Preliminary design for Arctic atmospheric radiative transfer experiments

If current plans are realized, within the next few years, an extraordinary set of coordinated research efforts focusing on energy flows in the Arctic will be implemented. All are motivated by the prospect of global climate change. SHEBA (Surface Energy Budget of the Arctic Ocean), led by the National Science Foundation (NSF) and the Office of Naval Research (ONR), involves instrumenting an ice camp in the perennial Arctic ice pack, and taking data for 12--18 months. The ARM (Atmospheric Radiation Measurement) North Slope of Alaska and Adjacent Arctic Ocean (NSA/AAO) Cloud and Radiation Testbed (CART) focuses on atmospheric radiative transport, especially in the presence of clouds. The NSA/AAO CART involves instrumenting a sizeable area on the North Slope of Alaska and adjacent waters in the vicinity of Barrow, and acquiring data over a period of about 10 years. FIRE (First ISCCP [International Satellite Cloud Climatology Program] Regional Experiment) Phase 3 is a program led by the National Aeronautics and Space Administration (NASA) which focuses on Arctic clouds, and which is coordinated with SHEBA and ARM. FIRE has historically emphasized data from airborne and satellite platforms. All three program anticipate initiating Arctic data acquisition during spring, 1997. In light of his historic opportunity, the authors discuss a strawman atmospheric radiative transfer experimental plan that identifies which features of the radiative transport models they think should be tested, what experimental data are required for each type of test, the platforms and instrumentation necessary to acquire those data, and in general terms, how the experiments could be conducted. Aspects of the plan are applicable to all three programs

Planck early results. VI. The High Frequency Instrument data processing

We describe the processing of the 336 billion raw data samples from the High Frequency Instrument (HFI) which we performed to produce six temperature maps from the first 295 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545 and 857GHz with an angular resolution ranging from 9.9 to 4.4 . The white noise level is around 1.5 μK degree or less in the 3 main CMB channels (100–217 GHz). The photometric accuracy is better than 2% at frequencies between 100 and 353 GHz and around 7% at the two highest frequencies. The maps created by the HFI Data Processing Centre reach our goals in terms of sensitivity, resolution, and photometric accuracy. They are already sufficiently accurate and well-characterised to allow scientific analyses which are presented in an accompanying series of early papers. At this stage, HFI data appears to be of high quality and we expect that with further refinements of the data processing we should be able to achieve, or exceed, the science goals of the Planck project

The Effect of Algorithm Form on Deformation and Instability in Tension

Equilibrium and flow equations have been developed for limited boundary conditions to describe deformation and localisation in tension. These equations have been used to study the influence of algorithmic form on deformation response for four simple algorithms. It is shown that the structure of the algorithm can have a profound effect on the extent and rate of localisation. These results from analytical solutions are compared to those from computer modelling of similar problems and the agreement is shown to be extremely good over the whole range

Preliminary evaluation of techniques for transforming regional climate model output to the potential repository site in support of Yucca Mountain future climate synthesis

The report describes a preliminary evaluation of models for transforming regional climate model output from a regional to a local scale for the Yucca Mountain area. Evaluation and analysis of both empirical and numerical modeling are discussed which is aimed at providing site-specific, climate-based information for use by interfacing activities. Two semiempirical approaches are recommended for further analysis

A wide range constitutive equation for medium and high strength steel

A Constitutive Equation has been determined for a medium strength steel and has been shown to have identical form to the modified Armstrong Zerilli equation used for iron. The strengthening mechanism in steel appears to act through a constant which is subject to thermal softening through the shear modulus but the part of the model describing thermally activated processes remains almost identical to that observed in iron. These observations suggest the possibility of using this equation as a generic form for a wide class of steels in which the determination of coefficients is simplified considerably

Simulations of semi-infinite penetration

Idealised materials deformation models have been used in conjunction with an analytical approach to study the penetration of kinetic energy penetrators into semi-infiinite targets. Numerical simulations were carried out using the DERA cAst Euler hydrocode. Deformation models used a modified form of the Armstrong-Zerilli bcc form [1, 2]. The projectile model included the physical and equation of state properties for a dense alloy with deformation defined by incorporating idealised constants in the model. It was shown that there is little variation in penetration depth within the range of properties likely to be achievable in practice. High strain rate sensitivity produces very high transient strength which provides essentially rigid body penetration. Equivalent performance was difficult to achieve by increasing the static strength alone because of the thermal softening contribution. In contrast thermal softening, of the right type, allows the curvature and constraint in the penetrator nose to produce a small head in a different way. In this case the strength of deformed material is decreased significantly alloywing the head to curve around sharply, creating only a small diameter cavity in the target