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Gyllencreutz, RichardORCID iD iconorcid.org/0000-0003-3193-8598
Publications (10 of 38) Show all publications
Greenwood, S. L., Avery, R. S., Gyllencreutz, R., Regnéll, C. & Tylmann, K. (2024). Footprint of the Baltic Ice Stream: geomorphic evidence for shifting ice stream pathways. Boreas, 53(1), 4-26
Open this publication in new window or tab >>Footprint of the Baltic Ice Stream: geomorphic evidence for shifting ice stream pathways
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2024 (English)In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 53, no 1, p. 4-26Article in journal (Refereed) Published
Abstract [en]

The Baltic Ice Stream, a large fast-flowing sector of the last Fennoscandian Ice Sheet that occupied the present-day Baltic Sea basin, was first conceptualized in the earliest days of glacial geological research in Scandinavia. Landform and sedimentological evidence from the terrestrial margins support the concept and numerical ice-sheet models demonstrate its existence and possible evolution. However, with evidence for the Baltic Ice Stream thus far limited to the terrestrial periphery, its true form, scale, function, and role in deglaciation have proven enigmatic. Here we present geomorphological evidence directly from the Baltic seabed that confirms the existence of and sheds light on the behaviour of the Baltic Ice Stream. Based on an extensive collection of high-, moderate- and low-resolution bathymetric terrain models covering a large proportion of the Baltic Sea floor, and complemented by LiDAR-data for the Baltic islands, we have identified and mapped >20 000 individual subglacial bedforms, meltwater landforms and grounding line landforms. We reconstruct a six-stage sequence of ice flow and retreat, finding that streaming was persistent in the Baltic but that pathways were variable in extent, timing and duration: different sectors of the Baltic exhibit asynchronous streaming and out-of-phase grounding line changes. During deglaciation, grounding line readvances occurred in both the southwestern and the northern Baltic Proper, and, while abundant iceberg ploughmarks attest to calving as a significant ice loss mechanism, lobate margins suggest supply to the Baltic catchment was consistently high. Our reconstruction is limited by a fragmentary geomorphic record. Here we put forward a first hypothesis for how the Baltic Ice Stream evolved, and hope it stimulates new geomorphic, stratigraphical and core data collection to extend the landform record, provide insights into subglacial and grounding line processes, and constrain the chronology for Baltic Ice Stream flow and retreat.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-223762 (URN)10.1111/bor.12634 (DOI)001085491500001 ()2-s2.0-85173801674 (Scopus ID)
Available from: 2023-11-15 Created: 2023-11-15 Last updated: 2024-01-12Bibliographically approved
Regnéll, C., Becher, G. P., Ohrling, C., Greenwood, S. L., Gyllencreutz, R., Blomdin, R., . . . Smith, C. (2023). Ice-dammed lakes and deglaciation history of the Scandinavian Ice Sheet in central Jämtland, Sweden. Quaternary Science Reviews, 314, Article ID 108219.
Open this publication in new window or tab >>Ice-dammed lakes and deglaciation history of the Scandinavian Ice Sheet in central Jämtland, Sweden
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2023 (English)In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 314, article id 108219Article in journal (Refereed) Published
Abstract [en]

