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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.

Mehr als verschüttete Täler: Dienen Tunneltäler als bevorzugte Fließwege für frisches Grundwasser in der Nordsee?

Die stetig wachsende Bevölkerung führt zu einem steigenden Bedarf an Frischwasser und die Entnahme von Grundwasser ist eine der wichtigsten Quellen diesen Bedarf zu decken. Engpässe in der Frischwasserversorgung haben die Suche Nachweis von frischem Grundwasser unter dem heutigen Meeresboden angetrieben. Die Rolle glazialer Strukturen, welche während der Vergletscherungen entstanden sind, ist jedoch im Hinblick auf das Vorkommen frischen Grundwassers noch wenig bekannt. Insbesondere sogenannte Tunneltäler (TT), welche sich unter den Eisschilden bildeten, könnten von besonderer Relevanz sein. Ihre Ausmaße (bis zu 5 km breit, 400 m tief, 100te km lang) spiegeln die gewaltigen Schmelzwassermengen wider, die den Untergrund unter den Eisschilden durchspülten. Ihre Entstehung und Füllung resultierte in stark durchlässigen Sanden und Kiesen im unteren Teil und feinkörnigen Ablagerungen im oberen Teil dieser Strukturen. Diese Konfiguration begünstigt eine Rolle als bevorzugte Fließwege für offshore Grundwasser. Zur Untersuchung des Potenzials von TT als bevorzugte Fließwege für offshore frisches Grundwasser (OFG), verfolgt dieses Projekt folgende Ziele: (O1) Durch die Kombination von elektromagnetischen und seismischen Daten wollen wir ein strukturgebundenes Widerstandsmodell für mehrere TT erstellen; (O2) Wir wollen die Salzgehaltswerte für verschiedene Architekturen und Tiefen von TT abschätzen; (O3) Aufbauend auf den ersten beiden Zielen wollen wir die Ergebnisse für das gesamte Arbeitsgebiet in ein detailliertes lithologisches 3D-Modell extrapolieren. Die sich daraus ergebende Salzgehaltsverteilung im Untergrund wird dazu beitragen, die Ober- und Untergrenzen des Volumens frischen Grundwassers abzugrenzen und die Grundlage für ein detailliertes Grundwassermodell schaffen. Folgende Schritte sind dazu nötig: (S1) Kartierung und Charakterisierung der räumlichen Heterogenität von TT anhand vorhandener seismischer Daten; (S2) Erstellung eines lithologischen Modells für den Untergrund zwischen Amrum und Helgoland von 0 bis 400 m Tiefe; (S3) Identifizierung vielversprechender Standorte und Durchführung von CSEM-Messungen (Controlled Source Electromagnetic) zur Untersuchung der Verteilung des elektrischen Widerstands im Untergrund (TT); (S4) Kombination von Widerstandsmessungen mit Mehrkanal-Seismikdaten (MCS) zur Ableitung des Salzgehalts der Porenflüssigkeit; (S5) Extrapolation der Ergebnisse für das gesamte lithologische Modell. Tunneltäler existieren in ehemals vergletscherten Regionen weltweit. Gelingt uns der Nachweis von OFG in Tunneltälern, hätte dies erhebliche Implikationen für bisher unbekannte Süßwasserverteilungen und hydrologische Systeme. Die uns zur Verfügung stehenden Daten bieten eine einzigartige Möglichkeit zur Integration von CSEM- und seismischen Messungen bei begrenztem Aufwand. Die Ergebnisse des Projekts werden einen neuen Blick auf offshore Gletscherlandschaften und ihre Rolle im pleistozänen Wasserkreislauf erlauben.

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

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).

