Abstract Extensive ice thickness surveys by NASA's Operation IceBridge enable over a decade of discharge measurements at high precision for the majority Greenland's marine‐terminating outlet glaciers, prompting reassessment temporal and spatial distribution glacier change. Annual 178 glaciers reveal that, despite widespread acceleration, only 15 accounted 77% 739 ± 29 Gt lost due to acceleration since 2000 four ~50%. Among top sources loss are several that have received little scientific...

<strong class="journal-contentHeaderColor">Abstract.</strong> We assess the recent contribution of Greenland ice sheet (GrIS) to sea level change. use mass budget method, which quantifies balance (MB) as difference between surface (SMB) and solid discharge across grounding line (<i>D</i>). A comparison with independent gravity change observations from GRACE shows good agreement for overlapping period 2002–2015, giving confidence in partitioning GrIS changes. The estimated 1995 value...

Abstract The freshwater budget of the Arctic and sub‐polar North Atlantic Oceans has been changing due, primarily, to increased river runoff, declining sea ice enhanced melting land ice. Since mid‐1990s this latter component experienced a pronounced increase. We use combination satellite observations glacier flow speed regional climate modeling reconstruct flux from Greenland sheet glaciers caps for period 1958–2016. cumulative anomaly exceeded 6,300 ± 316 km 3 by 2016. This is roughly twice...

Abstract Mass loss from the Greenland ice sheet (GrIS) has increased over last two decades in response to changes global climate, motivating scientific community question how GrIS will contribute sea‐level rise on timescales that are relevant coastal communities. Observations also indicate impact of a melting extends beyond rise, including ocean properties and circulation, nutrient sediment cycling, ecosystem function. Unfortunately, despite rapid growth interest mass its impacts, we still...

Abstract. Variability in tidewater outlet glacier behavior under similar external forcing has been attributed to differences shape (i.e., bed elevation and width), but this dependence not investigated detail. Here we use a numerical ice flow model show that the dynamics of glaciers are highly sensitive width topography. Our sensitivity tests indicate for with discharge, trunks wider those grounded over deeper basal depressions tend be closer flotation, so less dynamically induced thinning...

Abstract Freshwater fluxes from the Greenland ice sheet have increased over last two decades due to increases in liquid (i.e., surface and submarine meltwater) solid iceberg) fluxes. To predict potential sheet‐ocean‐climate feedbacks, we must know partitioning of freshwater Greenland, including conversion icebergs within glacial fjords. Here use repeat ~0.5 m‐resolution satellite images major fjords provide first observation‐based estimates meltwater flux dense matrix floating called...

ABSTRACT Icebergs calved from tidewater glaciers represent about one third to half of the freshwater flux Greenland ice sheet surrounding ocean. Using multiple satellite datasets, we quantify first fjord-wide distributions iceberg sizes and characteristics for three fjords with distinct hydrography geometry: Sermilik Fjord, Rink Isbræ Fjord Kangerlussuup Sermia Fjord. We estimate average total volumes in summer be 6.4 ± 1.5, 1.7 0.40 0.16 0.09 km 3 , respectively. Iceberg properties are...

Abstract We use satellite image processing techniques to measure surface elevation and velocity changes on a temperate surging glacier, Sít’ Kusá, throughout its entire 2013–2021 surge cycle. present detailed records of dynamic during quiescence (2013–2019) progression (2020–2021). Throughout quiescence, we observe order-of-magnitude speedups that propagate down-glacier seasonally from the glacier's upper northern tributary, above steep icefall, into reservoir zone for portion glacier. The...

Abstract The rate of mass loss from the Greenland ice sheet has increased over past decade due, in large part, to changes marine-terminating outlet glacier dynamics. These are attributed submarine melt rates floating tongues and submerged calving faces resulting coastal ocean heat transport. We use remotely sensed data calculate for 13 glaciers on a semi-annual basis between 2000 2010. assess temporal spatial variability calculated compare those variabilities concurrent change offshore...

Abstract Here we present a long‐term (1850–2200) best estimate of Greenland ice sheet (GrIS) freshwater runoff that improves spatial detail locations and temporal resolution. Ice discharge is taken from observations since 2000 assumed constant in time. Surface meltwater retrieved regional climate model output for the recent past parameterized future based on significant correlations between midtropospheric (500 hPa) summer temperature changes over GrIS. The simplicity this approach enables...

