Chemical and isotopic compositions of hydrothermal manifestations and minerals from the Broken Spur hydrothermal field

A representative collection of hydrothermal manifestations was sampled practically from all hydrothermal mounds of the Broken Spur hydrothermal vent field with use of the Mir manned submersibles during three cruises of R/V Akademik Mstislav Keldysh. Mineral associations characteristic for different morphological types of sulfide ores from hydrothermal pipes, plates, and diffusers are assessed. Particular attention is paid to distribution of minor elements and their distribution patterns determined by mineralogical zonation. Measured isotopic composition of sulfur in sulfide minerals varies from 0.4 to 5.2 per mil that indicates their similarity with ores from the Snake Pit vent field and is related to dilution of hot ore-bearing solutions by seawater and reduction of water sulfate ions to H2S with heavy isotopic composition.

A comparison of landslide inventories along the shoreline of Steamboat Island Peninsula, Thurston County, WA: office based protocol vs. field based protocol

The mountain ranges and coastlines of Washington State have steep slopes, and they are susceptible to landslides triggered by intense rainstorms, rapid snow melts, earthquakes, and rivers and waves removing slope stability. Over a 30-year timespan (1984-2014 and includes State Route (SR) 530), a total of 28 deep-seated landslides caused 300 million dollars of damage and 45 deaths (DGER, 2015). During that same timeframe, ten storm events triggered shallow landslides and debris flows across the state, resulting in nine deaths (DGER, 2015). The loss of 43 people, due to the SR 530 complex reactivating and moving at a rate and distance unexpected to residents, highlighted the need for an inventory of the stateís landslides. With only 13% of the state mapped (Lombardo et al., 2015), the intention of this statewide inventory is to communicate hazards to citizens and decision makers. In order to compile an accurate and consistent landslide inventory, Washington needs to adopt a graphic information system (GIS) based mapping protocol. A mapping protocol provides consistency for measuring and recording information about landslides, including such information as the type of landslide, the material involved, and the size of the movement. The state of Oregon shares similar landslide problems as Washington, and it created a GIS-based mapping protocol designed to inform its residents, while also saving money and reducing costly hours in the field (Burns and Madin, 2009). In order to determine if the Oregon Department of Geology and Mineral Industries (DOGAMI) protocol, developed by Burns and Madin (2009), could serve as the basis for establishing Washingtonís protocol, I used the office-based DOGAMI protocol to map landslides along a 40-50 km (25-30 mile) shoreline in Thurston County, Washington. I then compared my results to the field-based landslide inventory created in 2009 by the Washington Division of Geology and Earth Resources (DGER) along this same shoreline. If the landslide area I mapped reasonably equaled the area of the DGER (2009) inventory, I would consider the DOGAMI protocol useful for Washington, too. Utilizing 1m resolution lidar flown for Thurston County in 2011 and a GIS platform, I mapped 36 landslide deposits and scarp flanks, covering a total area of 879,530 m2 (9,467,160 ft2). I also found 48 recent events within these deposits. With an exception of two slides, all of the movements occurred within the last fifty years. Along this same coastline, the DGER (2009) recorded 159 individual landslides and complexes, for a total area of 3,256,570 m2 (35,053,400 ft2). At a first glance it appears the DGER (2009) effort found a larger total number and total area of landslides. However, in addition to their field inventory, they digitized landslides previously mapped by other researchers, and they did not field confirm these landslides, which cover a total area of 2,093,860 m2 (22,538,150 ft2) (DGER, 2009). With this questionable landslide area removed and the toes and underwater landslides accounted for because I did not have a bathymetry dataset, my results are within 6,580 m2 (70,840 ft2) of the DGERís results. This similarity shows that the DOGAMI protocol provides a consistent and accurate approach to creating a landslide inventory. With a few additional modifications, I recommend that Washington State adopts the DOGAMI protocol. Acquiring additional 1m lidar and adopting a modified DOGAMI protocol poises the DGER to map the remaining 87% of the state, with an ultimate goal of informing citizens and decision makers of the locations and frequencies of landslide hazards on a user-friendly GIS platform.

