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Forschergruppe (FOR) 1598: From Catchments as Organised Systems to Models based on Dynamic Functional Units (CAOS), Non-invasive geophysical and remote sensing methods to map and characterize relevant structures and processes

This project is a continuation of project F funded in the first phase of the DFG Research Group CAOS, where we evaluated the potential of different ground-based geophysical techniques for exploring hydrological systems regarding subsurface structures, characteristics, and processes. Building up on the results of this project, we now focus on further developing selected geophysical techniques (timelapse GPR imaging) for deepening our understanding of hydrological processes at the plot and hillslope scale. In addition, we propose to systematically evaluate modem remote sensing techniques because they cun-ently represent the only means to efficiently explore larger areas or entire catchments. Here, we focus on a combination of full-waveform laserscanning and hyperspectral imaging because they can provide detailed Information regarding geometrical and physical properties of earth's surface, respectively. To link remote sensing with point/plot/hillslope scale data as provided by geophysics and conventional hydrological field techniques, we believe that further methodological innovations are needed. For example, we plan to establish a unique field laboratory to better understand the responses of geophysical and remote sensing techniques to different natural and artificial hydrological events and to develop exploration strategies advancing the applicability of geophysics and remote sensing for hydrological applications at a variety of spatial scales.

Probabilistische Baugrundmodellierung für Planung und Entwicklung von Offshore-Windparks

Fraunhofer IWES steht mit seinen F&E-Aktivitäten für eine Beschleunigung des Ausbaus der Windenergie auf See. Das betrifft die Untergrunderkundung ebenso wie die Aufbereitung & Bereitstellung von Baugrundparametern für das technische Design von Offshore-Gründungsstrukturen. IWES hat im Anschluss an die Entwicklung seismischer Erkundungsmethoden einen Workflow für die integrierte Interpretation der geophysikalischen & geotechnischen Daten entwickelt, und A. um Bodenprofile relevanter Parameter an Lokationen ohne direkte Baugrundaufschlüsse zu erzeugen (synthetische CPT). Der Bedarf an innovativen Lösungen im Bereich der Baugrundmodellierung besteht, wie letzte Ausschreibungen von Behörden wie RVO (= Rijksdienst voor Ondernemend Nederland) & d. BSH zeigen. Statistische Analysen sind gefordert, um eine reguläre Nutzung synthetischer Baugrundprofile durch Einsatz zertifizierten Analysewerkzeugs zu ermöglichen. IWES & GuD stellen sich der Herausforderung, anknüpfend an existierende geostatistische Methoden, ein probabilistisches Baugrundmodell zu entwickeln. Dadurch wird eine Quantifizierung aller mit der Beschreibung des Baugrundes assoziieren Unsicherheiten (z.B. Heterogenität des Baugrundes, Messunsicherheiten usw.) erreicht, so dass im Ergebnis an jedem Modellpunkt bemessungsrelevanten Baugrundparameter 'mit Sicherheiten behaftet' abgeleitet werden können. Dazu sind sämtliche input-Größen in das Modell mit Streuungen zu integrieren. Das umfasst geophysikalische & geotechnische Mess- & Versuchsergebnisse sowie Modellunsicherheiten in interpolierten Bereichen. Eine umfassende statistische Analyse aller seismischen & geotechnische Informationen soll es ermöglichen, laterale Änderungen der relevanten geotechnischen Parameter zu quantifizieren. Geplant ist ein dreijähriges Forschungsprojekt durch Fraunhofer IWES & GuD Geotechnik und Dynamik Consult GmbH, mit begleitender Industrie-Arbeitskreis (EnBW, G-tec S.A., Ocean Floor Geophysics, Niedersachsenwasser, BSH und BAW)

INSPIRE: Airborne geophysical surveys for mapping the shallow subsurface in Germany (D-AERO)

Since the eighties BGR carries out helicopter borne measurements in Germany as well as in neighbouring and distant countries. In particular a series of continuous areas on the German North Sea coast are flown during the last years within the context of the D-AERO project. The helicopter of type Sikorsky S-76B is operated for the airborne geophysical survey of the earth's subsurface. Usually airborne electromagnetic, magnetic and radiometric measurements are carried out. The 13 GML files for each airborne geophysical survey area together with a Readme.txt file are provided in ZIP format (D-AERO-INSPIRE.zip). The Readme.text file (German/English) contains detailed information on the GML files content. Data transformation was proceeded by using the INSPIRE Solution Pack for FME according to the INSPIRE requirements of data specification Geology (D2.8.II.4_v3.0), Sub-theme Geophysics.

Higher frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, within the CTBT-relevant infrasound range (around 0.01-4 Hz), this dataset covers higher frequencies (1-3 Hz) and is therefore called the ‘hf’ product. The temporal resolution (time step and window length) is 5 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022

Very low frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, this dataset, called the ‘maw’ product, covers a very low frequency range of infrasound (0.02-0.07 Hz). The temporal resolution (time step and window length) is 30 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022.

Global reference histograms of the IMS infrasound broadband detection lists

This data set builds upon the broadband detection lists of the International Monitoring System (IMS)’s infrasound stations. The infrasound data of these stations are regularly (re-)processed at the German National Data Centre at BGR (e.g., Ceranna et al., 2019; https://doi.org/10.1007/978-3-319-75140-5_13) using the Progressive Multi-Channel Correlation (PMCC) array processing method (Cansi, 1995; https://doi.org/10.1029/95GL00468). The latest reprocessing with 26 one-third octave spaced frequency bands in the IMS band of interest (0.01 to 4 Hz) included all 53 stations that were certified within the period 2003 to 2020. Based on the resulting broadband detection lists, this data set expands on former analyses of the coherent ambient noise. For each station with a data availability of at least one year (by the end of 2020), monthly reference histograms for the detection parameters back azimuth, apparent speed, and root-mean-squared amplitude are provided. The histograms provide a means to determine the deviation from nominal monthly behaviour and thus enable assessing the plausibility of detections and potential anomalies – without determining their cause – in the detected parameters. Overall, these quality metrics will be, among other applications, a useful supplement to the open-access IMS infrasound data products provided by Hupe et al., which are also available in BGR’s product centre. Further details of the reference histograms are described in the following publication by Kristoffersen et al.: "Updated global reference models of broadband coherent infrasound signals for atmospheric studies and civilian applications" (https://doi.org/10.1029/2022EA002222).