Extensive glacial lakes dammed in the Scandinavian Mountains during the retreat of the last Scandinavian Ice Sheet were first hypothesised over a century ago. Here, using high-resolution LiDAR, we report >4500 relict shorelines, deltas and palaeo-channels related to ice-dammed lakes over a -30 000 km2 area of central Jämtland, west-central Sweden. Shorelines occur as flights on the valley sides, a consequence of sequential lowering of palaeo-lake levels during ice margin retreat and lower threshold outlets becoming ice-free. Based on the extent and elevation of shorelines, we identify requisite lake-damming ice-margin positions and lake drainage outlets, and we reconstruct the coupled evolution of ice-dammed lakes and the retreating ice margin. Beginning as a series of smaller ice-dammed lakes along the Swedish-Norwegian border, draining westward across the present-day water divide and into the Atlantic Ocean, the lakes successively coalesced during eastward ice margin retreat to form water bodies covering 1000s of km2 with 10s of km-long calving margins. Ultimately, the lake system coalesced into a single lake: the Central Jämtland Ice Lake, which exceeded 3500 km2 in area and 360 km3 in volume. Eventually, the damming ice-margin split in two, resulting in a large (-200 km2) catastrophic glacial lake outburst flood (GLOF) that reversed the drainage of the entire lake system from the west to an eastern outlet draining to the Baltic basin. We present new radiocarbon ages for one lake drainage event prior to the eastward outburst flood and, together with previously published deglacial ages and local varve records, we suggest that the region was possibly deglaciated within just 350 years, sometime between 10.5 and 9.2 cal ka BP. We tentatively correlate the penultimate drainage of the Central Jämtland Ice Lake to the zero-varve of the Swedish Time Scale, a drainage varve at Döviken, eastern Jämtland, raising the tantalising prospect of using the evolution of the ice-dammed lake system to tie the varve-based Swedish Time Scale to the radiocarbon timescale with a new programme of radiocarbon dating in central Jämtland. 

Keywords
Quaternary, Glaciation, Scandinavia, Geomorphology, Glacial, Deglaciation, Proglacial lakes, GLOF, Fennoscandian ice sheet, Isostasy
National Category
Geophysics
Identifiers
urn:nbn:se:su:diva-221150 (URN)10.1016/j.quascirev.2023.108219 (DOI)001049355300001 ()2-s2.0-85164734861 (Scopus ID)
Available from: 2023-09-14 Created: 2023-09-14 Last updated: 2023-09-14Bibliographically approved
Kylander, M. E., Martínez-Cortizas, A., Sjöström, J. K., Gåling, J., Gyllencreutz, R., Bindler, R., . . . Gallagher, K. (2023). Storm chasing: Tracking Holocene storminess in southern Sweden using mineral proxies from inland and coastal peat bogs. Quaternary Science Reviews, 299, Article ID 107854.
Open this publication in new window or tab >>Storm chasing: Tracking Holocene storminess in southern Sweden using mineral proxies from inland and coastal peat bogs
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2023 (English)In: Quaternary Science Reviews, ISSN 0277-3791, E-ISSN 1873-457X, Vol. 299, article id 107854Article in journal (Refereed) Published
Abstract [en]

Severe extratropical winter storms are a recurrent feature of the European climate and cause widespread socioeconomic losses. Due to insufficient long-term data, it remains unclear whether storminess has shown a notable response to changes in external forcing over the past millennia, which impacts our ability to project future storminess in a changing climate. Reconstructing past storm variability is essential to improving our understanding of storms on these longer, missing timescales. Peat sequences from coastal ombrotrophic bogs are increasingly used for this purpose, where greater quantities of coarser grained beach sand are deposited by strong winds during storm events. Moving inland however, storm intensity decreases, as does sand availability, muting potential paleostorm signals in bogs. We circumvent these issues by taking the innovative approach of using mid-infrared (MIR) spectral data, supported by elemental information, from the inorganic fraction of Store Mosse Dune South (SMDS), a 5000-year-old sequence from a large peatland located in southern Sweden. We infer past changes in mineral composition and thereby, the grain size of the deposited material. The record is dominated by quartz, whose coarse nature was confirmed through analyses of potential local source sediments. This was supported by further mineralogical and elemental proxies of atmospheric input. Comparison of SMDS with within-bog and regionally relevant records showed that there is a difference in proxy and site response to what should be similar timing in shifts in storminess over the ∼100 km transect considered. We suggest the construction of regional storm stacks, built here by applying changepoint modelling to four transect sites jointly. This modelling approach has the effect of reinforcing signals in common while reducing the influence of random noise. The resulting Southern Sweden-Storm Stack dates stormier periods to 4495–4290, 3880–3790, 2885–2855, 2300–2005, 1175–1065 and 715-425 cal yr BP. By comparing with a newly constructed Western Scotland-Storm Stack and proximal dune records, we argue that regional storm stacks allow us to better compare past storminess over wider areas, gauge storm track movements and by extension, increase our understanding of the drivers of storminess on centennial to millennial timescales.

