@article{2-s2.0-85091253817,

title = {Changes of glacier facies on Hornsund glaciers (Svalbard) during the decade 2007–2017},

author = { B. Barzycka and M. Grabiec and M. Błaszczyk and D. Ignatiuk and M. Laska and J.O.M. Hagen and J.A. Jania},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091253817&doi=10.1016%2fj.rse.2020.112060&partnerID=40&md5=b5780b8e8884ddd39b23acc4e892b50e},

doi = {10.1016/j.rse.2020.112060},

issn = {00344257},

year  = {2020},

date = {2020-01-01},

journal = {Remote Sensing of Environment},

volume = {251},

publisher = {Elsevier Inc.},

abstract = {Changes in glacier facies (glacier zones), such as firn or superimposed ice (SI), are good indicators of glacier response to climate change. They are especially important for fast-warming Svalbard, where only a few glaciers are under glaciological mass balance monitoring. This paper presents a first study of changes of glacier facies extent for three tidewater glaciers located in southern Spitsbergen (Svalbard) and it is based on both satellite remote sensing and terrestrial data analysis, covering two time spans: 2007–2017 for Hansbreen and 2012–2017 for Storbreen and Hornbreen. Satellite remote sensing analysis include unsupervised classification of Synthetic Aperture Radar (SAR) data from both decommissioned (ENVISAT ASAR) and modern satellite missions (RADARSAT-2; Sentinel-1). The results of the SAR classification are compared to the information on glacier zones retrieved from terrestrial data, i.e. shallow cores and visual interpretation of 800 MHz Ground Penetrating Radar (GPR) profiles. In addition, a novel application of the Internal Reflection Power (IRP) coefficient as an objective method of distinguishing glacier zones based on GPR data is discussed. Changes in glacier facies areas over time are analysed, as well as their correlation to Hansbreen's mass balance. The main finding of the study is that firn and SI of Hansbreen, Storbreen and Hornbreen significantly decreased over the study period. For example, due to continuous negative mass balance between 2010 and 2017, the contribution of firn area to Hansbreen's total area decreased ca. 14% (cumulative firn area loss during that time: ~45%) whereas since 2012 SI has not been distinguished as a vast area on this glacier. In addition, an east–west gradient of firn area loss was observed as a result of differences in local climate conditions. Therefore, for the common time span (i.e. 2012–2017) Hansbreen recorded a ca. 12% loss of firn contribution to glacier area whereas Hornbreen recorded ca. 9%. Finally, application of the IRP coefficient as an objective method of glacier zones discrimination by GPR data gave very good results, so the method is recommended for future analysis of glacier zones instead, or as a support, to popular visual interpretation of the GPR profiles. © 2020 Elsevier Inc.},

note = {5},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-85086330995,

title = {Reconciling Svalbard Glacier Mass Balance},

author = { T.V. Schuler and J. Kohler and N. Elagina and J.O.M. Hagen and A.J. Hodson and J.A. Jania and A.M. Kääb and B. Luks and J. Małecki and G. Moholdt and V.A. Pohjola and I. Sobota and W.J.J. Van Pelt},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85086330995&doi=10.3389%2ffeart.2020.00156&partnerID=40&md5=6548e5b0908cb1284060344aefb2183d},

