Ice Mass Research Articles

Automated mapping of glacial lakes using multisource remote sensing data and deep convolutional neural network

• GLNet is proposed for automated glacial lake mapping. • Result shows 0.98 accuracy, and 0.95 F- score over the test data. • GLNet transferability is tested over 3 sites in Himalaya and 1 in Karakoram. • Overall good agreement (R 2 =0.90) between GLNet and manual lake boundaries. The characteristics of glacial lakes are a precursor to glacier retreat, ice mass loss, velocity, and potential risk of Glacial Lake Outburst Floods (GLOF). The current state of the art for glacial lake mapping, especially in a high mountainous region, is limited to manual or semi-automated threshold-based methods. Here, we propose a fully automated novel approach for glacial lake mapping using a Deep Convolutional Neural Network (DCNN) and remote sensing data originating from various sources. A combination of these multisource remote sensing data (i.e., multispectral, thermal, microwave, and a Digital Elevation Model) is fed to the fully connected DCNN. The DCNN architecture, namely GLNet, is designed by choosing an optimum number and size of convolutional layers, filters, and other hyperparameters. Our proposed GLNet is trained on 660 images covering twelve sites spread across diverse climatic and topographic regions of the Himalaya. The robustness of the model is tested over three sites in the Eastern Himalaya and one site in the Western Himalaya. The classification results outperform the existing state-of-the-art datasets by achieving 0.98 accuracy, 0.95 precision, 0.95 recall, and 0.95 F- score over the test data. The results over test sites (F-score test site1: 0.91, test site 2: 0.80, test site3: 0.97, and test site4: 0.70) showed promising results and spatiotemporal transferability of the proposed method. The coefficient of determination (R 2 ) between GLNet predicted lake boundaries and reference lake boundaries exhibits excellent results (0.90). The study provides proof of concept for automated glacial mapping for large geographical regions via integrated capabilities of deep convolutional neural networks and multisource remote sensing data.

An experimental study of dynamic icing process on an Aluminum-Conductor-Steel-Reinforced power cable with twisted outer strands

An experimental campaign was conducted to investigate the dynamic icing process on an Aluminum-Conductor-Steel-Reinforced (ACSR) power cable with twisted outer strands and characterize the resultant wind loads experienced by the power cable under both dry rime and wet glaze icing conditions. In addition to recording the dynamic icing process over the cable surface with a high-resolution imaging system, the three-dimensional (3D) shapes of the ice layers accreted on the cable model were also quantified by using a novel 3D profile scanning system. While the evolution of the wake flow behind the iced ACSR cable was quantified with a Particle Image Velocimetry (PIV) system, the variation of the wind loads experienced by the cable model was also examined based on the measurements of force/moment transducers. Under the dry rime icing condition, opaque, grainy ice was found to accrete only within the impinging zone of airborne water droplets over the cable frontal surface without any noticeable water runback flow over the cable surface. In comparison, substantial unfrozen water was observed to run back over the cable surface under the wet glaze icing condition, causing the formation of transparent, glazy ice layer over a much wider area over the cable surface. Correlating with the formation of more complicated glazy ice humps/horns over the ACSR cable surface, the accumulated ice mass was found to grow much faster during glaze icing process, in comparison to that of rime icing case. While the resultant wind loads acting on the iced ACSR cable was found to decrease gradually with the increasing icing time under the rime icing condition, the corresponding values were found to increase continuously under the glaze icing condition.