Keywords
Storms, Holocene, Peat, Paleoclimate, Scandinavia, Mineralogy, Inorganic geochemistry
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-215294 (URN)10.1016/j.quascirev.2022.107854 (DOI)000917017800010 ()2-s2.0-85142750856 (Scopus ID)
Available from: 2023-03-13 Created: 2023-03-13 Last updated: 2023-03-13Bibliographically approved
Regnéll, C., Alexanderson, H., Greenwood, S. L., Gyllencreutz, R. & Öhrling, C. (2023). The Lund Moraine - the geomorphic limit of the last Young Baltic ice advance in the Öresund region. GFF
Open this publication in new window or tab >>The Lund Moraine - the geomorphic limit of the last Young Baltic ice advance in the Öresund region
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2023 (English)In: GFF, ISSN 1103-5897, E-ISSN 2000-0863Article in journal (Refereed) Epub ahead of print
Abstract [en]

Here we present geomorphological evidence of a previously unrecognised ∼50 km long, ice-marginal moraine complex in southwestern Skåne, southernmost Sweden, which we name the “Lund Moraine”. This lobate moraine marks a sharp boundary between heavily streamlined and gently undulating landscapes, and closely outlines the extent of the “Lund till/diamicton”. We interpret that the moraine was formed by a northward readvance, corresponding to a last Young Baltic readvance of the Scandinavian Ice Sheet into Öresund. Consequently, we infer that the “Lund till/diamicton” was formed subglacially, in contrast to earlier interpretations of it being a waterlain diamicton. Based on previously published dates, stratigraphically below “Lund till/diamicton”, we infer that this readvance occurred sometime after c. 16 cal. ka BP. This readvance could offer an explanation to the apparent discrepancy of observations of the postglacial marine limit from outside and inside the Lund Moraine. Our observations will hopefully settle the ∼50 years long controversy concerning the extent or even existence of such a readvance into Öresund. We expect that our findings will guide further work towards disentangling the complex deglacial history of Skåne and the wider Öresund region.

Keywords
Scandinavian Ice Sheet, Fennoscandian ice sheet, Low Baltic ice stream, Young Baltic ice stream, deglaciation, Skane, LiDAR
National Category
Geology
Identifiers
urn:nbn:se:su:diva-225556 (URN)10.1080/11035897.2023.2281676 (DOI)001128760400001 ()2-s2.0-85180178974 (Scopus ID)
Available from: 2024-01-17 Created: 2024-01-17 Last updated: 2024-01-17
Stockmann, G. J. J., Seaman, P., Balic-Zunic, T., Peternell, M., Sturkell, E., Liljebladh, B. & Gyllencreutz, R. (2022). Mineral Changes to the Tufa Columns of Ikka Fjord, SW Greenland. Minerals, 12(11), Article ID 1430.
Open this publication in new window or tab >>Mineral Changes to the Tufa Columns of Ikka Fjord, SW Greenland
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2022 (English)In: Minerals, E-ISSN 2075-163X, Vol. 12, no 11, article id 1430Article in journal (Refereed) Published
Abstract [en]

