AG Fernerkundung-GIS (Braun)

International Doctoral Programme: Measuring and Modelling Mountian Glaciers in a Changing Climate (IDP M³OCCA)

Project staff: Thorsten Seehaus, Johannes Fürst, Illaria Tabone, Matthias Braun

Improve current mass change estimates of glaciers by innovatve technologies, develop new and improve existing algorithms for variable retrieval by deep learning. In addition, we aim at assimilating and linking various geophysical models and improve their performance by machine learning techniques. For more information on IDP M³OCCA please visit the project website.

In cooperation with FAU (Informatics, Mathematics, Electrical Engineering), Bavarian Academy of Sciences, DLR Microwave Radar Institute in Oberpfaffenhofen and Technical University of Munich

Funding period 2022-2025

Funded within the Elite Network Bavaria by the Bavarian State Ministry of Science and the Arts

Climate sensitivity of western Antarctic Peninsula ice shelves (CSAPIS)

Project staff: Matthias Braun, Antonia Warnstedt, Martin Rückamp

Unlocking the glaciological information of historical aerial imagery to obtain long-term glacier mass balance information and to identify drivers of glacier changes on the Antarctic Peninsula (UNLOC)

Project staff: Thorsten Seehaus

The Antarctic Peninsula is a hot spot of global warming and leading to considerable changes in its ice sheet and outlet glaciers. Pronounced glacier recession has been reported since the 1950s throughout the Antarctic Peninsula and many of its ice shelves disintegrated or significantly retreated within the last decades. Consequently, the ice masses of the Antarctic Peninsula contribute significantly to global sea-level rise. However, estimates of the mass budget of the Antarctic Peninsula are subjected to considerable uncertainties due to various issues. Moreover, long-term information on the evolution of the mass balances exists only for a very limited amount of glaciers.Since the 1950s, various aerial campaigns were carried out to map the Antarctic Peninsula. The acquired photogrammetric imagery poses a “time capsule” of information on the historic glacier states. Thus, we aim within this project to unlock this information from the historic aerial imagery by applying state-of-the-art photogrammetric analysis techniques to reconstruct the former glacier surface elevations. The analysis will be supported by providing precise ground control points, which will be acquired during a joint aerial survey with AWI and DLR in late 2022. By combining the information revealed from the historic imagery with recent surface elevation information from the German bistatic SAR mission TanDEM-X, the computation of long-term glacier volume and mass changes on the Antarctic Peninsula will be facilitated. Finally, all available information on glacier changes will be correlated with oceanic, atmospheric, and glacier geometry parameters in order to identify driving factors of the revealed glacier variations. This information will facilitate a better understanding of the ongoing processes and interaction between the different spheres, and will be highly beneficial for projections of glacier evolution on the AP Ice Sheet and future sea-level rise contribution.

Funding period 2023-2026

Funded within the DFG Priority Programme Antarctic Research SPP1158

Large-scale Automatic Calving Front Segmentation and Frontal Ablation Analysis of Arctic Glaciers using Synthetic-Aperture Radar Image Sequences (LASSI)

Project staff: Thorsten Seehaus, Vincent Christlein

The arctic glaciers are strongly affected by global climate change, in particular due to the Arctic amplification phenomenon. Thus, they contribute significantly to current sea level rise. There exists only sparse information on glacier front variations as well as the evolution of frontal ablation and its drivers for the huge amount of tide water glaciers in the Arctic. However, the steadily increasing amount of available remote sensing data, in particular since the launch of the Sentinel satellites within the Copernicus Program by ESA and the European Commission, facilitates large-scale spatio-temporal monitoring of glacier changes. Within the proposed project, we aim at applying deep learning techniques to automatically map calving front positions of arctic tidewater glaciers, by means of Sentinel-1 SAR imagery. Therefore, we will implement and evaluate different deep learning segmentation models, including also time-series information from SAR image sequences. To improve the robustness and performance of our segmentation results, we will enlarge the field-of-view by incorporating attention mechanisms, apply multi-task learning, and fine-tune our best model in a semi-supervised manner on glaciers not yet included in the training database. Uncertainty bounds will increase the interpretability of our model’s results. For the best performing approach, a fully automated operational processing pipeline will be implemented and applied on the huge amount of available Sentinel-1 imagery throughout the Arctic. Subsequently, the obtained information on glacier front changes will be combined with information on ice flux at the termini and climatic mass balance data to estimate frontal ablation. By including information on total mass balances of the glaciers and climatic mass balance data from regional climate modeling or down-scaling of reanalysis data, the contribution of frontal and surface mass balances to the total mass balance will be estimated. Finally, the obtained results on glacier changes in combination with information on atmospheric, oceanic, sea ice, and glacier geometry parameters will be analyzed using multivariate statistical approaches to identify the drivers of the observed glacier changes. The project results will enhance our understanding of the ongoing processes and cross-links between the different spheres. Moreover, we will obtain fundamental reference data for numerical glacier modeling, subsequently leading to improved projections of glacier evolution and sea-level changes.