The extreme yet transient nature of glacial erosion

Ice can sculpt extraordinary landscapes, yet the efficacy of, and controls governing, glacial erosion on geological timescales remain poorly understood and contended, particularly across Polar continental shields. Here, we assimilate geophysical data with modelling of the Eurasian Ice Sheet — the third largest Quaternary ice mass that spanned 49°N to 82°N — to decipher its erosional footprint during the entire last ~100 ka glacial cycle. Our results demonstrate extreme spatial and temporal heterogeneity in subglacial erosion, with rates ranging from 0 to 5 mm a−1 and a net volume equating to ~130,000 km3 of bedrock excavated to depths of ~190 m. A hierarchy of environmental controls ostensibly underpins this complex signature: lithology, topography and climate, though it is basal thermodynamics that ultimately regulates erosion, which can be variously protective, pervasive, or, highly selective. Our analysis highlights the remarkable yet fickle nature of glacial erosion — critically modulated by transient ice-sheet dynamics — with its capacity to impart a profound but piecemeal geological legacy across mid- and high latitudes.

Out of the Qinghai-Tibet plateau: Genomic biogeography of the alpine monospecific genus Megadenia (Biscutelleae, Brassicaceae).

Numerous high-elevation alpine plants of the Qinghai-Tibet Plateau (QTP) also have disjunct distribution in adjacent low-altitude mountains. The out-of-QTP versus into-the-QTP hypothesis of alpine plants provide strong evidence for the highly disputed assumption of the massive ice sheet developed in the central plateau during the Last Glacial Maximum (LGM). In this study, we sequenced the genomes of most known populations of Megadenia, a monospecific alpine genus of Brassicaceae distributed primarily in the QTP, though rarely found in adjacent low-elevation mountains of north China and Russia (NC-R). All sequenced samples clustered into four geographic genetic groups: one pair was in the QTP and another was in NC-R. The latter pair is nested within the former, and these findings support the out-of-QTP hypothesis. Dating the four genetic groups and niche distribution suggested that Megadenia migrated out of the QTP to adjacent regions during the LGM. The NC-R group showed a decrease in the effective population sizes. In addition, the genes with high genetic divergences in the QTP group were mainly involved in habitat adaptations during low-altitude colonization. These findings reject the hypothesis of development massive ice sheets, and support glacial survival of alpine plants within, as well as further migration out of, the QTP.

Experimental Study on the Rheology and Cryo-Mechanism of Pile-Frozen Soil Interface

The rheological behavior of a pile-frozen soil interface can accelerate pile settlement in pile foundation engineering and deteriorate the bearing capacity of the pile in cold regions. This is the core basis for guiding the design of pile engineering and judging the service life of pile foundations. However, it is unclear how the rheological process is affected by the factors which determine the ad-freeze strength at the pile-frozen soil interface. In this paper, based on a series of Multistage Loading Creep Test (MLCT) for pile-frozen Qinghai-Tibet clay soil interface and microscopic observations of frozen soil, the rheological process and the cryo-mechanism of the interface were analyzed. The results showed that the decrease in soil temperature reduce the interface’s instantaneous deformation value and creep rate, which results from the temperature-dependent rheological behavior of ice. The trend also occurs in the soil with coarser particles and the pile with a rough surface. The presence of massive ice in frozen soil benefits the bearing capacity of the interface at a high temperature of -1°C. However, it can considerably increase the interface’s creep rate due to the influence of the rheological properties of ice at a relatively low temperature of -5°C. Either thick lenticular ice lens or chaotic reticulate cryo-structures in the frozen soil surrounding a pile will enhance the interface’s rheological properties. The interface exhibits the lowest instantaneous deformation value and the slowest creep rate for frozen soil with the massive cryo-structure, which is formed with optimum moisture content. From an engineering viewpoint, the settlement of a pile foundation can be reduced by controlling its instantaneous deformation or restraining its creep rate.