The submarine tufa columns of Ikka Fjord in Southwest Greenland have been studied during multiple field campaigns since 1995. The fjord contains close to thousand columns previously shown to consist of the metastable carbonate mineral ikaite (CaCO3·6H2O), which requires near-freezing conditions to remain stable over longer periods of time. During a field campaign to Ikka Fjord in the summer of 2019, seawater temperatures of 6–9 °C and visual physical changes to the columns were observed. These are the highest recorded seawater temperatures measured in Ikka Fjord in over three decades of research. In response, three selected columns at three different locations were sampled at their bases, middle, and top sections for mineralogical analysis. These samples were supplemented by a four further column samples and an extensive hydrographical campaign during fieldwork in the summer 2021. Here, we report the results of the mineralogical analyses performed by X-ray diffraction and µ-Raman Spectroscopy on these column samples. The results show that the columns analysed now consist of the less hydrated carbonate minerals, monohydrocalcite (CaCO3·H2O), aragonite, and calcite (CaCO3). One of the columns has completely altered into monohydrocalcite, whereas the other columns have crusts of ikaite and cores of monohydrocalcite ± aragonite and calcite. This change is interpreted as a dehydration reaction and mineral alteration from ikaite to monohydrocalcite continuing to aragonite ± calcite in response to being bathed in warming seawater. Hydrographic profilers and static dataloggers recorded seawater temperatures of 4–8 °C in the column-containing fjord areas during June–August 2021. The upper parts of the columns are particularly exposed to temperatures > 6 °C, considered to be the long-term stability threshold of ikaite in Ikka Fjord. The mineral dehydration reactions are irreversible. It is therefore predicted in a warming Arctic, ikaite will only appear as new growth on the columns for a short period, and that with time, the columns of Ikka Fjord will change mineralogy into mainly monohydrocalcite.

Keywords
ikaite, monohydrocalcite, mineral alteration, seawater, Ikka Fjord, tufa columns
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-213408 (URN)10.3390/min12111430 (DOI)000895600200001 ()
Available from: 2023-01-04 Created: 2023-01-04 Last updated: 2024-01-17Bibliographically approved
Seaman, P., Sturkell, E., Gyllencreutz, R., Stockmann, G. J. & Geirsson, H. (2022). New multibeam mapping of the unique Ikaite columns in Ikka Fjord, SW Greenland. Marine Geology, 444, Article ID 106710.
Open this publication in new window or tab >>New multibeam mapping of the unique Ikaite columns in Ikka Fjord, SW Greenland
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2022 (English)In: Marine Geology, ISSN 0025-3227, E-ISSN 1872-6151, Vol. 444, article id 106710Article in journal (Refereed) Published
Abstract [en]

Ikka Fjord in SW Greenland is world famous for its submarine, cold-water craving ikaite (CaCO3·6H2O) tufa columns. Due to the uniqueness of the columns, Ikka Fjord is declared a protected area by the Greenlandic authorities. In the summers of 2018–19, multibeam sonar bathymetry and aerial drone photogrammetric surveys were made in Ikka Fjord mapping and counting the columns and comparing the results to data from geophysical surveys of the fjord in 1995–96. The new surveys provide highly detailed maps of the fjord bathymetry and its columns, their height and position, and several hitherto unknown pockmarks in the seabed. A total of 938 individual columns and structures ranging 0.5–20 m in height from the sea floor were identified: a number surpassing the 678 taller columns (> 1 m) known from previous mapping. Our results support previous observations that the columns are restricted to the spatial extents of the Grønnedal-Íka igneous complex. The new survey data show that column distribution exhibits lineations and variable density over the fjord floor, notably that the innermost central deep part is free of columns. The tallest columns are observed to grow up to the halocline at approximately 2–4 m water depth. The majority of columns have reached only 15–50% of their growth potential. The ~60 columns of maximum growth stand in clusters, interpreted as representing exceptionally favourable growth settings. New seawater data collected in 2019 shows a worrying increase in temperature since the previous measurements in 1995 and 2007–2009, which could potentially affect the stability of the delicate columns of Ikka Fjord.

