Earth Sciences Commons^™

Inner-Shelf Circulation And Sediment Dynamics On A Series Of Shoreface-Connected Ridges Offshore Of Fire Island, Ny, John Warner, Jeffrey List, William Schwab, George Voulgaris, Brandy Armstrong, Nicole Marshall

George Voulgaris

Locations along the inner-continental shelf offshore of Fire Island, NY, are characterized by a series of shoreface-connected ridges (SFCRs). These sand ridges have approximate dimensions of 10 km in length, 3 km spacing, and up to ∼8 m ridge to trough relief and are oriented obliquely at approximately 30° clockwise from the coastline. Stability analysis from previous studies explains how sand ridges such as these could be formed and maintained by storm-driven flows directed alongshore with a key maintenance mechanism of offshore deflected flows over ridge crests and onshore in the troughs. We examine these processes both with a limited …

Measuring Eddy Heat And Constituent Fluxes With High-Resolution Na And Fe Doppler Lidars, Chester S. Gardner, Alan Z. Liu

Alan Z Liu

Inferring The Global Cosmic Dust Influx To The Earth’S Atmosphere From Lidar Observations Of The Vertical Flux Of Mesospheric Na, Chester S. Gardner, Alan Z. Liu, Dan Marsh, Wuhu Feng, John Plane

Alan Z Liu

The Lower Ordovician Fillmore Formation Of Western Utah: Storm-Dominated Sedimentation On A Passive Margin., Benjamin Dattilo

Benjamin F. Dattilo

No abstract provided.

Tempestites In A Teapot? Condensation-Generated Shell Beds In The Upper Ordovician, Cincinnati Arch, Usa., Benjamin F. Dattilo, Carlton E. Brett, Thomas J. Schramm

Benjamin F. Dattilo

Skeletal concentrations in mudstones may represent local facies produced by storm winnowing in shallow water, or time-specific deposits related to intervals of diminished sediment supply. Upper Ordovician (Katian) of the Cincinnati region is a mixed siliciclastic-carbonate succession including meter-scale cycles containing a shelly limestone-dominated phase and a mudstone-dominated phase. The “tempestite proximality model” asserts that shell-rich intervals originated by winnowing of mud from undifferentiated fair-weather deposits. Thus shell beds are construed as tempestites, while interbedded mudstones represent either fair-weather or bypassed mud. Meter-scale cycles are attributed to sea-level fluctuation or varying storm intensity. Alternatively, the “episodic starvation model” argues, on …

Sustainable Development, John Dernbach

John C. Dernbach

No abstract provided.

Global Meteorological Drought – Part 1: Probabilistic Monitoring, Will Pozzi

Will Pozzi

Near-real-time drought monitoring can provide decision-makers with valuable information for use in se- veral areas, such as water resources management, or inter- national aid. One of the main constrains of assessing the current drought situation is associated with the lack of re- liable sources of observed precipitation on a global scale available in near-real time. Furthermore, monitoring sys- tems also need a long record of past observations to pro- vide mean climatological conditions. To address these prob- lems, a novel probabilistic drought monitoring methodology based on ECMWF probabilistic forecasts is presented, where probabilistic monthly means of precipitation were derived from …

Locating Cryptotephra In Sediments Using Fluid Imaging Technology, Robert D'Anjou, Nicholas L. Balascio, Raymond S. Bradley

Raymond S Bradley

We report a new approach to locate and quantify cryptotephra in sedimentary archives using a continuously-imaging Flow Cytometer and Microscope (FlowCAM_). The FlowCAM rapidly photographs particles flowing in suspension past a microscope lens and performs semi-automated analysis of particle images. It has had primarily biological applications, although the potential sedimentological applications are numerous. Here we test the ability of this instrument to image irregularly shaped, vesicular glass shards and to screen sediment samples for the presence of cryptotephra. First, reference samples of basalt and rhyolite tephra (sieved <63>microns) were analyzed with the FlowCAM, demonstrating the ability of the instrument to …

Temporal And Spatial Evolution Of Wave-Induced Ripple Geometry: Regular Versus Irregular Ripples, Timothy Nelson, George Voulgaris

George Voulgaris

Concurrent observations of inner shelf near bed hydrodynamics and acoustic imagery of the seabed are used to relate wave-induced ripple geometry (wavelength and orientation) to near bed directional wave velocities. The observations were collected on the continental shelf of the South Atlantic Bight at water depths of 9.5 and 30 m off the coasts of South Carolina (median size 177 mm) and Georgia (388 mm), respectively. 2-D spectral analysis techniques are performed on the imagery to automate detection of ripple wavelength, orientation, and irregularity. Our analysis shows that ripple irregularity is a time-dependent process dependent on magnitude, direction, and duration …

Atmospheric Methane Over The Arctic Ocean: Thermal Ir Satellite And Ship- Based Observations, Leonid Yurganov

Leonid Yurganov

Recent warming of the Arctic stimulated speculations about dissociation of methane hydrates in the Arctic seabed and a new climatic positive feedback. Here, for the first time, methane low tropospheric satellite retrievals over the Arctic from two instruments: AIRS (Atmospheric IR Sounder) and IASI (Infrared Atmospheric Sounding Interferometer) were analyzed. Analyzed are data for areas over open water with high values of the vertical thermal contrast (ThC, defined here as the temperature difference between the surface and altitude of 4 km); they have been found to be reliable. The seasonal cycles of the data well correlate with the cycles measured …