The urgent ongoing contemporary climate change is drastically changing the Earth as we know it. In the Arctic, the climate is changing more drastically than the global average, and temperatures are rising significantly more. The phenomenon, known as Arctic amplification, is believed to happen by a combination of albedo reduction, cloud-feedback, and temperature inversion. Another important, but often overlooked, factor in Arctic climate change is dust. Dust does not only cause albedo reduction but has also been found to host syngenetic permafrost in Adventdalen, Svalbard. As permafrost is both a sensitive and important carbon reserve, holding twice as much carbon as currently available in the atmosphere, it is of great importance to understand the carbon storage mechanism of it. This study shows not only a correlation between cryostructures and organic carbon content but presents aeolian sedimentation rate as a possible cause of it. The results show that for syngenetic permafrost in Adventdalen, a high sedimentation rate yields structureless permafrost with low organic content. Inversely, a low sedimentation rate yields well defined cryostructures with high organic content. This shows that aeolian dust activity and loess deposits are vital to understand, in order to properly assess the cryostratigraphy and carbon content. / Den brådskande samtida klimatförändringen omarbetar dramatiskt vår värld. Arktis klimat förändras mer drastiskt än på resten av jorden och temperaturen stiger avsevärt snabbare. Fenomenet kallas förArktis förstärkning, eller Arctic Amplification, och antas ske på grund av synergier mellan minskning av albedo, molnfeedback och temperaturinversion. Damm är en annan viktig, men ofta underskattad faktor i klimatförändrarna i Arktis. Damm bidrar inte bara till en ökad reduktion av albedo utan dammavlagringar i Adventdalen Svalbard fungerar som en viktig grogrund för syngenetisk permafrost. Kolsänkan i permafrost är lika skör som den är viktig, då permafrost förvarar dubbelt så mycket kol som för nuvarande finns i atmosfären, men samtidigt stadigt tinar. Därför är det ytterst viktigt att förstå hur permafrost fungerar, själva mekanismerna bakom förvarandet av organisk kol. Detta arbete visar inte bara ett samband mellan kryostrukturer och organiskt kol i permafrost, utan föreslår att sedimentationshastighet är orsaken till det. Resultaten av LOI (loss on ignition) och kryostratigrafi tyder på att en hög sedimentationshastighet skapar en strukturlös permafrost som endast har låga halter av organisk materia. I det omvända fallet ger en låg sedimentationshastighet välformade kryostrukturer, och en permafrost med hög andel organisk materia. Detta visar på att sedimentationshastighet i loess är en viktig aspekt för att bedöma lagring av kol i permafrost, vilket är en avsevärd kolsänka att förstå i dagens klimatförändringar.

<p>Three different studies have been made; an analysis of the general weather situation at three weather stations in Svalbard, close to the main settlement Longyearbyen; an instrumental comparison between three weather stations operating at nearly the same place during a few days in October 2006; and a case study of a weather station at the mountain Breinosa compared to the station in the valley beneath.</p><p>The analysis of the general weather at the three stations, Adventdalen (data used from 2004-2006), Svalbard Airport (data used from 1994-2004) and Gruvefjellet (data used from 2002-2005) showed that it is clear that the local surroundings do contribute to a more locally produced weather. The mean wind speed in Adventdalen was shown to be 5.1 m/s and the wind direction was mostly from inland towards the coast. Channelling effects dominates the winds in the valley, resulting in high wind speeds. The channelled winds from Adventdalen often reach Svalbard Airport (average wind speed 4.8 m/s). At the Airport there is also a contribution of winds (mostly in summer) originating from the sea, e.g. sea breeze. In times when the weather at Svalbard Airport was more continental, Adventfjorden and Isfjorden were likely to be covered by ice. The higher location of Gruvefjellet most often contributes to low temperatures and an average wind speed of 3.9 m/s. However, the temperature at Adventdalen and the Airport are often colder than at Gruvefjellet due to the frequency of temperature inversions.</p><p>The instrumental comparison concerned three stations in Adventdalen. Data from the stationary weather station was compared with data from two temporarily stations during 4-7th October 2006. It is apparent that the stationary station needs calibration, at least when looking at the pressure measurements, where there clearly is an offset in the data.