Constraining storm-scale forecasts of deep convective initiation with surface weather observations

Thesis (Ph.D.)--University of Washington, 2016-06

Closed-Loop Deep Brain Stimulation: Bidirectional Neuroprosthetics for Tremor and BCI

Thesis (Ph.D.)--University of Washington, 2016-06

The interaction of nitrogen application and temperature during reproductive stage on spikelet sterility in field-grown rice

Increased grain yield in response to high rates of application of nitrogen (N) fertiliser is often limited by increased spikelet sterility, particularly under low temperature conditions in the New South Wales ( NSW) rice industry. In 3 field experiments, different N rates were applied for different sowing dates to investigate the interaction between N rate and temperature during microspore development on spikelet sterility and grain yield. In one experiment the effect of water depth on spikelet sterility was also investigated. Engorged pollen production, spikelet sterility, and yield and its components were recorded. Application of N affected a few different processes that lead into spikelet sterility. Application of N at both pre-flood (PF) and panicle initiation ( PI) significantly reduced the number of engorged pollen grains per anther, which was negatively correlated with spikelet sterility. Application of N and low temperature during microspore development with the absence of deep water also decreased pollen engorgement efficiency ( the percentage of pollen grains that were engorged). Application of N further increased spikelet density, which, in turn, increased both spikelet sterility and grain yield. The combined effect of spikelet density and low temperature during microspore development explained the 44% of variation in the number of engorged pollen grains per anther. Grain yield was decreased by low temperature during microspore development in the shallow water when N was applied. Spikelet sterility as a result of late sowing was strongly correlated with minimum temperature during flowering. It is concluded that N application reduced pollen number per anther as a result of increased spikelet density, and this made the spikelets more susceptible to low temperature, causing increased spikelet sterility.

Transmitting focussed B1 field and SENSE reconstruction using an 8-element transceive torso phased array coil

In this work, a new design concept in chest imaging for MRI application is presented. A focused, 8-element transceive torso phased array coil is designed to investigate transmitting focused B1 field deep within the torso to enhance signal intensity and use in conjunction with SENSE reconstruction technique. Hybrid FDTD/MOM method is used to accurately predict the RF behavior inside the human torso. The simulation results reported herein demonstrate the feasibility of the design concept which shows that B1 field focusing with SENSE reconstruction is achievable, and the 8-element transceive torso phased array coil has the advantage to be used in transmit and receive mode for optimum and fast chest imaging.

The deformation behaviour of the collapsing and destructured soils of the Sana'a area and their response to field treatment

Previous work has indicated the presence of collapsing and structured soils in the surface layers underlying Sana's, the capital of Yemen Republic. This study set out initially to define and, ultimately, to alleviate the problem by investigating the deformation behaviour of these soils through both field and laboratory programmes. The field programme was carried out in Sana'a while the laboratory work consisted of two parts, an initial phase at Sana's University carried out in parallel with the field programme on natural and treated soils and the major phase at Aston University carried out on natural, destructured and selected treated soils. The initial phase of the laboratory programme included classification, permeability, and single (collapsing) and double oedometer tests while the major phase, at Aston, was extended to also include extensive single and double oedometer tests, Scanning Electron Microscopy and Energy Dispersive Spectrum analysis. The mechanical tests were carried out on natural and destructed samples at both the in situ and soaked moisture conditions. The engineering characteristics of the natural intact, field-treated and laboratory destructured soils are reported, including their collapsing potentials which show them to be weakly bonded with nil to severe collapsing susceptibility. Flooding had no beneficial effect, with limited to moderate improvement being achieved by preloading and roller compaction, while major benefits were achieved from deep compaction. From these results a comparison between the soil response to the different treatments and general field remarks were presented. Laboratory destructuring reduced the stiffness of the soils while their compressibility was increasing. Their collapsing and destructuring mechanisms have been examined by studying the changes in structure accompanying these phenomena. Based on the test results for the intact and the laboratory destructured soils, a simplified framework has been developed to represent the collapsing and deformation behaviour at both the partially saturated and soaked states, and comments are given on its general applicability and limitations. It has been used to evaluate all the locations subjected to field treatment. It provided satisfactory results for the deformation behaviour of the soils destructed by field treatment. Finally attention is drawn to the design considerations together with the recommendations for the selection of potential improvement techniques to be used for foundation construction on the particular soils of the Sana's region.