Infrasonic Signatures of 1001 Rocket Launches for Space Missions

Rocket launches for space missions are well-defined ground-truth events generating strong infrasonic signatures. This data set covers ground-truth information for 1001 rocket launches from 27 global spaceports between 2009 and mid-2020. Infrasound signatures from up to 73% of the launches were identified at infrasound arrays of the International Monitoring System. The detection parameters were obtained using the Progressive Multi-Channel Correlation (PMCC) algorithm. Propagation and quality parameters supplement the PMCC detection parameters in this dataset. The results are provided for further use as a ground-truth reference in geophysical and atmospheric research. The open-access publication “1001 Rocket Launches for Space Missions and their Infrasonic Signature” (Pilger et al., 2021, Geophys. Res. Letters, doi:10.1029/2020GL092262) provides further details on this data set. Data format: The data are provided both as ASCII files (separate lists of infrasound signatures and rocket launch events, plus README files) and as a comprehensive netCDF file.

Microbarom low-frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, this dataset covers the dominant frequency range of microbaroms (0.15-0.35 Hz) and is therefore called the ‘mb_lf’ product. The temporal resolution (time step and window length) is 15 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022

Microbarom high-frequency data products of the International Monitoring System’s infrasound stations

This dataset consists of data products derived from broadband signal detection lists that have been processed for the certified infrasound stations of the International Monitoring System. More specifically, this dataset covers, among other phenomena, the upper frequency range of microbaroms (0.45-0.65 Hz) and is therefore called the ‘mb_hf’ product. The temporal resolution (time step and window length) is 15 min. For processing the infrasound data, the Progressive Multi-Channel Correlation (PMCC) array processing algorithm with a one-third octave frequency band configuration between 0.01 and 4 Hz has been used. The detected signals from the most dominant directions in terms of number of arrivals within a time window and the product-specific frequency range are summarized at predefined time steps. Along with several detection parameters such as the back azimuth, apparent velocity, or mean frequency, additional quantities for assessing the relative quality of the detection parameters are provided. The dataset is available as a compressed .zip file containing the yearly data products (.nc files, NetCDF format) of all certified stations (since 2003). Further information on the processing and details about the open-access data products can be found in: Hupe et al. (2022), IMS infrasound data products for atmospheric studies and civilian applications, Earth System Science Data, doi:10.5194/essd-14-4201-2022

Integrated observations from NEAR shore sourcES of Tsunamis: towards an early warning system (NEAREST)

The NEARESTproject (Integrated observations from NEAR shore sourcES of Tsunamis:  towards an early warning system) aimed at the identification and characterization of potential near-shore sources of tsunamis in the Gulf of Cadiz. This area is well known from the catastrophic earthquake and tsunami that destroyed Lisbon and several other places mainly along the EastAtlantic coast on November 1st, 1755. One of the project's work packages dealed with monitoring of recent seismic activity in the Gulf of Cadiz area. For this purpose 24 broadband ocean-bottom seismometers (OBS) from the German DEPAS instrument pool were deployed for 11 months in addition to the GEOSTAR multi-parameter deep-sea observatory and two temporary land stations in Portugal. The GEOSTAR observatory and the 24 OBS were deployed and recovered during two expeditions with RV Urania in 2007 and 2008. The OBSs consist of  three‐component Guralp CMG‐40T‐OBS seismometers and HighTech HTI‐04‐PCA/ULF hydrophones. A wide range of signals was recorded, ncluding teleseismic, regional and local earthquakes, and low‐frequency (∼20 Hz) vocalization of fin whales.  The GEOSTAR  observatory was again deployed between 2009 and 2011. The Portuguese temporary land station PDRG was additionally recording during the NEAREST project. Originally, the position of recovery on deck was taken to calculate the mean coordinate of the OBS at depth from deployment and recovery coordinates. In most cases the difference in coordinates between deployment and recovery is very small (table 3 and 4 in Carrara et al., 2008). For two stations, the location at the seafloor could be measured by triangulation (Carrara et al., 2008). Due to experience of other experiments over the years, we finally suggest to use the deployment coordinates as the station coordinates for all stations that could not be tri-angulated. The clocks were synchronized with GPS time before the deployment and if possible again after the recovery. Unfortunately, most of the batteries were empty at the end of the recording period. That either made it impossible to realize the second synchronisation (skew time measurement) or in some case also caused erroneous synchronisations. Therefore, the internal clock drift was estimated by ambient noise analysis (Corela, 2014). The internal clock drifts were corrected using a linear interpolation method. Generally, the data quality is very good, especially for the intended study of local and regional earthquakes. Studies relying on wideband seismological recordings can also be carried out. The sensor package and noise conditions hamper the use for broadband and very broadband applications. Unfortunately, also not all channels operated properly, therefore hampering the use of multi-component methods for the relevant stations. We thank the captain E. Gentile, crew, G. Carrara, and all participants of the R/V URANIA expeditions in 2007 and 2008. We are grateful to all people and institutions involved in the NEAREST project. Waveform data is available from the GEOFON data centre, under network code 9H.

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