In 2008 CISL commissioned Bluefire for the NCAR user community, one of the first IBM POWER6™ computers. A large portion of Bluefire was reserved from September through November 2008 for the Accelerated Scientific Discovery (ASD) program, the successor to the successful Breakthrough Science (BTS) initiative held in 2007 for researchers in the atmospheric, oceanic, and related sciences. The competitive selection process awarded eight university, NCAR, and joint university/NCAR projects with approximately 3M GAUs (equivalent to 2.14M processor hours). To support the computational efforts of the ASD initiative, CISL's Data Analysis Service Group (DASG) provided award recipients with data analysis and post-processing computing resources and storage (over 30 TBs of disk space), along with advanced user support for scientific visualization. The analysis phase of the ASD program will continue late into 2009. A sampling of the results from this program is shown below.

ASD Projects

Examining the role of small-scale processes on the global system in the
corona, the magnetosphere and the ionosphere

Aaron Ridley, University of Michigan
Ward Manchester, University of Michigan

Coronal mass ejections (CMEs) are energetic expulsions of plasma from the solar corona
that are driven by the release of magnetic energy typically in the range of 10^32−33
ergs. The
ma jority of CMEs originate from the eruption of pre-existing large-scale helmet streamers.
Less common fast CMEs typically come from smaller, more concentrated locations of magnetic
flux referred to as active regions. In this case, the CMEs often occur shortly after the flux
has emerged at the photosphere, but can also happen even as the active region is decaying.
While CMEs occur in a wide range of circumstances there are common features that suggest
that the coronal magnetic fields that spawn CMEs and large flares are coupled to the solar
interior. In the case of homologous CMEs, more than two-dozen eruptions may occur from
the same active region, often separated by only a few hours. Such repetitive behavior suggests
that the magnetic field can be continuously recharged over a relatively short period of time.
A connection of CMEs to the solar interior dynamo is suggested by the role CMEs play in
restructuring the global coronal magnetic field during the solar cycle by expelling magnetic
flux and helicity.

The above figure shows simulation of a magnetic flux rope 5000 km below the photosphere.
The central part of the flux rope is made buoyant and allowed to rise through the stratified
atmosphere. After the flux rope rises through the photosphere, we find it the upper extremity
of the rope erupts into the corona, while the main body (including the center line) remains
below the photosphere. The flux rope
is colored to show the vertical field strength. The upper part of the flux rope erupts as a result
of shear flows driven by the Lorentz force. The shear flows are the result of deformation of the magnetic field in the stratified atmosphere causes the electric current to be oblique to the
magnetic field, producing the Lorentz force that drives the horizontal shear flow (Manchester
et al. (2004)).

Eddy-Induced Tracer Variability

Sabine Mecking, Univ. Washington
Luanne Thompson, Univ. Washington
Julie McClean, Scripps Institute of Oceanography
Synte Peacock, NCAR/CGD
Frank Bryan, NCAR/CGD

The distribution of freon-11 in the deep waters of the Northwest Atlantic was simulated by a high-resolution ocean general circulation model This industrial chemical has been entering the ocean since the mid-20th century. It is carried into the deep ocean in high latitudes by the sinking of cold dense waters, and spreads towards the equator through narrow boundary
currents and through mixing by turbulent eddies. This simulation is being analyzed to characterize the magnitude of spatial and temporal variability in the ocean freon distribution associated with this eddy stirring and mixing process.

The following two images characterize the more familiar quantities of near surface salinity and vorticity from the same simulation. The vorticity image on the right was produced by Mat Maltrud of LANL.

The movies below show a time evolution of near-surface salinity in the Atlantic at monthly (left image) and 5-day sampling (right image).

Rotation and helicity in turbulent flows

Pablo Mininni, NCAR & University of Buenos Aires
Annick Pouquet, NCAR
Duane Rosenberg, NCAR

Invariance properties of a physical system govern its behavior: energy conservation in turbulence drives a wide distribution of energy among modes, as observed in geophysics, astrophysics and engineering. In hydrodynamic turbulence, the role of helicity (which measures departures from mirror symmetry) remains unclear since it does not alter this distribution. However, the interplay of rotation and helicity leads to significant differences. Using numerical simulations we show the occurrence of long-lived laminar cyclonic vortices together with turbulent vortices, reminiscent of recent tornado observations. Furthermore, the small scales are completely self-similar with no deviations from Gaussianity. This result points to the discovery of a small parameter in rotating helical turbulence.

