Commun. Jöklakort af íslandi/map of the glaciers of Iceland. Insulation effects of Icelandic dust and volcanic ash on snow and ice. Sensitivity of Vatnajökull ice cap hydrology and dynamics to climate warming over the next 2 centuries. The obtained mass change rate for the period 1950–1990 in their record is about double the rate that we find here (−4.0 vs. −1.7 Gt a−1). Using volume–area scaling to estimate changes in the volume of glaciers with a well-known subglacial topography, from variations in glacier area over decadal time spans, may be expected to be more accurate because this mainly relies on the assumption that the glacier maintains a similar shape as it responds to mass-balance variations with changes in its area and volume. 5, 590–598. Velicogna, I., Mohajerani, Y., Geruo, A., Landerer, F., Mouginot, J., Noel, B., et al. To estimate the maximum glacier volume at the end of the LIA, a volume–area scaling method is used based on the observed area and volume from the three largest ice caps (over 90% of total ice mass) at 5–7 different times each, in total 19 points. The glaciological year 2018/19 was among the most negative mass-balance years that were not significantly impacted by volcanic eruptions but by dust blown onto the glacier surface. The calving will continue to increase as the glaciers retreat, and should, along with other non-surface mass-balance components, be taken … All authors contributed to discussions at various stages of the work and during the revisions of the manuscript. Björnsson, H., Pálsson, F., Guðmundsson, M. T., and Haraldsson, H. H. (2002). An underwater pressure sensor capable of making 20 measurements per second was placed in front of the glacier to record calving-generated tsunami waves measuring 10 centimeters to 1 meter high. Björnsson, H., and Pálsson, F. (2008). The net mass change during these periods, which is obtained with the geodetic method, is not altered by this. (2005). When adding the non-surface mass-balance component from Jóhannesson et al. a−1. The glacier areas are derived from Hannesdóttir et al. The geodetic results were also used to scale (Jóhannesson et al., 2013) and validate (Pálsson et al., 2012) the glaciological measurements. In some years, the spring is cool, so glacier ice appears later from beneath the snow. (2013). Reviewed November 5, 2019 via mobile . Variations of southeast Vatnajökull ice cap (Iceland) 1650–1900 and reconstruction of the glacier surface geometry at the Little Ice Age maximum. Past and future sea-level change from the surface mass balance of glaciers. By Francis Xavier | August 15, 2019 11:53 am If you go kayaking in Alaska trying to witness a calving glacier you might get more than you bargained for. Global glacier changes: a revised assessment of committed mass losses and sampling uncertainties. Surface and bedrock topography of the Mýrdalsjökull ice cap, Iceland: the Katla caldera, eruption sites and routes of jökulhlaups. The total height of the ice was about 915 m (3,000 … The future mass loss will both be due to the already realized temperature increase (Mernild et al., 2013; Vaughan et al., 2013; Marzeion et al., 2018) and the projected continued warming. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Map of Iceland showing the glaciers considered in this study. JB, EM, EB, and TJ processed and contributed the geodetic estimates. Front. The volume of a glacier can be obtained by integrating the ice thickness, calculated as the difference between surface and bedrock DEMs. Front. The same applies for the uncertainty of the specific mass balance for Hofsjökull and Langjökull. 1) is likely to result in an overestimate of the glacier volume in ∼1890 for two reasons. A subset of the mass-balance observations from Vatnajökull, Hofsjökull, and Langjökull is submitted to the WGMS database on annual basis. doi:10.5194/tc-9-2399-2015, Marzeion, B., Kaser, G., and Maussion, F. (2018). Unprecedented atmospheric conditions (1948–2019) drive the 2019 exceptional melting season over the Greenland ice sheet. calving glaciers respond rapidly to regional environmental change, but predictive capacity is limited by the lack of suit-able models capable of simulating calving mechanisms re-alistically. Impact of supraglacial deposits of tephra from Grímsvötn volcano, Iceland, on glacier ablation. (2020); we describe the method below and the resulting mass change rates calculated from the area and volume changes are shown with purple boxes in Figures 3A,B,C. When calculating the uncertainty of each time series shown in Figure 3G, the uncertainty for each contribution ΔCV, ΔCL, ΔCH, and ΔCO (corresponding to Vatnajökull, Langjökull, Hofsjökull, and “others”, respectively) is derived by cumulating the assigned annual uncertainties. The 1996 eruption at Gjálp, Vatnajökull ice cap, Iceland: course of events, efficiency of heat tranfer, ice deformation and subglacial water pressure. Cryosphere 10, 159–177. GA, FP, and EM designed the study, wrote the paper, and made the figures. Steffen Glacier in 1987 and 2019 Landsat images. Phys. The time steps in this study correspond to the glaciological year (Cogley et al., 2011) from autumn to autumn, using the floating-date mass-balance system (Østrem and Brugman, 1991; Björnsson et al., 2002; Cogley et al., 2011), that is, the end of the summer melt season marks the start of a new glaciological year. Huge Cracks in Antarctic Glacier Foreshadow Epic Calving Event. (2020). Jökull 13, 31–33. 