Experimental Study on the Noise Evolution of a Horizontal Axis Icing Wind Turbine Based on a Small Microphone Array

In recent years, the global energy mix is shifting towards sustainable energy systems due to the energy crisis and the prominence of ecological climate change. Wind energy resources are abundant in cold regions, and wind turbines are increasingly operating in cold regions with wet natural environments, increasing the risk of wind turbine blade icing. To address the problem of noise source distribution and the frequency characteristic variation of wind turbines in natural icing environments, this paper uses a 112-channel microphone array to acquire the acoustic signals of a horizontal axis wind turbine with a diameter of 2.45m. Using the beamforming technique, the wind turbine noise evolution law characteristics under natural icing environment were studied by field experiments, and the noise source distribution and noise increase in different frequency bands under different icing mass and positions and different angles of attack were analyzed in detail. The results show that under the leading-edge and windward-side icing, the noise source gradually moves toward the blade tip along the spanwise direction with the increase in ice mass. In addition, the total sound pressure level at 460 r/min, 520 r/min, 580 r/min, and 640 r/min are increased by 0.82 dB, 0.85 dB, 0.91 dB, and 0.95 dB, respectively for the leading-edge icing condition in comparison with the uniform icing over the windward side of the blade.

Evaluation of the relationships and uncertainties of airborne and ground-based sea ice surface temperature measurements against remotely sensed temperature records

ABSTRACT Sea ice surface temperature (IST) is an important indicator of environmental changes in the Arctic Ocean. In this study, the relative performance of four mainstream IST records, i.e. airborne IST, infrared radiometer measured IST (IR IST), longwave radiation derived IST (LWR IST), and snow and ice mass balance array buoy derived IST (Buoy IST), were evaluated against the MODIS IST product. Bias, standard deviation (STD), and root mean square error (RMSE) were used to evaluate the data quality. Results revealed that airborne IST had the best accuracy, which was 0.21 K colder than MODIS IST, with STD of 1.46 K and RMSE of 1.47 K. Ground-based ISTs were biased with each other but all warmer than the MODIS IST. The IR IST had the best overall accuracy (bias = 0.55 K; STD = 1.52 K; RMSE = 1.61 K), while the LWR IST was the noisiest measurement with the largest outlier data percent. Besides, co-located IR and LWR ISTs were more consistent than any type of evaluated IST against MODIS IST (correlation coefficient = 0.99). Airborne and IR ISTs are thus the premier choice for monitoring the rapidly changing Arctic sea ice, together with satellite observations.

Experimental investigation and modeling of the pressure drop of ice slurry flow in horizontal pipe

This study was conducted on ice slurry made by 11% of monopropylene glycol with various ice mass fractions through a horizontal pipe. The pressure drops, densities, temperatures, and ice slurry mass flow rates were measured and analyzed. First of all, the values of the pressure drop were validated with experimental results available in the literature. Then a numerical study of the flow of the ice slurry by pseudomonophasic flow model, which assumes the absence of the slip velocity between the phases and treats the ice slurry as a homogeneous and laminar fluid with thermophysical properties of the mixture. The rheological properties confirmed the non-Newtonian character of the ice slurry. The results show that there is a good agreement between the pressure drops of the present work and the literature. It was also found that the numerical analysis is very close to the experimental values in the case of a shear thinning flow.

Vertical distribution of excess ice in icy sediments and its statistical estimation from geotechnical data (Tuktoyaktuk Coastlands and Anderson Plain, Northwest Territories)

Excess ice, found as massive ice and within icy sediments, is an important variable to quantify as it is a dominant control on the terrain and geotechnical response to permafrost thaw. A large amount of permafrost borehole data are available from the Tuktoyaktuk Coastlands; however, field geotechnical assessments typically only involve the estimation of visible ice. To add significant value to these data sets, a cryostratigraphic data set collected along the Inuvik–Tuktoyaktuk Highway (566 boreholes) is used to develop a beta regression model which predicts the excess ice content of icy sediments based on interval depth, visible ice content, material type, and Quaternary deposits. The resulting predictions are compared to recorded massive ice intervals and show that ground ice within icy sediments can contribute up to 65% of the excess ice and potential thaw strain within the first 10 m from the surface in this area. This study shows the general applicability of this approach and indicates that comparable, quantitative data on ground ice conditions should be collected with drilling programs to derive geotechnical variables and reduce modelling uncertainties so that ground ice data are available for quantitative analysis.

