GLORIA

GEOMAR Library Ocean Research Information Access

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2018-08-03
    Description: The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (〉15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.
    Keywords: Geochemistry, Geophysics, Planetary Science
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2021-06-14
    Description: In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion.
    Language: English
    Type: info:eu-repo/semantics/article
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2023-08-16
    Description: The HYDROCOASTAL project aims to enhance our understanding of interactions between the inland water and coastal zone, between the coastal zone and the open ocean, and the small-scale processes that govern these interactions. To achieve these aims, the HYDROCOASTAL project team has developed and implemented new SAR altimeter processing algorithms for the coastal zone and inland waters, and with these processed Sentinel 3A, 3B and Cryosat-2 data to generate an initial 2-year Test Data Set for selected regions. The performance of these new algorithms has been evaluated, by statistical analyses and comparison against in situ data. From this analysis, the best performing algorithms have been identified and implemented in a processing scheme to generate a global scale coastal zone and inland water SAR altimeter data set A series of case studies have assessed these products in terms of their scientific impacts. All the produced data sets will be available on request to external researchers, and full descriptions of the processing algorithms are available via the project web-site. The presentation will provide an overview of the project, and present key results from the coastal zone studies, which have investigated the potential scientific impact and benefits of the new data set in understanding processes in six different coastal regions, including the Severn Estuary in the UK; The German Bight, Southern Baltic and Elbe Estuary; The Venice Lagoon; The Thailand Coast; The Ebro River and Delta, and the Wadden Sea.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2023-08-16
    Description: “Fully focused” processing of SAR altimeter data provides opportunities for exciting new applications, as it provides hitherto unachievable along-track resolution (potentially under 10m). The objective of the FFSAR-Coastal Project is to evaluate the potential of FFSAR altimeter data to make a significant new contribution to coastal and estuarine monitoring systems. Two different environments are being considered: - The Severn Estuary and river: A highly dynamic mixed tidal estuary environment. - The lower Rhone Delta and Camargue: A low lying, flat river delta and wetland environment DTU Space have implemented the SMAP (Standalone Multi-Mission Altimetry Processor) and applied it to Sentinel 3A and 3B altimeter data for the two regions in the study) to generate time series of data for selected tracks, and these data validated against in-situ data. The in-situ data comprise data from existing tide gauges, but also from four newly installed innovative “micro-gauges” provided by vortex.io, two in each region. Drone campaigns with an embedded LiDAR altimeter have been carried out to provide high-resolution sea level measurements, to provide a water level profile between the micro-gauge location and the satellite ground track. Subsequent analysis has investigated the capability of FFSAR altimeter data to capture small scale physical signals (surface gradients, currents, roughness signatures) in highly tidal regions and to detect and measure tidal asymmetry/gradients across estuaries not seen with conventional altimetry. For the Rhône delta the analysis has focussed on the ability of FFSAR data to accurately map different low-lying channels and filaments.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    In:  XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG)
    Publication Date: 2023-06-20
    Description: The objective of this research is to apply spaceborne Earth observation to assess the energy that could be cropped from ocean waves in the coastal zone, in view of supporting the renewable energy industry to optimize their design of wave energy farming. An assessment of the wave energy potential is given for the French Atlantic façade and Portuguese coastal zone, which is characterized by high energy swell generated by remote westerly wind systems. The French Atlantic façade is characterized also by the strong wave-current interaction that modulates the spatial wave variability and determines the magnitude of the wave power.Our approach is based on the empirical method of Gommenginger et al. (2003) to estimate the energy period, required for the computation of the wave power density from radar altimeters’ significant wave height and radar backscatter coefficient.The feasibility of high-resolution satellite altimetry-based assessment of wave renewable energy potential in the coastal zone is examined, taking advantage of the increased spatial coverage of high-resolution satellite altimetry data from the CryoSat-2 data, which is specifically processed with the SAMOSA+ model retracker, which is available in the ESA Altimetry Virtual Laboratory (https://earthconsole.eu/altimetry-virtual-lab/). The study comprises an 11-year timespan from January 2011 to December 2022.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2023-07-03
