Dispersion and deposition of mineral dust from natural or anthropogenic sources can have both positive and negative effects on the environment depending on the geochemical and mineralogical composition of the dust. In Greenland, proglacial river systems draining the Greenland Ice Sheet occupy extensive areas of dust prone deposits, which are commonly mobilized and transported by winds of both katabatic and cyclonic origin and subsequently deposited as high latitude dust. The geochemical fingerprint of natural dust emitted along the latitudinal transect reflects the mineralogical and elemental composition of the bedrock underlying the Ice Sheet in the different geological provinces of Greenland. As dust emissions respond to changes in climate-sensitive drivers such as soil moisture, winds speed and precipitation, marked variations in natural dust emissions are present along the climatic gradient in Greenland, ranging from high latitude arctic deserts in North Greenland to low latitude shrub tundra in the South.

With a changing climate, interest has increased to access and exploit the rich mineral resources located in the Arctic. In Greenland, development of large-scale mines range from rare earth element mines in the sub-arctic South to zinc-lead mines in the high-arctic North. While the mining sector provides society with essential raw materials for a wide range of industrial processes as well as forming the basis for the transition into a global green economy, it also has significant environmental pitfalls, which should be avoided or mitigated. Mobilization, transport, and deposition of mineral dust from mine sites is often significant in regions susceptible to wind erosion because of the dry climate and lack of vegetation. Once dispersed into the environment, this mineral dust may impair important ecosystem functions due to its potential content of heavy metals and other trace elements, as well as cause concerns for public health.

To support the sustainable development of environmentally safe mining in sensitive Arctic land areas and reduce airborne environmental pollution, an improved understanding of processes leading to the dispersion of mineral dust in a changing Arctic is needed. This involves improved methods for monitoring dust emissions and dust deposition in a cold environment as well as analytical tools and methods to source trace and differentiate between natural and mining related dust. Accurate identification of individual dust sources subsequently makes it possible to mitigate emissions and target the regulation of mining activities towards these sources.

In the following, we present a new high latitude dust sampling location in Kangerlussuaq, West Greenland, where dust is collected using a wide array of passive and active dust samplers, including a continuously operated high volume dust sampler, which will offer filter samples of large air volumes (13.000 m³) at a weekly sampling frequency over multiple years. In addition, we would like to present data from a study (1) in which we developed a fast and cost-effective surface screening methodology that is easily applicable for dust source characterization in remote Arctic areas such as Greenland, where dry conditions and high winds create a high natural dust generation potential.

(1) Søndergaard, J. & Jørgensen, C.J. (2021) DOI: 10.1007/s11270-021-05095-2

How to cite: Jørgensen, C. J., Søndergaard, J., and Mosbech, A.: Geochemical fingerprinting of high latitude dust – potential environmental impacts of natural and mining related dust in Greenland in a changing climate., EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-2609, https://doi.org/10.5194/egusphere-egu23-2609, 2023.

Snow is a valuable resource in California. Snow from the Sierra Nevada sustains a diverse ecosystem and provides 3/4 of California’s Agricultural water supply. Because of its importance in water supply and global climate, snow accumulation, melt, and sublimation were ranked as the most important objectives in the 2017 Decadal Survey. This study employs a fully coupled meteorology‐chemistry‐snow model to investigate the impacts of both global warming and light‐absorbing particles (LAPs) on snow in the Sierra Nevada. Using self-organizing map (SOM) analysis with dust deposition and flux data from model and observations, we identify four typical dust transport patterns across the Sierra Nevada, associated with the mesoscale winds, Sierra barrier jet, North Pacific High, and long-range cross-Pacific westerlies, respectively. The satellite retrievals and model results show that LAPs in snow reduce snow albedo by 0.013 (0–0.045) in the Sierra Nevada during the ablation season (April-July), producing a midday mean radiative forcing of 4.5 W m⁻² which increases to 15–22 W m⁻² in July. LAPs in snow accelerate snow aging processes and reduce snow cover fraction, which doubles the albedo change and radiative forcing caused by LAPs. The impurity-induced snow darkening effects decrease snow water equivalent and snow depth by 20 and 70 mm in June in the Sierra Nevada bighorn sheep habitat. The earlier snowmelt reduces root-zone soil water content by 20%, deteriorating the forage productivity and playing a negative role in the survival of bighorn sheep. We also conduct the simulations using our coupled regional model to compare the impact of global warming vs. LAPs on snow melting by adopting the pseudo-global warming (PGW) approach to generate projections of future meteorological forcing. These results will be used to examine snow effects on endangered Sierra Nevada bighorn sheep and how a future climate might modify habitat and behavior.

