of intertidal flats. This includes multi-frequent as well as multi-temporal approaches. The methods are still under development and need further improvements. Especially with the opportunity to include data from additional sensors will advance the current methodology. Our long-term goal is to include the classification results in the operational monitoring system. First steps have been performed here with optical data but the improved information content retrieved from synergistic classification will bring us further to the needs of the users. A study will be performed how the data and results can be integrated into the operational monitoring program and which data fulfil the requirements of the users – also in terms of cost-benefit – for an operational application.
Algal Blooming in Regional Eddies due to Air-Sea Tranfers (ABREAST) (ISRO; leading partner Joint Research Centre of the EC) The poroject aims at the synergistic use of ocean colour and scatterometer winds, in order to assess the effects of air-sea interactions on algal blooming in different regions of the Mediterranean Sea. The comparison of (level 3) OCM-2 and Scatterometer data, composited at various time scales, will allow to examine the coupling between phytoplankton growth and wind-induced vertical mixing of surface waters. The case studies to be considered
comprise the Ligurian-Provençal Sea (where winter winds lead to deep convection that promote first nutrient upwelling, and then a sustained spring bloom, once the wind relaxes and stratification sets in), and the Levantine Basin (where upwelling due to Ekman pumping, within the cyclonic component of the wind-generated Rhodes-Srapetra vortex pair, also results in similar, if weaker, algal blooms). Continued monitoring of concurrent pigment concentration and wind speed, over a 3-year period, will improve current understanding of coupled biological and physical processes in sub-tropical seas. Further, comparing data from the OCEANSAT-2 mission and historical data sets from previous missions will allow to assess changes that might have occurred due to global warming (e.g. weaker blooming due to stronger stratification and consequent reduced nutrient input by vertical mixing, or again anticipated blooming due to an earlier onset of stratification).
TUTOR, AUTOR (DLR, ESA, JAXA; leading partner Brockmann Consult, partner German National Park Agency) The Wadden Sea is of major commercial and ecological significance, and has for centuries been exploited by man for communication, transportation, waste disposal, power generation, fisheries and amenity development. For this reason the governments of Germany, Holland and Denmark have proposed that areas of the Wadden Sea be added to the global list of Particularly Sensitive Sea Areas. Monitoring is an integral part of this process and having the appropriate tools for carrying out reliable and accurate measurements is essential for informed decision making. By comparing and combining the two remote sensing technologies, SAR and optical, it is hoped that new insights will be obtained into the potential of classifying tidal flat surface structures for monitoring purposes. The objectives are to assess the value of ALOS ADEN data in combination with both other SAR and optical multispectral scanner data to improve the classification and mapping of important Wadden Sea tidal flat structures (sediment type and mussel beds).
Systematic Analysis of Signatures of Dry-Fallen Intertidal Flats on ERS and ENVISAT SAR Imagery (SAasFEE) (ESA; partners German National Park Agencies) The distribution of sediments of a given particle size on intertidal flats is of great interest to scientists working in the field of morpho-dynamics and morphology of coastal environments. However, because of the repetitive flooding and the shallow water depth in these areas, intertidal flats are difficult to access both by boat, on foot or by land vehicles. This makes the measurement of soil surface parameters a difficult and time-consuming task. It is therefore worthwhile to conceive a remote sensing technique by which geophysical parameters of intertidal flats can be obtained and by which changes in the morphology and the sediment composition can be monitored. A classification system that is capable of meeting the above requirements has been suggested by Gade et al. (2008). In order to extend this system towards the use of SAR data from different satellites a deeper knowledge of the radar backscattering from intertidal flats and its dependence on environmental parameters and imaging geometry is needed. SAaSFEE uses archived ERS and ENVISAT SAR data to provide a data basis that is crucial for undergoing this challenging task.