9 (5), 399. doi:10.3390/rs9050399, Geirsdóttir, Á., Miller, G. H., Axford, Y., and Ólafsdóttir, S. (2009). a−1 and for Langjökull and Hofsjökull 0.85 m w.e. The uncertainties for each of the contributions, ΔCV, ΔCL, ΔCH, and ΔCO, are assumed to be independent and therefore ΔCVLHO is calculated as the square root of a quadratic sum (Eqs 2 and 3). The importance of accurate glacier albedo for estimates of surface mass balance on Vatnajökull: evaluating the surface energy budget in a regional climate model with automatic weather station observations. The data records are shown in Figures 2 and 3A,B,C. FIGURE 5. Most of these advance between a few hundred meters and several kilometers during surges (Björnsson et al., 2003), the average probably being close to 1 km. We almost DIED in Spencer Glacier calving - Alaska 2019 - YouTube (6) Geodetic mass-balance records for Langjökull (Pálsson et al., 2012), from 1937/38 to 1996/97 (red lines with uncertainties in Figure 3B) and 12 smaller glaciers (Figure 3D) from 1945/46 to 2016/17 (Belart et al., 2020) that cover 8.3% of the glacier area in Iceland. TJ contributed the non-surface mass-balance estimates. Talence, France: Bordeaux INP ENSEGID. Glaciol. Continuity of ice sheet mass loss in Greenland and Antarctica from the grace and grace follow-on missions. Geophys. 22, 131–159. Geophys. Mass balance of western and northern Vatnajökull, Iceland, 1991–1995. Ice-volume estimates at other times can be calculated by multiplying the annual specific mass balance (Figure 3) of each glacier by the corresponding glacier area, linearly interpolated with time between dates of area observations, converting the annual mass change into ice volume [assuming the conversion factor 0.85 (Huss, 2013); note that mass-balance records previously published that used conversion factor 0.9 (Pálsson et al., 2012; Jóhannesson et al., 2013) have been adjusted accordingly (Thorsteinsson et al., 2017)] and integrating the volume change relative to the date of the surface DEMs listed above. (2016). Ice calving, also known as glacier calving or iceberg calving, is the breaking of ice chunks from the edge of a glacier. (2020). Cryosphere Discuss. The surface mass balance from the glaciological method is obtained by measuring the snow water equivalent (w.e.) doi:10.5194/tc-11-1665-2017, Schmidt, L. S., Aðalgeirsdóttir, G., Pálsson, F., Langen, P. L., Guðmundsson, S., and Björnsson, H. (2019). Sci. The calving will continue to increase as the glaciers retreat, and should, along with other non-surface mass-balance components, be taken into account in future projections of mass loss of glaciers in Iceland. Pálsson, F., Guðmundsson, S., Björnsson, H., Berthier, E., Magnússon, E., Guðmundsson, S., et al. Conventionally, calving front posi- The uncertainty of the geodetic results of Langjökull in 1937/38 to 1996/97 varies between 0.10 and 0.50 m w.e. Values for the ratio F are specifically calculated for the periods 1994/95–2003/04, 2004/5–2009/10, and 2010/11–2016/17 (1.176, 1.131, and 1.056, respectively), corresponding to the geodetic mass-balance periods of Belart et al. The uncertainty of the total mass change for 1970/71 to 2017/18, 1992/93 to 2017/18, and 2005/06 to 2017/18 is therefore, For 1900/01 to 1989/90, the total uncertainty is. (2012)] was obtained in mid-August so the surface melting until the end of the melt season (late September) was not accounted for. The large mass loss in 1996/97 is due to the melting of ∼3.7 Gt of ice due to the subglacial Gjálp volcanic eruption in October 1996 (Guðmundsson et al., 2004), followed by a warm and sunny summer with low surface albedo due to dust precipitating onto the glacier surface. 110, F02011. (2004). A part of this non-surface mass balance is caused by calving activity, which was insignificant in the first half of the 20th century, but has been gradually increasing with the ongoing retreat of the outlet glaciers located in over-deepened troughs (Guðmundsson et al., 2019). 