doi = {10.3389/feart.2020.00156},

issn = {22966463},

year  = {2020},

date = {2020-01-01},

journal = {Frontiers in Earth Science},

volume = {8},

publisher = {Frontiers Media S.A.},

abstract = {Since the first estimates of Svalbard-wide glacier mass balance were made in the early 2000s, there has been great progress in remote sensing and modeling of mass balance, existing field records have been extended, field records at new locations have been added, and there has been considerable environmental change. There is a wide spread in the available estimates of both total mass balance and surface or climatic mass balance, but there is overall agreement that the glaciers on Svalbard have been losing mass since the 1960s, with a tendency toward more negative mass balance since 2000. We define criteria to select data that are representative and of high credibility; this subset shows a more coherent evolution and reduced spread. In addition, we combine individual field mass balance records collected by different groups into a single dataset that samples glaciers across Svalbard and a range of different size classes. We find a close relationship between measured specific surface mass balance and size of the glacier, in such a way that smaller glaciers experience more negative surface mass balances. A qualitatively similar relationship between the accumulation area ratio and glacier area is found for all glaciers in the Svalbard, suggesting that the relation derived from glaciological records is not only an artifact caused by the limited number of samples (n = 12). We apply this relation to upscale measured surface mass balance for a new estimate for all glaciers of Svalbard. Our reconciled estimates are −7 ± 4 Gt a–1 (2000–2019) for the climatic mass balance, and −8 ± 6 Gt a–1 for the total mass balance. The difference between the two represents the sum of frontal ablation and the combined uncertainty, which together amount to ca. −2 ± 7 Gt a–1. While this is consistent with a previous estimate of Svalbard-wide frontal ablation, the uncertainties are large. Furthermore, several large and long-lasting surges have had considerable and multi-year impact on the total mass balance, and in particular on calving rates, emphasizing the need for better-resolved and more frequently updated estimates of frontal ablation. © Copyright © 2020 Schuler, Kohler, Elagina, Hagen, Hodson, Jania, Kääb, Luks, Małecki, Moholdt, Pohjola, Sobota and Van Pelt.},

note = {40},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-84942412852,

title = {Historically unprecedented global glacier decline in the early 21st century},

author = { M. Zemp and H. Frey and I. Gärtner-Roer and S.U. Nussbaumer and M. Hoelzle and F. Paul and W. Haeberli and F. Denzinger and A.P. Ahlstrøm and B. Anderson and S. Bajracharya and C. Baroni and L.N. Braun and B.E. Càceres and G. Casassa and G. Cobos and L.R. Dàvila and H. Delgado Granados and M.N. Demuth and L. Espizua and A. Fischer and K. Fujita and B. Gądek and A. Ghazanfar and J.O.M. Hagen and P. Holmlund and N. Karimi and Z. Li and M. Pelto and P. Pitte and V.V. Popovnin and C.A. Portocarrero and R. Prinz and C.V. Sangewar and I. Severskiy and O. Sigurdsson and A. Soruco and R. Usubaliev and C. Vincent},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-84942412852&doi=10.3189%2f2015JoG15J017&partnerID=40&md5=873ba7676df8c3619dd96f52f11b26f9},

doi = {10.3189/2015JoG15J017},

issn = {00221430},

year  = {2015},

date = {2015-01-01},

journal = {Journal of Glaciology},

volume = {61},

number = {228},

pages = {745-762},

publisher = {International Glaciology Society},

abstract = {Observations show that glaciers around the world are in retreat and losing mass. Internationally coordinated for over a century, glacier monitoring activities provide an unprecedented dataset of glacier observations from ground, air and space. Glacier studies generally select specific parts of these datasets to obtain optimal assessments of the mass-balance data relating to the impact that glaciers exercise on global sea-level fluctuations or on regional runoff. In this study we provide an overview and analysis of the main observational datasets compiled by the World Glacier Monitoring Service (WGMS). The dataset on glacier front variations (∼42 000 since 1600) delivers clear evidence that centennial glacier retreat is a global phenomenon. Intermittent readvance periods at regional and decadal scale are normally restricted to a subsample of glaciers and have not come close to achieving the maximum positions of the Little Ice Age (or Holocene). Glaciological and geodetic observations (∼5200 since 1850) show that the rates of early 21st-century mass loss are without precedent on a global scale, at least for the time period observed and probably also for recorded history, as indicated also in reconstructions from written and illustrated documents. This strong imbalance implies that glaciers in many regions will very likely suffer further ice loss, even if climate remains stable.},

note = {428},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-67949123290,

title = {Tidewater glaciers of Svalbard: Recent changes and estimates of calving fluxes},

author = { M. Błaszczyk and J.A. Jania and J.O.M. Hagen},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-67949123290&partnerID=40&md5=658c48075fbaa626c1489f311726d3e0},