Coastal Ocean surface current Retrievals from SAR Image Sequences and comparisons with currents from optical imagery (CORSIS) (ESA; partners U Miami, U Colorado) Past experience has clearly demonstrated that the Maximum Cross Correlation (MCC) method can be reliably used to map coastal surface currents from sequential infrared satellite imagery. Recent study has extended this to sequences of ocean color imagery while other studies have demonstrated that sequential SAR images can as well be used when surface slicks are present. The aim of CORSIS is to further examine the use of SAR image sequences for surface current computation in areas where routine computation of surface currents is being performed off the U.S. east and west coasts and in the Baltic Proper. The SAR images offer increased resolution and all-weather sensing capabilities features that will become important with the future application of the resulting surface currents, e.g., to search and rescue operations by the U.S. Coast Guard.
completed:
DeMOSSS (EU-Russ.-Ukrain.; 2007-2009. DEvelopment of Marine Oil Spills/slicks Satellite monitoring System elements targeting the Black/Caspian/Kara/Barents Seas (DEMOSSS) was an INTAS project, whose goal was to develop and demonstrate components of a marine oil spill detection and prediction ssystem based on satellite SAR and other space data in combination with models for oil slick/spill monitoring, prediction and assessment of their impact on the environment. The results of the 24-months project were implemented as a prototype of a marine environment information service in Black/Caspian/Kara/Barents seas as a part of GMES.
MOPED (EU-Russ.-Ukrain.-Azerbajd.; 2007-2009). The aim of the INTAS project Monitoring of Oil Pollution using Earth Observation Data: a multisensor, multiplaform approach (MOPED) was to develop recommendations for a system to use all available information from satellites and independent sources in order to detect and (where possible) quantify chronic oil pollution (small spills and wastewater discharges), whilst reducing the risk of false positives.
WiSSCy (nation.; 2005-2008). Impact of Wind, Rain, and Surface Slicks on Air-Sea CO2 Transfer Velocity - Tank Experiments - (WiSSCy) was a cooperation between the University of Heidelberg and UHH. The goal was to improve the understanding of the parameterization of air-sea gas exchange with emphasis on CO2. Using UHH's linear wind-wave tank facility, gas exchange coefficients were inferred by measuring gas transfer under a wide variety of parameters such as wind, mechanically generated waves, rain, and surface films. Emphasis was on the physical processes involved in the air-sea gas exchange and its quantitative measurement, and experiments were performed for evasion and invasion to investigate if rain-induced gas transfer is symmetrical or asymmetrical. These experiments allowed to determine parameterizations of the gas exchange as a function of parameters of the atmospheric boundary layers as they are needed in climate models and for the analysis of satellite data.
DeCoP (EU-Russ.-Ukrain.; 2004-2006). The aim of the GMES project Detection and characterisation of organic pollution in the coastal environment (DeCoP) was to develop techniques for the synergistic use of satellite data to monitor pollution from pipe-line seeps, waste-water discharges, marine traffic and spillages from routine operations as part of offshore or tanker activities.
SIMP (EU-Russ.; 2004-2007). Slicks as Indicators for Marine Processes (SIMP) was a 3-years project aiming at spanning the wide range from small-to meso- and large-scale investigations in laboratory wind-wave facilities and dedicated field experiments, respectively. Four main study areas were identified: the Black Sea and Baltic Sea in Europe and the Sea of Japan and Okhotsk Sea in the Far East. Quasi-biogenic slicks (i.e. artificial surface films consisting of basic compounds of natural slicks) were deployed in test areas in the Black Sea and the Sea of Japan and were used for systematic analyses of dynamic processes. Laboratory experiments conducted in Hamburg and Nizhny Novgorod provided new insights into visco-elastic properties of surfactants and into their role in water wave damping in the presence of sub-surface turbulence. The findings were used to design, and were confirmed during, the field experiments. Frequent acquisition of multi-frequency satellite data allowed the detection and identification of meso-scale marine processes, and their tracking in space and time. The comprehensive analyses of satellite imagery improved our knowledge of dynamical (atmospheric and oceanic) processes in the coastal zone.
MARSAIS (EU; 2002-2003). Marine SAR Analysis and Interpretation System (MARSAIS) was an integrated information system for processing and information extraction from different types of Earth Observation data. By means of validated algorithms and models, MARSAIS generated a suite of quality controlles coastal zone products with information on sea state, currents and pollution. Products were then delivered through a web based User Interface.
Bluewater (EU; 2000-2002) was focussing on Computerised Video Camera Image Analysis For Monitoring Pollution In Water. The German team of UHH performed laboratory and field experiments on the detectability of (quasi-) biogenic marine surface films by video camera systems, and thereby provided the scientific background for the development of an automated video surveillance system of near-shore coastal waters.
