Unified Forecast System
Earth Prediction Innovation Center

UFS Webinar

Novel grid capabilities in GFDL’s dynamical core FV3

Dr. Joseph Mouallem

We present the latest grid-related capabilities implemented in Geophysical Fluid Dynamics Laboratory (GFDL)’s Finite-Volume Cubed-Sphere Dynamical Core (FV3): multiple nested grids and the Duo-Grid. First, two-way multiple same-level and telescoping grid nesting allows simulating various independent weather events in greater detail by resolving smaller-scale flow structures. Nested grids run concurrently on different sets of processors to optimize the overall computational performance. Second, a Duo-Grid system is implemented to reduce cubed-sphere grid imprinting in FV3. The Duo-Grid algorithm consists of remapping a tile’s halo data from neighboring tiles from kinked to natural locations along great circle lines. Results from idealized test cases show that error norms are greatly reduced and grid imprinting is practically eliminated in the numerical solutions. This comes at the expense of an increase in computational cost.

Joseph is a Computational Scientist /Research Engineer, currently working at the Weather and Climate Division of GFDL/NOAA and the Cooperative Institute for Modeling the Earth System at Princeton University.

 In 2014, as part of a dual degree program, he earned his BSc in Mechanical Engineering from the Lebanese University in 2014, and a MSc in Fluid Mechanics from the  National Institute of applied science of Lyon, France. In 2018, he completed his Ph.D. in Mechanical Engineering, specializing in Thermal and Fluid Sciences, from the University of São Paulo, Brazil, supported by a national scholarship award.

He then joined the Department of Mechanical and Mechatronics Engineering at the University of Waterloo, Canada, as a postdoctoral fellow and sessional lecturer focusing on fluid mechanics until early 2020 when he joined GFDL.

At Princeton and GFDL, he is currently developing new numerical technologies and algorithms in GFDL’s dynamical core FV3. Today he will talk about the multiple same level and telescoping nesting and the Duogrid in FV3.

Presentation Slides