How to cite: Qian, Y., Huang, H., He, C., Bair, N., and Rittger, K.: The lifecycle of snow in the Sierra Nevada USA: from snowfall to snowmelt and effects on endangered bighorn sheep, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3776, https://doi.org/10.5194/egusphere-egu23-3776, 2023.

The amplified climate effect of black carbon (BC) in the Arctic is widely acknowledged. Despite this, information on its deposition patterns and particularly sources are still scarce from the area. Arctic-wide atmospheric BC monitoring show decreasing BC concentrations since the 1990s. However, increasing amounts of BC deposition records from the area show more spatial variability in long-term trends, and some records suggest deviating trends between atmospheric BC concentrations and deposition. Particularly in the European Arctic (northern Fennoscandia and northwestern Russia) BC deposition trends seem to have increased in recent decades rather than decreased as suggested by models and observed for atmospheric concentrations. Such dissimilarities between atmospheric BC concentrations and deposition trends suggest different meteorological processes and sources driving these, which need to be further studied to understand the effects of different BC emissions on the Arctic climate. Although we have quantified different BC fractions from lake sediments and ice cores in the European Arctic indicating variable deposition trends during the last 300 years, the records suggest surprisingly similar sources of the deposited BC particles. Our future endeavors lie in further illuminating the sources of deposited BC in the Arctic and particularly studying the potential significance of Russian gas flaring and increasing peatland fires.

How to cite: Korhola, A. and Ruppel, M.: Past black carbon deposition and sources in the European Arctic depicted from lake sediments and ice cores, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5032, https://doi.org/10.5194/egusphere-egu23-5032, 2023.

Aerosols such as mineral dust particles reduce the surface albedo when deposited on snow. This leads to increased absorption of solar radiation. Especially in spring, this phenomenon can lead to increased snowmelt, which triggers further feedbacks at the land surface and in the atmosphere. Quantifying the magnitude of dust-induced variations is difficult because of the high variability in the spatial distribution of mineral dust and snow. We present an extension of a fully coupled atmospheric and land surface model system to investigate the effects of mineral dust on snow albedo across Eurasia. In a comprehensive ensemble simulation study, we investigated the short-term effects of an extreme Saharan dust deposition event in 2018. We found region-dependent feedbacks. Mountainous regions and areas near the snowline showed a strong impact from mineral dust deposition. The former showed a particularly strong decrease in snow depth. For instance, in the Caucasus Mountains we found a mean significant decrease in snow depth of -1.4 cm after one week. The latter showed a stronger feedback effect on surface temperature. In the flat region around the snow line, we found a mean significant surface warming of 0.9 K after one week. This study shows that the effects of mineral dust deposition depend on several factors. Primarily, these are elevation, slope, snow depth, and fraction of snow cover. Therefore, especially in complex terrain, it is necessary to use fully coupled models to study the effects of mineral dust on the snowpack and the atmosphere.

How to cite: Rohde, A., Vogel, H., Hoshyaripour, G. A., Kottmeier, C., and Vogel, B.: Regional Impact of Snow-Darkening During a Severe Saharan Dust Deposition Event in 2018 Across Eurasia, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-7762, https://doi.org/10.5194/egusphere-egu23-7762, 2023.