Keywords
Ikka Fjord, Tufa columns, Ikaite, Multibeam, Drone imagery, Mapping
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-201959 (URN)10.1016/j.margeo.2021.106710 (DOI)000748994900001 ()
Available from: 2022-02-09 Created: 2022-02-09 Last updated: 2022-02-09Bibliographically approved
Gowan, E. J., Zhang, X., Khosravi, S., Rovere, A., Stocchi, P., Hughes, A. L. C., . . . Lohmann, G. (2022). Reply to: Towards solving the missing ice problem and the importance of rigorous model data comparisons. Nature Communications, 13(1), Article ID 6264.
Open this publication in new window or tab >>Reply to: Towards solving the missing ice problem and the importance of rigorous model data comparisons
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2022 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 13, no 1, article id 6264Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Nature Research, 2022
Keywords
ice, problem solving
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-211721 (URN)10.1038/s41467-022-33954-x (DOI)000871563700003 ()36280673 (PubMedID)2-s2.0-85140564170 (Scopus ID)
Available from: 2022-11-25 Created: 2022-11-25 Last updated: 2023-03-28Bibliographically approved
Gowan, E. J., Zhang, X., Khosravi, S., Rovere, A., Stocchi, P., Hughes, A. L. C., . . . Lohmann, G. (2021). A new global ice sheet reconstruction for the past 80000 years. Nature Communications, 12(1), Article ID 1199.
Open this publication in new window or tab >>A new global ice sheet reconstruction for the past 80000 years
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2021 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 12, no 1, article id 1199Article in journal (Refereed) Published
Abstract [en]

The evolution of past global ice sheets is highly uncertain. One example is the missing ice problem during the Last Glacial Maximum (LGM, 26000-19000 years before present) - an apparent 8-28 m discrepancy between far-field sea level indicators and modelled sea level from ice sheet reconstructions. In the absence of ice sheet reconstructions, researchers often use marine delta O-18 proxy records to infer ice volume prior to the LGM. We present a global ice sheet reconstruction for the past 80000 years, called PaleoMIST 1.0, constructed independently of far-field sea level and delta O-18 proxy records. Our reconstruction is compatible with LGM far-field sea-level records without requiring extra ice volume, thus solving the missing ice problem. However, for Marine Isotope Stage 3 (57000-29000 years before present) - a pre-LGM period - our reconstruction does not match proxy-based sea level reconstructions, indicating the relationship between marine delta O-18 and sea level may be more complex than assumed. The configuration of past ice sheets, and therefore sea level, is highly uncertain. Here, the authors provide a global reconstruction of ice sheets for the past 80,000 years that allows to test proxy based sea level reconstructions and helps to reconcile disagreements with sea level changes inferred from models.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-192442 (URN)10.1038/s41467-021-21469-w (DOI)000623786100001 ()33623046 (PubMedID)
Available from: 2021-04-23 Created: 2021-04-23 Last updated: 2023-03-28Bibliographically approved
Sundblad, K., Salin, E., Claesson, S., Gyllencreutz, R. & Billström, K. (2021). The Precambrian of Gotland, a key for understanding the Proterozoic evolution in southern Fennoscandia. Precambrian Research, 363, Article ID 106321.
Open this publication in new window or tab >>The Precambrian of Gotland, a key for understanding the Proterozoic evolution in southern Fennoscandia
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2021 (English)In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 363, article id 106321Article in journal (Refereed) Published
Abstract [en]

Gotland is an island in the central part of the Baltic Sea, with up to 800 m Palaeozoic sedimentary rocks on top of a Precambrian basement belonging to the East European Craton. In this contribution, two major ductile deformation zones (Lickershamn - Östergarn and Lilla Karlsö-Ronehamn) are recognized and connected with the Vingåker-Nyköping and Linköping-Loftahammar Deformation Zones in the adjacent Fennoscandian Shield. These deformation zones constitute the borders between three main Precambrian segments that are correlated with crustal units within the Fennoscandian Shield and concealed parts of the East European Craton east of the Baltic Sea.

