GlacierMap: a citizen science mapping tool for evaluating glacier change and contributing to climate literacy

<p>Glacier retreat provides clear, visual evidence of environmental change in response to warming temperatures around the world. In the tropical Andes of Peru, glaciers act as critical buffers to water supply essential to water, food, and energy security downstream, especially during the dry season. The direct and indirect impacts of glacier change are an important part of the global sustainability challenge within the context of both climate change and increased pressures on resources. Public understanding around glacier-fed water supplies, and subsequent threats to this for millions of people due to climate change, is an important component of climate literacy.</p><p>In this context, we have developed a web-based interdisciplinary citizen science glacier mapping tool (GlacierMap) to help to raise awareness of these issues, particularly amongst UK high school pupils, and to contribute to increased public support for mitigating and adapting to the impacts of climate change. Users of GlacierMap undertake an interactive learning experience by mapping a glacier from two different periods (1984 and 2018) from freely available Landsat data, resulting in a visual demonstration of glacier retreat within Peru’s Cordillera Blanca, while learning more about the impacts of this retreat from information provided by the project. </p><p>During the first four months of data collection we integrated pre- and post-mapping questionnaires into the GlacierMap app to evaluate the extent to which participation in mapping impacted understanding of glacier change and concern regarding the associated impacts. We also assessed the value of ‘crowd-sourcing’ glacier mapping for the purposes of glacier monitoring and data generation through comparison of mapping conducted by the general public and that of a control group with previous education and/or work experience in glaciology. In doing so, we have identified a number of challenges and opportunities with regards to the use of a citizen science-based educational activity for climate learning. Challenges relate to recruitment of participants, evaluation, and ethics (particularly when working with children and young people), while opportunities were identified in terms of increasing public awareness, the provision of alternative forms of learning, and global reach.  </p>

A new glacier inventory for Svalbard from Sentinel-2 and Landsat 8 for improved calculation of climate change impacts

<p><span>Svalbard is famous for its numerous surge-type glaciers as well as for the harsh weather conditions of a highly maritime Arctic island, making regular observations of its glaciers challenging. However, the rapid changes of glacier geometry require a frequent update of their extent to perform accurate glacier-specific calculations such as their mass balance or contribution to sea level. The last inventory for Svalbard has been compiled by Nuth et al. (2013) from about 40 satellite scenes acquired by three different sensors (ASTER, Landsat, SPOT) on 30 unique days over a period of 10 years. Accordingly, any change assessment or other time dependent calculations are difficult to perform and a temporarily more consistent dataset is urgently required.</span></p><p><span>In this study we present the results of a new glacier inventory for Svalbard that has been derived from two Sentinel-2 swaths acquired for the main island within 3 days of 2017 and on 1 day in 2016 from Landsat 8 for Nordaustlandet. The images had overall very good snow conditions but in some regions late seasonal snow was hiding glaciers. Glacier mapping under local clouds in the very north and south could be performed by using further scenes from 2017 processed with GEE. We applied a simple red/SWIR band ratio to map clean ice and corrected wrong classifications (sea ice, lakes) or missing parts (debris cover) manually. New drainage divides and topographic parameters were derived from the ArcticDEM. </span></p><p>The new inventory counts 3136 glaciers >0.01 km<sup>2</sup> covering an area of 32,948 km<sup>2</sup>. Of these, glaciers < 1 km<sup>2</sup> cover 1.3% of the area but nearly 44% of the number whereas glac-iers >10 km<sup>2</sup> cover 91% of the area and 10% by number. Compared to the previous inventory we have 1468 glaciers more and 2.5% area less. However, when excluding the 2025 glaciers <1 km<sup>2</sup>, we only identified 1111 glaciers, i.e. 557 less than in the previous inventory. The differences are mostly due to newly considered entities, different drainage divides, glacier retreat and advance/surging. By excluding surge-type glaciers, a more meaningful determination of climate-related area changes can be performed. The presentation will discuss the differences of the new inventory to the RGI dataset, the specific glacier mapping challenges and our approach to solve them.</p>

Remote Sensing and GIS for Thematic Mapping of the Ak-Suu and Isfana River Basins in Kyrgyzstan

Geographic information systems (GIS) play a significant role in the thematic mapping to collect, store, analyze, visualize and deliver geospatial data today. The Ak-Suu and Isfana rivers flow into the Syrdarya river, which is used for irrigation and other purposes in Uzbekistan, Tajikistan and Kazakhstan. Thematic mapping of the river basins allow efficient use of natural and water resources in the region to mitigate the existing conflicts over water use by four Central Asian neighboring countries. SRTMGL1 DEM is applied in terrain modeling and river basin boundary delineation. Multispectral Landsat 8 and Sentinel-2 images were used in land use and glacier mapping. DEM, glacier, ecosystem, emergency and soil maps are designed and updated based on the cartographic materials, remote sensing, infrastructure and statistical datasets.