The Role of Massive Ice and Exposed Headwall Properties on Retrogressive Thaw Slump Activity

AbstractRetrogressive Thaw Slumps (RTSs), a highly dynamic form of mass wasting, are accelerating geomorphic change across ice‐cored permafrost terrain, yet the main controls on their activity are poorly constrained. Questions over the spatial variability of environmentally sensitive massive ice bodies and a paucity of high‐spatial and temporal resolution topographic data have limited our ability to project their development and wider impacts. This research addresses these key problems by investigating RTS processes on Peninsula Point—a well‐studied site for intra‐sedimental massive ice in the Western Canadian Arctic. Utilizing high‐resolution topographic data from drone surveys in 2016, 2017 and 2018 we (a) measure the temporal and spatial variations in headwall properties and retreat rates, (b) determine the spatial pattern of subsurface layering using passive seismic monitoring and (c) combine these to analyze and contextualize the factors controlling headwall retreat (HWR) rates. We find that headwall properties, namely massive ice and overburden thickness, are significant controls over rates of HWR. Where persistent massive ice exposures are present inland of the headwall, regardless of thickness, and overburden thickness remains <4 m, HWR is typically more than double that of other headwalls. Furthermore, a 3D site model was created by combining photogrammetric and passive seismic data, highlighting internal layering variability and demonstrating the limitations of extrapolations of internal layering based on headwall exposures. These results provide fresh insights into the in situ controls on HWR rates and new approaches to understanding their variability.

A Lagrangian Perspective of Microphysical Impact on Ice Cloud Evolution and Radiative Heating

AbstractWe generate trajectories in storm‐resolving simulations in order to quantify the effect of ice microphysics on tropical upper‐tropospheric cloud‐radiative heating. The pressure and flow field tracked along the trajectories are used to run different ice microphysical schemes, both one‐ and two‐moment formulations within the Icosahedral Non‐hydrostatic Model model and a separate offline box microphysics model (CLaMS‐Ice). This computational approach allows us to isolate purely microphysical differences in a variant of “microphysical piggybacking;” feedbacks of microphysics onto pressure and the flow field, for example, via latent heating, are suppressed. Despite these constraints, we find about a 5‐fold difference in median cloud ice mass mixing ratios (qi) and ice crystal number (Ni) between the microphysical schemes and very distinct qi distributions versus temperature and relative humidity with respect to ice along the trajectories. After investigating microphysical formulations for nucleation, depositional growth, and sedimentation, we propose three cirrus lifecycles: a weak source‐strong sink lifecycle whose longwave and shortwave heating are smallest due to short lifetime and low optical depth, a strong source‐weak sink lifecycle whose longwave and shortwave heating are largest due to long lifetime and high optical depth, and a strong source‐strong sink lifecycle with intermediate radiative properties.

Mapping Ice Flow Velocity of Tidewater Glaciers in Hornsund Fiord Area with the Use of Autonomous Repeat Image Feature Tracking (2018–2022)

Dynamic climate changes are particularly apparent in polar regions. Glaciers are retreatng towards the land at a very fast pace. This study demonstrates the application of the feature tracking method in the analysis of ice flow velocity in the region of the Hornsund fiord, southern Spitsbergen, in the years 2018–2022. The calculations were based on the Geogrid and autoRIFT environments and on the Sentinel 1 images. The study also employed external data, such as a numerical terrain model and reference velocity values. The input data, e.g., the chip size and the search limit, were prepared accounting for the specific character of the investigated area. The velocities were calculated for nine biggest glaciers which terminated in the fiord. The accuracy of the results was identified by calculating the median absolute deviation (MAD) of the obtained displacement velocity values from the reference value for areas identified as stable. The study also attempted a causal analysis of the influence of weather factors on the dynamics of ice mass displacement. A systematic year-to-year decrease of the velocity was observed for the entire fiord. In the case of several glaciers, changes related to the ablation season (summer) are also clearly visible. The research results are promising and fill a research gap related to the absence of permanent monitoring and analysis of the dynamics of ice flow in polar regions. It is the first complex and precise study of glacier surface velocity changes, performed on the basis of satellite radar images for the entire Hornsund fiord.

