Regions Of Greenland Research Articles

Glacier dynamic study of the Terre de Lambert glacier in Greenland based on Landsat 8 and Sentinel-1 data

With global temperatures on the rise, the trend of glacial melting is becoming increasingly evident. This study focuses on the northeastern region of Greenland as the research subject, utilizing remote sensing technology and geographic information technology to study glacial dynamics. Initially, the research processes Landsat 8 data using QGIS to classify the widespread snow and ice cover, facilitating the observation and analysis of its temporal variations. The study then narrows its focus to Terre de Lambert for further analysis. Subsequently, using satellite data from Sentinel-1 and employing SNAP, the research conducts an in-depth analysis of glacier flow speed in specific regions. Through intricate computational models and algorithms, precise glacier flow direction and speed maps are generated. By combining historical data, the study compares and analyzes the glacier flow speed between 2018 and from June 20th to July 14th, 2023. Results indicate that the glacier flow speed in 2023 during the same time frame was faster. Throughout the research process, limitations in current data acquisition and processing methods were identified. Thus, the paper suggests improvements to data acquisition and processing tools to enhance the efficiency of glacier flow speed studies. Theres a fervent hope for the emergence of more convenient, streamlined, and customizable temporal dimension tools for glacier flow speed data in the future. The research findings aim to draw global citizens attention to the issue of glacial melting and inspire collective actions to protect our planet.

Mapping high spatial resolution ionospheric total electron content by integrating Time Series InSAR with International Reference Ionosphere model

Total electron content (TEC) is a key parameter for characterizing the ionosphere. Conventional TEC measurement methods have low spatial resolution, hindering accurate representation of ionospheric spatial characteristics. Synthetic Aperture Radar (SAR) and Interferometric SAR (InSAR) have shown their potential for high-spatial-resolution TEC estimation. However, SAR-based absolute TEC estimation typically relies on full-polarimetric SAR images, while the InSAR-based method can only extract differential TEC. This study proposes a novel TEC mapping method integrating Time Series InSAR (TS-InSAR) with the International Reference Ionospheric (IRI) model and does not leverage full-polarimetric SAR data. The Advanced Land Observing Satellite-1 (ALOS-1) SAR images covering the Chile and Greenland regions were collected to test the proposed method. The TECs derived from the IRI model and International GNSS Service (IGS) and the electron density observed by the Incoherent Scattering Radar (ISR) site of SONDRESTROM were acquired to evaluate the performance and validate the accuracy of the proposed method, respectively. The results show that the proposed method can achieve TEC mapping with resolutions of tens of meters, much higher than the tens or hundreds of kilometers of the IRI and IGS TECs. The spatial features of our method-derived TECs show overall good consistency with those of the IRI and IGS TECs, but the described spatial information is more detailed. Also, compared to the original IRI model, the improvement rates of root-mean-square errors (RMSEs) between the estimated electron density and ISR observations exceeded 21.67% after the update using the TEC obtained from the proposed method. These experiments demonstrate the proposed method’s feasibility and reliability for ionospheric TEC mapping.

Sentinel-1 detection of ice slabs on the Greenland Ice Sheet

Abstract. Ice slabs are multi-meter-thick layers of refrozen ice that limit meltwater storage in firn, leading to enhanced surface runoff and ice sheet mass loss. To date, ice slabs have primarily been mapped using airborne ice-penetrating radar, which has limited spatial and temporal coverage. This makes it difficult to fully assess the current extent and continuity of ice slabs or to validate predictive models of ice slab evolution that are key to understanding their impact on Greenland's surface mass balance. Here, for the first time, we map the extent of ice slabs and superimposed ice facies across the entire Greenland Ice Sheet at 500 m resolution using dual-polarization Sentinel-1 (S-1) synthetic-aperture radar (SAR) data collected in winter 2016–2017. We do this by selecting empirical thresholds for the cross-polarized backscatter ratio and HV backscattered power that jointly optimize the agreement between airborne ice-penetrating radar data detections of ice slabs and the S-1 estimates of ice slab extent. Our results show that there is a strong correlation between C-band backscatter and the ice content of the upper ∼ 7 m of the firn column that enables ice slab mapping with S-1. Our new mapping shows that ice slabs are nearly continuous around the entire margin of the ice sheet. This includes regions in southwest Greenland where ice slabs have not been previously identified by ice-penetrating radar but where the S-1-inferred ice slab extent shows strong agreement with the extent of visible runoff mapped from optical imagery. The algorithm developed here lays the groundwork for the long-term monitoring of ice slab expansion with current and future C-band satellite systems and highlights the potential added value of future L-band missions for near-surface studies in Greenland.