    Description: Measuring the Earth energy imbalance (EEI) at the top of the atmosphere, is challenging as it is a globally integrated variable whose variations are small (0.5-1 W.m−2) compared to the amount of energy entering the climate system (~ 340 W/m²). Accuracies better than 0.1 W/m² are needed to evaluate the temporal variations of the EEI at decadal and longer time-scales. The CERES experiment provides EEI time variations with a typical uncertainty of ± 0.1 W/m² and shows a trend in EEI of 0.50 +/- 0.47 W/m² per decade over the period 2005-2019.The combination of space altimetry and space gravimetry measurements provides an estimate of the global ocean heat content (GOHC) change which is an accurate proxy of EEI (because 〉90% of the excess of energy stored in response to the EEI is accumulated in the ocean in the form of heat). In Marti et al. (2021), the GOHC was estimated at global scales based on the combination of space gravimetry and altimetry measurements over 2002-2016. Changes in the EEI were then derived with realistic estimates of its uncertainty.Here we present the improvements brought to the GOHC and EEI over an extended period (2002-2021), such as the calculation of the expansion efficiency of heat over the total water column, the improvement of barystatic sea level change solution, the empirical correction of the wet tropospheric correction of Jason-3 altimeter measurements (Barnoud et al., 2022).The space geodetic GOHC-EEI product based on space gravimetry and altimetry is available on AVISO at https://doi.org/10.24400/527896/a01-2020.003.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2023-07-07
    Description: Extreme sea level (ESL) events are the phenomena that result in exceptional water level at the coast, which can cause flooding, inundation, and erosion. Recent global scale studies show that relative sea level rise will increase the recurrence of ESL events, by reducing their return period. Also, the compound nature of these events, including the contribution from pluvial, fluvial, and ocean processes, is now understood to affect key processes in estuarine and delta environments. The EOatSEE project (https://eoatsee.eu/), funded by ESA under the Earth Observation Science for Society programmatic line, aims to provide a data-driven description of ESL events as a mean to advance scientific knowledge on this subject matter. It shall foster a community effort, bringing together the EO data provider and the numerical modelling communities, to fully exploit the novel capabilities and synergies offered by the latest advances in EO technology. In this work, a literature review and a collection of needs from the scientific community enabled the identification of current scientific challenges and technical requirements associated with process understanding, predictability and vulnerability & risk assessment of ESL events. Increasing the understanding of the non-linear interactions between oceanic and fluvial processes, and considering coastal morphology response within long-term flooding risk assessments are some examples of the scientific challenges identified, which are to be studied within 9 scientific demonstrators over 6 different coastal regions. Within IUGG2023, a set of preliminary results shall also be presented, as innovative solutions are developed and produced along EOatSEE to address those challenges.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2023-06-27
    Description: Lake ice thickness (LIT) and lake water level (LWL) are two thematic products of lakes as an Essential Climate Variable (ECV). Lake water levels are routinely estimated using radar measurements from satellite altimetry missions, but the retrieval of LIT from such missions is relatively new. While there is growing interest in the production of climate data records of LIT through the processing of historical time series, there is a need to examine the impact of varying ice and overlying snow properties on radar altimetry and microwave radiometry measurements through full ice seasons. There is also recent realization that the presence of ice cover on lakes has an impact on the quality of LWL estimates for several weeks/months of the year. Thin ice during initial ice formation, the absence of snow on the ice surface, the presence of deformation features (i.e. cracks in the ice and pressure ridges), and snow/ice melt onset introduce uncertainty in the retrieval of LIT and LWL from state-of-the-art algorithms.This talk will present results from a study that examined the sensitivity of radar backscatter and microwave brightness temperature measurements from satellite altimetry missions to varying snow and ice properties on large northern lakes. The presentation will cover results from: 1) forward modelling experiments of brightness temperature (18-37 GHz) and backscatter/waveforms (3-36 GHz) using the Snow Microwave Radiative Transfer (SMRT) model linked to a thermodynamic lake ice model; and 2) the comparison of forward simulations of radar backscatter and brightness temperature with measurements from Sentinel-3 and Jason-3 missions.
    Language: English
    Type: info:eu-repo/semantics/conferenceObject
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...