Recent EES Division Highlights

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March 31, 2009

Technician of the Year - Emily Kluk

Emily Kluk of EES-14 is a member of the Geochemistry and Geology Research Laboratory team. This team engages in experimental geochemistry for both fundamental geochemical research and customer driven applied science. Kluk prepares samples and maintains of an x-ray fluorescence instrument for analyzing trace elements in rocks and soils, and prepares samples for an x-ray diffraction unit. She also is the waste management coordinator and ALARA coordinator, and she took on the position as EES and ADCLES lead for the Worker Safety and Security Teams. Kluk consistently shows a high level of dedication and a willingness and ability to do what it takes to meet program deadlines. Her contributions have led her to be included as co-author on a large number of reports and peer-reviewed papers.

Improving Seismic Event Location in Asia for Nuclear Explosion Monitoring

The Ground Based Nuclear Explosion Team in EES-17 recently delivered an important new product to the Air Force Technical Applications Center (AFTAC). The product improves seismic event location accuracy and efficiency throughout Asia.

The Seismic Location Baseline Model, a new paradigm in the explosion monitoring effort, implements a 2.5 dimensional velocity model (a 2-dimensional model of the uppermost mantle with a 2D gradient below) for travel time calculation of a dominant regional seismic phase. Nuclear explosion monitoring uses seismic event location to determine proximity to known testing sites and identify new ones. Under treaties, it can help constrain locations of interest for onsite inspection.

Michael Begnaud was the primary LANL developer of this model in a joint effort with Lawrence Livermore National Laboratory. Lee Steck, in collaboration with Lawrence Livermore National Laboratory, delivered seismic array calibration parameters that typically are used in tandem with the travel time predictions. The LANL effort was supported by extensive data acquisition, integration, and quality control efforts by Julio Aguilar-Chang, Richard Stead, and Diane Baker. NNSA funded the work.

March 20, 2009

Novel Technique Developed to Image Earth's Structure

Monica Maceira (EES-17) and C. J. Ammon (Penn State University) developed a novel technique for simultaneous joint inversion of surface wave velocity and gravity observations to better constrain and image the Earth's structure.

Knowledge of the three-dimensional continental structure is needed to understand crustal generation and its geodynamic evolution. Combining these observations into a single inversion enables a self-consistent three-dimensional (3-D) shear velocity-density model with increased resolution of shallow geologic structures. An iterative, damped least squares inversion including smoothing is used to jointly model both data sets, using shear velocity variations as the primary model parameters. Synthetic data fits to the observations show how the 3-D velocity model obtained from the joint inversion can simultaneously fit both data sets, offering a compromise between fitting both data sets individually.

Three-dimensional S-wave velocity model at constant longitude (left) and latitude (right) slices. The depth range is indicated on the vertical axis. Warm colors indicate slow velocities meanwhile cold colors are representative of fast velocities.

The scientists used the inversion method to investigate the structure of the crust and upper mantle beneath the Tarim and the Junggar sedimentary basins in central Asia, which include the location of the Chinese nuclear test site at Lop Nor. These basins are in a region of dramatic tectonic processes that have left their mark in the region's extreme variability in topography. The main features of the model are: (1) low velocities in the basins dominate the images at shallow depths because of the large amount of sediments found in the basins; (2) high lower crust and upper mantle velocities underneath the Tarim basin, which indicates an old, cold, and thick lithosphere that has not been greatly deformed; and (3) velocity images suggest differences in crustal and upper mantle structure between eastern and western Tarim. Improved knowledge of the shear velocity structure of these two sedimentary basins is necessary to understand the geodynamic evolution of these large, important tectonic structures. Moreover, the better the models are, the more accurately scientists can detect, locate, and identify small events, which are recorded only at regional distances, and therefore improve monitoring capabilities for the comprehensive Nuclear Test Ban Treaty.

Reference: "Joint Inversion of Surface Wave Velocity and Gravity Observations and its Application to Central Asian Basins Shear Velocity Structure", Journal of Geophysical Research 114, B02314 (2009), doi:10.1029/2007JB005157.

EES-14 Scientist Recognized for Student Outreach

Julianna Fessenden-Rahn (EES-14) was recognized for technical contributions and her outreach efforts to students. She was instrumental in developing carbon sequestration programs for the Laboratory, and she has a lead role in developing LANL's efforts in the vital scientific areas of Monitoring Measurement and Verification, nuclear forensics, and isotope signatures of nuclear processing. According to her nominator, what sets her apart is "her extreme dedication to student education." She organized and led two educational programs focused on the environment.

She co-led the Research Experience in Carbon Sequestration summer program for two years and taught in it for several more. She also founded the Accord Pueblos Summer Environmental Science Program, which brings in tribal youth to study environmental science with LANL scientists.