Catchment-scale thawing and greening decreases long-term nitrogen export in NE Greenland

Climate change is expected to alter nitrogen (N) export from Arctic rivers, with potential implications for fragile coastal ecosystems and fisheries. Yet, the directionality of change is poorly understood, as increased mobilization of N in a ‘thawing’ Arctic is countered by higher rates of vegetative uptake in a ‘greening’ Arctic, particularly in the understudied region of Greenland. We use an unprecedented dataset of long-term (n = 18 years) river chemistry, streamflow, and catchment-scale changes in snow and vegetation to document changing riverine N loss in Greenland. We documented decreasing inorganic and organic N loads, linked to decreasing snow stores, warming soils, and enhanced plant uptake. Higher variability in N export across years also points to the increasing role of high flow events in driving downstream N loss. This alteration in N cycling may significantly reduce both inorganic and organic N transport across the terrestrial-aquatic boundary during the open water season in a rapidly warming Greenland.

Atmospheric teleconnections between the Arctic and the Baltic Sea region as simulated by CESM1-LE

Abstract. This paper examines teleconnections between the Arctic and the Baltic Sea region and is based on two cases of Community Earth System Model version 1 large ensemble (CESM-LE) climate model simulations: the stationary case with pre-industrial radiative forcing and the climate change case with RCP8.5 radiative forcing. The stationary control simulation's 1800-year long time series were used for stationary teleconnection and a 40-member ensemble from the period 1920–2100 is used for teleconnections during ongoing climate change. We analyzed seasonal temperature at a 2 m level, sea-level pressure, sea ice concentration, precipitation, geopotential height, and 10 m level wind speed. The Arctic was divided into seven areas. The Baltic Sea region climate has strong teleconnections with the Arctic climate; the strongest connections are with Svalbard and Greenland region. There is high seasonality in the teleconnections, with the strongest correlations in winter and the lowest correlations in summer, when the local meteorological factors are stronger. North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) climate indices can explain most teleconnections in winter and spring. During ongoing climate change, the teleconnection patterns did not show remarkable changes by the end of the 21st century. Minor pattern changes are between the Baltic Sea region temperature and the sea ice concentration. We calculated the correlation between the parameter and its ridge regression estimation to estimate different Arctic regions' collective statistical connections with the Baltic Sea region. The seasonal coefficient of determination, R2, was highest for winter: for T2 m, R2=0.64; for sea level pressure (SLP), R2=0.44; and for precipitation (PREC), R2=0.35. When doing the same for the seasons' previous month values in the Arctic, the relations are considerably weaker, with the highest R2=0.09 being for temperature in the spring. Hence, Arctic climate data forecasting capacity for the Baltic Sea region is weak. Although there are statistically significant teleconnections between the Arctic and Baltic Sea region, the Arctic impacts are regional and mostly connected with climate indexes. There are no simple cause-and-effect pathways. By the end of the 21st century, the Arctic ice concentration has significantly decreased. Still, the general teleconnection patterns between the Arctic and the Baltic Sea region will not change considerably by the end of the 21st century.

Spatial controls of methane uptake in upland soils across climatic and geological regions in Greenland

In the Arctic, the spatiotemporal variation of net methane uptake in upland soils depends on unresolved interactive controls between edaphic and microbial factors not yet included in current models, underpinning the uncertainty of upscaling the Arctic methane budget. Here we show that upland soils in Greenland are consistent methane sinks (−1.83 ± 0.19 nmol methane g−1 dw d−1) across a N-S (64–83 °N) pedoclimatic transect. We demonstrate that methane oxidizers abundance, soil pH, and available soil copper are important controls on the spatial variation in methane oxidation. We revised a soil biogeochemical model with a high-resolution land classification and meteorological data for Greenland and tested it against our methane uptake measurements. The model simulated well the magnitudes of observed methane uptake but not the spatial variation across all sites. This work provides novel insights into the controls of methane uptake, which are critical for the accuracy of methane budgets.