Over the past decades, an increasing number of Saharan dust storm events have been identified across Europe, using satellite measurements and imagery, numerical simulation data, meteorological analyses, air mass dispersion trajectories and surface observations, thus excluding subjective forcing factors. Both the frequency and intensity of dust storm events have been increasing over the last decade.
Saharan dust reached the Carpathian Basin at least 250 times between 1979 and 2022. The episodes of intense dust deposition in Hungary clearly showed the effect of the downwelling of high-latitude jet streams, leading to (1) extreme weather events and intense dust storms in the Atlas region and (2) increased atmospheric meridionality, which transported the large amounts of dust northwards.
To identify such events, we started our research in the North Atlantic region, where we identified 15 Saharan dust storm events in Iceland between 2008 and 2020, two of which were also surface sampled. The scope of these studies has now been extended to 1980 to 2022 to identify further events. Laboratory analyses of the sampled dust material have found abundant quartz particles larger than 100 µm, indicating that large dust particles can sometimes travel thousands of kilometres.
Similar studies have been initiated in the region of Finland, where 59 Saharan dust storm events were identified between 1980 and 2022. Note that we also found 22 dust storm events from the Aral-Caspian region and 5 episodes with Middle Eastern sources.
The research was supported by the NRDI projects FK138692 and RRF-2.3.1-21-2021.

How to cite: Varga, G., Rostási, Á., Csávics, A., Dagsson-Waldhauserova, P., Meinander, O., and Gresina, F.: Meridional Saharan dust transport towards higher latitudes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-8920, https://doi.org/10.5194/egusphere-egu23-8920, 2023.

Seasonal to long-term changes in albedo, or glacier darkening, is a critical parameter for energy and mass balance models. Yet many of these models employ simple parameterization schemes that darken snow and ice surfaces non-linearly through time. This simplification is not representative of the complex controls on albedo that vary spatially and temporally, driven by atmospheric processes, surface-atmosphere interaction, topography, and timing of glacier ice exposure. Albedo also spectrally varies, controlled by concentrations of light absorbing constituents (LACs) in the visible wavelengths and grain size in the near infrared wavelengths. Radiative forcing by LACs can enhance grain growth, leading to more rapid glacier darkening over the full solar spectrum. This process can accelerate as snow and ice melts because LACs tend to accumulate at the surface which can lead to increased radiative forcing over time for some glaciers. As temperatures warm, and aerosols increase due to land use change, drought, fire, and urbanization, it is likely that glacier darkening will intensify. To better quantify seasonal rates of darkening, and understand controls on intra- and interannual variability, we collected and analyzed a rich dataset obtained from imaging spectroscopy and lidar collected over Place Glacier in the Coast Mountains of British Columbia, Canada. Over the years 2021-2022, we acquired monthly data during the period of snow and glacier melt (March to October for 2021 and July to October 2022) using an aircraft with dedicated lidar (Riegl-780) and hyperspectral (Specim-Fenix; 451 bands) sensors. We processed these monthly acquisitions into 1-m, analysis-ready products. We describe our workflow for these products including development of snow and ice surface property retrievals in complex mountainous terrain. Our workflow yields retrievals that include broadband albedo, radiative forcing by LACs, and grain size. Radiative forcing from LACs can originate from abiotic and biotic sources, and we use the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) to interpret our retrievals with respect to contributions from dust and black carbon. We also highlight how these data can be used to understand seasonal glacier darkening events that occurred during a heat dome, snow algae blooms, and a late start to accumulation season. All these events are expected to increase in frequency or intensity due to climate change and hence, a better understanding of these physical processes will lead to improved physical models for future glacier evolution.

How to cite: Donahue, C., Menounos, B., Viner, N., Beffort, S., Gonzalez Arriola, S., White, R., and Heathfield, D.: Glacier darkening quantified from airborne imaging spectroscopy, Place Glacier, British Columbia, Canada, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-9330, https://doi.org/10.5194/egusphere-egu23-9330, 2023.