Funding period 2022-2025

Funded within the DFG Priority Programme Antarctic Research SPP1158

Polar-5 geodetic & geophysical airborne surveys on the Antarctic Peninsula (INSULATE & APPM)

Project staff: Thorsten Seehaus, Matthias Braun

The aim of this airborne survey is to acquire high-resolution aerial photography on the south-central Antarctic peninsula using the high-resolution Polar-MACS camera system. In addition, laser scanning and radio echo sounding will be carried out on Wordie Ice Shelf tributary glaciers.

In cooperation with AWI Bremerhaven and DLR Adlershof

Funding period 2021 & 2022

Polar-5 geodetic & geophysical airborne surveys in Fuego-Patagonia (PataFuego 2021 & 2022)

Project staff: Moritz Koch, Matthias Braun, Johannes Fürst

The activity aims at acquiring various glaciological variables over the icefield and glaciers of Patagonia and Tierra del Fuego. The Polar-5 aircraft is operated out of Puerto Natales, Chile. We acquire data with various sensor systems like laser scanner, a long-range laser altimeter, high-resolution aerial photography, accumulation radar and various meteorological instruments. We repeat tracks of previous measurements by other groups in order to allow precise elevation change measurements. The data also serves as reference for spaceborne elevation change measurements from the german TanDEM-X mission.

In cooperation with AWI Bremerhaven, TU Dresden and  TU Darmstadt as well as various partners from South America

Funding period 2021 & 2022

Ice thickness, remote sensing and sensitivity experiments using ice-flow modelling for
major outlet glaciers of the Southern Patagonian Icefield (ITERATE)

Project staff: Moritz Koch, Matthias Braun, Johannes Fürst

The project aims at improving our process understanding of glacier changes and their constraints and sensitivities to potential future perturbations. In order to achieve those goals we will acquire new data, update our existing comprehensive spatial databases and combine information into local-scale ice-flow modelling and an analysis of different forcing scenarios. Specifically we will acquire additional ice thickness data using helicopter-based ice penetrating radar surveys as well as airborne laser scanning surveys. The airborne surveys are carried our in close cooperation our international partners. We will temporally densify our spatial information on glacier extent from optical satellite data, compute surface velocity fields by intensity offset tracking from regular Sentinel-1 radar imagery and compute improved surface elevation and mass change estimates. We will assimilate our spatial fields in a state-of-the-art ice thickness reconstruction approach. Latter will be constraint by the new and existing ice thickness measurements from different groups as well as by novel bathymetric data in order to generate a new map of the bedrock topography. We will adapt our existing reconstruction approach since we will have to weight the different ice thickness measurements in regard to their quality. The last task comprises the setup of high-resolution ice dynamic models for specific glaciers, namely Perito Moreno, Upsala and Viedma glaciers. We will specifically test different calving routines implemented in ELMER/Ice and perform perturbation experiments in order to test the glaciers’ sensitivity on certain variables and parameters like bed elevation, basal friction, lake level, calving parameters and frontal ablation.

Funding period 2021-2024

Mass balance and ice dynamics of Antarctic Peninsula glaciers (MIT-AP)

Project staff: Thorsten Seehaus

Pronounced climatic changes have been observed at the Antarctic Peninsula within the past decades and its glaciers and ice caps have been identified as a significant contributor to global sea level rise. Dynamic thinning and speed-up was reported for various tidewater glaciers on the western Antarctic Peninsula. On the east coast, several ice shelves disintegrated since 1995. Consequently, former tributary glaciers showed increased flow velocities due to the missing buttressing, leading to substantial ice mass loss. Various studies were carried out to quantify the ice mass loss and ice discharge to the ocean at the Antarctic Peninsula using different approaches. However, the results are still subject to substantial uncertainties, in particular for the northern section of the Antarctic Peninsula (<70°S).

Thus, the aim of this project is to carry out an enhanced analysis of glacier mass balances and ice dynamics throughout the Antarctic Peninsula (<70°S) using various remote sensing data, in-situ measurements and model output. By analyzing bistatic SAR satellite acquisitions, an unprecedented spatial coverage with surface elevation change information at the study area will be achieved to compute multi-temporal geodetic glacier mass balances on regional and glacier scales. Information on ice dynamics will be derived from multi-mission SAR acquisitions using offset tracking techniques. In combination with latest ice thickness data sets the spatiotemporal variability of the ice discharge to the ocean will be evaluated. By including information from in-situ measurements and model output of atmospheric and oceanic parameters, driving factors of the obtained change patterns will be assessed to enhance the understanding of the ongoing change processes.

