Promising new approach allows global and regional climate models to share process information

June 30, 2014
PNNL scientists developed an approach that allows climate models at different scales to share parameterizations and other information.

A new climate modeling approach that combines a detailed regional model with a more wide-ranging global model was developed by a team of researchers at Pacific Northwest National Laboratory, in collaboration with the University of Wyoming. This approach, described in a recent article in the journal Geoscientific Model Development, improves the way models represent atmospheric particles, clouds, and particle-cloud interactions and how they vary at regional and local scales. The approach minimizes inconsistencies in how process information is parameterized—that is, translated into simplifications that well represent process complexity.

"Our approach facilitates comparisons and produces results that agree more closely with real-world observations than previous approaches," said Dr. Po-Lun Ma, PNNL atmospheric scientist and lead author of the paper.

Understanding the past and predicting future climate trends takes lots of computational power. Global climate models break up the planet in chunks of 100 kilometers and then average climate processes over that large grid space. Because of this large scale, scientists have struggled to accurately capture regional and local variations and extreme weather events in these models. Instead, researchers often use regional-scale climate models to characterize real-world weather events, but different representations of physical, chemical, and other processes between global and regional produce inconsistent information about the atmosphere. In this study, scientists used the new modeling approach to consistently share the climate's physical process complexities at all scales-global, regional, and local.

The PNNL research team transferred a set of Community Atmosphere Model version 5.1 (CAM5) physical parameters into the regional model Weather Research and Forecasting with Chemistry (WRF-Chem). The resulting approach allowed both the high-resolution regional model and the lower-resolution global model to share information, using the same equations and computer codes for the physical and chemical representation of clouds and aerosols and consistent estimates of emissions of gases and aerosol particles. Sharing information between the models helped the researchers understand the impact of model resolution on the simulation using a consistent framework and allowed them to avoid problems typically encountered when connecting models.

The team applied the approach at multiple horizontal resolutions over an area encompassing the northern Pacific Ocean, northeast Asia, and northwest North America for April 2008. This timeframe took advantage of the data collected by a series of field campaigns managed by the U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Climate Research Facility. The researchers then evaluated the model results against those field campaign measurements, data from satellites, and ground-based observations. The modules they created through this approach are now a part of WRF-Chem 3.5, which is available online for use by other researchers.

Scientists will use data from other field campaigns to determine which set of physical and chemical representations in the models produce results more consistent with observations and why. They will focus on simulations that explore how the scale of the model affects clouds and in different climate regimes.

Explore further: The proof is in the clouds

More information: Ma PL, PJ Rasch, JD Fast, RC Easter, WI Gustafson Jr, X Liu, SJ Ghan, and B Singh. 2014. "Assessing the CAM5 Physics Suite in the WRF-Chem Model: Implementation, Resolution Sensitivity, and a First Evaluation for a Regional Case Study." Geoscientific Model Development 7:755-778. DOI: 10.5194/gmd-7-755-2014

Related Stories

The proof is in the clouds

January 26, 2012

For most people, clouds are just an indication of whether it's a "good" or "bad" day. A team of scientists from Pacific Northwest National Laboratory found that certain clouds hold the key to climate behavior prediction. ...

Taming uncertainty in climate prediction

March 23, 2012

(PhysOrg.com) -- Uncertainty just became more certain. Atmospheric and computational researchers at Pacific Northwest National Laboratory used a new scientific approach called "uncertainty quantification," or UQ, that allowed ...

Fair-weather clouds hold dirty secret

April 26, 2013

(Phys.org) —Their fluffy appearance is deceiving. Fair-weather clouds have a darker side, according to scientists at Pacific Northwest National Laboratory. Fair-weather cumulus clouds contain an increasing amount of droplets ...

Researchers reconstruct Pacific storm track in climate model

April 18, 2014

(Phys.org) —The first study that combines different scales—cloud-sized and earth-sized—in one model to simulate the effects of Asian pollution on the Pacific storm track shows that Asian pollution can influence weather ...

Tagging tiny particles in turbulent clouds

May 30, 2014

(Phys.org) —Hitching tiny atmospheric particles to cloud formation enables climate models to represent the particles' effects on convective storm systems. Scientists at Pacific Northwest National Laboratory and collaborators ...

Recommended for you

Drought's lasting impact on forests

July 30, 2015

In the virtual worlds of climate modeling, forests and other vegetation are assumed to bounce back quickly from extreme drought. But that assumption is far off the mark, according to a new study of drought impacts at forest ...

A cataclysmic event of a certain age

July 27, 2015

At the end of the Pleistocene period, approximately 12,800 years ago—give or take a few centuries—a cosmic impact triggered an abrupt cooling episode that earth scientists refer to as the Younger Dryas.

'Carbon sink' detected underneath world's deserts

July 28, 2015

The world's deserts may be storing some of the climate-changing carbon dioxide emitted by human activities, a new study suggests. Massive aquifers underneath deserts could hold more carbon than all the plants on land, according ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.