Andrew Hoffman

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Sat, 01 Jun 2030 13:00:00 +0000

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Active and passive seismic surveys over the grounding zone of Eastwind Glacier, Antarctica

Thu, 01 Jan 2026 00:00:00 +0000

Melt channelization stronger than previously recognized: Ice sheets

Thu, 01 Jan 2026 00:00:00 +0000

Contact

Thu, 10 Apr 2025 00:00:00 +0000

Introducing the Oceans, Ice and Climate Group at Rice University

Thu, 10 Apr 2025 00:00:00 +0000

The Oceans, Ice, and Climate Group at Rice University investigates how ice sheets, and oceans interact to shape our planet’s coastlines. Our research focuses on the hidden estuarine landscapes at the grounding lines of the Antarctic and Greenland ice sheets, where glacier ice meets the ocean and drives both local and global change. We develop and deploy advanced radar systems and autonomous vehicles to image subglacial topography, measure vertical ice deformation, and monitor basal melt within ice-shelf cavities. By combining these observations with process-based ice-flow and ocean models, we study how internal ice properties, ocean heat content, and atmospheric forcing contribute to variability in melt rates, glacier discharge, and sea-level rise. Our group also explores how ice-sheet-driven sea-level changes intersect with societal vulnerability along coastlines, including in the U.S. Gulf Coast, where we apply terrestrial radar interferometry to monitor infrastructure, coastal erosion, and groundwater systems. Through interdisciplinary collaborations that span engineering, marine science, and climate modeling, we aim to build the tools and knowledge necessary to understand and adapt to coastal change in both polar and populated regions.

Opportunities

Thu, 10 Apr 2025 00:00:00 +0000

Research

Thu, 10 Apr 2025 00:00:00 +0000

Ice Flow

Sun, 05 Jan 2025 00:00:00 +0000

Englacial stresses cause ice to creep internally, with rates that depend strongly on temperature and on the evolving microstructure of crystal grains. In my group, we model glacier and ice-sheet motion to understand how englacial viscosity of the ice sheet and assumptions about slip at the ice-base interface affect glacier retreat. Using the finite element method and models like elmer/ice and icepack, we can solve equations that describe glacier flow and use some of the unique data our group collects to constrain physical processes that contribute to motion.

Multi-Element Radar

Sat, 04 Jan 2025 00:00:00 +0000

In my group, we also develop and use multi-element radar systems to image the internal structure, englacial properties, and basal conditions of glaciers and ice sheets. These systems can be used to geolocate off-nadir energy and construct 3D images of the ice-base topography and the 3D englacial structure of the ice sheet. Repeating these surveys, we can also perform multipass processing, which combines repeat surveys, coregisters passes, and performs coherent processing before interfering the coregistered profiles to map vertical displacement, strain rates, and vertical velocity. These data provide distributed observations of englacial deformation that are under-used in ice-flow model initialization.

Firn

Fri, 03 Jan 2025 00:00:00 +0000

Firn is the porous snow layer that compacts into glacier ice. Firn density, temperature, and energy evolution shape surface elevation change and set the radar wave speed, which feeds directly into satellite altimetry and radar-estimates of englacial structure. Our group has built firn models in a finite-element framework so compaction, heat transport, and meltwater processes can be solved consistently and used with inverse methods to assimilate observations of compaction to initialize poorly constrained densification parameters. These constraints improve the interpretation of radar travel times, satellite altimetry trends, and can be used to reconstruct past climate from firn observations.

Submarine Ice-Shelf Melt

Thu, 02 Jan 2025 00:00:00 +0000

Warm salty ocean water can circulate beneath ice shelves and melt them from below. Ice shelves float, so this melt does not raise sea level directly, but thinning reduces buttressing and can speed up the flow of grounded ice into the ocean. The IPCC links much of West Antarctica’s observed mass loss since the early 1990s to changes in ice shelves driven by basal melting, and estimates of Antarctic basal meltwater flux are on the order of 1100 to 1600 gigatons per year in recent decades. Antarctica’s grounded ice loss has already raised global mean sea level by about 7.4 ± 1.5 mm since 1992. Our group is developing methods that use time series of high-resolution stereo satellite imagery to map elevation change over floating ice. Repeated stereo DEMs are co-registered and differenced, then combined with estimates of englacial stresses and surface mass balance to isolate basal melt rates.

Amundsen Sea Embayment accumulation variability measured with global navigation satellite system interferometric reflectometry