Open access data in polar and cryospheric remote sensing

This paper aims to introduce the main types and sources of remotely sensed data that are freely available and have cryospheric applications. We describe aerial and satellite photography, satellite-borne visible, near-infrared and thermal infrared sensors, synthetic aperture radar, passive microwave imagers and active microwave scatterometers. We consider the availability and practical utility of archival data, dating back in some cases to the 1920s for aerial photography and the 1960s for satellite imagery, the data that are being collected today and the prospects for future data collection; in all cases, with a focus on data that are openly accessible. Derived data products are increasingly available, and we give examples of such products of particular value in polar and cryospheric research. We also discuss the availability and applicability of free and, where possible, open-source software tools for reading and processing remotely sensed data. The paper concludes with a discussion of open data access within polar and cryospheric sciences, considering trends in data discoverability, access, sharing and use.A. Pope would like to acknowledge support from the Earth Observation Technology Cluster, a knowledge exchange project, funded by the Natural Environment Research Council (NERC) under its Technology Clusters Programme, the U.S. National Science Foundation Graduate Research Fellowship Program, Trinity College (Cambridge) and the Dartmouth Visiting Young Scientist program sponsored by the NASA New Hampshire Space Grant.This is the final published version. It's also available from MDPI at http://www.mdpi.com/2072-4292/6/7/6183

Advances in Sea-Ice Research Based on Remotely Sensed Passive Microwave Data

The contributions made to our knowledge of polar sea ice since the early 1970s by passive microwave remote sensing are surveyed

RESPONSE OF CANADIAN ROCKIES GLACIER HYDROLOGY TO CHANGING CLIMATE

This thesis investigates the impact of snow and glaciers in mountain hydrology under changing climate conditions and glacier configurations in the Canadian Rockies, where a warming climate and glacier retreat cause concern about changes in mountain hydrology for water availability downstream. The general objectives of the study are (1) to model snow and glacier ablation and accumulation dynamics, (2) to determine how they influence high mountain hydrology, and (3) to improve hydrological modeling capacity in high mountain cold regions. The specific objectives are: (1) to develop a new model to estimate shortwave irradiance from temperature and humidity observations; (2) to include snow redistribution and the full energy and mass budget in a glacier hydrological modelling platform; (3) to apply the model to diagnose the individual and combined impacts of changes in climate and glacier mass on headwater hydrology. The thesis has four major parts. First, it describes the methodology used to produce meteorological data to force a hydrological model for the Peyto Glacier Research Basin (PGRB) in the Canadian Rockies. Second, it develops a new approach for estimating shortwave irradiance based on temperature and humidity observations that is suitable for snow and ice melt calculations for mountains and other cold regions around the world. Observations from thirty mostly mountain sites in South and North America, Europe and the Himalayas were used to evaluate existing algorithms and reanalysis products. The new algorithm, coupled to an existing extraterrestrial shortwave irradiance model, permitted more accurate estimation of shortwave irradiance from standard meteorological observations than was previously possible. The globally available reanalysis products also offer the potential for application to large-scale hydrological models. Third, the thesis develops a novel glacier hydrology model, developed within the Cold Regions Hydrological Model platform (CRHM), which is a physically based, integrated model capable of simulating the hydrology of both ice-covered and ice-free areas within a mountain basin. Fourth, the thesis focuses on diagnosing the impacts of climate change and changing glacier configuration on mountain headwater hydrology. The modelling results reveal that glacier retreat and ablation are due to the joint effect of a warming climate and an increase in ice exposure, which increase both seasonal melt and runoff. Increased streamflow is due to climate warming. However, the increases in melt and runoff are reduced somewhat by the reduction in glacial area. Such a modelling approach is important for diagnosing the hydrological responses from a glacierized basin in the context of climate change and variability and change in glacier configuration

Hydrometeorological, glaciological and geospatial research data from the Peyto Glacier Research Basin in the Canadian Rockies

