Coupled Weather and Wildfire Behavior Modeling at Los Alamos: An Overview

Over the past two years, researchers at Los Alamos National Laboratory (LANL) have been engaged in coupled weather/wildfire modeling as part of a broader initiative to predict the unfolding of crisis events. Wildfire prediction was chosen for the following reasons: (1) few physics-based wild-fire prediction models presently exist; (2) LANL has expertise in the fields required to develop such a capability; and (3) the development of this predictive capability would be enhanced by LANL`s strength in high performance computing. Wildfire behavior models have historically been used to predict fire spread and heat release for a prescribed set of fuel, slope, and wind conditions (Andrews 1986). In the vicinity of a fire, however, atmospheric conditions are constantly changing due to non-local weather influences and the intense heat of the fire itself. This non- linear process underscores the need for physics-based models that treat the atmosphere-fire feedback. Actual wildfire prediction with full-physics models is both time-critical and computationally demanding, since it must include regional- to local-scale weather forecasting together with the capability to accurately simulate both intense gradients across a fireline, and atmosphere/fire/fuel interactions. Los Alamos has recently (January 1997) acquired a number of SGI/Cray Origin 2000 machines, each presently having 32 to 64 processors. These high performance computing systems are part of the Department of Energy`s Accelerated Strategic Computing Initiative (ASCI). While offering impressive performance now, upgrades to the system promise to deliver over 1 Teraflop (10(12) floating point operations per second) at peak performance before the turn of the century

Sex Differences in Sand Lizard Telomere Inheritance: Paternal Epigenetic Effects Increases Telomere Heritability and Offspring Survival

To date, the only estimate of the heritability of telomere length in wild populations comes from humans. Thus, there is a need for analysis of natural populations with respect to how telomeres evolve.Here, we show that telomere length is heritable in free-ranging sand lizards, Lacerta agilis. More importantly, heritability estimates analysed within, and contrasted between, the sexes are markedly different; son-sire heritability is much higher relative to daughter-dam heritability. We assess the effect of paternal age on Telomere Length (TL) and show that in this species, paternal age at conception is the best predictor of TL in sons. Neither paternal age per se at blood sampling for telomere screening, nor corresponding age in sons impact TL in sons. Processes maintaining telomere length are also associated with negative fitness effects, most notably by increasing the risk of cancer and show variation across different categories of individuals (e.g. males vs. females). We therefore tested whether TL influences offspring survival in their first year of life. Indeed such effects were present and independent of sex-biased offspring mortality and offspring malformations.TL show differences in sex-specific heritability with implications for differences between the sexes with respect to ongoing telomere selection. Paternal age influences the length of telomeres in sons and longer telomeres enhance offspring survival

The diffusion of radiation /

"Contract W-7405-ENG.36 with the U.S. Atomic Energy Commission.""LA-2196 ; Physics and Mathematics ; (TID-4500, 13th Ed., Rev.)""Report written: April 1958 ; Report distributed: July 30, 1958."Includes bibliographical references.Mode of access: Internet

Numerical study of the motions of variously-shaped slabs accelerated by a hot gas /

Numerical computations have been performed to determine the motion of a two-dimensional slab of initially- cold gas accelerated by a hot gas. The cold-gas slab had a sequence of holes, flanges, or other perturbations to its otherwise straight, parallel, infinite bounding walls. In formation is also presented regarding pertinent characteristics of the computing method."Report distributed: January 26, 1959.""Report written: September 1958."Includes bibliographical references.Numerical computations have been performed to determine the motion of a two-dimensional slab of initially- cold gas accelerated by a hot gas. The cold-gas slab had a sequence of holes, flanges, or other perturbations to its otherwise straight, parallel, infinite bounding walls. In formation is also presented regarding pertinent characteristics of the computing method.Operated by the University of California for the U.S. Atomic Energy CommissionMode of access: Internet

Rise through the atmosphere of a hot bubble /

The Particle-in-Cell method for multidimensional fluid-dynamics calculations has been used on the IBM Stretch Computer to study the motion of a hot gas bubble created by a nuclear explosion in the earth's atmosphere. In the example, a total energy of 8.24 x 10(exp 20) ergs was deposited at an altitude of 95 km. After 2.85 sec the originally-heated air was moving upwards with a mass-averaged velocity of 3.5km/sec and was still accelerating somewhat, probably to an asymptotic value of 4.0 km/sec. Along the cylindrical axis at 2.85 sec, the upwards velocities varied from 0.0 km/sec at the bottom to 5.8 km/sec at the top; most of the central material was moving at velocities greater than 4.0 km/sec. This report also includes details concerning bubble shape, energy histories, and shock configurations."Contract W-7405-ENG.36 with the U.S. Atomic Energy Commission.""LAMS-2770; Physics; TID-4500 (18th Ed.)""Report written: October 1962; Report distributed: November 13, 1962."Includes bibliographical references.The Particle-in-Cell method for multidimensional fluid-dynamics calculations has been used on the IBM Stretch Computer to study the motion of a hot gas bubble created by a nuclear explosion in the earth's atmosphere. In the example, a total energy of 8.24 x 10(exp 20) ergs was deposited at an altitude of 95 km. After 2.85 sec the originally-heated air was moving upwards with a mass-averaged velocity of 3.5km/sec and was still accelerating somewhat, probably to an asymptotic value of 4.0 km/sec. Along the cylindrical axis at 2.85 sec, the upwards velocities varied from 0.0 km/sec at the bottom to 5.8 km/sec at the top; most of the central material was moving at velocities greater than 4.0 km/sec. This report also includes details concerning bubble shape, energy histories, and shock configurations.Mode of access: Internet

The particle-and-force computing method for fluid dynamics /

"Contract W-7405-ENG.36 with the U.S. Atomic Energy Commission.""LA-2567 ; Physics; TID-4500 (16th Ed.)""Report written: June 1961; Report distributed: October 3, 1961."Includes bibliographical references (p. 48-49).Mode of access: Internet

The particle-in-cell method for hydrodynamic calculatons /

A method is presented for solving hydrodynamic problems involving large distortions and compressions of the fluid in several space dimensions. The calculation procedure introduces finite difference approximations to the differential equations; the solution in practice is carried out by means of high-speed electronic computers. The paper discusses a number of characteristics of the method and illustrates these by presenting results of representative calculations."Contract W-7405-ENG.36 with the U.S. Atomic Energy Commission.""LA-2139 ; Physics and mathematics; (TID-4500, 13th edition)""Report distributed: November 8, 1957.""Report written: June 1957."A method is presented for solving hydrodynamic problems involving large distortions and compressions of the fluid in several space dimensions. The calculation procedure introduces finite difference approximations to the differential equations; the solution in practice is carried out by means of high-speed electronic computers. The paper discusses a number of characteristics of the method and illustrates these by presenting results of representative calculations.Operated by the University of California for the U.S. Atomic Energy CommissionMode of access: Internet