EURoPAK-B (national; 1998-2000). Experiments and Investigations on the Remote Sensing of Oceanic and Atmospheric Phenomena by Radar for Coastal Zone Applications (EURoPAK-B) was a project on the development of a remote sensing technique for underwater bottom topography on the basis of current measurements by airborne along-track InSAR. Two field experiments were carried out at test sites near the islands Heligoland and Sylt in the German Bight of the North Sea. The InSAR data acquisition and processing was carried out by Aero-Sensing Radarsysteme GmbH (now Intermap Technologies GmbH), Oberpfaffenhofen, Germany. Additional data and model results were obtained from the German Federal Maritime and Hydrographic Agency (BSH) and the German Federal Waterways Engineering and Research Institute (BAW), both Hamburg, and from the Institute for Coastal Research of GKSS Research Center GmbH, Geesthacht, Germany.
In the frame of a collaboration with the GKSS Research Center (national; 1999-2002) measurements in UHH's wind-wave tank were carried out with a range-resolving W-band radar, an X-band scatterometer, and a video camera. The aim of the project was to improve our knowledge about the development of wind-generated waves, their breaking, and their damping by monomolecular surface films.
AURORa (national; 1998-2001). The German national project Anwendungsorientierte Untersuchungen zur Regenfernerkundung über dem Ozean mit Radarverfahren (Application-oriented studies on remote sensing of rain over the ocean using radar techniques; AURORa) was devoted to improved studies of radar signatures of rain events (rain cells and rain bands) over the World's oceans. Laboratory measurements at UHH's wind-wave tank and field campaigns at a radar tower at the mouth of the river Elbe were used to gain further insight into both the very processes linked to rain impinging into the water surface and the effect heavy rain has on the radar backscatering from the ocean.
Clean Seas (EU; 1996-99) was a European Environment programme designed to evaluate the contribution that present and future satellite systems can make towards monitoring marine pollution. Systematic measurements were made over three European coastal zones, in the Central Baltic Sea, the Southern North Sea, and the North-Western Mediterranean Sea, to build an archive of repeat observations. Routinely acquired synthetic aperture radar (SAR) images of those test areas were used to generate first statistics on the spatial and seasonal distribution of marine oil pollution in European marginal seas.
SIR-C/X-SAR (intern.; 1993-96). The two Spaceborne Imaging Radar - C / X-Band Synthetic Aperture Radar missions were a joint project of the U.S. National Aeronautics and Space Administration (NASA), the German Space Agency (DARA) and the Italian Space Agency (ASI). In April and October 1994, an L-, C- and X-band SAR was flown on the space shuttle Endeavour during two 11-day missions. SAR images showing natural (biogenic) surface slicks as well as man-made (anthropogenic) mineral oil spills were analyzed with the aim to study whether or not active radar techniques can be applied to discriminating between these two kinds of surface films. Controlled slick experiments were carried out during both shuttle missions in the German Bight of the North Sea as well as in the northern part of the Sea of Japan and the Kuroshio Stream region where surface films of different visco-elastic properties were deployed within the swath of the shuttle radars.
SAMPLEX'92 (Dutch-German; 1992) was a collaborative German-Dutch oil recovery exercise in the German Bight of the North Sea. The Remote Sensing Unit at the Institute of Oceanography participated in this exercise with its multi-frequency/,multi-polarization scatterometer HELISCAT, which was flown on a (BO-105) helicopter and which was used to measure the radar contrast of different marine oil spills and its dependence on oil type and age.
SAXON-FPN (US-German; 1991-93). The Synthetic Aperture Radar and X Band Ocean Nonlinearities (SAXON) - Forschungsplattform Nordsee (FPN) program was a 3-year effort to investigate radar backscatter from the ocean and synthetic aperture radar (SAR) imagery of the ocean. A secondary objective of the program was to explore the relationship between acoustic and microwave scattering from the ocean surface. The program was a joint effort between the United States and the Federal Republic of Germany. It consisted primarily of a major field experiment (phase I) in the North Sea on and around the German Forschungsplattform Nordsee (FPN) during November 1990, a second, smaller field experiment (phase II) on the same platform in November 1991, and a series of four data analysis workshops.