Multiple Same-Level and Telescoping Grid Nesting

Tue, 07 Jun 2022 00:00:00 +0000

Motivation

Multi-scale modeling often requires simulations at many different resolutions. This work shows how to couple coarse and fine domains within a single dynamical core, enabling cost-effective high-resolution forecasts of localized phenomena like hurricanes.

Overview

Two-way multiple same-level and telescoping grid nesting capabilities are implemented in FV3 using GFDL’s Flexible Modeling System (FMS).

A nest is an additional grid that zooms in over a region of interest to resolve the small-scale structures needed for better forecasts of localized weather events such as severe storms and hurricanes. A telescoping nest is a nest within a nest, allowing resolution to be refined progressively over the target region.

Nests can be used in both global and regional domains, and each level of the hierarchy can refine the parent resolution by an arbitrary factor.

A telescoping configuration refining a global ~13 km grid down to ~4.3 km, ~1.4 km and ~0.5 km over the region of interest.

Computational design

The nested grids run concurrently on different sets of processors and interact two-way with their parent grids. This provides more accurate results on both the nest and the parent, and reduces load imbalance between processors.

Availability

Starting from the FV3 public release of 2021, multiple same-level and telescoping nests are fully functional and available to the broader scientific community. This drastically improves overall forecast performance and opens the door to numerous research possibilities for scientists and meteorologists alike.

Reference

Mouallem, J., Harris, L., and Benson, R.: Multiple same-level and telescoping nesting in GFDL’s dynamical core, Geoscientific Model Development, 15(11), 4355-4371, 2022. https://doi.org/10.5194/gmd-15-4355-2022

Multiple same-level and telescoping nesting in GFDL's dynamical core