Observed and modeled moulin heads in the Pâkitsoq region of Greenland suggest subglacial channel network effects

Abstract. In the ablation zone of land-terminating areas of the Greenland Ice Sheet, water pressures at the bed control seasonal and daily ice motion variability. During the melt season, large amounts of surface meltwater access the bed through moulins, which sustain an efficient channelized subglacial system. Water pressure within these subglacial channels can be inferred by measuring the hydraulic head within moulins. However, moulin head data are rare, and subglacial hydrology models that simulate water pressure fluctuations require water storage in moulins or subglacial channels. Neither the volume nor the location of such water storage is currently well constrained. Here, we use the Moulin Shape (MouSh) model, which quantifies time-evolving englacial storage, coupled with a subglacial channel model to simulate head measurements from a small moulin in Pâkitosq, western Greenland. We force the model with surface meltwater input calculated using field-acquired weather data. Our first-order simulations of moulin hydraulic head either overpredict the diurnal range of oscillation of the moulin head or require an unrealistically large moulin size to reproduce observed head oscillation ranges. We find that to accurately match field observations of moulin head, additional subglacial water must be added to the system. This subglacial baseflow is likely sourced from basal melt and nonlocal surface water inputs upstream. We hypothesize that the additional baseflow represents strong subglacial network connectivity throughout the channelized system and is consistent with our small moulin likely connecting to a higher-order subglacial channel.

Spatial Variability in the Primary Production Rates and Biomasses (Chl a) of Sea Ice Algae in the Canadian Arctic–Greenland Region: A Review

The aims of this review are to elucidate the spatial variation in the primary production rates and biomasses (Chl a) of sea ice algae in the Canadian Arctic–Greenland region, characterized by its comparable physical settings. A database was compiled from 30 studies of the production rates and biomasses (Chl a) of sea ice algae, the snow and ice thicknesses, ice types, nutrients (Si(OH)4, PO4, (NO3 + NO2)), and NH4 concentrations in the ice and below the ice from the region. Production rates were significantly higher (463 mg C m−2 d−1) in Resolute Bay and Northern Baffin Bay (317 mg C m−2 d−1), both in the Canadian Arctic, compared to a rate of 0.2 mg C m−2 d−1 in northeast Greenland. The biomasses reached 340 mg Chl a m−2 in Resolute Bay in comparison to 0.02 mg Chl a m−2 in southwest Greenland. Primary production at other Canadian and Greenland sites was comparable, but sea ice Chl a was higher (15.0 ± 13.4 mg Chl a m−2) at Canadian sites compared to Greenland ones (0.8 ± 0.5 mg Chl a m−2). Resolute and Northern Baffin Bay production rates were significantly higher when compared to other Arctic Ocean sites outside the studied region. The review concludes that the high production rates and biomasses in Resolute and Northern Baffin Bay are related to the inflow and mixing of nutrient-rich waters of Pacific origin. A conceptual model with drivers and inhibitors of the primary production of sea ice algae is proposed, and the database is compiled into a dataset of published data for further studies.

A new model for supraglacial hydrology evolution and drainage for the Greenland Ice Sheet (SHED v1.0)

Abstract. The Greenland Ice Sheet (GrIS) is losing mass as the climate warms through both increased meltwater runoff and ice discharge at marine-terminating sectors. At the ice sheet surface, meltwater runoff forms a dynamic supraglacial hydrological system which includes stream and river networks and large supraglacial lakes (SGLs). Streams and rivers can route water into crevasses or into supraglacial lakes with crevasses underneath, both of which can then hydrofracture to the ice sheet base, providing a mechanism for the surface meltwater to access the bed. Understanding where, when, and how much meltwater is transferred to the bed is important because variability in meltwater supply to the bed can increase ice flow speeds, potentially impacting the hypsometry of the ice sheet in grounded sectors, and iceberg discharge to the ocean. Here we present a new, physically based, supraglacial hydrology model for the GrIS that is able to simulate (a) surface meltwater routing and SGL filling; (b) rapid meltwater drainage to the ice sheet bed via the hydrofracture of surface crevasses both in and outside of SGLs; (c) slow SGL drainage via overflow in supraglacial meltwater channels; and, by offline coupling with a second model, (d) the freezing and unfreezing of SGLs from autumn to spring. We call the model the Supraglacial Hydrology Evolution and Drainage (or SHED) model. We apply the model to three study regions in southwest Greenland between 2015 and 2019 (inclusive) and evaluate its performance with respect to observed supraglacial lake extents and proglacial discharge measurements. We show that the model reproduces 80 % of observed lake locations and provides good agreement with observations in terms of the temporal evolution of lake extent. Modelled moulin density values are in keeping with those previously published, and seasonal and inter-annual variability in proglacial discharge agrees well with that which is observed, though the observations lag the model by a few days since they include transit time through the subglacial system, while the model does not. Our simulations suggest that lake drainage behaviours may be more complex than traditional models suggest, with lakes in our model draining through a combination of both overflow and hydrofracture and with some lakes draining only partially and then refreezing. This suggests that, in order to simulate the evolution of Greenland's surface hydrological system with fidelity, a model that includes all of these processes needs to be used. In future work, we will couple our model to a subglacial model and an ice flow model and thus use our estimates of where, when, and how much meltwater gets to the bed to understand the consequences for ice flow.

