HPCwire: Visualizing This

The Leading Source for Global News and Information Covering the Ecosystem of High Productivity Computing

Leading HPC
Solution Providers

HPCwire >> Topic >> Visualization

February 08, 2008

Visualizing This

NERSC's new Cray and analytics experts produce animations of climate models with fine details

A team of climate researchers who obtained early access to NERSC's new Cray XT4 said the powerful system produced simulations that offered details of oceanic and atmospheric phenomena, results that were difficult to obtain from other supercomputers before.

At the DOE's behest, scientists from the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory (GFDL) proposed a set of experiments using climate models with resolutions many times higher than those in the standard models, such as those used by the IPCC.

The high-resolution models offer not only a closer look at physical elements of the climate, such as tropical storms, but they also enable researchers to conduct a more in-depth analysis of climate change as higher-resolution phenomena in the ocean and atmosphere are resolved.

For years, scientists worldwide have relied on simulations with resolutions in the 100-kilometer range for studying forces that shape the oceans and the atmosphere. But the resolution isn't high enough to model details such as ocean vortices and clouds, phenomena that are critical for understanding regional climate variations. Developing a climate model is a computationally intensive task, and getting enough time on powerful supercomputers has always been a challenge.

GFDL scientists, located in Princeton, New Jersey, had developed models capable of modeling the global atmosphere at resolutions down to 5 km, and the ocean at resolutions between 10 km and 20 km. They also have designed experiments which generated 1 to 4 terabytes of data for every year of simulation. NERSC provided GFDL with the computation resources for this challenge by setting aside over 800,000 CPU hours on the new Cray XT4 named Franklin.

Franklin has nearly 20,000 processor cores and a top processing speed of more than 100 teraflops, making it one of the largest in the world. It arrived at NERSC early last year and passed rigorous testing, which was announced last November.

In addition to carrying out successful runs on Franklin, GFDL also received strong support from NERSC's Analytics Team in using animations to illustrate the results. Prabhat from the Analytics Team created a series of visual renderings of data that included sea surface temperatures and clouds and precipitations in different parts of the world.

"We are able to increase our models' resolutions because of our access to the NERSC machine. One of the results is we can see category 4 or 5 hurricanes in a 20-km model, and they are what we would expect to see in the real world," said V. Balaji, head of the Modeling Services Group at GFDL. Senior software developer Christopher Kerr at GFDL and other members of Balaji's team were responsible for enabling the software infrastructure to perform these scientific experiments. Richard Gerber, a NERSC consultant, resolved systemrelated issues so that the experiments could be performed on Franklin.

"The results of the visualization collaboration have been outstanding," Balaji added.

The NERSC Analytics Team used the VisIt visualization and analysis package to create images and movies for climate scientists at GFDL. VisIt, which recently won an R&D 100 award, was developed by the DOE Advanced Simulation and Computing Initiative (ASCI) to visualize and analyze the results of large-scale simulations. The team accelerated time to discovery by developing software that eliminates costly data format conversion barriers, namely extra computation, extra data storage and more manual processing steps. As a result, it was possible to load the simulation output generated on Franklin directly into VisIt for visual data exploration and analysis.

Developing the visualizations was a collaborative effort. The Analytics Team had extensive interactions with GFDL staff and scientists in order to create visualizations that focus on the most interesting and significant phenomena (e.g., the formation of tropical storms and ocean eddies). The visualizations present the simulation data in an accessible format using conventions familiar to the climate modeling community. Because of the work done by the Analytics Team, VisIt now provides GFDL scientists with the capability to do large-scale visualization of climate data, which was impossible with conventional visualization tools. The Analytics Team has installed VisIt at GFDL to allow scientists to use the new visualization capability on a day-to-day basis.

The climate modeling project, called the Coupled High-Resolution Modeling of the Earth System (CHiMES), began as a collaboration between NOAA/GFDL and DOE. The research uses comprehensive Earth system models (ESMs) and historical data to examine how climate has changed over time and what external forces will likely influence the climate in the future. The models are based on the Flexible Modeling System (FMS) developed by GFDL. FMS is a powerful computational infrastructure for constructing coupled climate models on high-end scalable computer architecture.