The Fårö-Northern Gotland segment is dominated by continental Jotnian sandstones and Svecofennian metasedimentary rocks, separated from each other by a fault and an associated dolerite dyke. The metasediments show a specific provenance pattern with 3.29 Ga, 2.95–2.63 Ga and 2.11–1.96 Ga sources, devoid of < 1.90 Ga detrital zircons. The Alby granite truncates the metasedimentary rocks of the Fårö-Northern Gotland segment and is part of the 1.58 Ga Riga rapakivi batholith. The Central Gotland segment is dominated by metabasalts and 1.90–1.88 Ga granitoids and is correlated with the Tiveden and Valdemarsvik areas in the Fennoscandian Shield. The amphibolites in the Southern Gotland segment are correlated with 1.87–1.86 Ga metabasalts, intercalated with the Västervik quartzites in the Fennoscandian Shield. They were intruded by TIB 0 granitoids, recognized at Frigsarve and correlated with the Askersund-Loftahammar granitoids in the Fennoscandian Shield. The TIB 0 granitoids on Gotland can also be followed to the east, first to the E6-1 offshore drill hole, 30 km west of the Latvian coast and further east into southwestern Latvia and western Lithuania as a major component in the Mid-Lithuanian Domain. The Kvarne granitoid on southernmost Gotland is correlated with the TIB 1a generation in the Fennoscandian Shield and with granitoids within the Mid-Lithuanian Domain.

1.48 Ga small stitching plutons on southern Gotland penetrate the TIB 0 and 1a granitoids and are correlated with the Götemar and Karlshamn plutons in the Fennoscandian Shield and several plutons in western and southern Lithuania.

Keywords
Gotland, Fennoscandia, Palaeoproterozoic, Trans-baltic correlation, Geochronology, Geochemistry
National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-198294 (URN)10.1016/j.precamres.2021.106321 (DOI)000687972900006 ()
Available from: 2021-11-08 Created: 2021-11-08 Last updated: 2022-02-25Bibliographically approved
Kylander, M. E., Söderlindh, J., Schenk, F., Gyllencreutz, R., Rydberg, J., Bindler, R., . . . Skelton, A. (2020). It's in your glass: a history of sea level and storminess from the Laphroaig bog, Islay (southwestern Scotland). Boreas, 49(1), 152-167
Open this publication in new window or tab >>It's in your glass: a history of sea level and storminess from the Laphroaig bog, Islay (southwestern Scotland)
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2020 (English)In: Boreas, ISSN 0300-9483, E-ISSN 1502-3885, Vol. 49, no 1, p. 152-167Article in journal (Refereed) Published
Abstract [en]

Severe winter windstorms have become an increasingly common occurrence over recent decades in northwestern Europe. Although there exists considerable uncertainty, storminess is projected to increase in the future. On centennial to millennial time scales in particular, the mechanisms forcing storminess remain unsettled. We contribute to available palaeostorm records by reconstructing changes over the last 6670 years using a coastal peat sequence retrieved from the ombrotrophic Laphroaig bog on Islay, southwestern Scotland. We use a combination of ash content, grain size and elemental chemistry to identify periods of greater storminess, which are dated to 6605, 6290-6225, 5315-5085, 4505, 3900-3635, 3310-3130, 2920-2380, 2275-2190, 2005-1860, 1305-1090, 805-435 and 275 cal. a BP. Storm signals in the first half of the record up to similar to 3000 cal. a BP are mainly apparent in the grain-size changes. Samples from this time period also have a different elemental signature than those later in the record. We speculate that this is due to receding sea levels and the consequent establishment of a new sand source in the form of dunes, which are still present today. The most significant events and strongest winds are found during the Iron Ages Cold Epoch (2645 cal. a BP), the transition into, and in the middle of, the Roman Ages Warm Period (2235 and 1965 cal. a BP) and early in the Little Ice Age (545 cal. a BP). The Laphroaig record generally agrees with regionally relevant peat palaeostorm records from Wales and the Outer Hebrides, although the relative importance of the different storm periods is not the same. In general, stormier periods are coeval with cold periods in the region as evidenced by parallels with increased ice-rafted debris in the North Atlantic, highlighting that sea-ice conditions could impact future storminess and storm track position.

National Category
Earth and Related Environmental Sciences
Identifiers
urn:nbn:se:su:diva-175101 (URN)10.1111/bor.12409 (DOI)000484313400001 ()
Available from: 2019-10-22 Created: 2019-10-22 Last updated: 2022-02-26Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-3193-8598

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