An ethnographic framework for identifying dog sledding in the archaeological record

For at least 9000 years dogs have been pulling sleds across the Arctic, facilitating subsistence strategies and migrations. Despite the enduring presence of dogs in the Arctic there is an absence of comprehensive studies of the material culture associate with dog sledding, including the diverse technical elements needed for the activity. This study proposes a framework for the recognition of reliable archaeological indicators of dog sledding. The outcome is based on comparisons between ethnographic information of the dog traction technology and archaeological sites from the Arctic regions of Siberia, Alaska, Canada, and Greenland using multivariate analysis. These sites were selected as case studies to encompass the breadth of geographical and Inuit cultural diversity where dog sledding traditionally has been practiced. We argue, that by using this framework it is possible to study dog sledding in the Arctic prior to the Thule Inuit period and gain more knowledge about the origin of the practice. By combining sources from ethnography, history and archaeology, our framework identified items involved in dog sledding that were universal to the practice as well as items that were regionally specific. However, the most reliable evidence for dog sledding is the presence of both sled parts, dog bones and equipment for harnessing the dogs.

Unraveling spatiotemporal patterns and multiple driving factors of surface ozone across China and its urban agglomerations management strategies

Since State Council launched the Action Plan for Air Pollution Prevention and Control in 2013, national concentration of fine particulate matter (PM2.5) has continued to decline in China, while surface ozone (O3) pollution shows an obvious rise. To identity hot regions and develop targeted policy, the spatiotemporal O3 variation and its population-weighted exposure features were analyzed in 337 cities across China, using autocorrelation analysis and grid exposure calculation. In the identified hot urban agglomerations, the correlation analysis and geographic weighted regression model (GWR) were used to study related meteorological factors and socioeconomic driving factors. O3 pollution and its human exposure were found to have significant spatial aggregation characteristics, showing a need for regional management policy. Beijing-Tianjin-Hebei Urban Agglomeration (BTH-UA), Central Plains Urban Agglomeration (CP-UA), and Yangtze River Delta Urban Agglomeration (YRD-UA) were identified as hot regions where O3 concentration exceeded 160 μg·m−3, exceedance rate was over 20% and population-weighted exposure risk was relatively high. Correlation analysis in the hot regions indicated high surface temperature, low relative humidity, and low wind speed were positive to O3 increase. Further, GWR results revealed that O3 in the majority of cities was positively related with population density (PD), the per capita GDP (Per_GDP), industrial soot emissions (ISE), industrial SO2 emissions (ISO2), and average annual concentration of inhaled fine particulate matter (PM10), and negatively related with total land area of administrative region (Administration) and area of green land (Green). From the regional driving factor difference, the targeted UA management policy was provided.

Greenland Subglacial Discharge as a Driver of Hotspots of Increasing Coastal Chlorophyll Since the Early 2000s

AbstractSubglacial discharge emerging from the base of Greenland's marine‐terminating glaciers drives upwelling of nutrient‐rich bottom waters to the euphotic zone, which can fuel nitrate‐limited phytoplankton growth. Here, we use buoyant plume theory to quantify this subglacial discharge‐driven nutrient supply on a pan‐Greenland scale. The modeled nitrate fluxes were concentrated in a few critical systems, with half of the total modeled nitrate flux anomaly occurring at just 14% of marine‐terminating glaciers. Increasing subglacial discharge fluxes results in elevated nitrate fluxes, with the largest flux occurring at Jakobshavn Isbræ in Disko Bay, where subglacial discharge is largest. Subglacial discharge and nitrate flux anomaly also account for significant temporal variability in summer satellite chlorophyll a (Chl) within 50 km of Greenland's coast, particularly in some regions in central west and northwest Greenland.