The CHiMES project seeks to understand how the overall climate responds to high-resolution phenomena such as ocean eddies, as well as how fine-scale events such as tropical storms respond to climate change. To answer these questions, the project has been divided into two parts. One is to study the climate's predictability over decades or longer using high-resolution coupled models. The second part is to study the correlations between tropical storms and climate change, a hot topic in the research world. Work by GFDL researchers on this subject appeared in over 35 publications in scientific peerreviewed journals last year.

For the hurricane research, CHiMES uses an atmospheric model based on the cubed sphere grid developed by lead scientist S.J. Lin at GFDL. This projection of a grid over the surface of the Earth, is a more scalable basis than latitudes and longitudes for solving the equations of computational fluid dynamics on a sphere. The researchers have done testruns using the cubed sphere and found that the highly scalable methodology would enable them to carry out simulations with a 5-km resolution.

"We can go a lot further on this model," Balaji said. "If the coupled model simulations done at NERSC represent today's leading edge, this model is already showing what will be possible when the next generation of hardware becomes available."

-----

Source: NERSC News, Jan. 2008 -- http://www.nersc.gov/news/nerscnews

Article Tools

Share & Save Options

Discussion

There are 0 discussion items posted.

Join the Discussion

You must be a registered user in order to comment on HPCwire stories.

Members enjoy:

	Access to Special Content, including Podcasts, Webcasts, and Whitepapers and more!
	Ability to take an active role in the discussions that are shaping the HPC technology discipline!
	Special offers available only to HPCwire members!

Become a Registered User Today!

Registered Users Log in Here to Comment

Email Address:	Password (case sensitive)

Remember me	Forgot Password?

RSS Feeds

Feeds by Topic

Feeds by Industry

Feeds by Content Type

Feature Articles

The New Science of Visual Analytics

When Jim Thomas set out to find new ways to deal with the mountains of information our society generates, he didn't just create a new organization, he created a new science. In this article we'll take a look at how the National Visualization and Analytics Center is transforming the problem of finding needles in haystacks into an opportunity for a more secure future.
Read More...

The Week in Review

ORNL Jaguar doubles its performance; the SC08 Cluster Challenge is gearing up; the University of Central Florida uses Army dollars to purchase an IBM super; and IBM's RoadRunner prepares to break the petaflop barrier. John West recaps those stories and more in our weekly wrap-up.
Read More...

Revaluating FPGAs for 64-bit Floating-Point Calculations

We now have generally available 2.5 GHz quad-core Opterons and Virtex-5 LX330, SX95T and recently announced SX240T FPGAs. In addition to this, Xilinx is releasing a new version of their floating-point cores that reduces the amount of logic and DSP slices needed for building floating-point function units. Taken together it is time to revisit Opteron floating-point performance versus FPGA performance.
Read More...

Read more HPCwire features...

Top Headlines

Parallel Processing Calls for a Fortress Mentality

May 14 | InfoWorld | Sun Microsystems is taking the lessons learned from Java and applying them to the application development challenges of the high performance computing realm. Read more...

IBM Set to Test the Fastest Computer in the World

May 14 | Computerworld | IBM is assembling the final pieces of what they hope will soon become the world's most powerful supercomputer. Read more...

IBM Shifts Cell to 65 Nanometers

May 13 | EETimes | IBM Corp. has announced the next-generation version of its Cell processor, the first specifically geared for computer servers. Read more...

Record-Setting Simulations on Ranger Reconstruct the Reionization Era

May 12 | Texas Advanced Computing Center | In the coming months, Dr. Michael L. Norman of UCSD will use Ranger, the world's most powerful supercomputer for open-science research, to perform the largest cosmological simulation to date. Read more...

2 AMD Executives Out in Restructuring Amid Slump

May 12 | BusinessWeek | Two executives have left AMD, including the head of the slumping chip maker's microprocessor division, as the company tries to engineer a dramatic turnaround to fend off larger rival Intel Corp. Read more...

Read more headlines...

Multimedia

Podcast: Interview with Ben Bennett of ClearSpeed Technology

Today, HPC organizations are requiring substantially more floating point performance to solve real-world problems. In this podcast, Ben Bennett, ClearSpeed General Manager, discusses how acceleration technology can improve the overall performance of standard x86-based systems...