Abstract Observed increases in iceberg discharge from Greenland’s marine-terminating glaciers over the past two decades have altered freshwater flux glacial fjords into surrounding ocean basins. Although variations due to ice-sheet change been investigated on a broad scale, distribution of melting calved glacier ice (i.e. icebergs) has not examined. Logistical challenges collecting situ data so far prevented detailed examination fluxes arising beneath waterline submarine melting). Here we...

Abstract Frontal ablation processes at marine‐terminating glaciers are challenging to observe and difficult represent in numerical ice flow models, yet play critical roles modulating sheet mass balance. Current models typically rely on simple iceberg calving prescribe either terminus positions or rates, but the relative accuracies uncertainties of these remain largely unconstrained scale. Here, we evaluate six published against spatially temporally diverse observations from 50 outlet...

Seasonal snow melt dominates the hydrologic budget across a large portion of globe. Snow accumulation and vary over broad range spatial scales, preventing accurate extrapolation sparse in situ observations to watershed scales. The lidar onboard Ice, Cloud, land Elevation, Satellite (ICESat-2) was designed for precise mapping ice sheets sea ice, here we assess feasibility depth-mapping using ICESat-2 data more complex rugged mountain landscapes. We explore utility ATL08 Land Vegetation Height...

Abstract. Marine-terminating outlet glaciers of the Greenland Ice Sheet have undergone substantial changes over past decade. The synchronicity these suggest a regional external forcing, such as in coastal ocean heat transport and/or increased surface melt and subglacial runoff. A distinct contrast rates ice front retreat has been observed between north south 69° N latitude on along East coast. This corresponds with northward limit subtropical waters carried by Irminger Current, suggesting...

Abstract Iceberg calving strongly controls glacier mass loss, but the fracture processes leading to iceberg formation are poorly understood due stochastic nature of calving. The size distributions icebergs produced during process can yield information on driving and also affect timing, magnitude, spatial distribution ocean fresh water fluxes near glaciers ice sheets. In this study, we apply fragmentation theory describe key behaviours, based observational modelling data from Greenland...

Abstract. Lidar is an effective tool to measure snow depth over key watersheds across the United States. Lidar-derived observations from airborne platforms have demonstrated centimeter-level accuracy at high spatial resolution. However, ground-based and lidar surveys are costly limited in space time. In recent years, there has been emerging interest using spaceborne estimate depth. Preliminary results altimeters such as NASA Ice, Cloud, Land Elevation Satellite-2 (ICESat-2) ca provide...

Frontal ablation at tidewater glaciers, which comprises iceberg calving and submarine subaerial melting, is a key boundary condition for numerical ice sheet models but remains difficult to measure in-situ. Although previous studies have provided frontal estimates over range of spatiotemporal scales, most use discharge as an approximation, thereby neglecting the influence terminus position change. Here, we present dataset 49 glaciers in Greenland that reliable near-terminus bathymetry data....

Abstract. Tracking the extent of seasonal snow on glaciers over time is critical for assessing glacier vulnerability and response glacierized watersheds to climate change. Existing cover products do not reliably distinguish from ice firn, preventing their use detection. Despite previous efforts classify surface facies using machine learning local scales, currently there no published comparison models classifying across different satellite image products. We present an automated detection...

Abstract Glacier surges are opportunities to study large amplitude changes in ice velocities and accompanying links subglacial hydrology. Although the surge phase is generally explained as a disruption glacier's ability drain water from bed, extent duration of this remain difficult observe. Here we present combination situ remotely sensed observations discharge evacuation during latter half an active subsequent quiescent period. Our data reveal intermittently efficient drainage prior...

Abstract. Iceberg discharge from the Greenland Ice Sheet accounts for up to half of freshwater flux surrounding fjords and ocean basins, yet spatial distribution iceberg meltwater fluxes is poorly understood. One primary limitations mapping fluxes, changes over time, dearth submarine melt rate estimates. Here we use a remote sensing approach estimate rates during 2011–2016 637 icebergs discharged seven marine-terminating glaciers fringing Sheet. We find that variations in generally follow...