Circum-Arctic changes in the flow of glaciers and ice caps from satellite SAR data between the 1990s and 2017

We computed circum-Arctic surface velocitymaps of glaciers and ice caps over the Canadian Arctic, Svalbard and the Russian Arctic for at least two times between the 1990s and 2017 using satellite SAR data. Our analyses are mainly performed with offset-tracking of ALOS-1 PALSAR-1 (2007–2011) and Sentinel-1 (2015–2017) data. In certain cases JERS-1 SAR (1994–1998), TerraSAR-X (2008–2012), Radarsat-2 (2009–2016) and ALOS-2 PALSAR-2 (2015–2016) data were used to fill-in spatial or temporal gaps. Validation of the latest Sentinel-1 results was accomplished by means of SAR data at higher spatial resolution (Radarsat-2Wide Ultra Fine) and ground-basedmeasurements. In general, we observe a deceleration of flow velocities for the major tidewater glaciers in the Canadian Arctic and an increase in frontal velocity along with a retreat of frontal positions over Svalbard and the Russian Arctic. However, all regions have strong accelerations for selected glaciers. The latter developments can be well traced based on the very high temporal sampling of Sentinel-1 acquisitions since 2015, revealing new insights in glacier dynamics. For example, surges on Spitsbergen (e.g., Negribreen, Nathorsbreen, Penckbreen and Strongbreen) have a different characteristic and timing than those over Eastern Austfonna and Edgeoya (e.g., Basin 3, Basin 2 and Stonebreen). Events similar to those ongoing on Eastern Austofonna were also observed over the Vavilov Ice Cap on Severnaya Zemlya and possibly Simony Glacier on Franz-Josef Land. Collectively, there seems to be a recently increasing number of glaciers with frontal destabilization over Eastern Svalbard and the Russian Arctic compared to the 1990s

Dynamics of Shifting Cultivation Landscapes in Northern Lao PDR Between 2000 and 2009 Based on an Analysis of MODIS Time Series and Landsat Images

The rotational nature of shifting cultivation poses several challenges to its detection by remote sensing. Consequently, there is a lack of spatial data on the dynamics of shifting cultivation landscapes on a regional, i.e. sub-national, or national level. We present an approach based on a time series of Landsat and MODIS data and landscape metrics to delineate the dynamics of shifting cultivation landscapes. Our results reveal that shifting cultivation is a land use system still widely and dynamically utilized in northern Laos. While there is an overall reduction in the areas dominated by shifting cultivation, some regions also show an expansion. A review of relevant reports and articles indicates that policies tend to lead to a reduction while market forces can result in both expansion and reduction. For a better understanding of the different factors affecting shifting cultivation landscapes in Laos, further research should focus on spatially explicit analyse

Sentinel-1 Support in the GAMMA Software

AbstractFirst results using the new Sentinel-1 SAR look very promising but the special interferometric wide-swath data acquired in the TOPS mode makes InSAR processing more challenging than for normal stripmap mode data. The steep azimuth spectra ramp in each burst results in very stringent co-registration requirements. Combining the data of the individual bursts and sub-swaths into consistent mosaics requires careful “book-keeping” in the handling of the data and meta data and the large file sizes and high data throughputs require also a good performance. Considering these challenges good support from software is getting increasingly important. In this contribution we describe the Sentinel-1 support in the GAMMA Software, a high-level software package used by researchers, service providers and operational users in their SAR, InSAR, PSI and offset tracking work

All-weather avalanche activity monitoring from space?

Information on avalanche activity or on non-activity on local and regional scale is of great value for avalanche warning services, traffic authorities and experts responsible for safety in communities or ski resorts. In particular during bad weather condition, such information is available only very limited or not at all. The aim of ESA IAP feasibility study "Improved Alpine Avalanche Forecast Service" was to investigate existing technology to overcome this gap. Of particular interest were radar-based techniques that have the potential to operate independently of daylight and weather conditions

Effect of a multinutrient intervention after ischemic stroke in female C57Bl/6 mice.

Stroke can affect females very differently from males, and therefore preclinical research on underlying mechanisms and the effects of interventions should not be restricted to male subjects, and treatment strategies for stroke should be tailored to benefit both sexes. Previously, we demonstrated that a multinutrient intervention (Fortasyn) improved impairments after ischemic stroke induction in male C57Bl/6 mice, but the therapeutic potential of this dietary treatment remained to be investigated in females. We now induced a transient middle cerebral artery occlusion (tMCAo) in C57Bl/6 female mice and immediately after surgery switched to either Fortasyn or an isocaloric Control diet. The stroke females performed several behavioral and motor tasks before and after tMCAo and were scanned in an 11.7 Tesla MRI scanner to assess brain perfusion, integrity and functional connectivity. To assess brain plasticity, inflammation and vascular integrity, immunohistochemistry was performed after sacrifice of the mice. We found that the multinutrient intervention had diverse effects on the stroke-induced impairments in females. Similar to previous observations in male stroke mice, brain integrity, sensorimotor integration and neurogenesis benefitted from Fortasyn, but impairments in activity and motor skills were not improved in female stroke mice. Overall, Fortasyn effects in the stroked females seem more modest in comparison to previously investigated stroked male mice. We suggest that with further optimization of treatment protocols more information on the efficacy of specific interventions in stroked females can be gathered. This in turn will help with the development of (gender-specific) treatment regimens for cerebrovascular diseases such as stroke

Introduction to GlobSnow Snow Extent products with considerations for accuracy assessment