</p><p>The third study was a case study concerned data from a station at the mountain Breinosa and Adventdalen. A new weather station will be put up during 2007 and data (16th December 2005 until 12th January 2006) from a temporarily station was used when determining the differences from the station down in the valley (Adventdalen). The wind speed is often just as high in the valley as at Breinosa due to channelling effects. The temperature in Adventdalen seems to be affected by the temperature at Breinosa. The air is chilled and sinks down to be channelled through the valley. There are some occasions when the temperature at the mountain is higher than beneath. During those events the wind speed is low and a temperature inversion develops at the ground.</p> / <p>Tre olika studier genomförts; en analysering av data från tre väderstationer på Svalbard;en instrumentell jämförelse mellan tre väderstationer på Svalbard nära huvudorten Longyearbyen; en fallstudie av data från en väderstation på berget Breinosa jämfört med situationen i Adventdalen nedanför.</p><p>Undersökningen av generella vädersituationen vid de tre stationerna, Adventdalen (data från 2004-2006), Svalbard Flygplats (data från 1994-2004) och Gruvefjellet (data från 2002-2005) visade tydligt att den lokala omgivningen bidrar mycket till hur vädret formas. Medelvindhastigheten i Adventdalen var 5,1 m/s och vindriktningen mestadels längs dalen ut mot fjorden. Kanaliseringseffekter dominerar vindarna i dalen och bidrar till de höga vindhastigheterna. Kanaliserade vindar från Adventdalen når ofta Svalbard Flygplats (medel vindhastighet 4,8 m/s). Vid Flygplatsen finns också ett visst bidrag från vindar utifrån havet (mestadels under sommaren), d.v.s. sjöbris. I situationer då vädret vid flygplatsen varit mer kontinentalt så har Adventfjorden mest troligt varit täckt av is.</p><p>Gruvefjellets höga placering bidrar till låga temperaturer och en medelvindhastighet på 3.9 m/s. Dock är temperaturen är ofta lägre i Adventdalen och vid Flygplatsen på grund av att det ofta förekommer temperaturinversioner i marknivå.</p><p>Den instrumentella jämförelsen berörde tre stationer i Adventdalen. Data från den stationära stationen jämfördes under 4-7 oktober 2006 med data från två temporära stationer. Det är tydligt att den stationära stationen är i behov av kalibrering. I alla fall är det uppenbart vid studien av lufttrycket som tydligt är förskjutet och visar ett lägre tryck.</p><p>Tredje studien var en fallstudie och data undersöktes från berget Breinosa och Adventdalen. En ny väderstation kommer att monteras på Breinosa under 2007 och data (16 december 2005 till 12 januari 2006) från en temporär station användes i studien. Vindhastigheten är ofta lika hög i dalen som på berget på grund av kanaliseringseffekter. Temperaturen i dalen förefaller vara påverkad av temperatursituationen på berget. Avkyld luft sjunker och kanaliseras ner i dalen. Det finns några tillfällen då temperaturen på berget Breinosa är högre än nere i dalen. Under de situationerna avtar vindhastigheten och en temperaturinversion bildas i marknivå.</p>

Three different studies have been made; an analysis of the general weather situation at three weather stations in Svalbard, close to the main settlement Longyearbyen; an instrumental comparison between three weather stations operating at nearly the same place during a few days in October 2006; and a case study of a weather station at the mountain Breinosa compared to the station in the valley beneath. The analysis of the general weather at the three stations, Adventdalen (data used from 2004-2006), Svalbard Airport (data used from 1994-2004) and Gruvefjellet (data used from 2002-2005) showed that it is clear that the local surroundings do contribute to a more locally produced weather. The mean wind speed in Adventdalen was shown to be 5.1 m/s and the wind direction was mostly from inland towards the coast. Channelling effects dominates the winds in the valley, resulting in high wind speeds. The channelled winds from Adventdalen often reach Svalbard Airport (average wind speed 4.8 m/s). At the Airport there is also a contribution of winds (mostly in summer) originating from the sea, e.g. sea breeze. In times when the weather at Svalbard Airport was more continental, Adventfjorden and Isfjorden were likely to be covered by ice. The higher location of Gruvefjellet most often contributes to low temperatures and an average wind speed of 3.9 m/s. However, the temperature at Adventdalen and the Airport are often colder than at Gruvefjellet due to the frequency of temperature inversions. The instrumental comparison concerned three stations in Adventdalen. Data from the stationary weather station was compared with data from two temporarily stations during 4-7th October 2006. It is apparent that the stationary station needs calibration, at least when looking at the pressure measurements, where there clearly is an offset in the data. The third study was a case study concerned data from a station at the mountain Breinosa and Adventdalen. A new weather station will be put up during 2007 and data (16th