March 16, 2009

U.S. Ambassador Visits the ARM Climate Research Facility's Nauru Site

The Atmospheric Radiation Measurement (ARM) Climate Research Facility (ACRF) is a DOE national user facility for the study of global change. Research includes the study of alterations in climate, land productivity, oceans or other water resources, atmospheric chemistry, and ecological systems that may alter the capacity of the Earth to sustain life. LANL manages the Tropical Western Pacific monitoring sites and the ARM Mobile Facility, which collect data for the models. The ARM Program has a Climate Research Facility on Nauru Island, the Republic of Nauru, which is located in the western South Pacific, approximately 1,200 miles northeast of Papua New Guinea. ARM selected the Nauru site because it is on the eastern edge of the Pacific warm pool under La Niña conditions, which affect weather patterns in the Pacific.

U.S. Ambassador Steven McGann during his visit to Nauru Island in February.

Steven McGann, the U.S. Ambassador to Fiji, Nauru, and other island nations, visited the Nauru site on February 7, 2009. He and Ms. Megan Kennett of the embassy arrived with Nauruan Foreign Department Officers. They were greeted by the local Nauruan ARM Climate Research Facility observers and were given a tour of the site's field instruments and equipment enclosures. Mr. McGann had been briefed generally about the ARM Program before his arrival, and the local Officer-in-Charge, Andrew Kaierua, further described the site's capabilities for measuring solar radiation as well as basic meteorology, cloud properties, and aerosols. The Ambassador watched the local staff as they performed the midday launch of the balloon-borne sounding system (SONDE), which provides in-situ measurements (vertical profiles) of both the thermodynamic state of the atmosphere, and the wind speed and direction. He questioned the observers on the specifics of the launch and was surprised to hear that the station had been operating for ten years. He complimented the observers for the excellent tour on such short notice and told them that the facility is important in this time of changing climate.

February 17, 2009

Carbon Dioxide Sequestration System Model Estimates Project Costs

EES-16 researchers are leading the development of a system-level model called CO₂-PENS (Predicting Engineered Natural Systems) to help understand the processes involved in sequestering carbon dioxide (CO₂) in underground reservoirs. The goal of building CO₂-PENS is to create a Performance Assessment/Risk Assessment tool to analyze hundreds of potential CO₂ sequestration sites across the USA. This project is part of a global effort to reduce global greenhouse gas concentrations and reduce the possibility of long-term damage to our environment.

Cover of Environmental Science & Technology showing geologic sequestration of carbon dioxide superimposed on an atmospheric release. Artwork by Anthony Mancino, PADSTE.

Work in EES spans a range of topics such as 1) numerical modeling of multiphase CO₂ flow and transport through porous rocks, 2) laboratory and numerical studies of the durability of cement in contact with CO₂, 3) field and numerical studies of how CO₂ leaking from below ground mixes in the atmosphere, 4) optimization of surface pipelines for transportation of CO₂, and 5) methods to detect CO₂ migration from potential reservoirs toward the surface. This partial list illustrates the many types of calculations involved in a model of the entire sequestration system. Individual process level models often must be abstracted or reduced in complexity to fit into the larger system framework, and EES and D divisions are collaborating to build large system-level simulators. The system level simulations must be run using a Monte Carlo approach to sample the ranges in parameter uncertainty associated with each physical process.

Present value cost per ton associated with wells and local pipelines. Bin probability is the percent of the 5000 realizations found in a given bin used to create the histogram. The bin sizes are different for the two cases to allow the data to be plotted on the same figure.

In a recently published paper featured on the cover of the journal Environmental Science & Technology and discussed in a news article entitled "Models of Carbon Storage Get Real", Philip Stauffer and EES-16 colleagues showed the usefulness of the system model approach for a prototype system involving the interaction between a process level injection module and an economic module. The injection module rapidly calculates how many wells will be required to inject a given mass of CO₂ into a specific reservoir considering uncertainty in permeability, porosity, and reservoir thickness. The economic module incorporates uncertainty in pipeline and drilling costs to estimate the final project costs. Fixed parameters that impact the results are the depth and temperature of the alternative target reservoirs.

Results for the two test cases showing the number of boreholes required to inject the CO₂ from a 1000 MW power plant. In each case 5000 realizations were run with values of permeability and porosity randomly chosen from the input parameter distributions.

The figure above shows a comparison in the number of wells required to inject a fixed amount of CO₂ between a Hot-Deep (155 C and 3 km) case and a Cold-Shallow (35 C and 1 km) case. Because of variations in density and viscosity, the Hot-Deep case results in fewer required boreholes. This translates into a lower total cost per ton of CO₂ injected even though the deeper wells cost more to drill.

