Kilometer-Scale E3SM Land Model Simulation over North America

TL;DR

This paper presents the development and execution of the first large-scale kilometer-resolution E3SM land model simulations over North America, demonstrating high performance and scalability on exascale computing systems.

Contribution

It introduces a novel, high-resolution land model simulation at a continental scale, utilizing extensive computational resources and demonstrating exceptional scalability and adaptability.

Findings

Simulated 21.6 million land gridcells at 1 km resolution over North America.

Achieved the largest km-scale ELM simulation to date, using 100,800 CPU cores.

Demonstrated high efficiency and scalability in large-scale Earth system modeling.

Abstract

The development of a kilometer-scale E3SM Land Model (km-scale ELM) is an integral part of the E3SM project, which seeks to advance energy-related Earth system science research with state-of-the-art modeling and simulation capabilities on exascale computing systems. Through the utilization of high-fidelity data products, such as atmospheric forcing and soil properties, the km-scale ELM plays a critical role in accurately modeling geographical characteristics and extreme weather occurrences. The model is vital for enhancing our comprehension and prediction of climate patterns, as well as their effects on ecosystems and human activities. This study showcases the first set of full-capability, km-scale ELM simulations over various computational domains, including simulations encompassing 21.6 million land gridcells, reflecting approximately 21.5 million square kilometers of North America at a 1 km x 1 km resolution. We present the largest km-scale ELM simulation using up to 100,800 CPU cores across 2,400 nodes. This continental-scale simulation is 300 times larger than any previous studies, and the computational resources used are about 400 times larger than those used in prior efforts. Both strong and weak scaling tests have been conducted, revealing exceptional performance efficiency and resource utilization. The km-scale ELM uses the common E3SM modeling infrastructure and a general data toolkit known as KiloCraft. Consequently, it can be readily adapted for both fully-coupled E3SM simulations and data-driven simulations over specific areas, ranging from a single gridcell to the entire North America.