scholarly journals Trace Evidence from Mars’ Past: Fingerprinting Transverse Aeolian Ridges

2019 ◽  
Vol 11 (9) ◽  
pp. 1060 ◽  
Author(s):  
Louis Scuderi ◽  
Timothy Nagle-McNaughton ◽  
Joshua Williams
Keyword(s):  
Trace Evidence ◽  
Algorithmic Approach ◽  
Physical Forcing ◽  
Remotely Sensed Imagery ◽  
Rapid Extraction ◽  
High Resolution Imagery ◽  
Field Check ◽  
Fingerprint Minutiae ◽  
Forcing Mechanisms ◽  
Manual Extraction

Linear dunes and human fingerprints share many characteristics. Both have ridges, valleys, and defects (minutiae) in the form of bifurcations and termination of ridgeline features. For dunes, determining how defects vary across linear and transverse dunefields is critical to understanding the physics of their formative processes and the physical forcing mechanisms that produce dunefields. Unfortunately, manual extraction of defect locations and higher order characteristics (type, orientation, and quality) from remotely sensed imagery is both time-consuming and inconsistent. This problem is further exacerbated when, in the case of imagery from sensors in orbit around Mars, we are unable to field check interpretations. In this research, we apply a novel technique for extracting defects from multiple imagery sources utilizing a robust and well-documented fingerprint minutiae detection and extraction software (MINDTCT: MINutiae DecTeCTion) developed by the National Institute of Standards and Technology (NIST). We apply our ‘fingerprinting’ approach to Transverse Aeolian Ridges (TARs), relict aeolian features commonly seen on the surface of Mars, whose depositional and formative processes are poorly understood. Our algorithmic approach demonstrates that automating the rapid extraction of defects from orbitally-derived high-resolution imagery of Mars is feasible and produces maps that allow the quantification and analysis of these features.

Use of Remotely Sensed Imagery in Cyber Warfare and Cyber Counterterrorism

2011 ◽  
pp. 298-305
Author(s):  
Gang Gong ◽  
Mark R. Leipnik
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Remotely Sensed ◽  
Aerial Photographs ◽  
The Internet ◽  
Cyber Warfare ◽  
Future Trends ◽  
Remotely Sensed Imagery ◽  
General Terms ◽  
High Resolution Imagery

Remote sensing refers to the acquisition of information at a distance. More specifically, it has come to mean using aerial photographs or sensors on satellites to gather data about features on the surface of the earth. In this article, remote sensing and related concepts are defined and the methods used in gathering and processing remotely sensed imagery are discussed. The evolution of remote sensing, generic applications and major sources of remotely sensed imagery and programs used in processing and analyzing remotely sensed imagery are presented. Then the application of remote sensing in warfare and counterterrorism is discussed in general terms with a number of specific examples of successes and failures in this particular area. Next, the potential for misuse of the increasing amount of high resolution imagery available over the Internet is discussed along with prudent countermeasures to potential abuses of this data. Finally, future trends with respect to this rapidly evolving technology are included.

scholarly journals Pumping methane out of aquatic sediments – forcing mechanisms that affect the temporal dynamics of ebullition

2013 ◽  
Vol 10 (11) ◽  
pp. 18687-18722 ◽  
Author(s):  
A. Maeck ◽  
H. Hofmann ◽  
A. Lorke
Keyword(s):  
Temporal Dynamics ◽  
Large Fraction ◽  
Atmospheric Methane ◽  
Continuous Sampling ◽  
Physical Forcing ◽  
Methane Budget ◽  
Global Budgets ◽  
Sampling Intervals ◽  
Forcing Mechanisms ◽  
Pressure Changes

Abstract. Freshwater systems contribute significantly to the global atmospheric methane budget. A large fraction of the methane emitted from freshwaters is transported via ebullition. However, due to its strong variability in space and time, accurate measurements of ebullition rates are difficult; hence, the uncertainty of its contribution to global budgets is large. Here, we analyze measurements made by continuously recording automated bubble traps in an impounded river in central Europe and investigate the mechanisms affecting the temporal dynamics of bubble release from cohesive sediments. Our results show that the main mechanisms for bubble release were pressure changes, originating from the passage of ship-lock induced surges and ship-passages. The response to physical forcing was strongly affected by previous outgassing. Ebullition rates varied strongly over all relevant timescales from minutes to days; therefore, representative ebullition estimates could only be inferred with continuous sampling over long periods. Since ebullition was found to be episodic, short sampling intervals of a few days or weeks will likely underestimate ebullition rates, which may result in an uncertainty of over 50% in current global freshwater emission estimates.

scholarly journals Pumping methane out of aquatic sediments – ebullition forcing mechanisms in an impounded river