Measurement report: High Arctic aerosol hygroscopicity at sub- and supersaturated conditions during spring and summer

Abstract. Aerosol hygroscopic growth and cloud droplet formation influence the radiation transfer budget of the atmosphere and thereby the climate. In the Arctic, these aerosol properties may have a more pronounced effect on the climate compared to the midlatitudes. Hygroscopic growth and cloud condensation nuclei (CCN) concentrations of high Arctic aerosols were measured during two field studies in the spring and summer of 2016. The study site was the Villum Research Station (Villum) at Station Nord in the northeastern region of Greenland. Aerosol hygroscopic growth was measured with a hygroscopic tandem differential mobility analyzer (HTDMA) over a total of 23 d, and CCN concentrations were measured over a period of 95 d. Continuous particle number size distributions were recorded, facilitating calculations of aerosol CCN activation diameters and aerosol κ values. In spring, average CCN concentrations, at supersaturations (SSs) of 0.1 % to 0.3 %, ranged from 53.7 to 85.3 cm−3, with critical activation diameters ranging from 130.2 to 80.2 nm and κCCN ranging from 0.28–0.35. In summer, average CCN concentrations were 20.8 to 47.6 cm−3, while critical activation diameters and κCCN were from 137.1 to 76.7 nm and 0.23–0.35, respectively. Mean particle hygroscopic growth factors ranged from 1.60 to 1.75 at 90 % relative humidity in spring, while values between 1.47 and 1.67 were observed in summer depending on the initial dry size. Although the summer aerosol number size distributions were characterized by frequent new particle formation events, the CCN population at cloud-relevant supersaturations was determined by accumulation-mode aerosols.

Ice-nucleating particles in northern Greenland: annual cycles, biological contribution and parameterizations

Abstract. Ice-nucleating particles (INPs) can initiate ice formation in clouds at temperatures above −38 ∘C through heterogeneous ice nucleation. As a result, INPs affect cloud microphysical and radiative properties, cloud lifetime, and precipitation behavior and thereby ultimately the Earth's climate. Yet, little is known regarding the sources, abundance and properties of INPs, especially in remote regions such as the Arctic. In this study, 2-year-long INP measurements (from July 2018 to September 2020) at Villum Research Station in northern Greenland are presented. A low-volume filter sampler was deployed to collect filter samples for offline INP analysis. An annual cycle of INP concentration (NINP) was observed, and the fraction of heat-labile INPs was found to be higher in months with low to no snow cover and lower in months when the surface was well covered in snow (> 0.8 m). Samples were categorized into three different types based only on the slope of their INP spectra, namely into summer, winter and mix type. For each of the types a temperature-dependent INP parameterization was derived, clearly different depending on the time of the year. Winter and summer types occurred only during their respective seasons and were seen 60 % of the time. The mixed type occurred in the remaining 40 % of the time throughout the year. April, May and November were found to be transition months. A case study comparing April 2019 and April 2020 was performed. The month of April was selected because a significant difference in NINP was observed during these two periods, with clearly higher NINP in April 2020. In parallel to the observed differences in NINP, also a higher cloud-ice fraction was observed in satellite data for April 2020, compared to April 2019. NINP in the case study period revealed no clear dependency on either meteorological parameters or different surface types which were passed by the collected air masses. Overall, the results suggest that the coastal regions of Greenland were the main sources of INPs in April 2019 and 2020, most likely including both local terrestrial and marine sources.

Monthly variation and correlation analysis of global temperature and wind resources under climate change