issn = {01380338},

year  = {2009},

date = {2009-01-01},

journal = {Polish Polar Research},

volume = {30},

number = {2},

pages = {85-142},

abstract = {The purpose of this study is to describe the current state of tidewater glaciers in Svalbard as an extension of the inventory of Hagen et al. (1993). The ice masses of Svalbard cover an area of ca 36 600 km2 and more than 60% of the glaciated areas are glaciers which terminate in the sea at calving ice-cliffs. Recent data on the geometry of glacier tongues, their flow velocities and front position changes have been extracted from ASTER images acquired from 2000-2006 using automated methods of satellite image analysis. Analyses have shown that 163 Svalbard glaciers are of tidewater type (having contact with the ocean) and the total length of their calving ice-cliffs is 860 km. When compared with the previous inventory, 14 glaciers retreated from the ocean to the land over a 30-40 year period. Eleven formerly land-based glaciers now terminate in the sea. A new method of assessing the dynamic state of glaciers, based on patterns of frontal crevassing, has been developed. Tide-water glacier termini are divided into four groups on the basis of differences in crevasse patterns and flow velocity: (1) very slow or stagnant glaciers, (2) slow-flowing glaciers, (3) fast-flowing glaciers, (4) surging glaciers (in the active phase) and fast ice streams. This classification has enabled us to estimate total calving flux from Svalbard glaciers with an accuracy appreciably higher than that of previous attempts. Mass loss due to calving from the whole archipelago (excluding Kvitøya) is estimated to be 5.0-8.4 km3 yr-1 (water equivalent - w.e.), with a mean value 6.75 ± 1.7 km3 yr-1 (w.e.). Thus, ablation due to calving contributes as much as 17-25% (with a mean value 21%) to the overall mass loss from Svalbard glaciers. By implication, the contribution of Svalbard iceberg flux to sea-level rise amounts to ca 0.02 mm yr-1. Also calving flux in the Arctic has been considered and the highest annual specific mass balance attributable to iceberg calving has been found for Svalbard.},

note = {164},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{2-s2.0-0031419806,

title = {The Mass Balance of Circum-Arctic Glaciers and Recent Climate Change},

author = { J.A. Dowdeswell and J.O.M. Hagen and H. Björnsson and A.F. Glazovsky and W.D. Harrison and P. Holmlund and J.A. Jania and R.M. Koerner and B. Lefauconnier and C.S.L. Ommanney and R.H. Thomas},

url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031419806&doi=10.1006%2fqres.1997.1900&partnerID=40&md5=c3a5aec164530a4d43f5256313cc4b98},

doi = {10.1006/qres.1997.1900},

issn = {00335894},

year  = {1997},

date = {1997-01-01},

journal = {Quaternary Research},

volume = {48},

number = {1},

pages = {1-14},

publisher = {Academic Press Inc.},

abstract = {The sum of winter accumulation and summer losses of mass from glaciers and ice sheets (net surface mass balance) varies with changing climate. In the Arctic, glaciers and ice caps, excluding the Greenland Ice Sheet, cover about 275,000 km2 of both the widely glacierized archipelagos of the Canadian, Norwegian, and Russian High Arctic and the area north of about 60°N in Alaska, Iceland, and Scandinavia. Since the 1940s, surface mass balance time-series of varying length have been acquired from more than 40 Arctic ice caps and glaciers. Most Arctic glaciers have experienced predominantly negative net surface mass balance over the past few decades. There is no uniform recent trend in mass balance for the entire Arctic, although some regional trends occur. Examples are the increasingly negative mass balances for northern Alaska, due to higher summer temperatures, and increasingly positive mass balances for maritime Scandinavia and Iceland, due to increased winter precipitation. The negative mass balance of most Arctic glaciers may be a response to a step-like warming in the early twentieth century at the termination of the cold Little Ice Age. Arctic ice masses outside Greenland are at present contributing about 0.13 mm yr-1 to global sea-level rise. © 1997 University of Washington.},

note = {181},

keywords = {},

pubstate = {published},

tppubtype = {article}

}