Canada First Research Excellent Fund’s Global Water Futures Programme, the National Sciences and Engineering Research Council of Canada’s Changing Cold Regions Network and Discovery Grants programme, the Canada Foundation for Innovation’s Canadian Rockies Hydrological Observatory, the Canada Research Chairs and Canada Excellence Research Chairs programmes, the Canadian Foundation for Climate and Atmospheric Sciences IP3 and WC2N networks, Natural Resources Canada, Environment Canada, Columbia Basin Trust, BC HydroPeer ReviewedThis paper presents hydrometeorological, glaciological and geospatial data from the Peyto Glacier Research Basin (PGRB) in the Canadian Rockies. Peyto Glacier has been of interest to glaciological and hydrological researchers since the 1960s, when it was chosen as one of five glacier basins in Canada for the study of mass and water balance during the International Hydrological Decade (IHD, 1965–1974). Intensive studies of the glacier and observations of the glacier mass balance continued after the IHD, when the initial seasonal meteorological stations were discontinued, then restarted as continuous stations in the late 1980s. The corresponding hydrometric observations were discontinued in 1977 and restarted in 2013. Datasets presented in this paper include high-resolution, co-registered digital elevation models (DEMs) derived from original air photos and lidar surveys; hourly off-glacier meteorological data recorded from 1987 to the present; precipitation data from the nearby Bow Summit weather station; and long-term hydrological and glaciological model forcing datasets derived from bias-corrected reanalysis products. These data are crucial for studying climate change and variability in the basin and understanding the hydrological responses of the basin to both glacier and climate change. The comprehensive dataset for the PGRB is a valuable and exceptionally long-standing testament to the impacts of climate change on the cryosphere in the high-mountain environment. The dataset is publicly available from Federated Research Data Repository at https://doi.org/10.20383/101.0259 (Pradhananga et al., 2020)

A spatio-temporal analysis of trends in Northern Hemisphere seasonal snow-cover, 1971-2017

Seasonal snow-cover (SSC) substantially alters surface physical properties over the Northern Hemisphere (NH). It modulates processes within the energy and water cycles, thereby influencing climatology, hydrology, geomorphology and ecology. In spring and summer, snowmelt provides an essential resource for humankind. The identification, quantification and explanation of changing spatial and temporal distributions of SSC helps to predict future impacts on natural and human environments, and informs development of mitigation and adaptation strategies. Because SSC is spatially and temporally heterogeneous, meaningful estimation of trends in its distribution and duration is dependent on long records of remotely-sensed imagery. The Rutgers University Global Snow Laboratory and the United States’ National Oceanic and Atmospheric Administration provide the longest such archive (NOAA-Rutgers Snow Archive, NRSA), dating from 1966. However, several studies have raised questions about the credibility of the signs and magnitudes of trends derived from the NRSA, suggesting that they may be artifacts of technological improvements introduced in 1999. This dissertation improves the spatial resolution at which NH SSC extent and duration trends during the NRSA’s longest continuous section (since 1971) are reported, building on previous hemispheric and continental studies. It demonstrates that the magnitudes of area-related trends are sensitive to assumptions adopted when estimating SSC extent from the NRSA, and that these sensitivities vary spatially. The study assesses whether temporal trajectories of SSConset trends imply abrupt changes in 1999, particularly over more complex terrain, and finds no evidence of this. It also explores the broader climatological contexts of these trends, together with estimated departures from mean conditions. Evidence is presented at monthly intervals for causative chains linking advection of mid-tropospheric warming from lower to higher latitudes, consequent inception of climatologically novel airflows, and the incidence of significant SSConset trends of both signs. Earlier onset of snow-dominated conditions is found to be driven by augmented moisture advected from lower latitudes (in eastern Eurasia) or zonally from oceanic sources (in North America) over regional monthly mean 0°C isotherms. Delayed onset is associated with drier or warmer airflows. These findings support the interpretation that the NRSA-based trends are plausible within their spatial and temporal contexts