2014 ◽  
Vol 11 (11) ◽  
pp. 2925-2938 ◽  
Author(s):  
A. Maeck ◽  
H. Hofmann ◽  
A. Lorke
Keyword(s):  
Temporal Dynamics ◽  
Large Fraction ◽  
Atmospheric Methane ◽  
Short Term ◽  
Continuous Sampling ◽  
Physical Forcing ◽  
Methane Budget ◽  
Global Budgets ◽  
Forcing Mechanisms ◽  
Pressure Changes

Abstract. Freshwater systems contribute significantly to the global atmospheric methane budget. A large fraction of the methane emitted from freshwaters is transported via ebullition. However, due to its strong variability in space and time, accurate measurements of ebullition rates are difficult; hence, the uncertainty regarding its contribution to global budgets is large. Here, we analyze measurements made by continuously recording automated bubble traps in an impounded river in central Europe and investigate the mechanisms affecting the temporal dynamics of bubble release from cohesive sediments. Our results show that the main triggers of bubble release were pressure changes, originating from the passage of ship lock-induced surges and ship passages. The response to physical forcing was also affected by previous outgassing. Ebullition rates varied strongly over all relevant timescales from minutes to days; therefore, representative ebullition estimates could only be inferred with continuous sampling over long periods. Since ebullition was found to be episodic, short-term measurement periods of a few hours or days will likely underestimate ebullition rates. Our results thus indicate that flux estimates could be grossly underestimated (by up to ~50%) if the correct temporal resolution is not used during data collection.

scholarly journals The Vorticity Budgets of North Atlantic Winter Extratropical Cyclone Life Cycles in MERRA Reanalysis. Part II: Decaying Phase*

2014 ◽  
Vol 71 (9) ◽  
pp. 3129-3143 ◽  
Author(s):  
Roohollah Azad ◽  
Asgeir Sorteberg
Keyword(s):  
North Atlantic ◽  
Life Cycles ◽  
Cyclonic Circulation ◽  
Negative Contribution ◽  
Physical Forcing ◽  
Vorticity Advection ◽  
Adiabatic Cooling ◽  
Upper Level ◽  
Forcing Mechanisms ◽  
Vorticity Tendency

Abstract The role of physical forcing mechanisms that contribute to the decay of winter North Atlantic extratropical cyclones during the period 1979–2009 are examined using the Modern-Era Retrospective Analysis for Research and Applications (MERRA). The paired Zwack–Okossi tendency equation and omega equation explained in part I of this paper is employed to investigate the total effects of forcing processes (the direct effect of the forcing mechanisms and the indirect effect of the induced adiabatic cooling) that dissipate the 950-hPa cyclonic geostrophic vorticity at the cyclone center. Composite analyses reveal that the commencement of the decay is associated mainly with the upper-level anticyclonic vorticity advection, cold-air advection, and positive ageostrophic vorticity tendency. The secondary contributor to the dissipation of cyclonic circulation is the lower-tropospheric adiabatic cooling induced mainly by friction and positive ageostrophic vorticity tendency. The dynamics is found to be different at the beginning of the decay than in the later stages. While the negative tilt of troughs aloft and the surface cyclone is required for cyclolysis to occur, low air processes show a greater effect in the termination of the low pressure systems. Further, the total effect of the vorticity advection and temperature advection terms are modest, while the ageostrophic vorticity tendency and friction terms show a greater total negative contribution. This is because the two latter terms decrease the cyclonic geostrophic vorticity at the low center through both their direct and indirect effects. The latent heat release maximizing at 800–700 hPa produces cyclonic circulation, thus reducing the spindown of decaying cyclones.

scholarly journals Physical Forcing Mechanisms Controlling the Variability of Chlorophyll-a over the Royal-Charlotte and Abrolhos Banks—Eastern Brazilian Shelf

PLoS ONE ◽  
2015 ◽  
Vol 10 (2) ◽  
pp. e0117082 ◽  
Author(s):  
Renato David Ghisolfi ◽  
Meyre Pereira da Silva ◽  
Felipe Thomaz dos Santos ◽  
Ricardo Nogueira Servino ◽  
Mauro Cirano ◽  
...  
Keyword(s):  
Chlorophyll A ◽  
Physical Forcing ◽  
Forcing Mechanisms

Algorithmic Approach to Analysis of Queuing System with Finite Queues and Jump-like Priorities

2012 ◽  
Vol 44 (12) ◽  
pp. 43-54 ◽  
Author(s):  
Agasi Zarbali ogly Melikov ◽  
Leonid A. Ponomarenko ◽  
Che Soong Kim
Keyword(s):  
Queuing System ◽  
Algorithmic Approach ◽  
Finite Queues
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