Renewable energy is widely used as an alternative source of energy, and climate change has a significant impact on its variation and harnessing. This study conducted a monthly scale analysis of global temperature and wind-speed variations and their correlations using Theil–Sen’s median linear regression and Mann-Kendall test from 1989 to 2021. The results revealed that the global temperature averagely increased by 0.34 °C/10 a from 1989 to 2021, showing clearly increasing trends in most months but with significant differentiation in each month. The regions of East Europe Plain, Central Siberia, Central Asia, and Greenland showed the most significant increasing temperature trends ranging from 0.17 to 0.49 °C/10 a. Additionally, the regions in the East Europe Plain, Siberia, and North America showed distinctly decreasing temperature trends ranging from 0.27 to 0.51 °C/10 a. The global average wind speed changed slightly, with slopes of −0.026, −0.014, and 0.019 m/(s⋅10 a) for eastward, northward, and synthesis wind, respectively. However, the decreasing trends were relatively evident in regions across central Europe via the south of the Eastern European Plain to the north of Central Asia with slopes ranging from −0.13 to −0.3 m/(s⋅10 a). These monthly variations in eastward, northward, and synthesis wind speeds showed significant correlations with temperature, and the correlation coefficients (CCs) differed significantly for each month. For positive CCs higher than 0.34 and negative CCs lower than −0.35 (p < 0.05), the land coverage areas reached 72.3 million km2, accounting for 48% of the global land area. In addition, the synthesis wind speed showed significant positive and negative CCs with temperature, especially from November to March of the following year. The highly positive CCs of global temperature and synthesis wind speed are primarily distributed across land areas from Europe to Siberia, North America, and North Africa in the Northern Hemisphere. The areas with high negative CCs are distributed across South America, South Africa, and Australia in the Southern Hemisphere. Climate change has a substantial impact on wind-speed variation, which should be considered during wind source harnessing. Monthly variation analysis of global temperature and wind speed and their correlation could provide key scientific support for climate change adaptation and wind resource harnessing.

Monitoring Seasonal Fluctuation and Long‐Term Trends for the Greenland Ice Sheet Using Seismic Noise Auto‐Correlations

AbstractOne important feature of the Greenland Ice Sheet (GrIS) change is its strong seasonal fluctuation. Taking advantage of deployed seismographic stations in Greenland, we apply cross‐component auto‐correlation of seismic ambient noise to measure in‐situ near surface relative velocity change (dv/v) in different regions of Greenland. Our results demonstrate that dv/v measurements for most stations have less than 3 months lag times in comparison to the surface mass change. These various lag times may provide us constraints for the thickness of the subglacial till layer over different regions in Greenland. Moreover, in southwest Greenland, we observe a change in the long‐term trend of dv/v for three stations, which might be consistent with the mass change rate (dM/dt) due to the “2012–2013 warm‐cold transition.” These observations suggest that seismic noise auto‐correlation technique may be used to monitor both seasonal and long‐term changes of the GrIS.

Classification of Arctic Sea Ice Type in CFOSAT Scatterometer Measurements Using a Random Forest Classifier

The Ku-band scatterometer called CSCAT onboard the Chinese–French Oceanography Satellite (CFOSAT) is the first spaceborne rotating fan-beam scatterometer (RFSCAT). A new algorithm for classification of Arctic sea ice types on CSCAT measurement data using a random forest classifier is presented. The random forest classifier is trained on the National Snow and Ice Data Center (NSIDC) weekly sea ice age and sea ice concentration product. Five feature parameters, including the mean value of horizontal and vertical polarization backscatter coefficient, the standard deviation of horizontal and vertical polarization backscatter coefficient and the copol ratio, are innovatively extracted from orbital measurement for the first time to distinguish water, first-year ice (FYI) and multi-year ice (MYI). The overall accuracy and kappa coefficient of sea ice type model are 93.35% and 88.53%, respectively, and the precisions of water, FYI, and MYI are 99.67%, 86.60%, and 79.74%, respectively. Multi-source datasets, including daily sea ice type from the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF), NSIDC weekly sea ice age, multi-year ice concentration (MYIC) provided by the University of Bremen, and SAR-based sea ice type released by Copernicus Marine Environment Monitoring Service (CMEMS) have been used for comparison and validation. It is shown that the most obvious difference in the distribution of sea ice types between the CSCAT results and OSI SAF sea ice type are mainly concentrated in the marginal zones of FYI and MYI. Furthermore, compared with OSI SAF sea ice type, the area of MYI derived from CSCAT is more homogeneous with less noise, especially in the case of younger multiyear ice. In the East Greenland region, CSCAT identifies more pixels as MYI with lower MYIC values, showing better accuracy in the identification of areas with obvious mobility of MYI. In conclusion, this research verifies the capability of CSCAT in monitoring Arctic sea ice classification, especially in the spatial homogeneity and detectable duration of sea ice classification. Given the high accuracy and processing speed, the random forest-based algorithm can offer good guidance for sea ice classification with FY-3E/RFSCAT, i.e., a dual-frequency (Ku and C band) scatterometer called WindRAD.

