Graph Neural Network as Computationally Efficient Emulator of Ice-sheet and Sea-level System Model (ISSM)
Younghyun Koo, Maryam Rahnemoonfar
TL;DR
This work addresses the computational bottleneck of CPU-only ISSM by introducing a GPU-based Graph Convolutional Network (GCN) emulator trained on 20-year Pine Island Glacier simulations. The GCN ingests inputs $x$, $y$, time, and basal melting rate to predict outputs $v_x$, $v_y$, and ice thickness $h$, using five graph convolutional layers with 128 features and distance-weighted neighbor aggregation. Fidelity analyses show correlations exceeding $0.996$ (and up to near $0.998$ reported) with ISSM for velocity and thickness, with GCN outperforming a Fully Convolutional Network baseline. In terms of performance, the GPU-based GCN achieves about $33.8\times$ speedup over CPU ISSM, enabling rapid exploration of basal-melting-rate scenarios and future sea-level impacts, thereby offering a scalable tool for climate-change impact studies on Antarctic and Greenland ice sheets.
Abstract
The Ice-sheet and Sea-level System Model (ISSM) provides solutions for Stokes equations relevant to ice sheet dynamics by employing finite element and fine mesh adaption. However, since its finite element method is compatible only with Central Processing Units (CPU), the ISSM has limits on further economizing computational time. Thus, by taking advantage of Graphics Processing Units (GPUs), we design a graph convolutional network (GCN) as a fast emulator for ISSM. The GCN is trained and tested using the 20-year transient ISSM simulations in the Pine Island Glacier (PIG). The GCN reproduces ice thickness and velocity with a correlation coefficient greater than 0.998, outperforming the traditional convolutional neural network (CNN). Additionally, GCN shows 34 times faster computational speed than the CPU-based ISSM modeling. The GPU-based GCN emulator allows us to predict how the PIG will change in the future under different melting rate scenarios with high fidelity and much faster computational time.