UAVs for Science in Antarctica

Remote sensing is a very powerful tool that has been used to identify, map and monitor Antarctic features and processes for nearly one century. Satellite remote sensing plays the main role for about the last five decades, as it is the only way to provide multitemporal views at continental scale. But the emergence of small consumer-grade unoccupied aerial vehicles (UAVs) over the past two decades has paved the way for data in unprecedented detail. This has been also verified by an increasing noticeable interest in Antarctica by the incorporation of UAVs in the field activities in diversified research topics. This paper presents a comprehensive review about the use of UAVs in scientific activities in Antarctica. It is based on the analysis of 190 scientific publications published in peer-reviewed journals and proceedings of conferences which are organised into six main application topics: Terrestrial, Ice and Snow, Fauna, Technology, Atmosphere and Others. The analysis encompasses a detailed overview of the activities, identifying advantages and difficulties, also evaluating future possibilities and challenges for expanding the use of UAV in the field activities. The relevance of using UAVs to support numerous and diverse scientific activities in Antarctica becomes very clear after analysing this set of scientific publications, as it is revolutionising the remote acquisition of new data with much higher detail, from inaccessible or difficult to access regions, in faster and cheaper ways. Many of the advances can be seen in the terrestrial areas (detailed 3D mapping; vegetation mapping, discrimination and health assessment; periglacial forms characterisation), ice and snow (more detailed topography, depth and features of ice-sheets, glaciers and sea-ice), fauna (counting penguins, seals and flying birds and detailed morphometrics) and in atmosphere studies (more detailed meteorological measurements and air-surface couplings). This review has also shown that despite the low environmental impact of UAV-based surveys, the increasing number of applications and use, may lead to impacts in the most sensitive Antarctic ecosystems. Hence, we call for an internationally coordinated effort to for planning and sharing UAV data in Antarctica, which would reduce environmental impacts, while extending research outcomes.info:eu-repo/semantics/publishedVersio

Space-Based Remote Sensing of the Earth: A Report to the Congress

The commercialization of the LANDSAT Satellites, remote sensing research and development as applied to the Earth and its atmosphere as studied by NASA and NOAA is presented. Major gaps in the knowledge of the Earth and its atmosphere are identified and a series of space based measurement objectives are derived. The near-term space observations programs of the United States and other countries are detailed. The start is presented of the planning process to develop an integrated national program for research and development in Earth remote sensing for the remainder of this century and the many existing and proposed satellite and sensor systems that the program may include are described

Remote sensing of the mountain cryosphere: Current capabilities and future opportunities for research

Remote sensing technologies are integral to monitoring the mountain cryosphere in a warming world. Satellite missions and field-based platforms have transformed understanding of the processes driving changes in mountain glacier dynamics, snow cover, lake evolution, and the associated emergence of hazards (e.g. avalanches, floods, landslides). Sensors and platforms are becoming more bespoke, with innovation being driven by the commercial sector, and image repositories are more frequently open access, leading to the democratisation of data analysis and interpretation. Cloud computing, artificial intelligence, and machine learning are rapidly transforming our ability to handle this exponential increase in data. This review therefore provides a timely opportunity to synthesise current capabilities in remote sensing of the mountain cryosphere. Scientific and commercial applications were critically examined, recognising the technologies that have most advanced the discipline. Low-cost sensors can also be deployed in the field, using microprocessors and telecommunications equipment to connect mountain glaciers to stakeholders for real-time monitoring. The potential for novel automated pipelines that can process vast volumes of data is also discussed, from reimagining historical aerial imagery to produce elevation models, to automatically delineating glacier boundaries. Finally, the applications of these emerging techniques that will benefit scientific research avenues and real-world societal programmes are discussed