Deep Herschel view of obscured star formation in the Bullet cluster

We use deep, five band (100–500 μm) data from the Herschel Lensing Survey (HLS) to fully constrain the obscured star formation rate, SFR_FIR, of galaxies in the Bullet cluster (z = 0.296), and a smaller background system (z = 0.35) in the same field. Herschel detects 23 Bullet cluster members with a total SFR_FIR = 144±14 M_⨀ yr^-1. On average, the background system contains brighter far-infrared (FIR) galaxies, with ~50% higher SFR_FIR (21 galaxies; 207± 9 M_⨀ yr^-1). SFRs extrapolated from 24 μm flux via recent templates (SFR_24 µm) agree well with SFRFIR for ~60% of the cluster galaxies. In the remaining ~40%, SFR_24 µm underestimates SFR_FIR due to a significant excess in observed S_100/S_24 (rest frame S_75/S_18) compared to templates of the same FIR luminosity.

The permafrost carbon inventory on the Tibetan Plateau : a new evaluation using deep sediment cores

Acknowledgements We are grateful for Dr. Jens Strauss and the other two anonymous reviewers for their insightful comments on an earlier version of this MS, and appreciate members of the IBCAS Sampling Campaign Teams for their assistance in field investigation. This work was supported by the National Basic Research Program of China on Global Change (2014CB954001 and 2015CB954201), National Natural Science Foundation of China (31322011 and 41371213), and the Thousand Young Talents Program.

Numerical detection of the Gardner transition in a mean-field glass former.

Recent theoretical advances predict the existence, deep into the glass phase, of a novel phase transition, the so-called Gardner transition. This transition is associated with the emergence of a complex free energy landscape composed of many marginally stable sub-basins within a glass metabasin. In this study, we explore several methods to detect numerically the Gardner transition in a simple structural glass former, the infinite-range Mari-Kurchan model. The transition point is robustly located from three independent approaches: (i) the divergence of the characteristic relaxation time, (ii) the divergence of the caging susceptibility, and (iii) the abnormal tail in the probability distribution function of cage order parameters. We show that the numerical results are fully consistent with the theoretical expectation. The methods we propose may also be generalized to more realistic numerical models as well as to experimental systems.

A new genus Abyssogena from deep-water vents and seeps

A new genus Abyssogena is established for A. phaseoliformis (Métivier, Okutani & Ohta, 1986) and A. kaikoi (Okutani & Métivier, 1986), which were previously assigned to the genus Calyptogena Dall, 1891, and also for two new species, A. southwardae and A. novacula. The most characteristic features of Abyssogena are an elongate shell up to about 280 mm in length; a pallial line starting from the ventral margin of the anterior adductor scar; secondary pallial attachment scars developed dorsal to the pallial line; radially arranged hinge teeth with a reduced anterior cardinal tooth in the right valve; and presence of an inner ctenidial demibranch only. Abyssogena occurs in deep water from 2,985 to 6,400 m and is distributed in the Pacific and Atlantic Oceans at cold seeps along continental margins and hydrothermal vents at mid-oceanic ridges. Some species have a remarkably wide geographic distribution; A. southwardae is present throughout the Atlantic and A. phaseoliformis is present in Japan, Kuril-Kamchatka, as well as Aleutian Trenches. No fossils of Abyssogena are known.

DEP-derived density from two snow trenches from Kohnen Station, Dronning Maud Land, Antarctica from the 2012/13 field season

The density of firn is an important property for monitoring and modeling the ice sheet as well as to model the pore close-off and thus to interpret ice core-based greenhouse gas records. One feature, which is still in debate, is the potential existence of an annual cycle of firn density in low-accumulation regions. Several studies describe or assume seasonally successive density layers, horizontally evenly distributed, as seen in radar data. On the other hand, high-resolution density measurements on firn cores in Antarctica and Greenland showed no clear seasonal cycle in the top few meters. A major caveat of most existing snow-pit and firn-core based studies is that they represent one vertical profile from a laterally heterogeneous density field. To overcome this, we created an extensive dataset of horizontal and vertical density data at Kohnen Station, Dronning Maud Land on the East Antarctic Plateau. We drilled and analyzed three 90 m long firn cores as well as 160 one meter long vertical profiles from two elongated snow trenches to obtain a two dimensional view of the density variations. The analysis of the 45 m wide and 1 m deep density fields reveals a seasonal cycle in density. However, the seasonality is overprinted by strong stratigraphic noise, making it invisible when analyzing single firn cores. Our density dataset extends the view from the local ice-core perspective to a hundred meter scale and thus supports linking spatially integrating methods such as radar and seismic studies to ice and firn cores.