December 2005 until 12th January 2006) from a temporarily station was used when determining the differences from the station down in the valley (Adventdalen). The wind speed is often just as high in the valley as at Breinosa due to channelling effects. The temperature in Adventdalen seems to be affected by the temperature at Breinosa. The air is chilled and sinks down to be channelled through the valley. There are some occasions when the temperature at the mountain is higher than beneath. During those events the wind speed is low and a temperature inversion develops at the ground. / Tre olika studier genomförts; en analysering av data från tre väderstationer på Svalbard;en instrumentell jämförelse mellan tre väderstationer på Svalbard nära huvudorten Longyearbyen; en fallstudie av data från en väderstation på berget Breinosa jämfört med situationen i Adventdalen nedanför. Undersökningen av generella vädersituationen vid de tre stationerna, Adventdalen (data från 2004-2006), Svalbard Flygplats (data från 1994-2004) och Gruvefjellet (data från 2002-2005) visade tydligt att den lokala omgivningen bidrar mycket till hur vädret formas. Medelvindhastigheten i Adventdalen var 5,1 m/s och vindriktningen mestadels längs dalen ut mot fjorden. Kanaliseringseffekter dominerar vindarna i dalen och bidrar till de höga vindhastigheterna. Kanaliserade vindar från Adventdalen når ofta Svalbard Flygplats (medel vindhastighet 4,8 m/s). Vid Flygplatsen finns också ett visst bidrag från vindar utifrån havet (mestadels under sommaren), d.v.s. sjöbris. I situationer då vädret vid flygplatsen varit mer kontinentalt så har Adventfjorden mest troligt varit täckt av is. Gruvefjellets höga placering bidrar till låga temperaturer och en medelvindhastighet på 3.9 m/s. Dock är temperaturen är ofta lägre i Adventdalen och vid Flygplatsen på grund av att det ofta förekommer temperaturinversioner i marknivå. Den instrumentella jämförelsen berörde tre stationer i Adventdalen. Data från den stationära stationen jämfördes under 4-7 oktober 2006 med data från två temporära stationer. Det är tydligt att den stationära stationen är i behov av kalibrering. I alla fall är det uppenbart vid studien av lufttrycket som tydligt är förskjutet och visar ett lägre tryck. Tredje studien var en fallstudie och data undersöktes från berget Breinosa och Adventdalen. En ny väderstation kommer att monteras på Breinosa under 2007 och data (16 december 2005 till 12 januari 2006) från en temporär station användes i studien. Vindhastigheten är ofta lika hög i dalen som på berget på grund av kanaliseringseffekter. Temperaturen i dalen förefaller vara påverkad av temperatursituationen på berget. Avkyld luft sjunker och kanaliseras ner i dalen. Det finns några tillfällen då temperaturen på berget Breinosa är högre än nere i dalen. Under de situationerna avtar vindhastigheten och en temperaturinversion bildas i marknivå.

The sinking of dense shelf waters down the continental slope (or “cascading”) contributes to oceanic water mass formation and carbon cycling. Cascading is therefore of significant importance for the global overturning circulation and thus climate. The occurrence of cascades is highly intermittent in space and time and observations of the process itself (rather than its outcomes) are scarce. Global climate models do not typically resolve cascading owing to numerical challenges concerning turbulence, mixing and faithful representation of bottom boundary layer dynamics. This work was motivated by the need to improve the representation of cascading in numerical ocean circulation models. Typical 3-D hydrostatic ocean circulation models are employed in a series of numerical experiments to investigate the process of dense water cascading in both idealised and realistic model setups. Cascading on steep bottom topography is modelled using POLCOMS, a 3-D ocean circulation model using a terrain-following s-coordinate system. The model setup is based on a laboratory experiment of a continuous dense water flow from a central source on a conical slope in a rotating tank. The descent of the dense flow as characterised by the length of the plume as a function of time is studied for a range of parameters, such as density difference, speed of rotation, flow rate and (in the model) diffusivity and viscosity. Very good agreement between the model and the laboratory results is shown in dimensional and non-dimensional variables. It is confirmed that a hydrostatic model is capable of reproducing the essential physics of cascading on a very steep slope if the model correctly resolves velocity veering in the bottom boundary layer. Experiments changing the height of the bottom Ekman layer (by changing viscosity) and modifying the plume from a 2-layer system to a stratified regime (by enhancing diapycnal diffusion) confirm previous theories, demonstrate their limitations and offer new insights into the dynamics of cascading outside