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       Advancing the knowledge of climate change and understanding its consequences


CCSI Brown Bag

A multiscale strategy for modeling root water uptake in next-generation watershed models 

Scott L. Painter
Seminar Location: 
Building 4500N Room F119
Seminar Time: 
Saturday, May 30, 2015 - 12:00

Root water uptake in moisture-limited conditions has traditionally been represented in watershed models through empirical correlations that restrict transpiration based on soil moisture state. Although such empirical approaches may be reliably calibrated in current conditions, the lack of a strong mechanistic basis raises questions about the reliability of empirical approaches in future drought conditions that may be outside the range of present-day conditions used to develop the correlations. Models that explicitly solve for 3-D moisture content in soils surrounding an explicitly or implicitly represented root architecture (e.g. R-SWMS, aRoot) have started to emerge and have potential to improve the mechanistic basis for root water uptake models. A computational strategy for using that fine-scale modeling approach to inform coarse-scale watershed models is under development. At the fine scale, capability to model flow in a 3-D explicitly represented root architecture coupled to a 3-D representation of the surrounding soil is being implemented in the highly parallel PFLOTRAN code. This fine-scale root-soil model will then be used to develop and parameterize more approximate representations for use at coarser scales. In particular, a multidomain approach that represents root xylem, rhizosphere, soil near–field, and bulk soil as distinct but interacting flow systems is being explored. By explicitly solving for moisture content in the boundary layer between roots and bulk soil, dynamic changes in root–soil hydraulic resistance is expected to be better represented. In addition, hydraulic redistribution – the movement of water from wetter to drier soil along roots – is explicitly represented in the proposed approach. Although the research is targeting one specific process, hydraulic coupling, the proposed multiscale strategy provides a potential computational framework for next-generation process-rich watershed models for investigating climate change impacts on water supply, nutrient export, and the carbon cycle in critical watersheds. 

CCSI Seminar

High-Order Adaptive Mesh Refinement (AMR) and Variable-Resolution Techniques for Atmospheric General Circulation Models

Christiane Jablonowski
Speaker's Title: 
Associate Professor
Speaker's Affiliation: 
University of Michigan
Seminar Location: 
JICS Auditorium Building 5100 Room 128
Seminar Time: 
Wednesday, April 8, 2015 - 10:00
Katherine J. Evans

The talk reviews two approaches to high-order variable-resolution modeling that have recently been designed for atmospheric General Circulation Models. The first approach is based on the Adaptive Mesh Refinement (AMR) library Chombo that supports fourth-order finite volume methods for block-structured adaptive meshes on cubed-sphere grids. The Chombo-AMR model has been jointly developed by the Lawrence Berkeley National Laboratory and the University of Michigan. The second variable-resolution approach is based on the Spectral Element (SE) dynamical core that has been implemented on a cubed-sphere grid in the Community Atmosphere Model (CAM). The latter has been jointly developed by NCAR and various Department of Energy laboratories.

The talk discusses the characteristics of both variable-resolution methods using a hierarchy of test cases and flow scenarios. In particular, the AMR-Chombo model is evaluated in the 2D shallow-water framework, and various refinement criteria are compared. The CAM-SE model is assessed in an idealized 3D dynamical core framework as well as in aqua-planet and realistic configurations. Special attention is paid to the flow conditions in the grid transition regions to assess whether spurious noise is present. The talk highlights the many application areas of variable-resolution techniques which e.g. span tropical cyclone forecasting and regional climate modeling.

UV-CDAT team wins Federal Laboratory Consortium Interagency Partnership Award

Members of the Oak Ridge National Laboratory (ORNL) Climate Change Science Institute and the National Center for Computational Sciences were part of a team that won the prestigious Federal Laboratory Consortium (FLC) Interagency Partnership Award for 2015 for the Ultra-Scale Visualization Climate Data Analysis Tools (UV-CDAT) project. The award will be presented at the FLC annual meeting in Denver in April.

Permafrost thaw study investigates landscape changes on Alaska’s Seward Peninsula

Now in its third year, the Oak Ridge National Laboratory Climate Change Science Institute’s (CCSI’s) Model-Data Fusion project (as it is called for short) consolidates data from satellite imaging, remote sensing, and fieldwork in Arctic Alaska to assess the thawing of permafrost, or frozen soil, and its impact on carbon release and uptake.

Homeland Security awards ORNL team for highlighting climate change risks to vulnerable Maine bay

Members of Oak Ridge National Laboratory’s (ORNL’s) Climate Change Science and Urban Dynamics Institutes, in collaboration with team members from the US Department of Homeland Security (DHS) and other US Department of Energy national laboratories, have been awarded the DHS Office of Infrastructure Protection’s Trailblazer Award for their contributions to a DHS project known as the Regional Resiliency Assessment Program (RRAP).

ORNL forest threat warning system in White House’s “top 25” climate resilience tools

ForWarn, the early warning system for forest threats developed by Oak Ridge National Laboratory (ORNL) and Climate Change Science Institute researchers and collaborators, has been included in the US Climate Resilience Toolkit’s “top 25” tools.

ORNL’s James Hack elected Fellow of American Meteorological Society

James Hack, director of the National Center for Computational Sciences at the Department of Energy’s Oak Ridge National Laboratory (ORNL), has been elected a 2015 Fellow by the American Meteorological Society (AMS). Hack, also founding director of ORNL’s Climate Change Science Institute, was cited for his “outstanding contributions to advancing the atmospheric and related sciences, technologies, applications and services for the benefit of societ

Subsurface science expert Scott Painter joins CCSI staff from LANL

The Climate Change Science Institute (CCSI) at Oak Ridge National Laboratory (ORNL) welcomes subsurface flow and reactive transport modeler Scott Painter. Scott is joining multiple ORNL projects, including the Next-Generation Ecosystem Experiments (NGEE)–Arctic and NGEE–Tropics. He will also lead one of the use cases for the new Interoperable Design of Extreme-scale Application Software (IDEAS) project, which he helped develop.

Slide image details

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Image provided by Jamison Daniel, NCCS.




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Global temperature anomalies from 1880 - 2010 (land and ocean). Image source:




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Risk assessment for future coastal inundation and erosion for properties at Manly Beach, north of Sydney, Australia. Image provided by Ben Preston, ORNL.


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Spruce and Peatland Responses Under Climatic and Environmental Change (SPRUCE) Field Experiment in Grand Rapids, MN.  Images provided by Paul Hanson.

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Global carbon emissions from fossil fuels combustion and cement manufacturing 1850-2010.  Image source: