Melting Characteristics of Snow Cover on Tidewater Glaciers in Hornsund Fjord, Svalbard

In recent years, the Svalbard area, especially its southern section, has been characterised by an exceptionally thin snow cover, which has a significant impact of the annual mass balance of glaciers. The objective of this study was to determine melting processes of the snow cover deposited on 11 glaciers that terminate into Hornsund Fjord during the melting period of 2014. The study included analyses of snow pits and snow cores, meteorological data collected from automatic weather stations and Polish Polar Station Hornsund, and supervised classification of six Landsat 8 images for assessing the progress of snow cover melting. The calculated Snow-Covered Area (SCA) varied from 98% at the beginning of the melting season to 43% at the end of August. The melting vertical gradient on Hansbreen was -0.34 m 100 m-1, leading to surface melting of -1.4 cm water equivalent (w.e.) day-1 in the ablation zone (c. 200 m a.s.l. (above sea level)) and -0.7 cm w.e. day-1 in the accumulation zone (c. 400 m a.s.l.). Furthermore, the study identified several observed features such as low snow depth in the accumulation zone of the Hornsund glaciers, a large proportion of the snow layers (12-27%) produced by rain-on-snow events, and a frequent occurrence of summer thermal inversions (80% annually), indicating that the area is experiencing intensive climate changes

Influence of snowpack internal structure on snow metamorphism and melting intensity on Hansbreen, Svalbard

This paper presents a detailed study of melting processes conducted on Hansbreen - a tidewater glacier terminating in the Hornsund fjord, Spitsbergen. The fieldwork was carried out from April to July 2010. The study included observations of meltwater distribution within snow profiles in different locations and determination of its penetration time to the glacier ice surface. In addition, the variability of the snow temperature and heat transfer within the snow cover were measured. The main objective concerns the impact of meltwater on the diversity of physical characteristics of the snow cover and its melting dynamics. The obtained results indicate a time delay between the beginning of the melting processes and meltwater reaching the ice surface. The time necessary for meltwater to percolate through the entire snowpack in both, the ablation zone and the equilibrium line zone amounted to c. 12 days, despite a much greater snow depth at the upper site. An elongated retention of meltwater in the lower part of the glacier was caused by a higher amount of icy layers (ice formations and melt-freeze crusts), resulting from winter thaws, which delayed water penetration. For this reason, a reconstruction of rain-on-snow events was carried out. Such results give new insight into the processes of the reactivation of the glacier drainage system and the release of freshwater into the sea after the winter period

The role of atmospheric precipitation in introducing contaminants to the surface waters of the Fuglebekken catchment, Spitsbergen

Although the Svalbard Archipelago is located at a high latitude, far from potential contaminant sources, it is not free from anthropogenic impact. Towards the Fuglebekken catchment, in the southern part of Spitsbergen, north of Hornsund fjord, contaminants can be transported from mainland pollution sources. In the precipitation and surface water collected in the catchment, the following elements were detected and quantified: Ag, Al, As, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Cs, Mo, Ni, Pb, Sb, Se, Sr, Tl, U, Vand Zn. Additionally, pH, electrical conductivity and total organic carbon (TOC) were determined in those samples. The acidic reaction of precipitation waters was identified as an important factor intensifying the metal migration in this Arctic tundra environment. The air mass trajectory, surprisingly, explained the variability of only a small fraction of trace elements in precipitation water. The air mass origin area was correlated only with the concentrations of As, V and Cr. Wind directions were helpful in explaining the variability of Mn, U and Ba concentrations (east north-easterly wind) and the contents of B, As, Rb, Se, Sr and Li in precipitation (south-westerly wind), which may indicate the local geological source of those. Atmospheric deposition was found to play a key role in the transport of contaminants into the Fuglebekken catchment; however, the surface water composition was modified by its pH and TOC content

The Role of Winter Rain in the Glacial System on Svalbard

Rapid Arctic warming results in increased winter rain frequencies, which may impact glacial systems. In this paper, we discuss climatology and precipitation form trends, followed by examining the influence of winter rainfall (Oct–May) on both the mass balance and dynamics of Hansbreen (Svalbard). We used data from the Hornsund meteorological station (01003 WMO), in addition to the original meteorological and glaciological data from three measurement points on Hansbreen. Precipitation phases were identified based on records of weather phenomena and used—along with information on lapse rate—to estimate the occurrence and altitudinal extent of winter rainfall over the glacier. We found an increase in the frequency of winter rain in Hornsund, and that these events impact both glacier mass balance and glacier dynamics. However, the latter varied depending on the degree of snow cover and drainage systems development. In early winter, given the initial, thin snow cover and an inefficient drainage system, rainfall increased glacier velocity. Full-season winter rainfall on well-developed snow was effectively stored in the glacier, contributing on average to 9% of the winter accumulation

Seasonal changes in submarine melting mechanisms controlling frontal ablation of Hansbreen, Svalbard