Shown below are visualizations produced with VAPOR (www.vapor.ucar.edu) of a small region at late times in a 1536^3 simulation of helical rotating turbulence. From left-to-right, top-to-bottom are the z component of velocity, vorticity intensity with velocity field lines in red, a close-up of the vorticity field, and helicity (alignment of velocity and vorticity, green is negative and blue-magenta is positive). The Reynolds number for the simulation is ~5600 and the Rossby number is ~0.06. Note the co-location of laminar structures, with smooth paths, and a tangle of vortex filaments with more complex paths. These structures co-exist at very disparate scales.

Effect of Global Warming on U.S. Regional Climate

Greg Holland, NCAR
Jim Hurrell, NCAR
James Done, NCAR
Joe Tribbia, NCAR
Peter Webster, Georgia Tech
Asuka Suzuki-Parker, NCAR
Ruby Leung, PNL

NCAR scientists are using a combination of weather and climate computer models to simulate the atmosphere in three dimensions at resolutions ranging from about 20 miles across a large part of the Northern Hemisphere to as fine as 2.5 miles in targeted areas of North America. This strategy enables scientists to forecast future climate in detail for specific regions without overloading existing supercomputing resources. Researchers will examine three decades in detail: 1995-2005, 2020-2030, and 2045-2055. They will use statistical techniques to fill in the gaps between these decades. A major goal is to examine how several decades of greenhouse-gas buildup could affect regional climate with particular emphasis on water resources over the Western US.


Atmospheric rivers of moisture flowing up from the tropical Pacific against the West Coast of the US. These rich moisture sources contribute to powerful winter storms over that often produce damaging winds and flash floods. See the movie: low resolution or high resolution.	Model-derived 'satellite imagery' of a powerful winter storm impacting the West Coast of the US. These data will be used to explore how these powerful events may change in the future and how these changes may affect water resources in the Western US. See the movie: low resolution or high resolution.

	See the movie here.

Assessing Winter Precipitation, Snowpack and Runoff Processes from Colorado’s Headwater Basins using a Very High Resolution Fully Coupled Atmospheric-Hydrologic Model

Roy Rasmussen, NCAR/RAL
Kyoko Ikeda, NCAR
Changhai Liu, NCAR/MMM
Fei Chen, NCAR
Mukul Tewari, NCAR
David Gochis, NCAR/RAL
Greg Thomson, NCAR
David Yates, NCAR
Aiguo Dai, NCAR/CGD, ESSL
Kathy Miller, NCAR/ISSE
Mitch Moncrieff, NCAR/MMM
Vand Grubisic, Univeristy of Vienna
Jimmy Dudhia, NCAR
Kristi Arsenault, George Mason University
Paul Houser, George Mason University
Noah Molotch, UCLA
Zong-Liang Yang, University of Texas

Snowpack is the most important source in the western U.S., and thus
it is critical that water managers be provided with as accurate as
possible estimate of the likely changes expected of this resource
in the future. Previous climate studies have shown that the head
waters region of the Colorado river seems to be a particularly
difficult area for climate model to handle, with inconsistent
snowpack trends in this region from both the 3rd and 4th IPCC reports
(2001, 2007), despite consistent prediction of temperature increases
in this region from all climate models. In this study WRF simulations
of snowfall between 1 November and 1 May were performed over the
Colorado Headwaters region for: (1) retrospective years (2001-02,
2003-04, 2005-06, and 2007-8) at a horizontal grid resolution of 2
km, (2) 2007-08 season at coarser resolution of 6, 18, and 36 km
using North American Regional Reanlalysis data, and (3) future
climate scenario at 2 km grid resolution using NARR data for the
retrospective years perturbed with the CCSM3 model output for an
A1B simulation conducted for the IPPC report to initialize the
simulation. Key questions explored in this study are, (1) will the
predicted increase in snowfall due to a warmer, moister climate be
enough to offset the enhanced melting and sublimation due to the
warmer temperatures, (2) will this be sufficient to maintain river
flow at current levels, or is it expected to decrease, and (3) how
high resolution of the regional climate model do we need to answer
these questions. Analysis is currently in progress. Figures 1-3
highlight preliminary results from the study thus far.

