More Like this

1. Holocene accumulation and ice flow near the West Antarctic Ice Sheet Divide ice core site

   https://doi.org/10.1002/2015JF003668  

   Koutnik, Michelle R.; Fudge, T. J.; Conway, Howard; Waddington, Edwin D.; Neumann, Thomas A.; Cuffey, Kurt M.; Buizert, Christo; Taylor, Kendrick C. (May 2016, Journal of Geophysical Research: Earth Surface)
2. How Sea Ice Drift Influences Sea Ice Area and Volume

   https://doi.org/10.1029/2021GL093069  

   Wagner, T. J.; Eisenman, I.; Mason, H. C. (October 2021, Geophysical Research Letters)

   null (Ed.)
3. Basal debris of the NEEM ice core, Greenland: a window into sub-ice-sheet geology, basal ice processes and ice-sheet oscillations

   https://doi.org/10.1017/jog.2022.122  

   Blard, Pierre-Henri; Protin, Marie; Tison, Jean-Louis; Fripiat, François; Dahl-Jensen, Dorthe; Steffensen, Jørgen P.; Mahaney, William C.; Bierman, Paul R.; Christ, Andrew J.; Corbett, Lee B.; et al (August 2023, Journal of Glaciology)

   Abstract We present new data from the debris-rich basal ice layers of the NEEM ice core (NW Greenland). Using mineralogical observations, SEM imagery, geochemical data from silicates (meteoric¹⁰Be, εNd,⁸⁷Sr/⁸⁶Sr) and organic material (C/N, δ¹³C), we characterize the source material, succession of previous glaciations and deglaciations and the paleoecological conditions during ice-free episodes. Meteoric¹⁰Be data and grain features indicate that the ice sheet interacted with paleosols and eroded fresh bedrock, leading to mixing in these debris-rich ice layers. Our analysis also identifies four successive stages in NW Greenland: (1) initial preglacial conditions, (2) glacial advance 1, (3) glacial retreat and interglacial conditions and (4) glacial advance 2 (current ice-sheet development). C/N and δ¹³C data suggest that deglacial environments favored the development of tundra and taiga ecosystems. These two successive glacial fluctuations observed at NEEM are consistent with those identified from the Camp Century core basal sediments over the last 3 Ma. Further inland, GRIP and GISP2 summit sites have remained glaciated more continuously than the western margin, with less intense ice-substratum interactions than those observed at NEEM. 

   more » « less
4. Stability of Ice Shelves and Ice Cliffs in a Changing Climate

   https://doi.org/10.1146/annurev-earth-040522-122817  

   Bassis, Jeremy N.; Crawford, Anna; Kachuck, Samuel B.; Benn, Douglas I.; Walker, Catherine; Millstein, Joanna; Duddu, Ravindra; Åström, Jan; Fricker, Helen; Luckman, Adrian (May 2024, Annual Review of Earth and Planetary Sciences)

   The largest uncertainty in future sea-level rise is loss of ice from the Greenland and Antarctic Ice Sheets. Ice shelves, freely floating platforms of ice that fringe the ice sheets, play a crucial role in restraining discharge of grounded ice into the ocean through buttressing. However, since the 1990s, several ice shelves have thinned, retreated, and collapsed. If this pattern continues, it could expose thick cliffs that become structurally unstable and collapse in a process called marine ice cliff instability (MICI). However, the feedbacks between calving, retreat, and other forcings are not well understood. Here we review observed modes of calving from ice shelves and marine-terminating glaciers, and their relation to environmental forces. We show that the primary driver of calving is long-term internal glaciological stress, but as ice shelves thin they may become more vulnerable to environmental forcing. This vulnerability—and the potential for MICI—comes from a combination of the distribution of preexisting flaws within the ice and regions where the stress is large enough to initiate fracture. Although significant progress has been made modeling these processes, theories must now be tested against a wide range of environmental and glaciological conditions in both modern and paleo conditions. ▪ Ice shelves, floating platforms of ice fed by ice sheets, shed mass in a near-instantaneous fashion through iceberg calving. ▪ Most ice shelves exhibit a stable cycle of calving front advance and retreat that is insensitive to small changes in environmental conditions. ▪ Some ice shelves have retreated or collapsed completely, and in the future this could expose thick cliffs that could become structurally unstable called ice cliff instability. ▪ The potential for ice shelf and ice cliff instability is controlled by the presence and evolution of flaws or fractures within the ice. 

   more » « less
5. Buffer gas cooled ice chemistry. II. Ice generation and mm-wave detection of molecules desorbed from an ice

   https://doi.org/10.1063/5.0225903  

   Hager, T J; Moore, B M; Borengasser, Q D; Kanaherarachchi, A C; Renshaw, K T; Radhakrishnan, S; Hall, G E; Broderick, B M (September 2024, The Journal of Chemical Physics)

   This second paper in a series of two describes the chirped-pulse ice apparatus that permits the detection of buffer gas cooled molecules desorbed from an energetically processed ice using broadband mm-wave rotational spectroscopy. Here, we detail the lower ice stage developed to generate ices at 4 K, which can then undergo energetic processing via UV/VUV photons or high-energy electrons and which ultimately enter the gas phase via temperature-programmed desorption (TPD). Over the course of TPD, the lower ice stage is interfaced with a buffer gas cooling cell that allows for sensitive detection via chirped-pulse rotational spectroscopy in the 60–90 GHz regime. In addition to a detailed description of the ice component of this apparatus, we show proof-of-principle experiments demonstrating the detection of H2CO products formed through irradiation of neat methanol ices or 1:1 CO + CH4 mixed ices. 

   more » « less