The project results will contribute fundamental information to international initiatives and institutions like IMBIE, IPCC and WGMS and address several “Advancing Earth System Science Challenges of the Living Planet”, defined by ESA.

Funding period 2020-2022

SATELLITE – A stochastic eStimATe of sEa Level contribution from gLaciers and Ice caps using satellite remoTe sEnsing

Project staff: Christian Sommer, Philipp Malz, , Matthias Braun

The project aims at deriving a stochastic global sampling for ice volume and mass loss of glaciers and ice caps based on repeat satellite observations. For this purpose we will develop a respective sampling strategy. We propose two observation intervals: a period 2000-2012 between 56°S and 60°N and a second interval covering 2012 to 2014 or later (globally) in order to quantify potential changes in ice volume/mass loss rates.

Geodetic glacier-specific mass balances will enable us to quantitatively compare changes and change rates in different regions of the world using the same methodology. We base our analysis on data from the German satellite mission TanDEM-X and integrate it with observations and data products from other sources (like SRTM, ASTER, Landsat, ICESat-1/2, WGMS records, field and airborne measurements). The German TanDEM-X satellite mission operated since 2010 provides a unique database with its bi-static satellite configuration.

Funding period : 2016-2019

Website: www.spp-sealevel.de

Funded by

FRAGILE – Next generation framework for global glacier forecasting

Worldwide glacier retreat outside the two large ice sheets is increasingly tangible and the associated ice-loss has dominated the cryospheric contribution to sea-level change for many decades. This retreat has also become symbolic for the effects of the generally warming climate. Despite the anticipated importance for future sea-level rise, continuing glacier retreat will affect seasonal freshwater availability and might add to regional water-stress in this century. Here, I envision a novel self-consistent, ice-dynamic forecasting framework for global glacier evolution that will lift the confidence in forward projections for this century to new heights. For the first time, each glacier on Earth will be treated as a three-dimension body within its surrounding topography without using any form of geometric simplification. The heart of the framework is the systematic utilisation of the rapidly growing body of information from satellite remote sensing. For this purpose, I intend to pass on to ensemble assimilation techniques that transiently consider measurements as they become available. This will streamline and increase the total information flow into glacier models. In terms of climatic forcing, global products will be replaced by regional forecasts with high-resolution climate models. Moreover, a more realistic representation of the local energy balance at the glacier surface is pursued that ensures multi-decadal stability in the melt formulation. The envisaged 3D finite-element modelling framework also allows a direct integration of iceberg calving, which is, on global scales, an oftenunconsidered dynamic ice-loss term. To this day, a key limitation of glacier projections is the poorly constrained ice volume and its distribution at present. Here, I put forward a promising remedy that builds on multi-temporal satellite information to calibrate a state-of-the-art reconstruction approach for mapping basinwide ice thickness on virtually any glacier.

European Research Council (ERC) – Starting Grant
Period: 2021 – 2026
Project staff: Theresa Diener, Johannes Fürst

GROCE (TP 7): Supra-glacial melt water at the 79° Glacier, Greenland

Project staff: Katrina Bartek, Matthias Braun

The subproject will detect supra-glacial meltwater ponds in its spatial and temporal variation. Hereto, data of various national and European SAR systems, like TerraSAR-X and TandDEM-X, COSMO-Skymed, Sentinel-1 as well as optical data from the Sentinel-2 mission will be used. To map the melt dynamics and the supra-glacial lakes we develop novel algorithms based on deep learning. We will also estimate the depth and volume of the meltwater ponds combining field observations and data from the NASA ICESat-2 spaceborne laser altimeter.

Project partners:

• Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI)
• GEOMAR – Helmholtz Zentrum für Ozeanforschung
• Marum – Zentrum für Marine Umweltwissenschaften der Universität Bremen
• Technische Universität Dresden
• Universität Bonn

Laufzeit: 2017 – 2020, 2020-2023

Web site: www.groce.de

Funded by

MAGIC – The Mountain Glacier Forecast Framework

General glacier retreat around the globe has become iconic to illustrate the effects of global warming and we anticipate that this demise will continue and significantly add to global sea-level rise. Ice loss can also induce shifts in regional water resources, putting some places at high risk of year-around freshwater availability. Better projections of glacier retreat are therefore essential in terms of coastal impact, water management and hydro-glaciological risks. The overall aim of the project is to provide a framework to improve past and future glacier volume projections. The process-based framework will be based on the open-source ice-flow model Elmer/Ice and will allow to reduce three potentially important sources of uncertainty. Anticipating the continuously growing body of information from satellite remote sensing, we will improve and develop robust data assimilation methods to infer the basal topography beneath the ice and calibrate ice-flow parameters for a better representation of the initial state and ice dynamics. The flow model will be coupled to an enhanced surface mass balance model that exhibits a stable melt relation over relevant multi-decadal timescales. Based on ensemble simulations, the framework will allow to better quantify the interaction and propagation of these uncertainties. As a proof of concept, the framework will be applied to hindcast and forecast glacier evolutions in the French Alps and in Cordillera Darwin (Chile). These sites have been chosen because for both glacier sites ice-flow is considered important and because of the availability of in-situ and remotely sensed observations. The two sites will further serve as challenging test setups to scrutinise the applicability, performance and robustness of the modelling framework under different climatic conditions and dynamic settings.

