A5090900549- Cryospheric studies and observations
- Winter Sports Injuries and Performance
- Arctic and Antarctic ice dynamics
- Climate change and permafrost
- Landslides and related hazards
- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Polar Research and Ecology
- Environmental Changes in China
- Atmospheric and Environmental Gas Dynamics
- Synthetic Aperture Radar (SAR) Applications and Techniques
- Arctic and Russian Policy Studies
- Electron and X-Ray Spectroscopy Techniques
- Icing and De-icing Technologies
- Flood Risk Assessment and Management
- Geophysics and Gravity Measurements
- RNA modifications and cancer
- Ga2O3 and related materials
- Atmospheric chemistry and aerosols
- Oceanographic and Atmospheric Processes
- Medical Imaging and Pathology Studies
- Remote Sensing and Land Use
- Geochemistry and Geologic Mapping
- Freezing and Crystallization Processes
- Climate variability and models
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung
2012-2025
University of Tübingen
2013-2015
TH Bingen University of Applied Sciences
2015
Bernstein Center for Computational Neuroscience Tübingen
2013
RWTH Aachen University
2013
Glacier mass changes are a valuable indicator of climate variability and monsoon oscillation on the underexplored Tibetan Plateau. In this study data from Ice Cloud Elevation Satellite (ICESat) is employed to estimate elevation glaciers Plateau between 2003 2009. order get representative sample size ICESat measurements, were grouped into eight climatically homogeneous sub-regions. Most negative budgets − 0.77 ± 0.35 m w.e. a−1 found for Qilian Mountains eastern Kunlun while gain + 0.37 0.25...
Abstract Knowledge about the long-term response of High Mountain Asian glaciers to climatic variations is paramount because their important role in sustaining river flow. Here, a satellite-based time series glacier mass balance for seven climatically different regions across Asia since 1960s shows that loss rates have persistently increased at most sites. Regional budgets ranged from −0.40 ± 0.07 m w.e.a −1 Central and Northern Tien Shan −0.06 Eastern Pamir, with considerable temporal...
Abstract Melt ponds forming on Arctic sea ice in summer significantly reduce the surface albedo and impact heat mass balance of ice. Therefore, their areal coverage, which can undergo rapid change, is crucial to monitor. We present a revised method extract melt pond fraction (MPF) from Sentinel‐2 satellite imagery, evaluated by MPF products higher‐resolution helicopter‐borne imagery. The analysis evolution during MOSAiC campaign 2020, shows split Central Observatory (CO) into level highly...
Abstract The Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition took place between October 2019 and September 2020 giving rare opportunity to monitor sea-ice properties over a full annual cycle. Here we present 24 high-resolution orthomosaics 14 photogrammetric digital elevation models surface around icebreaker RV Polarstern March 2020. dataset is based on >34.000 images acquired by helicopter-borne optical camera system with survey flights covering...
This study assesses the response on ice dynamics of Petermann Glacier, a major outlet glacier in northern Greenland, to 2012 and possible future calving event. So far Glacier has been believed be dynamically stable as another large event 2010 had no significant impact flow velocity or grounding line retreat. By analyzing time series remotely sensed surface velocities, we find an average acceleration 10% between winter 2011/2012 2016/2017. increase is not linear but can separated into two...
The drainage divides of ice sheets separate the overall glaciated area into multiple sectors. These basins are essential for partitioning mass changes sheet, as they specify over which basin specific measurements integrated. delineation on is challenging due to their gentle slopes accompanied by local terrain disturbances and complex patterns movement. Until now, in Greenland have been mostly delineated along major divides, results large sectors containing outlet glaciers. However, when...
Supraglacial liquid water at the margins of ice sheets has an important impact on surface energy balance and can also influence flow when supraglacial lakes drain to bed. Optical imagery is able monitor during summer season. Here we developed alternative method using polarimetric SAR from Sentinel-1 2017–2020 distinguish between other types margin Northeast Greenland Ice Stream. This allows hydrology be monitored winter months too. We found that majority persist over winter. When comparing...
Abstract. The Northeast Greenland Ice Stream (NEGIS) extends around 600 km upstream from the coast to its onset near ice divide in interior Greenland. Several maps of surface velocity and topography exist, but their accuracy is not well constrained by situ observations. Here we present results a GPS mapping an area located approximately 150 East Ice-core Project (EastGRIP) deep-drilling site. A strain net consisting 63 poles was established observed over years 2015–2019. covers 35 40 km,...
Abstract. The role of polar regions is increasing in terms megatrends such as globalization, new transport routes, demography, and the use natural resources with consequent effects on regional transported pollutant concentrations. We set up ERA-PLANET Strand 4 project “iCUPE – integrative Comprehensive Understanding Polar Environments” to provide novel insights observational data global grand challenges an Arctic focus. utilize integrated approach combining situ observations, satellite...
The usability of multispectral satellite data for detecting and monitoring supraglacial meltwater ponds has been demonstrated western Greenland. For a multitemporal analysis large regions or entire Greenland, largely automated processing routines are required. Here, we present sequence algorithms that allow an Sentinel-2 search, download, processing, generation consistent dense melt pond area time-series based on open-source software. We test our approach ~82,000 km2 at the 79 °N Glacier...
Sea-ice ridges constitute a large fraction of the ice volume in Arctic Ocean, yet we know little about evolution these masses. Here examine thermal and morphological an first-year sea-ice ridge, from its formation to advanced melt. Initially mean keel depth was 5.6 m sail height 0.7 m. The initial rubble macroporosity (fraction seawater filled voids) estimated at 29% drilling 43%–46% buoy temperature. From January until mid-April, ridge consolidated slowly by heat loss atmosphere total layer...
