Physical Sciences and Mathematics Commons^™

Investigating The Thermodynamics And Seismic Profile Of The Europan Hydrosphere Through Pure-Water Modeling And Saltwater Experiments, Samantha Rosenfeld

Honors Theses

We explore the properties of the hydrosphere on Europa involving both a modeling technique and experimental methods. We perform a computational analysis of the thermodynamic properties for an ideal, pure-water Europan ice shell using a Python programming framework called SeaFreeze. We create four models assuming surface temperatures of either 50 K or 140 K and ice shell thicknesses of either 3 km or 30 km. We observe mostly linear trends for the density and seismic wave velocities with respect to depth and find that surface temperature has the greatest effect on the models. Simultaneously, we experimentally investigate the phase diagram …

Long Lived Second Mode Internal Solitary Waves In The Andaman Sea, J.M. Magalhaes, J.C.B. Da Silva, Maarten C. Buijsman

Faculty Publications

Internal waves are density oscillations propagating along the ocean’s inner stratification, which are now acknowledged as a key constituent of the ocean’s dynamics. They usually result from barotropic tides, which flow over bottom topography, causing density oscillations to propagate along the pycnocline with a tidal frequency (i.e. internal tides). These large-scale waves propagate away from their forcing bathymetry and frequently disintegrate into nonlinear short-scale (higher-frequency) internal wave packets. Typically, short-scale internal wave observations in the ocean are associated with vertical structures (in the water column) of the lowest fundamental mode. Higher vertical modes have recently been documented as well, but …

Florida Science: The Science That Makes Florida Different, Terence W. Cavanaugh

Secondary Level Resources

This book was created to assist students with their understanding of how science occurs in Florida. When teaching science or any subject it’s important to remember to begin with the concrete and then move to the abstract. I have found that it has helped my students when I begin by teaching science concepts in a concrete manner and expand from there. For example, when I taught about topographic maps, the students were much more successful in their learning when I started with local topographic maps that included the school and the surrounding area than with places that had mountains or …

The Role Of Blowing Snow In The Activation Of Bromine Over First-Year Antarctic Sea Ice, R. M. Lieb-Lappen, R. W. Obbard

Dartmouth Scholarship

It is well known that during polar springtime halide sea salt ions, in particular Br^-, are photochemically activated into reactive halogen species (e.g., Br and BrO), where they break down tropospheric ozone. This research investigated the role of blowing snow in transporting salts from the sea ice/snow surface into reactive bromine species in the air. At two different locations over first-year ice in the Ross Sea, Antarctica, collection baskets captured blowing snow at different heights. In addition, sea ice cores and surface snow samples were collected throughout the month-long campaign. Over this time, sea ice and surface snow …

Kinetic Fractionation Of Gases By Deep Air Convection In Polar Firn, K. Kawamura, J. P. Severinghaus, M. R. Albert, Z. R. Courville

Dartmouth Scholarship

A previously unrecognized type of gas fractiona- tion occurs in firn air columns subjected to intense convec- tion. It is a form of kinetic fractionation that depends on the fact that different gases have different molecular diffusivi- ties. Convective mixing continually disturbs diffusive equi- librium, and gases diffuse back toward diffusive equilibrium under the influence of gravity and thermal gradients. In near- surface firn where convection and diffusion compete as gas transport mechanisms, slow-diffusing gases such as krypton (Kr) and xenon (Xe) are more heavily impacted by convec- tion than fast diffusing gases such as nitrogen (N2) and ar- gon …

Discontinuities And Alfvenic Fluctuations In The Solar Wind, G. Paschmann, S. Haaland, B. Sonnerup, T. Knetter

Dartmouth Scholarship

We examine the Alfvenicity of a set of 188 solar wind directional discontinuities (DDs) identified in the Cluster data from 2003 by Knetter (2005), with the objective of separating rotational discontinuities (RDs) from tangential ones (TDs). The DDs occurred over the full range of solar wind velocities and magnetic shear angles. By performing the Walen test in the de Hoffmann–Teller (HT) frame, we show that 77 of the 127 crossings for which a good HT frame was found had plasma flow speeds exceeding 80 % of the Alfven speed at an average angular deviation of 7.7◦; 33 cases had speeds …

Bottled Sky, Ioannis Michalou(Di)S

The STEAM Journal

Cloud-hunter Ioannis ΜICHALOU(di)S, lies in wait of air streams, grapping pieces of sky, shaping them, molding them, and baptizing them as ‘aerosculptures’. MICHALOU(di)S is the first visual artist worldwide to use art and science in a unique way. His latest Art-Science achievement is ‘Bottled Sky’. He states:

“In October 2001, while I was trying to create a cubic nephele, in the Visual Arts Research Centre of Massachusetts Institute of Technology (MIT), I came upon the silica aerogel for the first time... It is a space technology material, intangible -consisting of 99.9% air and 0.1% glass - which has been recently …

Process-Evaluation Of Tropospheric Humidity Simulated By General Circulation Models Using Water Vapor Isotopologues: 1. Comparison Between Models And Observations, Camille Risi, David Noone, John Worden, Christian Frankenberg, Gabriele Stiller, Michael Kiefer, Bernd Funke, Kaley Walker, Peter Bernath, Matthias Schneider, Debra Wunch, Vanessa Sherlock, Nicholas Deutscher, David Griffith, Paul O. Wennberg, Kimberly Strong, Dan Smale, Emmanuel Mahieu, Sabine Barthlott, Frank Hase, Omaira García, Justus Notholt, Thorsten Warneke, Geoffrey Toon, David Sayres, Sandrine Bony, Jeonghoon Lee, Derek Brown, Ryu Uemura, Christophe Sturm