Thermal regime of the Grigoriev ice cap and the Sary-Tor glacier in the inner Tien Shan, Kyrgyzstan

Abstract. The thermal regime of glaciers and ice caps represents the internal distribution of ice temperatures. An accurate knowledge of the thermal regime of glaciers and ice caps is important to understand their dynamics and response to climate change and to model their evolution. Although the assumption is that most ice masses in the Tien Shan are polythermal, this has not been examined in appropriate detail so far. In this research, we investigate the thermal regime of the Grigoriev ice cap and the Sary-Tor glacier, both located in the inner Tien Shan in Kyrgyzstan, using a 3D higher-order thermomechanical ice flow model. Input data and boundary conditions are inferred from a surface energy mass balance model, a historical air temperature and precipitation series, ice thickness measurements and reconstructions, and digital elevation models. Calibration and validation of the englacial temperatures are performed using historical borehole measurements on the Grigoriev ice cap and radar measurements for the Sary-Tor glacier. The results of this study reveal a polythermal structure of the Sary-Tor glacier and a cold structure of the Grigoriev ice cap. The difference is related to the larger amount of snow (insulation) and refreezing meltwater (release of latent heat) for the Sary-Tor glacier, resulting in higher surface layer temperature, especially in the accumulation area, which is subsequently advected downstream. Further, ice velocities are much lower for the Grigoriev ice cap, with consequent lower horizontal advection rates. A detailed analysis concerning the influence of temperature and precipitation changes at the surface reveals that the thermal structure of both ice bodies is not constant over time, with recent climate change causing increasing ice temperatures in higher areas. The selected ice masses are representative examples of the (inner) Tien Shan glaciers and ice caps. Therefore, our findings and the calibrated parameters can be generalised, allowing improved understanding of the dynamics and future evolution of other glaciers and ice caps in the region.

Facies analysis and depositional environment of the Carboniferous Singa Formation: Case study

Due to limited information, this paper aims to present a detailed facies analysis and depositional environment of the Carboniferous age, Singa Formation at Pulau Ular, Langkawi, Kedah. One exposed outcrop at Hill C was examined in detail, and one sedimentary log was created. The log is categorized bed by bed into several facies according to lithology and sedimentary structures. The focus was to identify the facies succession and to analyze the depositional environment as Singa Formation. This study is vital to reconstructing the pattern of past glacial as it will provide the crucial link between glacial processes and history, ice masses, and a more comprehensive Earth system. The Singa Formation is concluded into coarsening upward facies successions based on the facies succession grades upward from offshore facies. The depositional environment of Pulau Ular is interpreted as a coastal and a glacier depositional environment. Eight facies have been recognized; shale (FC1), shale with burrows (FC2), siltstone (FC3), shale with burrows, clay to silt (FC4), laminated shale with dropstone (FC5), sandstone that consists of dropstone (FC6), shale consists of dropstone (FC7) and sandstone with diamictite rock (FC8). Facies shale, sandstone, and siltstone proved that the study area is a coastal depositional environment, while facies consisting of dropstones and diamictite show that the study area is a glacier depositional environment.

Ocean currents break up a tabular iceberg.