Deutsche Forschungsgemeinschaft (DFG) – Project ID: 431767937
Period: 2020-2023
Project staff: Franziska Temme, Johannes Fürst, Fabien Gillet-Chaulet

EU BiodivERsA, DFG FE 1331/3-1

Funding period: 2014-2017

Project team: Hannes Feilhauer, Sandra Skowronek

Biodiversity conservation includes the development of warning and rapid response systems for biological invasions and urges investigations of their impacts on ecosystem function and services. In this context, the systematic, objective, and synoptic view on Earth of remote sensing systems offers a great opportunity to target biological invasion and their impact across various spatial and temporal scales. Within DIARS we aim to

1. characterize the ecosystem impact of invasive plant species through the combined use of field and remotely sensed data.

2. support monitoring, prediction of spread and risk assessment of invasive plant species as preconditions for management measures and mitigation.

For this purpose, we analyse and map the local distribution of the invasive species Campylopus introflexus, Prunus serotina and Oxalis pes-caprae and their impact on ecosystems in Germany and France.

Project website: DIARS

Project partners:

• Carnegie Department of Global Ecology, Stanford, CA, USA
• Fondazione Edmund Mach, San Michele all’Adige, Italy
• KIT, Karlsruhe, Germany
• KU Leuven, Leuven, Belgium
• U de Picardie Jules Vernes, Amiens, France
• Vito, Mol, Belgium

Gefördert durch die

DFG FE 1331/2-1

Funding period: 2013-2014

Project team: Hannes Feilhauer

Maps of vegetation patterns such as spatial variation in floristic composition, plant traits and plant functional types are required in ecology, ecosystem modelling and nature conservation. One frequently applied approach to generate these maps relies on imaging spectroscopy. In this approach, statistical relationships between a vegetation sample and the corresponding canopy reflectance are quantified and subsequently applied onto the imagery.

Although several successful examples of such applications exist, fundamental questions regarding the causal relations between vegetation patterns and canopy reflectance are still open. In particular the role of canopy optical traits remains poorly understood. Canopy optical traits determine the reflectance signal of vegetation and include canopy biochemistry, morphological and structural properties. CaTReS aims to test the qualitative and quantitative contribution of these traits to remote sensing of vegetation patterns in a test site in Southern Bavaria.

Gefördert durch die

DFG-Priority Programme 1158 Antarctic Research

BR2105/8-1

Funding period: 2009-2014 (completed)

This project aims to gain understanding of ongoing and potential changes of Wilkins and GeorgeVI ice shelves on the south-western Antarctic Peninsula. Both are located in an area of the supposed climatic limit of viability of ice shelves and have already shown considerable ice front retreat. The break-up events in 2008 and 2009 on Wilkins Ice Shelf exemplified their potential of disintegration.

Within a multi-institutional, interdisciplinary approach including remote sensing (FAU Erlangen-Nürnberg), modeling of the ice dynamics (Alfred-Wegener-Institut) and fracture mechanics (TU Kaiserslautern), we aim to improve the understanding of the impacts of temperature increase on ice shelf stability.

The remote sensing component includes the mapping of surface structures and fracture development over time, as well as the derivation of surface velocity fields by SAR interferometry and feature tracking for the Wilkins Ice Shelf, which are required as input datasets for modeling of fracture and ice dynamics. For this purpose, we use multi-temporal optical and SAR imagery (Alos Palsar, TerraSAR-X, ERS, ENVISAT). Further work tasks include the investigation of ice thickness changes based on altimetry data and the mapping of the grounding line using Differential SAR Interferometry. The observed quantities are interpreted in the context of ice dynamics and fracture mechanics.