of the controlled laboratory conditions. In further numerical experiments, the idealised geometry of the conical slope is retained but up-scaled to oceanic dimensions. The NEMO-SHELF model is used to study the fate of a dense water plume of similar properties to the overflow of brine-enriched shelf waters from the Storfjorden in Svalbard. The overflow plume, resulting from sea ice formation in the Storfjorden polynya, cascades into the ambient stratification resembling the predominant water masses of Fram Strait. At intermediate depths between 200-500m the plume encounters a layer of warm, saline AtlanticWater. In some years the plume ‘pierces’ the Atlantic Layer and sinks into the deep Fram Strait while in other years it remains ‘arrested’ at Atlantic Layer depths. It has been unclear what parameters control whether the plume pierces the Atlantic Layer or not. In a series of experiments we vary the salinity ‘S’ and the flow rate ‘Q’ of the simulated Storfjorden overflow to investigate both strong and weak cascading conditions. Results show that the cascading regime (piercing, arrested or ‘shaving’ - an intermediate case) can be predicted from the initial values of S and Q. In those model experiments where the initial density of the overflow water is considerably greater than of the deepest ambient water mass we find that a cascade with high initial S does not necessarily reach the bottom if Q is low. Conversely, cascades with an initial density just slightly higher than the deepest ambient layer may flow to the bottom if the flow rate Q is high. A functional relationship between S/Q and the final depth level of plume waters is explained by the flux of potential energy (arising from the introduction of dense water at shallow depth) which, in our idealised setting, represents the only energy source for downslope descent and mixing. Lastly, the influence of tides on the propagation of a dense water plume is investigated using a regional NEMO-SHELF model with realistic bathymetry, atmospheric forcing, open boundary conditions and tides. The model has 3 km horizontal resolution and 50 vertical levels in the sh-coordinate system which is specially designed to resolve bottom boundary layer processes. Tidal effects are isolated by comparing results from model runs with and without tides. A hotspot of tidally-induced horizontal diffusion leading to the lateral dispersion of the plume is identified at the southernmost headland of Spitsbergen which is in close proximity to the plume path. As a result the lighter fractions in the diluted upper layer of the plume are drawn into the shallow coastal current that carries Storfjorden water onto the Western Svalbard Shelf, while the dense bottom layer continues to sink down the slope. This bifurcation of the plume into a diluted shelf branch and a dense downslope branch is enhanced by tidally-induced shear dispersion at the headland. Tidal effects at the headland are shown to cause a net reduction in the downslope flux of Storfjorden water into deep Fram Strait. This finding contrasts previous results from observations of a dense plume on a different shelf without abrupt topography. The dispersive mechanism which is induced by the tides is identified as a mechanism by which tides may cause a relative reduction in downslope transport, thus adding to existing understanding of tidal effects on dense water overflows.

Waste rock piles from coal mining of tertiary bituminous coal in Longyearbyen, Svalbard, show sulfide oxidation and subsequent acid mine drainage (AMD) production. The aim was to establish deeper understanding of AMD prediction based on Mineralogy and Geochemistry of coal and AMD samples. Mineralogical investigation of both coal and rock samples was performed with Automated SEM (ZEISS-Sigma VP300-Mineralogic System) as well as RAMAN. ICP-MS analysis was performed on solid and water samples. The pH from in situ measurements of AMD between 2,5-7,0. Eh varied from 222-569 mV (corresponding pe value of 3,7-9,6). This study showed that time of AMD in an oxidative environment was a key factor in iron concentration and iron speciation the AMD. This could not however be concluded in terms of age of mine site but rather the site-specific setting. The main minerals found in coal samples were pyrite (FeS2), siderite (FeCO3), calcite (CaCO3) and apatite (Ca5(PO4)3). Pyrites were identified with framboidal and euhedral textures and were found inside the maceral matter and in over- and underlying rocks respectively. SEM analysis of coal samples indicated that the modes of mineral formation was changing over the course of the Longyear seam. This study found that framboidal or euhedral textures of pyrite had different impacts in the AMD production. Framboidal pyrite was found to generate a greater amount of acidity than euhedral pyrites due to larger specific surface area and could therefore pose larger problems in AMD management.