Figure 1: Time history of accumulative precipitation between 1
November 2007 and 1 May 2008 comparing average precipitation simulated
with the WRF model at 2, 6, 18, and 36 km grid resolutions and
measured at 112 SNOTEL sites (http://www.wcc.nrcs.usda.gov/snotel/)
throughout the Colorado Headwaters domain and simulated with the
model. Average of values at four grid points nearest to the individual
SNOTEL sites were taken from the simulation outputs. Precipitation
from the PRISM data base (http://www.prism.oregonstate.edu/) is
also overlaid. The figure indicates that precipitation simulated
at a grid resolution of 2 and 6 km agree well with the measurements
at SNOTEL sites. Precipitation is significantly underestimated (15
% at 18 km, 30 % at 36 km) at coarser resolutions. The main reason
for the better agreement with the observations with 2 and 6 km
resolutions is the improved resolution of topography which better
resolves vertical motions.

Figure 2: Spatial distribution of total precipitation simulated at
(a) 36 km, (b) 18 km, (c) 6 km, and (d) 2 km grid resolutions for
the simulation period between 1 November 2007 and 1 May 2008. Panel
(e) shows the total precipitation measured at 112 SNOTEL sites
during the same six month period. Compared with the 18 and 36 km
resolution runs, at 2 and 6 km resolutions the model produced more
snowfall over the mountain peaks, which agree well with the
observations (e), and less precipitation over the valleys. Analysis
showed that the improved spatial distribution at 2 and 6 km is
related to stronger vertical motions produced near the mountain
peaks as mentioned in Fig. 1. Since the peaks are also colder in
the 2 and 6 km simulations, the snow at the peaks last longer than
in the 18 and 36 km runs. This can have significant impact on the
subsequent melting and sublimation of snow and its evolution into
streamflow.

Figure 3: Time history of precipitation accumulation from the
retrospective simulation using NARR data from 2007-08 (labeled
Current Climate) and the NARR data perturbed for future climate
based on the CCSM3 output for an A1B simulation [labeled PGW
(Pseudo-Global Warming)]. The result indicate an increase in
precipitation by ~14 % in a warmer future climate.

Simulating the Effects of Anthropogenically Enhanced Global Radiative Forcing on Convective Storms and Associated Weather Hazards

Robert J. Trapp, Purdue Univ.
Noah S. Diffenbaugh, Purdue Univ.
Michael E. Baldwin, Purdue Univ.
Matthew Huber, Purdue Univ.

Mechanisms of Convection-Wave Interactions

Stefan Tulich, CIRES, University of Colorado, Boulder
George Kiladis, NOAA, Earth System Research Laboratory

This project seeks to improve our mechanistic understanding of
convection-wave interactions in the Tropics, with an emphasis on
zonally-propagating, inertia-gravity waved disturbances with periods
< 2.5 days. Such disturbances are of interest owing to their strong
ties to the diurnal cycle and potential role in the genesis of
severe tropical storms, such as Hurricane Andrew 1992. Furthermore,
space-time spectra of high-resolution satellite data show a dramatic
westward bias in the propagation direction of these high-frequency wave
modes, begging explanation and perhaps holding critical clues about
wave-convection modulation mechanisms. A suite of carefully designed
nested cloud-resolving model experiments on an equatorial beta-plane
was performed using the Weather-Research Forecast (WRF)model system,
to address these issues.

Collisionless Magnetic Reconnection in the Earth’s Magnetosphere

Michael Shay. Univ. of Delaware
Paul Cassak, Univ. of Delaware
Tulasi Parashasr, Univ. of Delaware
Kittipat Malakit, Univ. of Delaware.

Magnetic reconnection plays a critical role in the Earth’s magnetosphere, allowing solar wind plasma to
enter the magnetosphere, driving global convection, and energizing particles which can threaten satellites
and astronauts. As the United States becomes more dependent on satellite communications and manned
space missions expand in scope, the ability to understand and forecast our space weather system becomes
more critical.

In this Accelerated Scientific Discovery proposal, we seek to answer some basic physics questions relating
to magnetic reconnection in the Earth’s magnetosphere. The two basic questions are:

What controls the structure and scales of the newly discovered two-scale electron diffusion region?
What controls the structure of the diffusion region and associated signatures during asymmetric magnetic reconnection?

Visualization Gallery

Wintertime Polar Vortex

Data courtesy of: Mark Taylor, Los Alamos National Lab

Visualization by: John Clyne, NCAR

2008 Accelerated Scientific Discovery at NCAR