Project team

Matthias Braun, Melanie Rankl

BayIntAn – Reconstruction of climate at Glaciar Perito Moreno

Funding period: 2014

Klimarekonstruktion am Perito Moreno Gletscher in Patagonien auf Basis von dendro-ökologischen Untersuchungen, meteorologischen Messungen und Fernerkundung
Die Messung verschiedener dendroökologischer Parameter wie Jahrringbreiten, Holzdichte und die Analyse der zeitlichen Variabilität der stabilen Isotope ermöglicht es Rückschlüsse auf vergangene Klimabedingungen zu ziehen, bevor irgendwelche Klimamessungen in der Region gemacht wurden (wir erwarten Aufzeichnungslängen von etwa 200 Jahren). Die dendrochronologischen Zeitreihen werden mit meteorologischen Daten einer automatischen Wetterstation am Südrand des Glaciar Perito Moreno kalibriert, die seit fast zwei Jahrzehnten kontinuierlich aufzeichnet. Dies ermöglicht es, eine Beziehung zwischen den in Baumringen gespeicherten Umweltvariablen und dem lokalen Klima herzustellen. Das ermittelte Klimasignal wird mit dem Gletscherverhalten und der Sensibilität des Gletschers gegenüber klimatischen Veränderungen verknüpft.
Der Perito Moreno ist der einzige Gletscher im Nationalpark Los Glaciares mit fast 2 Jahrzehnten ununterbrochenen meteorologischen Messdaten und einer einzigartigen Lage, um die Jahrringmessungen mit in-situ meteorologischen Beobachtungen zu kalibrieren. Die Baumarten der Gattung Nothofagus oberhalb der rezenten Lateralmoräne garantieren eine sehr starke Verbindung zwischen lokalem Klima und den Baumring Informationen sowie eine lange zeitliche Aufzeichnung. Anschließend an den Standort am Perito Moreno wird entlang des klimatischen Transekts, von feuchteren in trockenere Bedingungen, beprobt – die Standorte innerhalb des Nationalparks repräsentieren feuchte Bedingungen, während die Standorte außerhalb des Parks (nach Osten) trockenere Bedingungen aufweisen.

In Kooperation mit Pedro Skvarca, Glaciarium, El Calafate, Argentinien).

Anschubfinanzierung des Bayerischen Förderprogramms zur Anbahnung internationaler Forschungskooperationen (BayIntAn), 2014.

Gefördert durch:
BAYLAT (Bayerische Hochschulzentrum für Lateinamerika)
BayFor (Bayerische Forschungsallianz)
BayIntAn (Bayerisches Förderprogramm zur Anbahnung internationaler Forschungskooperationen)

Projektbeteiligte/ Project team

Björn Saß, Jussi Grießinger, Matthias Braun

EU FP7 IRSES

Funding period 2012-2016

IMCONet is an international Research Network that follows an interdisciplinary approach to understand the consequences of Climate Change in coastal Western Antarctica. A Network for Staff Exchange and Training, IMCONet is funded by the Marie Curie Action IRSES (International Research Staff Exchange Scheme) of the 7th Framework Programme of the European Union. The activity brings European, South American and US scientists together to advance climate and (eco-) system change research at the Western Antarctic Peninsula (WAP), a region of recent rapid aerial warming.

IMCONet objectives are

DFG-Priority Programme 1158 Antarctic Research

BR 2105/9-1

Funding period: 2012-2015

Climate conditions along the Antarctic Peninsula have considerably changed in the last 50 years. The glaciers on the Western Antarctic Peninsula have already shown reactions of change by speed-up and surface lowering. The disintegration of the Larsen-A and B Ice Shelves, the ice shelves in the Larsen Inlet, Prinz-Gustav-Channel and Wordie Ice Shelf have led to a surge-type behaviour of tributary glaciers to which much of the current contribution of Antarctic Peninsula ice to sea level rise is attributed. However, quantifications of mass loss from the peninsula using different observations and methods are still ambiguous.

The aim of our project is on to improve the quantifications of mass loss in the area of the former Northern Larsen-A embayment as well as for Western Antarctic Peninsula glaciers. In order to achieve those goals we analyse time series of satellite data from ERS 1/2, Envisat, Radarsat 1, ALOS PALSAR, TanDEM-X & TerraSAR-X and Rapideye to determine glacier velocity changes for these regions over the last 20 years. Furthermore we generate digital elevation models from TanDEM-X mission data in order to calculate surface elevation changes. Our products are backed up with GNSS ground truth measurements from joint German-Argentine (DNA_IAA)  field campaigns  and laser altimetry done by collaborating partners (Alfred Wegener Institut, Bremerhaven). In an integrated analysis those data sets are linked to achieve a better glaciological understanding of underlying processes and to estimate the ice mass loss at the study region.

Project team

Matthias Braun, Thorsten Seehaus

Gletschermonitoring in Hochasien mittels TanDEM-X InSAR und weiterer Erdbeoachtungssensorik