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

Forschergruppe (FOR) 5094: Dynamik des tiefen Untergrundes von Hochenergiestränden, Teilprojekt: Morphodynamik, Grundwasserströmung und -transport

Durch DynaDeep wird ein Verständnis der Funktionsweise und Relevanz des Land-Meer Übergangs im Untergrund von Hochenergiestränden gewonnen werden. Wir nehmen an, dass dieser einen hoch dynamischen Bioreaktor und einzigartiges mikrobiologisches Habitat darstellt und Netto-Stoffflüsse in Richtung Meer stark beeinflusst. Um dieses Ziel zu erreichen werden sechs Teilprojekte gemeinsam Felduntersuchungen und experimentelle Arbeiten durchführen und diese mit mathematischen Modellen integrativ kombinieren. P1 wird Grundwasserströmungs- und -transportprozesse als Funktion hydro- und morphodynamischer Randbedingungen untersuchen. Wir postulieren, dass die gegenwärtigen Konzepte zur Grundwasserströmung und Salzverteilung in subterranen Ästuaren unter Tideeinfluss für Hochenergiebedingungen nicht anwendbar sind. Stattdessen erwarten wir dynamische und variable Änderungen von Salinitäten, Fließrichtungen und Aufenthaltszeiten. P1 wird die Strandmorphologie mit Hilfe von Kameraaufnahmen, Laserscannern und Drohnen untersuchen und diese mit numerischen Modellen kombinieren, um typische Adaptionszeiten und -skalen der Strandmorphologie abzuleiten. Durch nicht-invasive geophysikalische Methoden werden die Salzverteilungsmuster im Untergrund zu verschiedenen Zeiten abgeleitet werden. Umwelttracer werden genutzt, um Aufenthaltszeiten im Untergrund zu bestimmen. Morphologische, hydro(geo)logische und geophysikalische Daten des STE Online Observatory dienen der Erstellung numerischer Modelle, die Grundwasserströmung und Salztransport abbilden. Die Kenntnis der Verteilung von Wasserkörpern und -grenzflächen, Fließgeschwindigkeiten, Aufenthaltszeiten und des Ausmaßes der Mischung im Untergrund bildet die Grundlage für die biogeochemischen Untersuchungen in den Teilprojekten P2-P6.

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.

GeolDG: 3D-Seismik in der Ausschließlichen Wirtschaftszone Deutschlands

Der Datensatz umfasst die Nachweisdaten der 3D-seismischen Surveys, die in den Anwendungsbereich des Geologiedatengesetzes fallen und deren überdeckte Flächen mindestens teilweise in der Ausschließlichen Wirtschaftszone Deutschlands liegen.

Processed seismic data of Cruise Nares 2001

The Scientific staff and crew onboard CCGS Louis S. St. Laurent (LSL) returned September the 10th, 2001 from a scientific expedition to the Nares Strait, the northernmost waterway connecting the Arctic and Atlantic oceans. The data format is Society of Exploration Geophysicists SEG Y. The ice conditions in the strait required the support of Canada's largest ice breaker. The ship was a versatile platform for 34 scientists to accomplish their marine investigation. The LSL has a history of supporting international scientific expeditions including an oceanographic transect of the Arctic Ocean in 1994 and a biological study of the Canadian Arctic Islands in 1999. Germany (Bundesanstalt für Geowissenschaften und Rohstoffe, BGR) and Canada (Geological Survey of Canada) undertook a 5-week scientific cruise to study and explore the geological structure and evolution of the Nares Strait. The primary objective was the study of structural features relating to the formation of the Arctic Ocean and, in particular, the study of the Wegener Fault. This fault is a linear boundary between Greenland and Ellesmere Island which was noted by the German scientist Alfred Wegener in 1915 and later became the subject of a major scientific controversy. The co-operative cruise, which was planned over a period of 2 years, provided the basis for a wide range of scientific investigations, from marine seismic work and climate change studies through airborne magnetic investigations to geodetic survey measurements and geological sampling onshore. Systematic geophysical offshore studies in this key area had not been undertaken before. Where towing of seismic equipment was not possible because of ice coverage, magnetic maps were made using a helicopter-borne magnetic sensor system. Sediment and water samples taken during the cruise provide information on changes in climate and sea ice cover from the last ice-age to the present. An 11 m-long sediment core from outer Jones Sound is the longest core ever taken in the Canadian Arctic channels and holds clues to the detailed climate history of northern Baffin Bay.

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