Authors include P.H. Stauffer, H.S. Viswanathan, and R.J. Pawar (all of EES-16); and G.D. Guthrie (formerly PADSTE-SPO, currently at NETL).

"A System Model for Geologic Sequestration of Carbon Dioxide" Environmental Science and Technology 43, 565-570 (2009). The DOE Zero Emission Research and Technology (ZERT) Program supported this work.

February 16, 2009

ARM Mobile Facility Completes Deployment in China - Azores Next

The goal of DOE's Atmospheric Radiation Measurement (ARM) Program is to improve the treatment of cloud and radiation physics in global climate models. Los Alamos National Laboratory manages the Tropical Western Pacific monitoring sites and the ARM Mobile Facility (AMF), which collect data for the models. The AMF completed a successful 8-month deployment in the People's Republic of China.

Anchored by the AMF in Shouxian, additional instrumented sites to the east and
north provided a comprehensive atmospheric data set for studying aerosol effects in the region.

The most complex field campaign deployment to date, the AMF collected data (in the four areas shown on the map above) from different climate regimes and with high aerosol loadings of different optical, physical, and chemical property. High concentrations of aerosol particles in the region may influence the atmosphere across the Pacific rim, especially the radiation balance and cloud properties.

Preliminary analyses of multiple satellite data sets over China indicate complex and unique aerosol indirect effects which impact cloud reflectivity and precipitation processes. Therefore both in-situ measurements and independent ground-based remote sensing data are needed to verify the satellite findings and gain a deeper understanding of these effects. Mobile Facile measurements obtained from the study sites during the deployment in China will help scientists validate satellite-based data, understand the mechanisms of the aerosol indirect effects in the region, and examine the roles of aerosols in affecting regional climate and atmospheric circulation with a special focus on the impact of the east Asian monsoon system. The dismantle team, led by LANL's Tropical Western Pacific/ARF Management Office, spent two weeks in January to pack and prepare the AMF for transport to the next deployment site in the Azores, Portugal.

Several AMF instruments were located on the roof of the Shouxian National
Climate Observatory, while the primary AMF operations area (shown immediately above)
and the instrument field were located just outside the building.

February 12, 2009

Project Develops Next Generation Process to Model Subsurface Events

Peter Lichtner (EES-16) leads the DOE Scientific Discovery Through Advanced Computing (SciDAC) project, "Modeling Multiscale-Multiphase-Multicomponent Subsurface Reactive Flows using Advanced Computing". This project is developing the next generation reactive flow and transport code, PFLOTRAN, for modeling subsurface processes. The project involves a multidisciplinary team from LANL, Pacific Northwest National Laboratory, Oak Ridge National Laboratory (ORNL), Argonne National Laboratory, and the University of Illinios at Urbana-Champaign. The project has received a total allocation of 20,000,000 cpu hours to run on ORNL's Jaguar XT4 Cray machine and Environmental Molecular Science Laboratory's Chinook high performance computer through a 2009 DOE INCITE award and a petascale early access award at ORNL. The code has been run with over 27,000 processor cores on the XT4 Cray Jaguar and has approached petascale performance.

The ability to model multiscale subsurface processes is essential for obtaining an accurate predictive capability of contaminant transport. Predictive modeling of reactive flows is a daunting task because of the wide range of spatial scales involved - from the pore to the field scale - ranging over more than six orders of magnitude, and the wide range of time scales involved - from seconds or less to millions of years. Heterogeneity, multiphase interfacial effects, and multicomponent geochemical reactions add further complexity to the system. This complexity necessitates advances in modeling capabilities. Physical and chemical processes either in PFLOTRAN or under development include multicomponent chemistry involving hundreds of aqueous, gaseous and solid constituents, multiphase fluid flow, Richards equation for variably saturated media, multiple interacting continua, and colloid facilitated transport of contaminants. The PFLOTRAN enhanced modeling capabilities will be used to improve the understanding of radionuclide migration at the DOE Hanford facility, where sub-millimeter-scale mass transfer effects have thwarted attempts at remediation efforts; and modeling sequestration of carbon dioxide (CO₂) in deep geologic formations, where resolving density-driven fingering patterns is necessary to accurately describe the rate of dissipation of the CO₂ plume. (See figure below.)

Click image to view larger version.
 
Left - Example of PFLOTRAN simulation showing a 3D model of the Hanford 300 Area uranium plume.
Right - Example of PFLOTRAN simulation of CO₂ sequestration over an elapsed time of 300 years. The simulation shows that fingering of dissolved CO₂ during subsurface carbon sequestration enhances the rate of dissipation of supercritical CO₂.

Other Archived Highlights