Projektteam: Matthias Braun, Melanie Rankl, Philipp Malz

Projektlaufzeit: 2015-2017

Übergeordnetes Projektziel ist eine Eignungsanalyse von Daten der TanDEM-X Science Phase sowie die Entwicklung einer Prozessierungskette zur Ableitung geodätischer Massenbilanzen. Zudem sollen Änderungen der Dynamik und  Ausdehnung der Gletscher Hochasiens auf verschiedenen zeitlichen und räumlichen Skalen erfasst werden. Das zu entwickelnde Produkt ist ein validiertes „Methodeninstrumentarium zur Gletscherbeobachtung“, das nicht nur in Hochasien,  sondern auch in anderen Gebirgsregionen zur Beobachtung der dem globalen Klimawandel unterliegenden Gletscher eingesetzt werden kann. Die Innovation liegt in der Bewertung des Potenzials der experimentellen Aufnahmemodi der TanDEM-X Science Phase für die glaziologische Fernerkundung in Bezug zur bisherigen Aufnahmekonfiguration sowie in der Kombination mit glaziologischen Produkten basierend auf Daten verschiedenster Satellitenmissionen. Das  interferometrische Potenzial der Mission und dessen Eignung für steile Hochgebirgstopographien soll systematisch analysiert und Empfehlungen für die weitere Missionsplanung gegeben werden. Am Projektende soll eine verbesserte regionale Aussage zu den Massenänderungen der Gletscher in Hochasien stehen, die z.B. in internationale Berichte wie den IPCC AR6 einfließen kann.

Projektpartner: Prof. Dr. Volker Hochschild, Eberhard-Karls Universität Tübingen

gefördert durch:

HGF Alliance

Funding period: 2012-2017

The HGF Alliance “Remote Sensing and Earth System Dynamics” (EDA) aims at the development and evaluation of novel bio/geo-physical information products derived from data acquired by a new generation of remote sensing satellites; and their integration in Earth system models for improving understanding and modelling ability of global environmental processes and ecosystem change.

The key objective of the proposed Alliance is to prepare the HGF centers and the national/international science community for the utilisation and integration of bio/geo-physical products provided by the next generation radar remote sensing missions (e.g. Tandem-L) into the study of natural and anthropogenic impact on Earth’s ecosystems by:

• developing new bio/geo-physical information products from remote sensing data;
• integrating the new products into Earth system models;
• improving the understanding and modelling of dynamic processes;
• providing a unique forum for the education of a new generation of scientists.

Our working group forms part of the cryosphere workpackage of the HGF Alliance. We analyse SAR data in regard to changes in ice dynamics, volume and mass changes as well as glacier extent using SAR coherence. Our aim is to contribute to an improved system understanding merging the information terieved from earth observation with other data sources. For this purpose we develop algorithms based on data set from ALOS PALSAR and TerraSAR-X/TanDEM-X that provide respective products.

Project team

Saurabh Vijay, Melanie Rankl, Thorsten Seehaus, Matthias Braun

Full HGF-EDA Website

belspo

Funding period: 2016-2018

Project team: Hannes Feilhauer, Sandra Skowronek, and Iris Unberath

Species invasions are among the most important threats to the functioning of the Earth’s ecosystems. Invasion biologists have mainly focused so far on the effects that invasive plant species have on native populations and communities. The response of ecosystem functioning to invasion has received considerably less attention. In INPLANT we explore the capability of imaging spectroscopy data to define optically distinguishable functional types (‘optical types’) as a means to quantify the effects of invasive plants on ecosystem functioning. Spectroscopy data allow to characterize the canopy biochemistry, as such allowing a discrimination between subtle physiological differences among plant species, and enable a straightforward link to ecosystem processes. The optical types are expected to outperform, or at least complement, conventional functional trait approaches when predicting changes in ecosystem functioning through plant invasion. The principal idea behind INPLANT is that invasive plant species may have physical-chemical properties that differ from native species. These physical-chemical properties can be directly linked to ecosystem functioning changes following invasions, and they can be largely quantified based on the optical reflectance spectra of the species, which are detectable due to recent developments in remote sensing technology.

Project partners: KU Leuven, Leuven, Belgium

This project devotes itself to the question, what is the change in height by the densification of firn.

The test area is the Vestfonna Ice Cap (VIC) on the island Nordaustlandet in the north east of Svalbard. The VIC is ~2400 km² in size and has a dome like shape with well defined outlet glaciers. Further test sites with a magnificent in situ measurement archive are welcome.

The propulsion are inaccuracies introduced during the conversion between measured volume change into glacier mass changes. Until now, we calculated glacier mass balances with a constant conversion factor of 850 kg m^-3 or the density of ice (917 kg m^-3) for entire glacier basins, altitude dependent density variations and firn layer thickness were unnoticed this way. Or we used constant densities for the ablation (900 kg m^-3) and accumulation (600 kg m^-3) areas, whereby not homogeneous density variations with varying climate conditions were not considered. A decline of the accuracy in the amount of mass change is the consequence. This inaccuracy is a systematic component of uncertainty in geodetically determined mass balances, and thus need to be addressed for accuracy improvement.
The aim is to develop a firn elevation change model (FecMo) Surface Energy Balance (SEB) parameters (e.g. radiation, temperature, wind speed, precipitation, cloud cover fraction). At the moment the model is based on the COupled Snowpack and Ice surface energy and MAss balance glacier model (COSIMA) developed by Huintjes et al. (2015) (link to the open access Git repository). Latter model consists of a SEB model and an integrated subsurface model. Beside the surface energy component, the model has a discrete layer based subsurface structure.

