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The Arctic is warming rapidly, significantly reducing the Greenland ice sheet (GrIS) surface mass balance (SMB) and raising its contribution to global sea‐level rise. Since these trends are expected to continue, it is essential to explore the GrIS SMB response to projected climate warming. We compare projections from three polar regional climate models, RACMO, MAR, and HIRHAM, forced by the Community Earth System Model CESM2 under a high‐end warming scenario (SSP5‐8.5, 1970–2099). We reveal different modeled SMB by 2100, including a twofold larger annual surface mass loss in MAR (−1735 Gt/yr) and HIRHAM (−1698 Gt/yr) relative to RACMO (−964 Gt/yr). Discrepancies primarily stem from differences in projected runoff, triggering melt‐albedo positive feedback and subsequent modeled ablation zone expansion. In addition, we find different responses of modeled meltwater production to similar atmospheric warming. Our analysis suggests clear avenues for model developments to further improve SMB projections and contribution to sea‐level rise. Plain Language Summary: We explore how three different polar climate models predict the future surface mass balance (SMB) of the Greenland ice sheet (GrIS), a major contributor to global sea‐level rise. Our results show that SMB projections among these models differ significantly by the end of the century. Differences primarily stem from how models convert meltwater into surface runoff toward the ocean, a crucial SMB component that directly contributes to sea‐level rise. Another key factor is the response of these models to climate warming, substantially affecting future melting rates. Our research highlights the need for further improvements of these climate models. By identifying and understanding the drivers behind model differences, we can improve SMB predictions and better estimate future global sea‐level rise. Key Points: With identical forcing, Greenland Ice Sheet surface mass balance from 3 regional climate models shows a two‐fold difference by 2100Different runoff projections stem from substantial discrepancies in projected ablation zone expansion, and reciprocallyThe response of meltwater production to similar atmospheric warming differs significantly among regional climate models [ABSTRACT FROM AUTHOR]

Greenland Ice Sheet surface elevation is changing as mass loss accelerates. In understanding elevation change, the magnitudes of physical processes involved are important for interpretation of altimetry and assessing changes in these processes. The four key processes are surface mass balance (SMB), firn densification, ice dynamics, and isostatic adjustment. We quantified these processes at Summit, Greenland, where monthly Global Navigation Satellite System (GNSS) snowmobile traverses measured elevation change from 2008 to 2018. We find an elevation increase of 0.019 m a−1. The sum of the effects of the four processes reproduces the measured elevation time series, in linear trend and in intra‐annual variability. The short‐term variability in elevation is primarily explained by the variability in SMB. Since SMB has not changed significantly over the last century, and the other processes change over longer time scales, the elevation change likely has been ongoing for at least the last 100 years. Key Points: Measurements of ice sheet elevation, flow divergence, firn densification, and accumulation are self‐consistent at Summit, GreenlandThe ice sheet surface at Summit, Greenland, is rising at 1.9 cm/year over the last decade, a trend likely unchanged in the last centuryShort‐term ice sheet elevation changes are dominated by surface mass balance changes [ABSTRACT FROM AUTHOR]