Highlights • GlobSnow Snow Extent provides 17-years data record for Fractional snow cover (FSC). • Snow extent products cover the Northern Hemisphere in 0.01 deg. resolution. • FSC retrieval uses SCAmod method enabling fractional snow mapping also in forests. • Landsat TM/ETM+-based reference is not always representative for validation of FSC

Web-GIS Visualisation of Permafrost-Related Remote Sensing Products for ESA GlobPermafrost

The GlobPermafrost project focuses on the accessibility of remote sensing data. This comprises of data product generation as well as on specific infrastructure to give information on and access to data. Further information regarding project status and events are available from www.globpermafrost.info. An online user survey conducted within the project highlights that GIS software is applied by a great deal of the user community. Additionally, data preview was requested by the majority of the survey participants. The Permafrost Information System PerSys will be conceptualized as an open access geospatial data dissemination and visualization portal. PerSys will allow raster and vector products visualisation resulting from GlobPermafrost such as land cover classifications, Landsat/Sentinel Trend datasets, lake and wetland extents, InSAR-based land surface deformation maps, block glaciers’ velocity fields, spatial permafrost model outputs, LST datasets, and many more. The data will be published as WebGIS services relying on OGC-standardized Web Mapping Service (WMS) and Web Feature Service (WFS) technologies for data display and visualization. The technical WebGIS environment will be hosted at AWI where a geodata infrastructure has been implemented comprising of ArcGIS for Server 10.4, PostgreSQL 9.2 and a browser-driven data viewer unit based on Leaflet (http://leafletjs.com). Independently, we will provide an ‘Access - Restricted Data Dissemination Service’, which will be available to users for testing frequently updated versions of project datasets. In addition, the European Research Council (ERC) funded PETA-CARB project (http://www.awi.de/) developing the Arctic Permafrost Geospatial Centre (APGC) where PerSys will become a core project. The APGC Data Catalogue will contain all final products of GlobPermafrost and links to the derived permanent DOI-based ESA remote sensing products archived in PANGAEA data repository

ELBARA II, an L-Band Radiometer System for Soil Moisture Research

L-band (1–2 GHz) microwave radiometry is a remote sensing technique that can be used to monitor soil moisture, and is deployed in the Soil Moisture and Ocean Salinity (SMOS) Mission of the European Space Agency (ESA). Performing ground-based radiometer campaigns before launch, during the commissioning phase and during the operative SMOS mission is important for validating the satellite data and for the further improvement of the radiative transfer models used in the soil-moisture retrieval algorithms. To address these needs, three identical L-band radiometer systems were ordered by ESA. They rely on the proven architecture of the ETH L-Band radiometer for soil moisture research (ELBARA) with major improvements in the microwave electronics, the internal calibration sources, the data acquisition, the user interface, and the mechanics. The purpose of this paper is to describe the design of the instruments and the main characteristics that are relevant for the user

Circumpolar mapping of permafrost temperature and thaw depth in the ESA Permafrost CCI project

Permafrost is an Essential Climate Variable (ECV) within the Global Climate Observing System (GCOS), which is characterized by subsurface temperatures and the depth of the seasonal thaw layer. Complementing ground-based monitoring networks, the Permafrost CCI project funded by the European Space Agency (ESA) 2018-2021 will establish Earth Observation (EO) based products for the permafrost ECV spanning the last two decades. Since ground temperature and thaw depth cannot be directly observed from space-borne sensors, we will ingest a variety of satellite and reanalysis data in a ground thermal model, which allows to quantitatively characterize the changing permafrost systems in Arctic and High-Mountain areas. As recently demonstrated for the Lena River Delta in Northern Siberia, the algorithm uses remotely sensed data sets of Land Surface Temperature (LST), Snow Water Equivalent (SWE) and landcover to drive the transient permafrost model CryoGrid 2, which yields ground temperature at various depths, in addition to thaw depth. For the circumpolar CCI product, we aim for a spatial resolution of 1km, and ensemble runs will be performed for each pixel to represent the subgrid variability of snow and land cover. The performance of the transient algorithm crucially depends on the correct representation of ground properties, in particular ice and organic contents. Therefore, the project will compile a new subsurface stratigraphy product which also holds great potential for improving Earth System Model results in permafrost environments. We present simulation runs for various permafrost regions and characterize the accuracy and ability to reproduce trends against ground-based data. Finally, we evaluate the feasibility of future “permafrost reanalysis” products, exploiting the information content of various satellite products to deliver the best possible estimate for the permafrost thermal state over a range of spatial scales

The SIBERIA -II Project as seen by Envisat ASAR

ABSTRACT In the SIBERIA-II project Earth Observation (EO) data are used to derive a set of products, which are then fed into global and regional greenhouse gas accounting approaches. The overall aim of the project is to devise an integrated "EO-modelling" methodology for full carbon accounting at regional scale, and to quantify the accounting for an over 3 Mio km 2 area in Central Siberia. For the derivation of the EO products, SIBERIA-II makes use of most of current orbiting satellites and currently represents the major user of ASAR ENVISAT data. Within the project several issues ranging from data post-processing to derivation of EO-products and development of new techniques for land applications are treated. An experiment on geometric and radiometric validation of Wide Swath data showed the importance of the processor used for preparing the data to be further used in applications. The interferometric coherence from ASAR repeat-pass pairs acquired under stable winter conditions shows contrast between forests and bare soils. Alternating Polarisation data seems to be promising for forest/non-forest mapping. For wetlands, ASAR Wide Swath data is used for the operational monitoring of open water surfaces, reaching high classification accuracy. ASAR Wide Swath is also evaluated for pollution damage identification and fire scar detection. Finally, the long time series of ERS and ASAR Image Mode data allows detecting deforestation activities over almost one decade