Influence of glacier type on bloom phenology in two Southwest Greenland fjords

Along Greenland's coastline, the magnitude and timing of primary production in fjords is influenced by meltwater release from marine-terminating glaciers. How local ecosystems will adapt as these glaciers retreat onto land, forcing fundamental changes in hydrography, remains an open question. To further our understanding of this transition, we examine how marine- and land-terminating glaciers respectively influence fjord bloom phenology. Between spring and autumn 2019, we conducted along-fjord transects of hydrographic variables, biogeochemical properties and pico- and nanophytoplankton counts to illustrate the contrasting seasonal bloom dynamics in the fjords Nuup Kangerlua and Ameralik. These fjords are in the same climatic region of west Greenland but influenced by different glacial structures. Nuup Kangerlua, a predominantly marine-terminating system, was differentiated by its sustained second summer bloom and high Chl a fluorescence in summer and autumn. In Ameralik, influenced by a land-terminating glacier, we found higher abundances of pico- and nanophytoplankton, and high cyanobacteria growth in autumn. The summer bloom in Nuup Kangerlua is known to be coincident with subglacial freshwater discharge sustaining renewed nutrient supply to the fjord. We observe here that the intermediate baroclinic circulation, which creates an inflow at subsurface depths, also plays an important role in increasing nutrient availability at shallower depths and potentially explains the distribution of primary producers. Our observations suggest that the retreat of marine-terminating glaciers onto land, with consequent increases in surface water temperature and stratification, and reduced light availability, may alter the magnitude, composition, and distribution of summer productivity.

The Prevalence of Inflammatory Bowel Disease in Greenland.

Inflammatory bowel disease (IBD) is sparsely investigated in Arctic populations. The aim of this study was to estimate the prevalence of ulcerative colitis (UC) and Crohn's disease (CD) in Greenland. Cross-sectional nationwide data on demography, anthropometry, biochemistry, and pharmacotherapy were extracted from the electronic medical records in Greenland. Diagnoses of UC and CD were based on International Classification of Diseases-Tenth Revision and International Classification of Primary Care-Second Edition coding and treatment with mesalazine. Data from Statistics Greenland were used for prevalence calculations. In total, 254 patients in Greenland experienced IBD, with 214 cases of UC and 40 cases of CD. The overall IBD prevalence was 0.45%, distributed as 0.38% with UC and 0.07% with CD. The IBD prevalence was similar across the 5 regions of Greenland. However, a higher prevalence was observed in the region main towns with the largest populations (0.53%) compared with the small towns along the coastline (0.29%). UC patients were prescribed mesalazine treatment with a frequency of 78%. Furthermore, 10% of all IBD patients received treatment with nonspecific immunomodulators and 7% received biologics. This study estimates the prevalence and uncovers characteristics of IBD in Greenland. Although CD may be underdiagnosed or less prevalent, the overall prevalence of IBD in Greenland parallels Scandinavian countries and North America. These results boost the knowledge on autoimmune diseases in arctic populations and may guide clinicians in their management of IBD in Greenland. Furthermore, the results may encourage research in IBD across the Arctic regions.

The Effect of Species and Sex on the Element Content of Muskox (Ovibos moschatus) and Caribou (Rangifer tarandus groenlandicus) Tissues

Muskox (Ovibos moschatus) and caribou (Rangifer tarandus groenlandicus) are wild ruminants that inhabit the Greenland tundra. They are part of the diet of many Greenlanders, being important sources of protein and micronutrients such as iron. The objective of this study is to analyse the element profiles of three tissues from these species: skeletal muscle, liver and adipose tissue, and to determine if they are affected by species and sex (male vs. female). Samples were obtained from annual hunts in two different regions of West Greenland. Element profiles were analysed using inductively-coupled plasma–optical emission spectrometry. The interaction between species and sex was only detected in Na (sodium) in the muscle and adipose tissue, where male and female caribou had the highest concentrations, respectively. The effect of sex was not statistically significant in the liver samples and only occasionally in the other tissues. Species was the most relevant factor in element profiles found in this study. Caribou had higher concentrations of K (potassium) and S (sulphur) in the muscle and liver. Fewer differences were detected between species in the adipose tissue, compared to the other tissues. These differences may reflect the feeding behaviour and the geographical location of both species. This study contributes to evaluate the element composition of the edible tissue of these wild ungulate species, as well as evaluating the factors of sex and species that could differentiate their composition.