Global Positioning System (GPS) provides critical geodetic constraints on Earth's elastic response induced by ice and other mass loadings in Greenland. Previous studies focused on long‐term ice mass changes, with relatively fewer studies on transient signals and had used fewer GPS stations. Here we reconstructed 44 Greenland‐wide coastal decadal GPS time series using multichannel singular spectral analysis and quantified the origins of spatiotemporal patterns of transient to seasonal signals. We used an exhaustive list of geophysical processes, including surface mass balance (SMB), atmospheric pressure, continental hydrology, nontidal ocean loading, bedrock thermal expansion, precipitation, runoff, and ice discharge, and identified that most of Greenland's GPS sites exhibit SMB‐induced transient signals during 2012–2015, with maximum displacement reaching 20.45 mm. Analyses of differenced time series between adjacent GPS stations near peripheral glaciers reveal that locally varying seasonal signals are primarily attributable to SMB, followed by atmosphere. Plain Language Summary: Prior studies on Greenland ice sheet mass change mainly focused on long‐term and accelerated signals. However, the effects of multisource geophysical mechanisms on GPS observed transient or abrupt signals are relatively less studied, including quantifying locally varying spatiotemporal patterns between adjacent Global Positioning System (GPS) stations over entire Greenland. In this study, we model crustal displacements caused by an exhaustive list of geophysical mechanisms in Greenland, including atmospheric pressure, continental water storage, nontidal ocean circulation loading, bedrock thermal expansion, surface mass balance, and ice discharge. We then reconstruct the transient signals from 44 Greenland‐wide coastal GPS decadal records using multichannel singular spectral analysis. The differenced time series between adjacent GPS stations located near the peripheral glaciers reveals that locally varying deformation is primarily caused by surface mass balance loading, followed by atmosphere loading. Most of GPS observed transient signals are attributable to surface mass balance and ice discharge loading, 2009 to mid‐2011, and 2012 to 2015, which can reach a maximum displacement of 20.5 mm, with a mean displacement of 5.97 mm. Key Points: Interpretation of Greenland‐wide 44 GPS deformation time series, manifested by multisource seasonal and transient mass loading signalsWe use M‐SSA reconstructed Greenland GPS and modeled deformation data to quantify origins of spatiotemporal loading patternsDifferenced GPS time series between adjacent sites reveals that locally varying seasonal signals are primarily attributable to SMB [ABSTRACT FROM AUTHOR]

The Canadian Arctic Archipelago comprises multiple small glaciers and ice caps, mostly concentrated on Ellesmere and Baffin Islands in the northern (NCAA, Northern Canadian Arctic Archipelago) and southern parts (SCAA, Southern Canadian Arctic Archipelago) of the archipelago, respectively. Because these glaciers are small and show complex geometries, current regional climate models, using 5‐ to 20‐km horizontal resolution, do not properly resolve surface mass balance patterns. Here we present a 58‐year (1958–2015) reconstruction of daily surface mass balance of the Canadian Arctic Archipelago, statistically downscaled to 1 km from the output of the regional climate model RACMO2.3 at 11 km. By correcting for biases in elevation and ice albedo, the downscaling method significantly improves runoff estimates over narrow outlet glaciers and isolated ice fields. Since the last two decades, NCAA and SCAA glaciers have experienced warmer conditions (+1.1°C) resulting in continued mass loss of 28.2 ± 11.5 and 22.0 ± 4.5 Gt/year, respectively, more than doubling (11.9 Gt/year) and doubling (11.9 Gt/year) the pre‐1996 average. While the interior of NCAA ice caps can still buffer most of the additional melt, the lack of a perennial firn area over low‐lying SCAA glaciers has caused uninterrupted mass loss since the 1980s. In the absence of significant refreezing capacity, this indicates inevitable disappearance of these highly sensitive glaciers. [ABSTRACT FROM AUTHOR]

The article describes a procedure for separating chiral mixtures in real simulated moving bed (SMB) technology and presents a new flexible unit, the FlexSMB-LSRE. An extended SMB separation methodology was applied which considers different unit design particularities and a measures to compensate either dead volumes switching time asymmetries or delay in order to be able to separate a racemic mixture of guaifenesin with product purities higher than 98% and productivity of 23 g enantiomer/dm³CPS day in the lab-scale.

A simple unmixed reservoir was developed for the one column chromatograph with recycle analogous to an SMB (Analog) to replace mixed tanks or a complicated unmixed reservoir. Separation of the 1,1' bi-2-naphthol enantiomers was studied. In the linear range the purity index (PI) of the Analog with mixed tanks is 87.5, PI = 94.8 for the unmixed reservoir Analog, and PI = 96.9 for the SMB. SMB scaling rules, extended to Analogs, are used to increase the product purities of the unmixed reservoir Analog to match SMB purities but with lower productivity. Then productivity is increased at constant purity by operating at the maximum allowable pressure drop (15 bar) in each step. After scaling, the unmixed reservoir Analog's productivity was higher than the productivity of a standard SMB (one recycle pump) at the same purities (PI = 96.9), and the mixed tanks Analog's productivity was 3.5 times higher than the standard SMB, but with a significantly lower purity. [ABSTRACT FROM AUTHOR]

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