Chemistry & Biochemistry Faculty Publications

The goal of this study is to determine how H₂O and HDO measurements in water vapor can be used to detect and diagnose biases in the representation of processes controlling tropospheric humidity in atmospheric general circulation models (GCMs). We analyze a large number of isotopic data sets (four satellite, sixteen ground-based remote-sensing, five surface in situ and three aircraft data sets) that are sensitive to different altitudes throughout the free troposphere. Despite significant differences between data sets, we identify some observed HDO/H₂O characteristics that are robust across data sets and that can be used to evaluate …

Process-Evaluation Of Tropospheric Humidity Simulated By General Circulation Models Using Water Vapor Isotopic Observations: 2. Using Isotopic Diagnostics To Understand The Mid And Upper Tropospheric Moist Bias In The Tropics And Subtropics, Camille Risi, David Noone, John Worden, Christian Frankenberg, Gabriele Stiller, Michael Kiefer, Bernd Funke, Kaley Walker, Peter Bernath, Matthias Schneider, Sandrine Bony, Jeonghoon Lee, Derek Brown, Christophe Sturm

Chemistry & Biochemistry Faculty Publications

Evaluating the representation of processes controlling tropical and subtropical tropospheric relative humidity (RH) in atmospheric general circulation models (GCMs) is crucial to assess the credibility of predicted climate changes. GCMs have long exhibited a moist bias in the tropical and subtropical mid and upper troposphere, which could be due to the mis-representation of cloud processes or of the large-scale circulation, or to excessive diffusion during water vapor transport. The goal of this study is to use observations of the water vapor isotopic ratio to understand the cause of this bias. We compare the three-dimensional distribution of the water vapor isotopic …

A Temporal Approximate Deconvolution Model For Large-Eddy Simulation, C. D. Pruett, B. C. Thomas, C. E. Grosch, T. B. Gatski

CCPO Publications

A temporal approximate deconvolution model (TADM) is developed for large-eddy simulation and is demonstrated for plane-channel flow at Re-tau=590. The TADM combines explicit causal time-domain filtering with linear deconvolution (defiltering) to approximate unfiltered fields and residual stress to arbitrarily high order. The TADM methodology appears to lead to a robust family of residual-stress models that should provide a viable alternative to conventional (spatial) filtering for applications in which spatial filtering is problematic, e.g., for problems requiring unstructured or highly stretched grids. (c) 2006 American Institute of Physics.

The Temporally Filtered Navier-Stokes Equations: Propertes Of The Residual Stress, C. D. Pruett, T. B. Gatski, Chester E. Grosch, W. D. Thacker

CCPO Publications

Recent interest in the development of a unifying framework among direct numerical simulations, large-eddy simulations, and statistically averaged formulations of the Navier-Stokes equations, provides the motivation for the present paper. Toward that goal, the properties of the residual (subgrid-scale) stress of the temporally filtered Navier-Stokes equations are carefully examined. This includes the frame-invariance properties of the filtered equations and the resulting residual stress. Causal time-domain filters, parametrized by a temporal filter width 0infinity, the residual stress is equivalent to the long-time averaged stress, and the Reynolds-averaged Navier-Stokes equations are recovered from the temporally filtered equations. The predicted behavior at the …

Analyzing Mean Transport Equations Of Turbulence And Linear Disturbances In Decaying Flows, W. D. Thacker, T. B. Gatski, C. E. Grosch

CCPO Publications

The decay of laminar disturbances and turbulence in mean shear-free flows is studied. In laminar flows, such disturbances are linear superpositions of modes governed by the Orr-Sommerfeld equation. In turbulent flows, disturbances are described through transport equations for representative mean quantities. The link between a description based on a deterministic evolution equation and a probability-based mean transport equation is established. Because an uncertainty in initial conditions exists in the laminar as well as the turbulent regime, a probability distribution must be defined even in the laminar case. Using this probability distribution, it is shown that the exponential decay of the …

Effects Of Wind, Density, And Bathymetry On A One-Layer Southern Ocean Model, John M. Klinck

CCPO Publications

Steady solutions from a one-layer, wind-driven, primitive equation model are analyzed to determine the importance of wind forcing, pressure gradient force due to the climatological density distribution and bottom form drag on circulation in the Southern Ocean. Five simulations are discussed: three wind-forced simulations, with differing bathymetry (flat bottom, 15% bathymetry, and full bathymetry), one case with full bathymetry forced with the density-induced pressure force, and one case with full bathymetry forced by both wind and density-induced pressure gradients. The simulations presented here confirm the previous speculation (Munk and Palmen, 1951) that form drag is effective in balancing the driving …

Temperature Conditions At Orono, Maine, Ernest Claude Drew

Electronic Theses and Dissertations

This thesis is an outgrowth of a much larger piece of work which the Department of Physics, thru its instructors and major students, has undertaken to complete. The task referred to, is the compilation, arrangement, and summarizing of the various meteorological records taken at the University of Maine for the past forty-four years. These records were begun in the above department by Dr. M. C. Fernald in the year 1869 and were continued by him until 1893. The work was then transferred to the Experiment Station, where observations were made under the direction of Doctors W. H. Jordan and C. …