High-resolution Modeling
High resolution improves model accuracy and allows important small-scale processes to be simulated, reducing dependence on uncertain parameterizations. Model resolution is limited by computing power. Climate models are carefully designed to “fit” into a target computer.
High-resolution Atmosphere Modeling
Much of the most destructive behavior of the atmosphere occurs at scales of a few hundred down to a few kilometers. However, many high-impact weather events cannot be directly simulated in low-resolution climate models. Hurricanes only appear as weak lows in low-resolution models, and severe thunderstorms do not appear at all. Less intense but no less important are persistent features due to small-scale topography. Much of the precipitation in mountainous regions, so often critical for water supply in the surrounding region, is forced by small, steep slopes. Even larger-scale climate patterns are affected by smaller-scale features. Drag and blocking by mountains critically alters the global circulation of the atmosphere, and gravity waves caused by tropical thunderstorms cause a reversal of stratospheric winds about every 13 months.
High-resolution Climate Modeling
GFDL’s CM2.1 climate model, incorporating 1o ocean and 2o atmospheric components, was developed to produce output and science for the IPCC 4th assessment report. When evaluated over a broad suite of metrics this model was found to produce a high quality simulation of the present-day climate and its variability. In addition to other applications, GFDL uses the CM2.1 model for experimental seasonal predictions as part of the North American Multi-Model Ensemble (NMME).
High-resolution Ocean Modeling
The ocean mesoscales are largely dominated by baroclinic eddies, fronts, and boundary currents and they have length scales between roughly 10km-150km. Mesoscale flows are the primary cause for the ocean transport of heat, carbon, nutrients, momentum, vorticity, and other properties. However, they are extremely difficult to explicitly represent in global climate models due to their relatively small scales (about 10-times smaller than the analogous synoptic atmospheric eddies). Furthermore, the submesoscales (1km-10km) are emerging as an important dynamical regime due to their impacts on vertical motion in the upper ocean and for providing a dynamical connection to the even smaller scales where mixing and dissipation occurs. Dynamical processes at the mesoscales and submesoscales are relevant for understanding and modeling interactions near the coasts, including upwelling of nutrients for ecosystems and the movement of ocean heat under high latitude ice-shelves that can have important implications for sea level.
Research Highlights
- The resolution dependence of contiguous US precipitation extremes in response to CO2 forcing
Aug 22, 2016 - An Extreme Event of Sea-level Rise along the Northeast Coast of North America in 2009-2010
Feb 24 2015 - Response to CO2 doubling of the Atlantic Hurricane Main Development Region in a High-Resolution Climate Model
Apr 15 2013 - Controls of Global Snow Under Climate Change
Feb 15 2013 - Some counter-intuitive dependencies of tropical cyclone frequency on parameters in a GCM
Apr 20 2012 - A Model Study of Heat Waves over North America: Meteorological Aspects and Projections for the 21st Century
Mar 12 2012 - Simulated climate and climate change in the GFDL CM2.5 high-resolution coupled climate model. Journal of Climate.
Delworth et al, 2012
Recent Publications
- Rapid mixing and exchange of deep-ocean waters in an abyssal boundary current
2019 - Identifying Lagrangian coherent structures in a mesoscale eddy-permitting ocean model
October 2018 - Lagrangian timescales of Southern Ocean upwelling in a hierarchy of model resolutions
January 2018 - Frequency-domain analysis of forced versus intrinsic ocean surface kinetic energy variability in GFDL’s CM2-O model hierarchy
March 2018 - CO2-induced ocean warming around the Antarctic ice sheet in an eddying global climate model
September 2017 - Preconditioning of the Weddell Sea polynya by the ocean mesoscale and dense water overflows
October 2017 - Spiraling pathways of global deep waters to the surface of the Southern Ocean
August 2017 - Seasonal Forecasts of Major Hurricanes and Landfalling Tropical Cyclones using a High-Resolution GFDL Coupled Climate Model
November 2016 - Mechanisms of Southern Ocean heat uptake and transport in a global eddying climate model
March 2016 - Enhanced warming of the northwest Atlantic Ocean under climate change
January 2016 - Simulation and Prediction of Category 4 and 5 Hurricanes in the High-Resolution GFDL HiFLOR Coupled Climate Model
December 2015 - Role of mesoscale eddies in cross-frontal transport of heat and biogeochemical tracers in the Southern Ocean
December 2015 - Impacts on ocean heat from transient mesoscale eddies in a hierarchy of climate models
February 2015