2,221 research outputs found

    NASA World Wind: Visualization Technology for Spatial Data

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    Spatial information intelligence is a global issue that will increasingly affect our ability to survive as a species. Collectively we must better appreciate the complex relationships that make life on Earth possible. Providing spatial information in its native context can accelerate our ability to process that information. To maximize this ability to process information, three basic elements are required: data delivery (server technology), data access (client technology), and data processing (information intelligence). NASA World Wind provides the open source client technology based on open standards. The possibilities for data processing and data sharing are enhanced by this inclusive infrastructure for geographic information. It is interesting that this open source and open standards approach, unfettered by proprietary constraints, provides for unlimited innovation with this technology

    NASA WorldWind: Open Source Visualization Technology for Earth Observation

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    NASA WorldWind: Open Source Visualization Technology for Earth Observation WorldWind, open source virtual globe technology for Java, iOS, Android and Web, is provided by NASA and is architected as API-centric modular componentry. This enable it to be continually optimized and feature-enriched in ways that allow applications based on this SDK (Software Development Kit) to benefit Earth Observation, especially Open Science, with minimal or no adjustment for the decade ahead. The next-generation National Airspace System (NAS) aviation management system for the U.S. Federal Aviation Administration, FAA, uses WorldWind, as do applications currently being developed by the European Space Agency, along with several other US and European government agencies and industry partners. This presentation will demonstrate several NASA open source use cases for WorldWind technology that include advances being made to optimize access to NetCDF and HDF data via WebWorldWind.NASA WorldWind: Multidimensional Geospatial Web Platform The ability to see spatial data in its native context is essential for that data to be appreciated whether by the scientific community, policy and decision-makers or the general public. Recently, the accessibility of spatial data has dramatically improved. Without the need to install an application, spatial data can now be experienced via any web browser, mobile devices included. For developers, by simply updating the app on your server, the latest version of your application is now immediately available to your entire usercommunity. Unlike other virtual globes such as Google Earth, NASA World Wind offers something very special, full control to customize the interface with any features or functionalities you might need. You decide how the data is accessed and experienced. This allows you to provide maximum value of the information to your user community. The web version of NASA WorldWind (WebWorldWind) has made it possible for a whole new suite of applications for managing and sharing spatial data. Apps built with this web version are ideal for immediate social media type activity and also facilitate delivery of sophisticated data exchange scenarios such as weather and climate research, disaster response, personal navigation, and industrial-strength tracking for transportation, supply chain, aviation and satellites. WebWorldWind is an application component, not an app in itself. It is written in JavaScript and provides the real world geographic context for spatial data and information visualization, using a rich set of shapes and graphic primitives. WebWorldWind also provides platform independence, while accommodating any number of data types. Web WorldWind runs on any platform via a browser, i.e., Internet Explorer, Firefox, Chrome and Safari. Features include, 3D virtual globe, 2D map with multiple projection choices (Mercator, Polar, UPS, Equirectangular), imagery and elevation import, extensible, data retrieval (via REST, WMS, WCS, WFS, Bing, User-Defined), decluttering, measurement, accurate line-ofsight, subsurface visualization, and more

    Topographic Effects on the Path and Evolution of Loop Current Eddies

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    Eddy-topography (ET) interactions are important in determining the path and evolution of oceanic eddies, including Loop Current Eddies (LCE) in the Gulf of Mexico (GOM). We use the Hybrid Coordinate Ocean Model and satellite altimetry data to investigate the ET interactions and the impact on LCE pathway evolution in the GOM. Satellite altimetry reveals that LCEs translate dominantly westward in the central GOM and strongly collide and reflect against topography near the continental slope in the northern and western GOM. The result is the frequent generation of an anticyclone-cyclone (AC) pair in conjunction with the LCEs. In the absence of lateral or surface boundary forcing but including realistic topography, simulations initialized with idealized eddies at various locations in the GOM reveal the following results. Southward eddy reflection from the northern slope occurs when a cyclone drastically strengthens east of the anticyclone because of the ET collision. The prevailing westward propagation in the central GOM occurs because the cyclone is very dispersive toward nearby topographic features, causing a reduced southward component of drift and/or moves to the south, forming a meridional AC pair, causing an enhanced westward component. ET collision is strongest over the northwestern slope (north of 24 degrees N) because of the eddy colliding relatively normal to the steep slope, and the eddy typically tracks anticyclonic pathways during the collision/reflection process. Along the western slope, a strong ET collision produces a southeastward reflection, and the accompanying cyclone to the northeast strongly enhances the reflection. Near the southern GOM slope, eddy pathways tend to propagate alongslope with an onshore-offshore oscillatory trajectory because of the competition between topographic and planetary beta effects. In the southwestern GOM a bimodal pathway occurs, i.e., northward migration with an anticyclonic route for relatively stronger eddies and southward dissipative propagation along the shelf edge for weaker ones