S’appuyant sur de longues missions de terrain, ce travail offre le regard quantitatif et qualitatif d’ungéographe sur la dynamique nivo-glaciaire en région polaire dans un contexte de changement climatiqueactuel. Il s’inscrit dans le cadre du programme ANR Hydro-Sensor-FLOWS mis en oeuvre dansla mouvance de l’Année Polaire Internationale. En amont de ce programme pluridisciplinaire visant àcomprendre le fonctionnement hydrologique d’un petit hydrosystème polaire il fallait adjoindre uneétude plus spécifique concernant le rôle de la neige et de la glace dans l’équation hydrologique : c’estl’objet de cette thèse.Le bassin glaciaire de l’Austre Lovénbreen (10 km2, Spitsberg – 79°N) a servi de terrain d’étude dansune approche géographique à échelle locale. De nombreuses méthodes ont été testées tant sur leterrain (stations photo automatiques, carottages de la neige, DGPS et GPR) que pour l’exploitationdes données acquises.Au total, ce travail suit la dynamique nivo-glaciaire pendant trois années (2008, 2009 et 2010) à partirde 15 séries de carottages en 40 points du bassin, de mesures de densité, de profils nivologiques,de bilan de masse et de suivi continu, en 20 points, de la température de l’air. Outre l’image satellite,ce travail s’appuie également sur une collection de 3 clichés journaliers acquis en 10 points dubassin. Des méthodes ont été développées pour corriger géométriquement les photos afin d’en fairedes documents en projection verticale dont il est possible de tirer de l’information quantitative. Lesoutils de la géomatique ont permis de spatialiser l’information ponctuelle et d’établir à des pas detemps variables, par croisement des données acquises in situ, les diverses lames entrant dansl’équation hydrologique (précipitations, fonte potentielle de la neige et de la glace en relation avec leslames écoulées). Les trois années consécutives de suivi offrent des conditions très différentes quirévèlent le rôle constant et modérateur des températures et celui beaucoup plus impulsif des précipitations.Ce travail pose également le problème des mesures et de leur fiabilité dans un milieu aussi sévère etaussi impétueux que l’Arctique. / Leaning on long field campaigns, this thesis offer both qualitative and quantitative overview of polarregion nivo-glaciologic dynamics through a geographic approach, in context of climate change. Thiswork is part of the Hydro-sensor FlOWS program taking place during the International Polar Year.Upstream of this pluridisciplinary program aimed at understanding the hydrological processes of asmall polar hydrosystem, it was necessary to add a more specific study on the role of snow and icein the hydrological equation : this is the subject of this PhD.The glacial basin of Austre Lovénbreen (10 km2, Spitsberg – 79°N) served as a field of study in ageographical approach at local scale. Many methods have been tested both in the field (automaticphoto station, snow coring, DGPS and GPR) and for the data processing.Overall, this work follows the snow and ice dynamics for three years (2008, 2009 and 2010) from 15sets cores of 40 points of the basin, density measurements, nivologic profiles, mass balance and thecontinuous monitoring, on 20 points, of the air temperature. Besides the satellite images, this workalso leans on a collection of 3 daily photos acquired in 10 points of the basin. Methods were developedto geometrically correct photos in order to provide data wich could be used as a vertical projectioninto a GIS software to get quantitative informations. The geomatrical tools gave the possibility tohave accurate spatial representation at different time scale, by crossing data acquired in situ, lesdiverses lames entrant dans l’équation hydrologique (precipitation, potential melting of snow and icein relation to the lames passed).Three consecutive years of monitoring provide very different conditions that reveal temperatures’sconstant role of moderator, and the much more impulsive behavior of precipitations.This work also raises the problem of measurements and their reliability in a binding environment asthe Arctic

No description available.