1 Thank kennethj133 . Res. Howard Ulrich, a fisherman visiting Lituya Bay with his 8-years-old son that day, at first heard a loud rumbling noise from up at the head of the … a−1. The geodetic mass balance of Eyjafjallajökull ice cap for 1945–2014: processing guidelines and relation to climate. Modelling the 20th and 21st century evolution of Hoffellsjökull glacier, SE-Vatnajökull, Iceland. doi:10.1002/grl.50278, Björnsson, H., Pálsson, F., Sigurðsson, O., and Flowers, G. E. (2003). doi:10.1080/20014422.1940.11880686, Thorarinsson, S. (1943). There is large interannual variability that often is impacted by volcanic eruptions enhancing the melt and dust or volcanic tephra blown onto the glacier surface from their sediment-rich vicinity. Glaciers in Iceland are all temperate and cover about 10% of the area of the country (Björnsson and Pálsson, 2008), with the largest ice cap Vatnajökull (∼7,700 km2, ∼2,870 km3, in the year 2019) located near the southeast coast, two smaller ice caps Langjökull (∼835 km2, ∼171 km3, in the year 2019) and Hofsjökull (∼810 km2, ∼170 km3, in the year 2019) in the central highlands [area estimates are from Hannesdóttir et al. (2015). The dotted gray line shows the least square fit of Eq. Ann. Cryosphere 9, 565–585. Return to rapid ice loss in Greenland and record loss in 2019 detected by the GRACE-FO satellites. J. Glaciol. The uncertainty of 0.1 m w.e. a−1 for Vatnajökull, which is responsible for most of the 1.5 ± 1.0 Gt a−1 mass gain of Icelandic glaciers during that period. After 1994/95, an estimate of the annual variability of the mass change for other glaciers than the three largest is included by calculating the net mass change for each glaciological year, using the corresponding F value for each period. Ask kennethj133 about Mendenhall Glacier Visitor Center. We focus on two envi-ronmental processes: undercutting by submarine … Climate change 2013: the physical science basis. the end of the Little Ice Age (LIA) in Iceland. Cryosphere 9, 139–150. Figure 4). (2020). doi:10.1038/NGEO2999, Christian, J. E., Koutnik, M., and Roe, G. (2018). This pattern of glacier evolution is similar across the North Atlantic region as shown by records from glaciers in Greenland (Bjørk et al., 2012), Svalbard (Möller and Kohler, 2018), and Norway (Weber et al., 2019; Andreassen et al., 2020). In the period 1890–2019, Vatnajökull, Langjökull, and Hofsjökull lost 12 ± 4, 29 ± 8, and 25 ± 6%, respectively, relative to their estimated mass in 1890. 11 Front. Mass loss by calving contributes significantly to the uncertainty of sea-level rise projections. doi:10.3189/172756403781816365, Brun, F., Berthier, E., Wagnon, P., Kääb, A., and Treichler, D. (2017). doi:10.1017/jog.2020.37, Jóhannesson, T., Raymond, C., and Waddington, E. (1989). Two of us skated, while the oth… Images were acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite from 2000 to 2019. Annual glaciological mass-balance measurements started on Hofsjökull in the glaciological year 1987/88 (Thorsteinsson et al., 2017), in 1991/92 on Vatnajökull, and 1996/97 on Langjökull (Björnsson et al., 1998; Björnsson et al., 2002). Since 2001, mass-balance measurements have also been carried out on an irregular basis on Mýrdalsjökull (Ágústsson et al., 2013). tweet. doi:10.1016/j.cosust.2013.11.003. 8, 11–18. The area loss since the end of the Little Ice Age (LIA) is ∼2,200 km2 and ∼750 km2 since the year 2000, or about 40 km2 (or 0.4%) per year (Hannesdóttir et al., 2020). Glacier change in Norway since the 1960s—an overview of mass balance, area, length and surface elevation changes. Received: 30 December 2019; Accepted: 13 October 2020;Published: 26 November 2020. 7, 96. doi:10.3389/feart.2019.00096. (2020) (−15.9 ± 4 Gt a−1 for 2002–2019) is almost twice as large as our estimate, possibly due to signal leakage from mass changes of the neighboring Greenland Ice Sheet or an overcompensation for the effect of glacial isostatic rebound (e.g., Sørensen et al., 2017). 117, F04010. 209, 226–233. FIGURE 2. 28, 2107–2118. This is because ΔCV is by far the largest single contributor to the total uncertainty. The effect of signal leakage and glacial isostatic rebound on GRACE-derived ice mass changes in Iceland. Many glaciers started retreating from an advanced position near their LIA terminal moraines in the last decades of the 19th century, even if they reached the absolute maximum extent somewhat earlier. The calving was caused by ice above the water melting, putting pressure on ice still under the water. We present results from a new approach combining the continuum model Elmer/Ice and the discrete element/particle model HiDEM, applied to Store Glacier, a large calving glacier in West Greenland. (2019) extend the record for Icelandic glaciers back to 1950 using mass-balance observations from Storglaciären in Sweden and Storbreen in Norway. The high mass losses of 1996/97 and 2009/10 are conspicuous. doi:10.1038/s41561-019-0300-3, Flowers, G., Marshall, S., Björnsson, H., and Clarke, G. (2005).
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