In December 2020, giant tabular iceberg A68a (surface area 3900 km2) broke up in open ocean much deeper than its keel, indicating that the breakage was not immediately caused by collision with the seafloor. Giant icebergs with lengths exceeding 18.5 km account for most of the calved ice mass from the Antarctic Ice Sheet. Upon calving, they drift away and transport freshwater into the Southern Ocean, modifying ocean circulation, disrupting sea ice and the marine biosphere, and potentially triggering changes in climate. Here, we demonstrate that the A68a breakup event may have been triggered by ocean-current shear, a new breakup mechanism not previously reported. We also introduce methods to represent giant icebergs within climate models that currently do not have any representation of them. These methods open opportunities to explore the interactions between icebergs and other components of the climate system and will improve the fidelity of global climate simulations.

A simple model for daily basin-wide thermodynamic sea ice thickness growth retrieval

Abstract. As changes to Earth's polar climate accelerate, the need for robust, long–term sea ice thickness observation datasets for monitoring those changes and for verification of global climate models is clear. By linking an algorithm for retrieving snow–ice interface temperature from passive microwave satellite data to a thermodynamic sea ice energy balance relation known as Stefan's law, we have developed a retrieval method for estimating thermodynamic sea ice thickness growth from space: Stefan's Law Integrated Conducted Energy (SLICE). With an initial condition at the beginning of the sea ice growth season, the method can model basin-wide absolute sea ice thickness by combining the one-dimensional SLICE retrieval with an ice motion dataset. The advantages of the SLICE retrieval method include daily basin-wide coverage, lack of atmospheric reanalysis product input requirement, and a potential for use beginning in 1987. Validation of the retrieval against measurements from 10 ice mass balance buoys shows a mean correlation of 0.89 and a mean bias of 0.06 m over the course of an entire sea ice growth season. Despite its simplifications and assumptions relative to models like the Pan-Arctic Ice–Ocean Modeling and Assimilation System (PIOMAS), basin-wide SLICE performs nearly as well as PIOMAS when compared against CryoSat-2 and Operation IceBridge using a linear correlation between collocated points.

Experimental research on the thermal method of drilling by melting the well in ice mass with simultaneous controlled expansion of its diameter

During the seasonal work of the 64th Russian Antarctic Expedition in 2018-2019 at the “Vostok” drilling facility named after B.B.Kudryashov (“Vostok” station, Antarctic) specialists of Saint Petersburg Mining University conducted experimental investigations on the process of drilling by melting with simultaneous expansion of wells in the ice mass. A test bench and a full-scale model of a thermohydraulic reamer-drilling tool were developed, manufactured and tested for the research. The first bench tests of the full-scale model proved its efficiency and suitability for experimental drilling with simultaneous expansion of wells in ice mass; its operational capabilities were determined and the drawbacks that will be taken into account in future were found out. The article substantiates the choice of constructive elements for thermohydraulic reamer-drilling tool. It is determined that the technology of full diameter drilling with simultaneous expansion of the well in ice mass can be implemented by combining contact drilling by melting and convective expansion with creation of forced near-bottomhole annular circulation of the heated heat carrier. Dependencies of expansion rate on main technological parameters were determined: active heat power of heating elements in penetrator and circulation system, mechanical drilling rate, pump flow rate. According to the results of investigations, the experimental model of thermohydraulic reamer-drilling tool will be designed and manufactured for testing in conditions of well 5G.

Energy and glacier mass balance of Fürkeleferner, Italy: past, present, and future