    Persian Gulf response to a wintertime shamal wind event

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    The results from a~1 km resolution Hybrid Coordinate Ocean Model (HYCOM),forced by 1/2° Navy Operational Global Atmospheric Prediction System (NOGAPS) atmospheric data, were used in order to study the dynamic response of the Persian Gulf to winter time shamal forcing. Shamal winds are strong northwesterly winds that occur in the Persian Gulf area behind southeast moving cold fronts. The period from 20 November to 5 December 2004 included a well-defined shamal event that lasted 4–5 days. In addition to strong winds (16ms_1) the winter shamal also brought cold dry air(Ta=20 °C, qa=10 gkg-1) which led to a net heat loss in excess of 1000 W m-2 by increasing the latent heat flux. This resulted in SST cooling of up to 10°C most notably in the northern and shallower shelf regions. A sensitivity experiment with a constant specific humidity of qa= 15 gkg-1 confirmed that about 38% of net heat loss was due to the air– sea humidity differences. The time integral of SST cooling closely followed the air–sea heat loss, indicating an approximate one-dimensional vertical heat balance. It was found that the shamal induced convective vertical mixing provided a direct mechanism for the erosion of stratification and deepening of the mixed layer by 30m. The strong wind not only strengthened the circulation in the entire Persian Gulf but also established a northwestward flowing Iranian Coastal Current (ICC,25–30cms-1) from the Strait of Hormuz to about 52°E, where it veered off shore. The strongest negative sea level of 25–40cm was generated in the northern most portion of the Gulf while the wind set up against the coast of the United Arab Emirates established a positive sea level of 15–30 cm. The transport through the Strait of Hormuz at 56.2°E indicated an enhanced out flow of 0.25Sv (Sv=106 m3 s-1) during 24 November followed by an equivalent in flow on the next day

    Upper-Ocean Response to Hurricane Ivan in a 1/25 Degrees Nested Gulf of Mexico HYCOM

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    [ 1] A 20-layer, 1/25 degrees nested Gulf of Mexico (GoM) Hybrid Coordinate Ocean Model (HYCOM) has been employed to examine the evolving three-dimensional ocean response to Hurricane Ivan during 14 - 16 September 2004. Results from several combinations of numerical experiments with and without assimilation of satellite-altimetry sea-surface height (SSH) are being analyzed and compared for the September 2004 hurricane period. A comparison of simulated zonal and meridional velocities using data assimilation shows improved agreement with profiler observations. The amplitude of the cold wake ( similar to 6 degrees C) produced by these simulations compared reasonably well with the observed changes in SST before and after the storm; however, the region of extreme cooling varied depending on the simulated location of the warm core eddy (WCE) that had detached from the Loop Current ( LC). While the simulated location of the WCE and LC in the assimilation runs agree better with satellite altimetry, the storm-induced SST cooling was 40% - 50% greater than the observed cooling. Overall, similar to 64% of the cooling was due to vertical mixing caused by turbulence generated from strong shear-stress across the base of the mixed layer. Vertical advection (upwelling) caused a significant portion of cooling (23.4%) in those runs that included data assimilation; a three fold increase from the nonassimilative runs (7%). This enhanced upper- ocean cooling was caused primarily by the prestorm thermal stratification; a shallower thermocline ( similar to 40 m) and a stronger upper- thermocline temperature gradient compared with the nonassimilative runs. In all the experiments the air-sea exchange was a small component of the mixed-layer heat budget which overall accounted for similar to 4

    On the Mechanisms of Episodic Salinity Outflow Events in the Strait of Hormuz

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    Observations in the Strait of Hormuz (26.26 degrees N, 56.08 degrees E) during 1997-98 showed substantial velocity fluctuations, accompanied by episodic changes in the salinity outflow events with amplitude varying between 1 and 2 psu on time scales of several days to a few weeks. These events are characterized by a rapid increase in salinity followed by an abrupt decline. The mechanisms behind these strong pulses of salinity events are investigated with a whigh-resolution (similar to 1 km) Hybrid Coordinate Ocean Model (HYCOM) with particular reference to the year 2005. In accordance with the observations, the simulated salinity events are characterized by strong coherence between the enhanced flows in zonal and meridional directions. It is inferred that most of the simulated and observed outflow variability is associated with the continuous formation of strong mesoscale cyclonic eddies, whose origin can be traced upstream to around 26 degrees N, 55.5 degrees E. These cyclonic eddies have a diameter of about 63 km and have a remnant of Persian Gulf water (PGW) in their cores, which is eroded by lateral mixing as the eddies propagate downstream at a translation speed of 4.1 cm s(-1). The primary process that acts to generate mesoscale cyclones results from the barotropic instability of the exchange circulation through the Strait of Hormuz induced by fluctuations in the wind stress forcing. The lack of salinity events and cyclogenesis in a model experiment with no wind stress forcing further confirms the essential ingredients required for the development of strong cyclones and the associated outflow variability

    Extraction and Visualization of Orientation Data from Virtual Geologic Surfaces with MATLAB®