The spectral reflectance of snow and ice varies widely depending on several quantities related (1) to the local environmental variables, such as the solar zenith angle and the surface slope, (2) to the physical properties of the snow, such as the grain size and the snow liquid content, and (3) to the presence of light-absorbing particles (LAPs).  Different absorption features are displayed in snow spectra. In particular, the absorption at 1030 nm has been exploited for estimating the grain effective radius of snow both from remote and proximal sensing data (Dozier et al., 2009, Garzonio et al., 2018). This absorption feature has been also used for the retrieval of the liquid water content (LWC) of surface snow since it is characterized by a shift toward shorter wavelengths when LWC increases (Green et al., 2006). Taking benefit of this spectral shift of the absorption feature, we applied a continuum removal approach to obtain both the grain equivalent radius and the LWC value. Furthermore, the accumulation of LAPs, such as dust, black carbon, volcanic ash, and pigmented snow algae on the snowpack albedo increases the absorption of solar radiation and induces a positive surface radiative forcing, enhancing the surface melting.

In this contribution, we show a retrieval algorithm to estimate the variables of snow (i.e., snow grain size, snow water equivalent, LAPs concentration) by using the openly available radiative transfer model BioSnicar (Bio-optical Snow, Ice, and Aerosol Radiative model) to simulate the spectral albedo of snow and the absorption of solar light in the snowpack. We present data from two experimental sites located in the Eastern Alps (Stelvio Pass and Brenta Dolomites) collected using a Spectral Evolution spectroradiometer. Measured variables of snow with a Snow Sensor device were compared with those estimated from BioSnicar simulations. Moreover, the impurities content in snow samples collected will be analyzed in a laboratory to better constrain modeling results. Remote sensing is a fundamental tool for characterizing snow cover properties, from the accumulation of LAPs to the wet/dry state of the snow, and the use of satellite sensors (e.g. PRISMA) opens the possibility for monitoring their spatial and temporal variability. This may have an important impact on snow hydrology studies, mainly for monitoring snow melting and improving the management of freshwater resources in the Alpine environment.

How to cite: Ravasio, C., Garzonio, R., Di Mauro, B., and Colombo, R.: Multi-scale remote sensing and modeling for estimating liquid water content and LAPs on snow in the European Alps, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16143, https://doi.org/10.5194/egusphere-egu23-16143, 2023.

The study of aerosol chemical composition in the Antarctic plateau can provide basic information on the main natural (and also anthropogenic) inputs, atmospheric reactivity, and long-range transport processes of the aerosol components. Moreover, chemical and physical processes occurring at the atmosphere-snow interface are yet not fully understood and work is needed to assess the impact of atmospheric chemistry on snow composition and to better interpret ice core records retrieved at those sites.

At this purpose, simultaneous aerosol and surface snow samplings were set up and run at Dome C station (75° 06’ S; 123° 20’ E, 3233 m a.s.l) all year-round since 2004/05 and are still ongoing through various PNRA Projects, particularly LTCPAA (2016-2020) and STEAR (2020-2023).

Aerosol and snow samples were analysed for main and trace ion markers, aiming to better constrain extent and timing of the main natural sources (sea salt, marine biogenic, mineral dust) and to detect the possible contribution of anthropic inputs (biomass burning, wildfires, local contamination). In addition, such a study might help in improving our knowledge of transport processes (free troposphere, stratosphere-troposphere exchange) and atmospheric reaction processes (such as neutralization, chemical fractionation).

A comparison with ozone measurements, carried out continuously over the same period, is also attempted, to better address the atmospheric processes involving the atmosphere-snow exchanges of N-cycle species and atmosphere oxidative properties.

How to cite: Traversi, R., Becagli, S., Caiazzo, L., Cristofanelli, P., Nardin, R., Putero, D., and Severi, M.: 15-yr long records of aerosol and surface snow chemical composition at Dome C (High Antarctic Plateau), EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5749, https://doi.org/10.5194/egusphere-egu23-5749, 2023.