The new Swiss Glacier Inventory SGI2020: From a topographic to a glaciological dataset

<p>A glacier inventory describes the extent of all glaciers at a given point in time and in periods of rapid glacier change a frequent update is needed. The Swiss Glacier Inventory 2010 (SGI2010) is the last official inventory for Switzerland and was derived by manual digitization from high-resolution (25 cm) aerial orthophotographs from swisstopo (Federal Office of Topography). To regularly produce a revised inventory, based on the high-quality aerial images from swisstopo acquired at a three-year interval, the workload cannot be covered by GLAMOS (Glacier Monitoring Switzerland, www.glamos.ch) on its own. As part of the development of the new topographic landscape model of Switzerland (swissTLM<sup>3D</sup>), swisstopo introduced – based on requirements defined by GLAMOS – the object class “glaciers”. This secures that Swiss glaciers are recurrently mapped based on high-resolution data on a long term. Swiss Glacier Inventories can therefore be derived by GLAMOS from the TLM object class “glaciers”.</p><p>The SGI2020 is the first glacier inventory produced by GLAMOS based on the new workflow and stands out with an unprecedented level of detail regarding glacier mapping. As the glacier-excerpt from the swisstopo TLM is a landcover dataset, produced according to guidelines for topographical purpose, it does not fit all glaciological requirements. Here, we present the necessary steps and adjustments to derive a new glacier inventory for the period 2013-2018 that fits all glaciological criteria. Furthermore, we compare the resulting dataset with former SGI’s and pin down the major changes and differences emerging from different methodologies used. We particularly emphasize on problematic definitions of glacier boundaries related to snow coverage and/or supraglacial debris and provide updated results for glacier area changes in the Swiss Alps over the last decades.</p>

Comparison of different remote sensing methods for glacier mapping in Afghanistan

<p>Glaciers are important sources of fresh water particularly in arid regions which have low summer precipitation. Moreover, retreating glaciers can cause serious hazards by destabilizing slopes or causing outbursts of glacial lakes. Therefore glacier monitoring is an essential task for water resources and risk management. Recently, efforts have been made to monitor glaciers using manual or semi-automated remote sensing techniques. However a particular challenge remains: as glaciers retreat they commonly develop a surface debris layer that optically is similar to zones that have not been glaciated or that are truly deglaciated: the debris cover on the glacier surface has a similar reflectance to surrounding moraines in the visible to near-infrared wavelength region. In other hand, where debris cover develops, it may insulate ice from solar radiation and diurnal temperature rises, and this will also reduce melt. Therefore, debris cover on glacier boundaries critically hinders the global inventory of glaciers. To overcome the challenges this study uses a multiple band ratio approach. The method was tested for delineating three glaciers in Afghanistan at different scales and locations to map both clean ice and debris-covered ice. We used Landsat Enhanced Thematic Mapper Plus, and a 5-meter resolution digital surface model DSM data to extract the morphological parameters. Since clean glacier ice has a high reflectivity in the visible to near-infrared wavelengths, at first we used NDIS to extract the clean ice area, but It was found that the NDSI method for glacier mapping is less sensitive to cast shadows and steep terrain. Similarly, a slope parameter has tested to map the debris cover ice area but it did not map areas with gentle slopes correctly.</p><p>Nonetheless, NIR and SWIR were identified as potential candidates for distinguishing between glaciers in shade and clean ice for the debris free case; and a combination of those bands in three different ratios and thresholds was applied successfully (Red/SWIR>= 1.5, Pan/SWIR>0.1, and NIR/SWIR>1). With regards to debris-covered ice the thermal infrared bands show potential in resolving such ambiguity, as considerable temperature differences are found to exist between debris covered ice and surrounding moraines. However, we found that thermal infrared bands have too coarse a resolution (60m) for valley glaciers. Hence, we developed a new band ratio image combining thermal infrared and panchromatic bands to better distinguish periglacial debris and supraglacial debris. This new band ratio image is given by (PAN-TIR)/(PAN+TIR), and is named as normalized supraglacial debris index (NSDI).</p><p>Accuracy assessment was carried out through comparisons of the classified maps with a manual delineation done using 1-meter high resolution RGB image with same temporal resolution. The accuracy assessment shows that the results from the proposed method are in good agreement with the manual delineation. The proposed synergistic approach therefore appears useful in the accurate mapping of debris-covered glaciers in Afghanistan.</p>

APPLICATION OF UNMANNED AERIAL VEHICLES FOR GLACIER RESEARCH IN THE ARCTIC AND ANTARCTIC

Unmanned aerial vehicles or drones are nowadays widely used in a broad field of scientific and commercial applications. Despite this, it is quite a new method for glacier mapping in polar regions and has a lot of advantages, as well as disadvantages over more classical remote sensing instruments. Here we examine the main issues associated with the application of drones for glacier research from our experience in Iceland, Greenland and the Antarctic. We use DJI Phantom series drones for the obtaining of aerial photographs and produce digital surface models (resolution of 8 – 16 cm) and orthomosaics (resolution of 2 – 4 cm) for glacier mapping. Several issues related to the ground control points, geolocation using Global Navigation Satellite System receiers and creation of final products are addressed as well. We recommend the further use of drones in remote polar areas because it allows obtaining very high-resolution orthomosaics and digital surface models that are not achieved by other methods. Short summer season, raw weather with precipitation and winds, limited drone flight duration and problems with connection cables are the main issues everyone can encounter working in polar regions but all issues can be restricted with careful planning and readiness to gather data whenever it is possible during all field campaign.