We describe the annual pattern of frontal ablation driven by submarine melting mechanisms at the Hansbreen terminus: these are reflected in the intensity and spatial distribution of calving events. Analysis of time-lapse images of the Hansbreen front in conjunction with oceanographic and meteorological data shows that calving intensity is driven primarily by seawater temperature. Regression analysis also highlights the importance of air temperature, which we take to be a proxy for surface ablation and subglacial discharge. This, combined with seasonal changes in ice cliff tortuosity and the increasing significance of wave motion outside the ablation season, enabled us to determine seasonal changes in the mechanisms of ice cliff undercutting by submarine melting. While submarine melting controlled by estuarine circulation primarily drives frontal ablation in summer, wave-driven melting at the waterline is more important outside the ablation season. During winter, ice cliff undercutting by melting is suspended by low seawater temperature, negligible subglacial water discharge and sea-ice cover. The most intense frontal ablation, recorded in summer, was related to higher sea temperature and vigorous estuarine circulation

Climate change is rapidly deteriorating the climatic signal in Svalbard glaciers

The Svalbard archipelago is particularly sensitive to climate change due to the relatively low altitude of its main ice fields and its geographical location in the higher North Atlantic, where the effect of Arctic amplification is more significant. The largest temperature increases have been observed during winter, but increasing summer temperatures, above the melting point, have led to increased glacier melt. Here, we evaluate the impact of this increased melt on the preservation of the oxygen isotope (δ18O) signal in firn records. δ18O is commonly used as a proxy for past atmospheric temperature reconstructions, and, when preserved, it is a crucial parameter to date and align ice cores. By comparing four different firn cores collected in 2012, 2015, 2017 and 2019 at the top of the Holtedahlfonna ice field (1100 m a.s.l.), we show a progressive deterioration of the isotope signal, and we link its degradation to the increased occurrence and intensity of melt events. Our findings indicate that, starting from 2015, there has been an escalation in melting and percolation resulting from changes in the overall atmospheric conditions. This has led to the deterioration of the climate signal preserved within the firn or ice. Our observations correspond with the model's calculations, demonstrating an increase in water percolation since 2014, potentially reaching deeper layers of the firn. Although the δ18O signal still reflects the interannual temperature trend, more frequent melting events may in the future affect the interpretation of the isotopic signal, compromising the use of Svalbard ice cores. Our findings highlight the impact and the speed at which Arctic amplification is affecting Svalbard's cryosphere.</p

Newly identified climatically and environmentally significant high-latitude dust sources

Dust particles from high latitudes have a potentially large local, regional, and global significance to climate and the environment as short-lived climate forcers, air pollutants, and nutrient sources. Identifying the locations of local dust sources and their emission, transport, and deposition processes is important for understanding the multiple impacts of high-latitude dust (HLD) on the Earth\u27s systems. Here, we identify, describe, and quantify the source intensity (SI) values, which show the potential of soil surfaces for dust emission scaled to values 0 to 1 concerning globally best productive sources, using the Global Sand and Dust Storms Source Base Map (G-SDS-SBM). This includes 64 HLD sources in our collection for the northern (Alaska, Canada, Denmark, Greenland, Iceland, Svalbard, Sweden, and Russia) and southern (Antarctica and Patagonia) high latitudes. Activity from most of these HLD sources shows seasonal character. It is estimated that high-latitude land areas with higher (SI ≥0.5), very high (SI ≥0.7), and the highest potential (SI ≥0.9) for dust emission cover >1 670 000 km$^{2}$, >560 000 km$^{2}$, and >240 000 km$^{2}$, respectively. In the Arctic HLD region (≥60$^{∘}$ N), land area with SI ≥0.5 is 5.5 % (1 035 059 km$^{2}$), area with SI ≥0.7 is 2.3 % (440 804 km$^{2}$), and area with SI ≥0.9 is 1.1 % (208 701 km$^{2}$). Minimum SI values in the northern HLD region are about 3 orders of magnitude smaller, indicating that the dust sources of this region greatly depend on weather conditions. Our spatial dust source distribution analysis modeling results showed evidence supporting a northern HLD belt, defined as the area north of 50$^{∘}$ N, with a “transitional HLD-source area” extending at latitudes 50–58∘ N in Eurasia and 50–55$^{∘}$ N in Canada and a “cold HLD-source area” including areas north of 60$^{∘}$ N in Eurasia and north of 58$^{∘}$ N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia. Using the global atmospheric transport model SILAM, we estimated that 1.0 % of the global dust emission originated from the high-latitude regions. About 57 % of the dust deposition in snow- and ice-covered Arctic regions was from HLD sources. In the southern HLD region, soil surface conditions are favorable for dust emission during the whole year. Climate change can cause a decrease in the duration of snow cover, retreat of glaciers, and an increase in drought, heatwave intensity, and frequency, leading to the increasing frequency of topsoil conditions favorable for dust emission, which increases the probability of dust storms. Our study provides a step forward to improve the representation of HLD in models and to monitor, quantify, and assess the environmental and climate significance of HLD