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April 2008
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3 - STEM Education: Preventing the pipeline from leaking - Tomislava Vukicevic, Atmospheric and Oceanic Sciences, University of Colorado, Boulder |
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5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 - Dr. Hiram Levy, NOAA | 25 | 26 | 27 | 28 - Dr. Bruce Fryxell, Los Alamos National Laboratory, CRASH Research Scientist candidate | 29 | 30 |
STEM Education: Preventing the pipeline from leaking
April 3, 2008 - 11:30 am
The College of Engineering and Tau Beta Pi invites you to a free panel luncheon where you can voice your opinions and learn how to get involved: Featuring panelists from the UM community: Jill Andrews – Director, Office of Engineering Outreach and Engagement (OE)^2 Perry Samson – Associate Chair and Professor Department of Atmospheric, Oceanic and Space Sciences Richard Hill – Graduate Student, Department of Mechanical Engineering Aaron Santos – Research Fellow, Department of Chemical Engineering America is at risk of losing its place as the global leader in innovation if we do not address the issues. Other countries are currently outpacing the U.S. in science and technology. In 2004, the NAS study found that China graduated more than 600,000 engineers; India, 350,000 and America, only 70,000. How can we address this trend? What is the current state of public education in regards to science, technology, engineering, and math (the STEM fields)? How can we encourage and prepare students to become leaders in the STEM fields? Are there steps that should be taken or programs that can be implemented to help prevent ‘the STEM pipeline from leaking?’ **Free Middle Eastern food from Jerusalem Garden**
closeTomislava Vukicevic, Atmospheric and Oceanic Sciences, University of Colorado, Boulder
April 3, 2008 - 3:30 pm
A new look at data assimilation and inversion problems in atmospheric sciences. Data assimilation and inversion problems are involved in almost every aspect of quantitative analysis in atmospheric sciences from observing by indirect measurements to prediction and projections by numerical models. Contemporary literature on common data assimilation and inversion techniques typically refers to theoretical basis of the techniques as a straightforward generalization of the Bayesian rule for conditional probabilities when applied under assumptions of errorless linear model and Gaussian statistics. The data assimilation and inversions are however, more often than not done with complex nonlinear models and observations for which these assumptions are not necessarily valid. To help understand impact of model nonlinearities, Gaussian statistics and modeling and observation errors a new approach is used which is based on a generalized formulation of the statistical inverse problem theory that does not make explicit use of the Bayesian rule. Based on the new approach an analysis of data assimilation and inversion solutions was done by numerical evaluation of the associated probability density functions on examples of two relatively simple but representative dynamical models of atmospheric processes. Relationship between properties of common data assimilation and inversion techniques and the generalized solutions will be discussed with an outlook at furthering benefits from inverse methodology in atmospheric sciences.
closeDr. Hiram Levy, NOAA
April 24, 2008 - 3:30 pm
Title: "Climate Change Science Program: Synthesis and Assessment Product 3.2 or Climate vs. Air Quality?" Abstract: By year 2100, "IPCC" projected decreases in sulfate aerosol and increases in black carbon aerosol contribute a significant portion of the simulated A1B surface air warming relative to the year 2000; 0.2oC (southern hemisphere), 0.4oC globally, 0.6oC (northern hemisphere), 1.5-3oC (wintertime Arctic), and 1.5-2oC (~40% of the total) in the summertime United States. These changes are also responsible for a significant decrease in central US late-summer root-zone soil water and precipitation. These changes in short-lived air pollutants produce a global average increase in radiative forcing of ~1 W/m2; over East Asia it exceeds 5 W/m2. However, the resulting regional patterns of surface temperature warming are uncorrelated to the forcing pattern (correlation coefficient of -0.172) and similar to the temperature patterns for well-mixed greenhouse gases (global pattern-correlation coefficient of 0.8) with the strongest summertime warming occurring over the continental US, Mediterranean Sea and southern Europe. It should be noted that the projections of future pollution emissions are extremely uncertain, particularly looking out to 2100.
closeDr. Bruce Fryxell, Los Alamos National Laboratory, CRASH Research Scientist candidate
April 28, 2008 - 1:00 pm
Title: Simulation of Turbulent Flows With Strong Shocks Abstract: Computation of turbulent flows with strong shocks is a very challenging problem, since the requirements for a method to produce accurate results for turbulence are orthogonal to those needed to treat shocks properly. In order to prevent an unphysical rate of decay of the turbulent structures, it is necessary to use a method with very low numerical dissipation. Because of this, central difference schemes are widely used. However, computing strong shocks with a central difference scheme can produce unphysical post-shock oscillations that corrupt the entire flow unless additional dissipation is added. This dissipation can be difficult to localize to the area near the shock and can lead to inaccurate treatment of the turbulence. Modern high-resolution shock-capturing methods usually use upwind algorithms to provide the dissipation necessary to stabilize shocks. However, this upwind dissipation can also lead to an unphyical rate of decay of the turbulence. This talk will discuss a hybrid method for simulating turbulent flows with strong shocks that couples a high-order central difference scheme with a high-resolution shock-capturing method. The shock-capturing method is used only in the vicinity of discontinuities in the flow, while the central difference scheme is used in the remainder of the computational domain. Results of this new method will be shown for a variety of test problems, including Richtmyer-Meshkov instabilities and the interaction of a shock with a turbulent flow field.
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