IMPLICATIONS OF MODULATING GLACIERS AND SNOW COVER IN MONGOLIA

Mongolia’s cryosphere (glaciers and snow cover) drives ecosystem services and in turn, supports emerging economies in the water-restricted country. However, as Mongolia experiences long-term drought conditions and an increase in annual air temperatures at twice the global rate, the potential adverse effects of the changing cryosphere during a period of climate uncertainty will have cascading implications to water availability and economic development. Using several data sources and methods, I partitioned my dissertation into two components to determine the hydrologic and economic implications of modulations in Mongolia’s cryosphere. The first component is an examination of glacier recession in Mongolia’s Altai Mountains, where I identified the major drivers of glacier recession and the role of glaciers in the regional hydrology. In the second component we created novel techniques to detect snowmelt events and to determine their role in large annual livestock mortality across Mongolia. In chapter 2 we identified a rate of glacier recession of 6.4 ± 0.4 km2 yr-1 from 1990-2016, resulting in an overall decrease in glacier area of 43%, which were comparable to rates of recession in mountain ranges across Central Asia. In chapter 3 we found that glaciers contributed up to 22% of the regional hydrology in the glaciated Upper Khovd River Basin (UKRB) and glacier melt contributions began to decrease after 2016, suggesting an overall depletion of accumulation zones. In chapter 4, we developed a novel approach to detect snow melt events in Alaska, USA – due to its high satellite coverage, climate monitoring network, and previous existing studies – and produced a gridded geospatial data product. In chapter 5, we expanded on the novel methods developed in chapter 4 to determine the spatio-temporal role of snowmelt events on large annual livestock mortality in Mongolia. Results showed strong correlations between snowmelt events and mortality in the southern Gobi during the fall and the central and western regions during the spring. As Mongolia continues to develop climatically vulnerable economic industries, future modulations in Mongolia’s cryosphere will likely decrease regional water-availability and amplify annual livestock mortality

Using a new generation of remote sensing to monitor Peru’s mountain glaciers

Remote sensing technologies are integral to monitoring mountain glaciers in a warming world. Tropical glaciers, of which around 70% are located in Peru, are particularly at risk as a result of climate warming. Satellite missions and field-based platforms have transformed understanding of the processes driving mountain glacier dynamics and the associated emergence of hazards (e.g. avalanches, floods, landslides), yet are seldom specialised to overcome the unique challenges of acquiring data in mountainous environments. A ‘new generation’ of remote sensing, marked by open access to powerful cloud computing and large datasets, high resolution satellite missions, and low-cost science-grade field sensors, looks to revolutionise the way we monitor the mountain cryosphere. In this thesis, three novel remote sensing techniques and their applicability towards monitoring the glaciers of the Peruvian Cordillera Vilcanota are examined. Using novel processing chains and image archives generated by the ASTER satellite, the first mass balance estimate of the Cordillera Vilcanota is calculated (-0.48 ± 0.07 m w.e. yr-1) and ELA change of up to 32.8 m per decade in the neighbouring Cordillera Vilcabamba is quantified. The performance of new satellite altimetry missions, Sentinel-3 and ICESat-2, are assessed, with the tracking mode of Sentinel-3 being a key limitation of the potential for its use over mountain environments. Although currently limited in its ability to extract widespread mass balance measurements over mountain glaciers, other applications for ICESat-2 in long-term monitoring of mountain glaciers include quantifying surface elevation change, identifying large accumulation events, and monitoring lake bathymetry. Finally, a novel low-cost method of performing timelapse photogrammetry using Raspberry Pi camera sensors is created and compared to 3D models generated by a UAV. Mean difference between the Raspberry Pi and UAV sensors is 0.31 ± 0.74 m, giving promise to the use of these sensors for long-term monitoring of recession and short-term warning of hazards at glacier calving fronts. Together, this ‘new generation’ of remote sensing looks to provide new glaciological insights and opportunities for regular monitoring of data-scarce mountainous regions. The techniques discussed in this thesis could benefit communities and societal programmes in rapidly deglaciating environments, including across the Cordillera Vilcanota