Modelling the Sun's small scale global photospheric magnetic field

We present a new model for the Sun's global photospheric magnetic field during a deep minimum of activity, in which no active regions emerge. The emergence and subsequent evolution of small- scale magnetic features across the full solar surface is simulated, subject to the influence of a global supergranular flow pattern. Visually, the resulting simulated magnetograms reproduce the typical structure and scale observed in quiet Sun magnetograms. Quantitatively, the simulation quickly reaches a steady state, resulting in a mean field and flux distribution that are in good agreement with those determined from observations. A potential coronal magnetic field is extrapolated from the simulated full Sun magnetograms, to consider the implications of such a quiet photospheric magnetic field on the corona and inner heliosphere. The bulk of the coronal magnetic field closes very low down, in short connections between small-scale features in the simulated magnetic network. Just 0.1% of the photospheric magnetic flux is found to be open at 2:5 Rʘ, around 10 - 100 times less than that determined for typical HMI synoptic map observations. If such conditions were to exist on the Sun, this would lead to a significantly weaker interplanetary magnetic field than is presently observed, and hence a much higher cosmic ray flux at Earth.

Toward assessing the effects of aerosols on deep convection: a numerical study using the WRF-Chemistry model

As the formative agents of cloud droplets, aerosols play an undeniably important role in the development of clouds and precipitation. Few meteorological models have been developed or adapted to simulate aerosols and their contribution to cloud and precipitation processes. The Weather Research and Forecasting model (WRF) has recently been coupled with an atmospheric chemistry suite and is jointly referred to as WRF-Chem, allowing atmospheric chemistry and meteorology to influence each other’s evolution within a mesoscale modeling framework. Provided that the model physics are robust, this framework allows the feedbacks between aerosol chemistry, cloud physics, and dynamics to be investigated. This study focuses on the effects of aerosols on meteorology, specifically, the interaction of aerosol chemical species with microphysical processes represented within the framework of the WRF-Chem. Aerosols are represented by eight size bins using the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) sectional parameterization, which is linked to the Purdue Lin bulk microphysics scheme. The aim of this study is to examine the sensitivity of deep convective precipitation modeled by the 2D WRF-Chem to varying aerosol number concentration and aerosol type. A systematic study has been performed regarding the effects of aerosols on parameters such as total precipitation, updraft/downdraft speed, distribution of hydrometeor species, and organizational features, within idealized maritime and continental thermodynamic environments. Initial results were obtained using WRFv3.0.1, and a second series of tests were run using WRFv3.2 after several changes to the activation, autoconversion, and Lin et al. microphysics schemes added by the WRF community, as well as the implementation of prescribed vertical levels by the author. The results of WRFv3.2 runs contrasted starkly with WRFv3.0.1 runs. The WRFv3.0.1 runs produced a propagating system resembling a developing squall line, whereas the WRFv3.2 runs did not. The response of total precipitation, updraft/downdraft speeds, and system organization to increasing aerosol concentrations were opposite between runs with different versions of WRF. Results of the WRFv3.2 runs, however, were in better agreement in timing and magnitude of vertical velocity and hydrometeor content with a WRFv3.0.1 run using single-moment Lin et al. microphysics, than WRFv3.0.1 runs with chemistry. One result consistent throughout all simulations was an inhibition in warm-rain processes due to enhanced aerosol concentrations, which resulted in a delay of precipitation onset that ranged from 2-3 minutes in WRFv3.2 runs, and up to 15 minutes in WRFv.3.0.1 runs. This result was not observed in a previous study by Ntelekos et al. (2009) using the WRF-Chem, perhaps due to their use of coarser horizontal and vertical resolution within their experiment. The changes to microphysical processes such as activation and autoconversion from WRFv3.0.1 to WRFv3.2, along with changes in the packing of vertical levels, had more impact than the varying aerosol concentrations even though the range of aerosol tested was greater than that observed in field studies. In order to take full advantage of the input of aerosols now offered by the chemistry module in WRF, the author recommends that a fully double-moment microphysics scheme be linked, rather than the limited double-moment Lin et al. scheme that currently exists. With this modification, the WRF-Chem will be a powerful tool for studying aerosol-cloud interactions and allow comparison of results with other studies using more modern and complex microphysical parameterizations.