The energy and mass balance of mountain glaciers translate into volume changes that play out as area changes over time. From this, together with former moraines during maximum advances, information on past climate conditions and the climatic drivers behind during glacier advances can be obtained. Here, we use the distributed COupled Snowpack and Ice surface energy and mass balance model in PYthon (COSIPY) to simulate the present state of an Italian glacier, named Fürkeleferner, for the mass balance years 2013–2017. Next, we investigate the local climate during the time of the last “Little Ice Age” (LIA) maximum glacier advance using COSIPY together with the LIA glacier outline retrieved from moraine mapping and a digital elevation model (DEM) adapted for the glacier’s geometry at the time of the LIA as a benchmark. Furthermore, the glacier’s sensitivity to future air temperature increase of +1 K and +2 K is investigated using the same model. For all simulations, meteorological data of closely located climate stations are used to force the model. We show the individual monthly contribution of individual energy and mass balance components. Refreezing during the summer months is an important component of the energy and mass balance, on average about 9 % relative to total annual ablation. The results from simulating past climate show a 2.8 times larger glacier area for Fürkeleferner during the LIA than today. This further implies a 2.5 K colder climate, assuming that the amount of precipitation was 10 %–20 % in excess of today’s value. Concerning further temperature increase of 2 K, the glacier would only consist of the ablation area implying sustained mass loss and eventual total mass loss. Even under current climatic conditions, the glacier area would have to decrease to 17 % of its current area to be in a steady state. We discuss the reliability of the results by comparing simulated present mass balance to measured mass balances of neighboring glaciers in the European Alps and with short-term measurements on Fürkeleferner itself. In conclusion, we are able to show how the glacier responds to past and future climate change and determine the climatic drivers behind.

The Antarctic contribution to 21st-century sea-level rise predicted by the UK Earth System Model with an interactive ice sheet

Abstract. The Antarctic Ice Sheet will play a crucial role in the evolution of global mean sea level as the climate warms. An interactively coupled climate and ice sheet model is needed to understand the impacts of ice–climate feedbacks during this evolution. Here we use a two-way coupling between the UK Earth System Model and the BISICLES (Berkeley Ice Sheet Initiative for Climate at Extreme Scales) dynamic ice sheet model to investigate Antarctic ice–climate interactions under two climate change scenarios. We perform ensembles of SSP1–1.9 and SSP5–8.5 (Shared Socioeconomic Pathway) scenario simulations to 2100, which we believe are the first such simulations with a climate model that include two-way coupling of atmosphere and ocean models to dynamic models of the Greenland and Antarctic ice sheets. We focus our analysis on the latter. In SSP1–1.9 simulations, ice shelf basal melting and grounded ice mass loss from the Antarctic Ice Sheet are generally lower than present rates during the entire simulation period. In contrast, the responses to SSP5–8.5 forcing are strong. By the end of the 21st century, these simulations feature order-of-magnitude increases in basal melting of the Ross and Filchner–Ronne ice shelves, caused by intrusions of masses of warm ocean water. Due to the slow response of ice sheet drawdown, this strong melting does not cause a substantial increase in ice discharge during the simulations. The surface mass balance in SSP5–8.5 simulations shows a pattern of strong decrease on ice shelves, caused by increased melting, and strong increase on grounded ice, caused by increased snowfall. Despite strong surface and basal melting of the ice shelves, increased snowfall dominates the mass budget of the grounded ice, leading to an ensemble mean Antarctic contribution to global mean sea level of a fall of 22 mm by 2100 in the SSP5–8.5 scenario. We hypothesise that this signal would revert to sea-level rise on longer timescales, caused by the ice sheet dynamic response to ice shelf thinning. These results demonstrate the need for fully coupled ice–climate models in reducing the substantial uncertainty in sea-level rise from the Antarctic Ice Sheet.

Greenland Interannual Ice Mass Variations Detected by GRACE Time‐Variable Gravity

AbstractTo better understand the impact of climate forcing on Greenland ice sheet (GrIS), we study the GrIS mass variations on the interannual timescale as observed by the satellite mission of Gravity Recovery and Climate Experiment (GRACE). By employing the method of empirical orthogonal function) analysis, we find: (a) That the GrIS interannual mass variations are significantly correlated with the Pacific Decadal Oscillation, suggesting a connection to the changes of the Icelandic Low (a permanent low‐pressure system) related to PDO; (b) An East‐West Costal Dipole related to precipitation anomaly subjects to the North Atlantic Oscillation; (c) Certain contribution of the Atlantic Multidecadal Oscillation to GrIS mass variations in the form of temperature and runoff anomalies.