To remove access restrictions by proprietary software, COSIMA-FecMo is developed in the programming language Python. Simple configuration and site specific initialization options will be implemented, additionally it will be possible to replace entire Py-modules (e.g. precipitation, albedo, densification) if more accurate modules are available. The python model will be offered to the scientific community.

FecMo will be forced by climate reanalysis data (e.g. Modèle Atmosphérique Régional (MAR), ERA-interim data from the ECMWF). The forcing will be validated by a AWS network on and around the ice cap. One part of AWS data was recorded during the International Polar Year Project Kinnvika (IPY Kinnvika) between 2007 and 2010, another part is free of charge from the MET Norway (eKlima) and the UNIS. FecMo will be calibrated by in situ measurements from the IPY Kinnvika on mass balance components (ablation, snow package character, firn properties).

The project combines remote sensing data (TanDEM-X, ICESat, CryoSat-2, Sentinel-1A, Aster) and methods (DInSAR, geodetic approach), climate data reanalysis and downscaling (MAR/ERA-Interim) and the extensive analysis of the IPY Kinnvika archive (GPR, snow pit, stake and AWS measurements, GPS and DGPS profiles).

At the end of our study, we will be able to derive layer based firn densities and to estimate firn densification on glaciers and ice caps to retrieve the amount of elevation change that is attributed to compaction.

Project members: Björn Saß

Bibliography:

Huintjes E, Sauter T, Schröter B, et al (2015) Evaluation of a Coupled Snow and Energy Balance Model for Zhadang Glacier, Tibetan Plateau, Using Glaciological Measurements and Time-Lapse Photography. Arct Antarct Alp Res 47:573–590. doi: 10.1657/AAAR0014-073

This work is funded by the German Environmental Foundation Scholarship Program (Deutsche Bundesstiftung Umwelt, DBU).

Global surface temperatures have risen by ~0.7°C over the previous century. Due to an inherent amplification of climatic changes in high latitudes, warming has been more expressed in Polar Regions. One eminent consequence is the general retreat of Svalbard glaciers observed throughout the last century. In the last decades, southern Svalbard glaciers have even moved on to thin at dramatically increasing rates. This latest thinning trend is however not confirmed throughout the Arctic. The reason relies in the unique climatic conditions on Svalbard. Since warm ocean currents in the North Atlantic reach the southern tip of the archipelago, the climate is rather warm and variable for its latitudinal band. Evolution of Svalbard glaciers has therefore often been suggested to play a precursor role for the other Arctic regions.Within the Arctic, Svalbard is unique in another respect, as glacier extents and elevation changes are well characterised over several decades. However, the interpretation of these geometric changes in terms of the climatic evolution is inhibited, as they arise from both the climatic surface mass balance and from ice flow divergence. The latter depends on glacier geometry and dynamics, and is not necessarily directly controlled by changes in climatological parameters. Yet, observations on glacier thicknesses and velocities are sparse and temporally incoherent, which impedes to this day a reliable quantification of the dynamic control on Svalbard glacier changes. By extension, we have only a vague idea on how much volume is annually discharged by iceberg calving at the marine ice fronts. Ice discharge presumably explains a large portion in the total mass budget, as more than half of the ice-covered area drains through marine-terminated glaciers.The aim of the research proposal is to expand the knowledge on the ice dynamic component of glacier evolution to the entire Svalbard archipelago. To this end, surface velocities are inferred from satellite remote sensing, which, in turn, serve to reconstruct the bedrock topography beneath all ice-covered areas. The reconstruction makes use of the mass conservation principle, provides therefore a flow-consistent thickness map and is already implemented in our ice flow model. Information on both ice velocities and ice thickness are a prerequisite to quantify the ice flow divergence that explains a, to this day, largely unknown portion of glacier changes. The reconstruction will therefore make it possible to better interpret recent geometric changes in the light of the observed atmospheric warming in the Arctic. Moreover, previous extrapolations for archipelago-wide estimates of ice volume and discharge can be improved on a physical basis. As the bedrock reconstruction is consistent with the observed ice flow, the map will facilitate the application of ice flow models on Svalbard. With our flow model, we aim at inferring the contribution of basal sliding to present glacier flow.