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    High-resolution visualization of surfaces of geologic interest, at a multitude of scales, using 3D point cloud technologies provides an opportunity to analyze spatial relationships of surfaces using orientation data. We present a MATLAB® script that produces planar geologic attitude data (e.g., strike, dip, and dip-direction data) from 3D datasets (e.g., point clouds, 3D scanning). The method utilizes Cartesian coordinates of triangular planar surfaces and converts them into matrices of conventional geologic attitude data. Spatial relationships among data points can be investigated, using polar tangent diagrams, stereographic analysis, or geologic curvature analysis. We utilize this script to create synthetic graphical plots (e.g., stereograms, tangent diagrams) from geomechanically realistic, virtual, folded surfaces produced by dynamic modeling. Synthetic graphical diagrams are of considerable usefulness in interpreting graphical plots (e.g., stereograms) of attitude data from natural folded rock surfaces, particularly in locations with poor exposure.This script outputs attitude data (strike, dip, and dip direction) in a spreadsheet and as a text file for use in other visualization software.A tangent diagram is created and displayed in this script for rapid visualization and fold shape assessment. The MATLAB script is readily modified to accept multiple data formats for input (e.g., MATLAB variables, *.csv files, etc.) and output (e.g., *.csv files, *.txt files, etc.)

    Mean Atlantic Meridional Overturning Circulation Across 26.5° N From Eddy-Resolving Simulations Compared to Observations

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    Observations along 26.5 degrees N are used to examine the time mean structure of the Atlantic meridional overturning circulation (AMOC) in eddy-resolving simulations with the Hybrid Coordinate Ocean Model (HYCOM). The model results yield a 5 year mean AMOC transport of 18.2 Sv, compared to 18.4 Sv based on data. The modeled northward limb of the AMOC has a vertical structure similar to observations. The southward limb is shallower than observed but deeper than other ocean general circulation models and includes a secondary transport maximum near 4000 m corresponding to Nordic Seas Overflow Water. The modeled flow through the Florida Strait and the deep western boundary current (DWBC) east of Abaco, Bahamas, are also approximately consistent with observations. The model results are used to clarify the sources of the northward AMOC transport and to explore the circulation pattern of the southward transport in the western subtropical North Atlantic in the range 18-33 degrees N. About 14.1 Sv of the modeled northward AMOC transport is through the Florida Strait and the remainder through the mid-ocean, primarily in the Ekman layer, but also below 600 m. The modeled AMOC transport is about 2/3 surface water and 1/3 Antarctic Intermediate Water with no contribution from the thermocline water in between. In the western subtropical North Atlantic the model results depict a complicated deep circulation pattern, associated with the complex bathymetry. The DWBC flows southward then eastward in both the upper and lower North Atlantic Deep Water (NADW) layers but with different offshore recirculation pathways, and there exists a second, more northern branch of eastward flow in the lower NADW layer

    Timing of Deformation along the Iron Springs Thrust, Southern Sevier Fold-and-Thrust Belt, Utah: Evidence for an Extensive Thrusting Event in the mid-Cretaceous

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    The temporal and spatial distribution of strain associated with the Sevier orogeny in western North America is significantly different in the southern end of the belt, at the latitude of Las Vegas, Nevada, than farther to the north at the latitude of Salt Lake City, Utah. Reasons for these differences have been speculative as a lack of temporal constraints on thrusting in the intervening region hindered along-strike correlation across the belt. We determined a crystallization age of 100.18 ± 0.04 Ma for zircons extracted from a recently recognized dacite lapilli ash-fall tuff near the base of the synorogenic Iron Springs Formation. We propose the name “Three Peaks Tuff Member” for this unit, and identify a type stratigraphic section on the western flank of the “Three Peaks,” a topographic landmark in Iron County, Utah. Field relationships and this age constrain movement on the Iron Springs thrust and the end of the sub-Cretaceous unconformity in the critical intervening area to latest Albian/earliest Cenomanian. Movement on the Iron Springs thrust was synchronous with movement on multiple Sevier thrusts at ~100 Ma, indicating that the mid-Cretaceous was a period of extensive thrust-fault movement. This mid-Cretaceous thrusting event coincided with a period of global plate reorganization and increased convergence, and hence an increased subduction rate for the Farallon Plate beneath North America. The accelerated subduction contributed to a Cordilleran arc flare-up event and steepening of the orogenic wedge, which triggered widespread thrusting across the retroarc Sevier deformation belts. Additionally, based on temporal constraints and the strong spatial connection of mid-Cretaceous thrusts to lineaments interpreted as pre-orogenic transform faults, we suggest that temporal and spatial variations along the strike of the orogenic belt reflect tectonic inheritance of basement structures associated with the edge of the rifted Precambrian craton

    Evaluation of environmental sampling methods for detection of Staphylococcus aureus on fomites

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    We evaluated a variety of methods to recover S. aureus from inanimate surfaces. Two contact agar plates and three swab sampling methods were tested on porous and non-porous surfaces and bar soap. The cost and ease of use of each method was also evaluated. S. aureus was recovered using all methods on both porous and non-porous surfaces. S. aureus could not be detected on three of four brands of soap
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