Abstract. Due to their remoteness, altitude and harsh climatic conditions, little is known about the glaciological parameters of ice caps on Tibetan Plateau. This study presents a geodetic mass balance estimate Purogangri Ice Cap, Tibet's largest field between 2000 2012. We utilized data from actual TerraSAR-X mission its add-on for digital elevation measurements compared it with Shuttle Radar Topography Mission. The employed sets are ideal this approach as both were acquired at X-band...
Abstract Ice-shelf channels are long curvilinear tracts of thin ice found on Antarctic shelves. Many them originate near the grounding line, but their formation mechanisms remain poorly understood. Here we use ice-penetrating radar data from Roi Baudouin Ice Shelf, East Antarctica, to infer that morphology several ice-shelf is seeded upstream line by large basal obstacles indenting below. We interpret each obstacle as an esker ridge formed sediments deposited subglacial water conduits, and...
Abstract Migration of subglacial water underneath thick Antarctic ice is difficult to observe directly but known influence flow dynamics. Here, we analyze a 6‐year time series displacement maps from differential Sentinel‐1 SAR interferometry (DInSAR) in the upstream region Jutulstraumen Glacier. Our results reveal short‐term (between 12 days and 1 year) interconnected subsidence‐ uplift events surface, which interpret as pressure response drainage filling lakes. This indicates an episodic...
Abstract Only a few localised ice streams drain most of the from Greenland Ice Sheet. Thus, understanding stream behaviour and its temporal variability is crucially important to predict future sea-level change. The interior trunk 700 km-long North-East Stream (NEGIS) remarkable due lack any clear bedrock channel explain presence. Here, we present 3-dimensional analysis folding advection stratigraphic horizons, which shows that flow shear margins in upper NEGIS were fully developed only ca...
Abstract Most glaciers on the Tibetan Plateau are difficult to assess as they located in remote regions at high altitude. This study focuses surface energy-balance (SEB) and mass-balance (MB) characteristics of Purogangri ice cap (PIC). A ‘COupled Snowpack Ice energy MAss balance model’ (COSIMA) is applied without observational data from ground. The model forced by a meteorological dataset High Asia Refined analysis. Model results for annual surface-elevation changes MB agree well with...
Abstract The ice stream geometry and large surface velocities at the onset region of Northeast Greenland Ice Stream (NEGIS) are not yet well reproduced by sheet models. quantification basal sliding a parametrization conditions remains major gap. In this study, we assess NEGIS in systematic analysis airborne ultra‐wideband radar data. We evaluate roughness return echoes context current velocity. observe change from smooth to rougher bed where widens, distinct anisotropy, indicating preferred...
Abstract Future projections of global mean sea level change are uncertain, partly because our limited understanding the dynamics Greenland’s outlet glaciers. Here we study Nioghalvfjerdsbræ, an glacier Northeast Greenland Ice Stream that holds 1.1 m sea-level equivalent ice. We use GPS observations and numerical modelling to investigate role tides as well elastic contribution flow. find ocean alter basal lubrication up 10 km inland grounding line, their influence is best described by a...
Abstract. The 79° North Glacier (Nioghalvfjerdsbrae, 79NG) is one of three remaining glaciers with a floating tongue in Greenland. Although the glacier has been considered exceptionally stable past, earlier studies have shown that ice thinned recent decades. By conducting high-resolution ground-based and airborne radar measurements conjunction satellite remote-sensing observations, we find significant changes geometry 79NG. In vicinity grounding line, 500 m high subglacial channel grown...
Abstract. Since 2004, Halji village, home of the oldest Buddhist Monastery in north-western Nepal, has suffered from recurrent glacial lake outburst floods (GLOFs). A sudden englacial drainage a supraglacial lake, located at distance 6.5 km was identified as source flood. The topography basin mapped by combining differential Global Positioning System (DGPS) measurements with structure-from-motion (SFM) approach using terrestrial photographs. From this model maximum filling capacity been...
This study investigates seasonal ice dynamics of Nioghalvfjerdsfjorden or 79$^\circ$N Glacier, one the major outlet glaciers North East Greenland Ice Stream. Based on remote sensing data and in-situ GPS measurements we show that surface melt water is quickly routed to ice-bedrock interface with a direct response velocities measured at surface. From temporally highly resolved time series found summer peak up 22% faster than their winter baseline. These average out 9% above when relying lower...
Abstract. Ice shelves play a key role in the stability of Antarctic Sheet due to their buttressing effect. A loss as result increased basal melting or ice shelf disintegration will lead discharge. Some exhibit channels at base that are not yet fully understood. In this study, we present situ melt rates channel which is up 330 m high and located southern Filchner Shelf. Maximum observed 2 yr−1. Melt inside decrease direction flow turn freezing ∼55 km downstream grounding line. While closer...
Melt ponds on Arctic sea ice play a critical role in the ice-albedo feedback, influencing energy budget and climate. While satellite-derived products provide broad-scale estimates of melt pond fraction, detailed information individual properties direct high-resolution comparisons with other remain limited. In this study, we combine airborne observations thickness model output to evaluate representation simulations.Melt properties, particular along flight tracks are derived using RGB imagery,...
Abstract. Melt ponds play a crucial role in modulating the energy balance of Arctic sea ice by reducing surface albedo. While is becoming younger and smoother, this raises questions about how these changes affect melt pond characteristics, as effect deformation features, such pressure ridges, on development large spatial scales remains insufficiently understood. Here, we analyze 70 km² high resolution airborne optical imagery coincided laser altimeter data from three research flights north...