Deutsche Forschungsgemeinschaft (DFG) – Projektnummer 274939856

Remote Sensing of Mountain Glaciers

Assessment of essential climate variables to support international initiatives
– Development and refinement of methods, exemplarily applied in the tropical Andes
Methodenentwicklung und -verfeinerungen mit

GEKKO Gebirgsgletscher Essentielle Klimavariablen der KryOsphere

The glaciers of the tropical Andes represent an important water resource, but they are strongly affected by climate change. The regional water supply depends on the melt water and consequently on the mass balance of the glaciers. The goal of this project is to quantify glacier changes in the tropical Andes by analyzing different remote sensing data sets (SAR, optical imagery). Various glaciological variables (e.g., glacier extend, surface type, equilibrium line altitude, surface velocity) and their changes are going to be determined. Geodetic glacier mass balance is going to be derived from TanDEM-X and SRTM elevation models. New and upcoming Sensors like Sentinel-1&2 will be integrated in the analysis to estimate their capabilities for glacier monitoring. The results will provide essential information of the current state and ongoing changes of glaciers in the tropical Andes. An additional outcome is going to be a refined monitoring system for mountain glaciers.

Project team

Matthias Braun, Thorsten Seehaus

Founded by DLR & BMWI

IMProved gEodetiC glaCier mAss BaLancE measurements by integrating remote sensing, surface mass balance and firn compaction modelling – a case study from James Ross Island, Antarctica (IMPECCABLE)

Duration: 2016-2019

The aim of this project is an improvement of current estimates of glacier mass loss at James Ross island (JRI) on the east coast of the Antarctic Peninsula by comparing geodetic and flux approaches.

Glaciers draining into the ice shelves responded with flow acceleration and increased ice discharge to ice shelf disintegration (e.g. Larsen A/B) in the last years. There are still many uncertainties in mass balance modelling e.g. due to neglecting mass loss due to calving, unclear grounding line position, as well as errors in measured ice-thickness or conversion from volume to mass. Therefore, the differences between different models are not negligible and in situ measurements for validation are necessary.

This projects will try to overcome these limitations by the integration of the following measurements into the model creation:

• In situ surface mass balance measurements, installation of two automatic weather stations and time lapse cameras on Gourdon Glacier

• Static and kinematic differential as well as continuous GNSS measurements on JRI plateau and Gourdon Glacier

• Ground Penetrating Radar surveys by helicopter

• Elevation and volume change measurements by DinSAR

• Ice dynamics from repeat TerraSAR-X acquisitions

Project-Members: Stefan Lippl, Prof. Dr. Matthias Braun

Project-Partners: Dr. Daniel Nyvlt, Dr. Kamil Laska, Dr. Zdenek Stachon (Masaryk University, Brno), Dr. Zbynek Engel (Carles University, Prague), Ing. Sebastian Marinsek (Instituto Antártico Argentino)

Founded by DFG under number BR2105/13-1 within the czech-german collaborative candidacy 2015

Tapping the potential of Earth Observations (TAPE) – FAU Emerging Fields Initiative

Project staff: Thorsten Seehaus, Lukas Sochor, Matthias Braun, Johannes Fürst, Eberhard Bänsch, Andreas Maier, Nora Gourmelon

The aim of this project is to analyse the time series of Earth observation (EO) data with innovative ‘deep learning’ methods in order to develop efficient algorithms for dealing with the large amounts of data involved. The value of these EO products is further increased by advanced interpolation techniques and assimilation in geophysical models from applied mathematics.

Funding period 2019-2022

Funded by FAU

Development of an interactive data portal for the processing and distribution of glaciological variables derived from Sentinel-1 data (for glaciers and ice caps outside of the polar ice sheets) (RETREAT)

Project staff: Matthias Braun, Thorsten Seehaus, Peter Friedl

Glaciers and ice caps are essential climate variables and a longterm monitoring of cryospheric changes is of high scientific and socio-economic interest. The Sentinel satellites of the European Copernicus Program provide a continues stream of remote sensing data covering glaciers and ice caps. The aims of this project are: To implement an automatic processing chain on CODE-DE to derive glacier flow speed and extent information from Sentinel data; to archive, visualize and provide the obtained products via an interactive user interface. By using intensity feature tracking, glacier flow speed fields are computed based on Sentinel-1 SAR image pairs. Glacier extent is mapped by analyzing the coherence pattern of repeat pass SAR acquisitions. Moreover, calibrated SAR intensity images as well as Sentinel-2 RGB composites are also included in the database. Additionally, glaciological datasets (e.g. glacier inventories, altimeter data, digital elevation models) from different sources (external and from the work group) will be included and visualized in the database in order to support the online analysis of glaciological changes. The goal is to establish an interactive glaciological data portal for a broad spectrum (science, education, media, politics) of users.

Funding period 2018-2020

Funded by BMWK

Past, present and future glacier evolution in the Tropical Andes (PPF-TA)

Project staff:  Thorsten Seehaus

Initial funding by FAU Emerging Talents Initiative for project preparation.

Within the project, the aerial imagery archive of Prof. E. Jordan was transferred to FAU, widely digitized and a precursor study was conducted.

Funding period 2021-2022

Funded by FAU Emerging Talents Initiative