S'appuyant sur de longues missions de terrain, ce travail offre le regard quantitatif et qualitatif d'un géographe sur la dynamique nivo-glaciaire en région polaire dans un contexte de changement climatique actuel. Il s'inscrit dans le cadre du programme ANR Hydro-Sensor-FLOWS mis en oeuvre dans la mouvance de l'Année Polaire Internationale. En amont de ce programme pluridisciplinaire visant à comprendre le fonctionnement hydrologique d'un petit hydrosystème polaire il fallait adjoindre une étude plus spécifique concernant le rôle de la neige et de la glace dans l'équation hydrologique : c'est l'objet de cette thèse. Le bassin glaciaire de l'Austre Lovénbreen (10 km2, Spitsberg - 79°N) a servi de terrain d'étude dans une approche géographique à échelle locale. De nombreuses méthodes ont été testées tant sur le terrain (stations photo automatiques, carottages de la neige, DGPS et GPR) que pour l'exploitation des données acquises. Au total, ce travail suit la dynamique nivo-glaciaire pendant trois années (2008, 2009 et 2010) à partir de 15 séries de carottages en 40 points du bassin, de mesures de densité, de profils nivologiques, de bilan de masse et de suivi continu, en 20 points, de la température de l'air. Outre l'image satellite, ce travail s'appuie également sur une collection de 3 clichés journaliers acquis en 10 points du bassin. Des méthodes ont été développées pour corriger géométriquement les photos afin d'en faire des documents en projection verticale dont il est possible de tirer de l'information quantitative. Les outils de la géomatique ont permis de spatialiser l'information ponctuelle et d'établir à des pas de temps variables, par croisement des données acquises in situ, les diverses lames entrant dans l'équation hydrologique (précipitations, fonte potentielle de la neige et de la glace en relation avec les lames écoulées). Les trois années consécutives de suivi offrent des conditions très différentes qui révèlent le rôle constant et modérateur des températures et celui beaucoup plus impulsif des précipitations. Ce travail pose également le problème des mesures et de leur fiabilité dans un milieu aussi sévère et aussi impétueux que l'Arctique

Short breeding period and harsh climatic conditions are major limiting factors to which birds have to adapt in northern tundra regions. Despite this fact, dozen species of birds annually migrate into these regions to increase their chances to breed successfully. My diploma thesis focuses on incubation behaviour of the Arctic tern (Sterna paradisaea). The research for my thesis took place on the Norwegian archipelago Svalbard, in two particular locations: Adolfbukta and Longyearbyen. By using the method of continuous video recording, I described incubation behaviour of this specie in detail. Human activity is very different on each of Adolfbukta and Longyearbyen. On site Adolfbukta study was conducted during seasons 2012 and 2014, both with different predation pressure. Having known that, I could evaluate the impact of human activity as well as the impact of different predation pressure on incubation behaviour and breeding ecology of Arctic tern. The presence of human close to the colony had significant effect on incubation behaviour. Due to higher disturbances, incubating birds tended to leave their nests more often, attention paid to the nest was smaller and calm incubation (sleeping on the nest) was shorter by a half. Human activity had no effect on other displays such as average clutch size or...

Most of the glacier-caused sea level rise to date has been sourced from melt and icebergs from marine-terminating glaciers. Marine-terminating glaciers drain nearly all the Greenland and Antarctic ice sheets and many polar ice caps, ice fields, and mountain glaciers. However, we previously did not know how much solid mass, or frontal ablation, was lost by these glaciers, a key component of glacier mass balance. This thesis quantifies the area change and mass loss of marine-terminating glaciers in the Northern Hemisphere from 2000 to 2020 by quantifying glacier retreat, advance, and frontal ablation. In total, the 1704 marine-terminating glaciers in the Northern Hemisphere lost an average of 389.7 ± 1.6 km² a⁻¹ of their terminus from 2000 to 2020, for a total of 7527 ± 31 km², with 123 glaciers ceasing to be marine-terminating over this period. Overall, 85.3% of glaciers retreated, 2.5% advanced, and the remaining 12.3% did not change outside of uncertainty limits. Frontal ablation of marine-terminating glaciers, not including the Greenland Ice Sheet, contributed an average of 44.47 ± 6.23 Gt a⁻¹ of ice to the ocean from 2000 to 2010, and 51.98 ± 4.62 Gt a⁻¹ from 2010 to 2020. Ice discharge from 2000 to 2020 was equivalent to 2.10 ± 0.22 mm of sea-level rise and comprised approximately 79% of frontal ablation, with the remainder from terminus retreat. In Greenland, frontal ablation totaled 522.00 ± 17.38 Gt a⁻¹ for 2000-2010 and 559.05 ± 12.59 Gt a⁻¹ for 2010-2020. Ice discharge comprised ~90% of frontal ablation during both periods, while volume loss due to terminus retreat comprised the remainder. In total, Greenland accounted for 90% of northern hemisphere frontal ablation from 2000 to 2020. When combined with climatic-basal mass balance estimates this allows for the first estimate of complete Northern Hemisphere glacier mass budgets, which shows that Arctic Russia, Greenland, and Svalbard have positive climatic-basal balances. For the first time, this thesis provides complete frontal ablation estimates for the entire Northern Hemisphere of 522.0 ± 17.4 Gt a⁻¹ for 2000-2010 and 559.1 ± 12.6 Gt a⁻¹ for 2010-2020.