Headwall retreat of ground-ice slumps, Banks Island, Northwest Territories

1987 ◽  
Vol 24 (6) ◽  
pp. 1077-1085 ◽  
Author(s):  
Antoni G. Lewkowicz
Keyword(s):  
Northwest Territories ◽  
Latent Heat ◽  
Field Measurements ◽  
Geometric Factor ◽  
Ground Ice ◽  
Model Based ◽  
Banks Island ◽  
Sand Hills ◽  
Ground Slope ◽  
The Relationship

The relationship between ice-face ablation and headwall retreat is described for three ground-ice slumps in the Sand Hills moraine, southwest Banks Island. Retreat exceeds ablation by a geometric factor that depends on the slope of the ice and the gradient of the surrounding terrain. Amounts of retreat predicted from ice-ablation calculations compare favourably with field measurements, except at the start of thermokarst activity in the spring or when the ground ice remains covered by debris for long periods.Long-term headwall retreat for slumps in southern Banks Island with different orientations and ice contents can be estimated using a model based on meteorological information. The model predicts headwall recession of 11 m/a for a ground-ice slump facing south and 8.8–9.3 m/a for one facing north, with inputs of a 35 °ice face, a ground slope of 5°, and a volumetric latent heat of 270 MJ/m3. These predictions are close to the maximum rates of retreat over a 10 year period as measured from air photographs.

A new underwater positioning model based on average sound speed

2021 ◽  
pp. 1-17
Author(s):  
Yixu Liu ◽  
Xiushan Lu ◽  
Shuqiang Xue ◽  
Shengli Wang
Keyword(s):  
Efficient Algorithm ◽  
Sound Speed ◽  
Incident Angle ◽  
Function Model ◽  
Positioning Accuracy ◽  
Correction Model ◽  
Model Based ◽  
Underwater Positioning ◽  
Speed Function ◽  
The Relationship

Abstract The layout of seafloor datum points is the key to constructing the seafloor geodetic datum network, and a reliable underwater positioning model is the prerequisite for achieving precise deployment of the datum points. The traditional average sound speed positioning model is generally adopted in underwater positioning due to its simple and efficient algorithm, but it is sensitive to incident angle related errors, which lead to unreliable positioning results. Based on the relationship between incident angle and sound speed, the sound speed function model considering the incident angle has been established. Results show that the accuracy of positioning is easily affected by errors related to the incident angle; the new average sound speed correction model based on the incident angle proposed in this paper is used to significantly improve the underwater positioning accuracy.

scholarly journals YERSINIOSIS IN FREE-RANGING MUSKOXEN ON BANKS ISLAND, NORTHWEST TERRITORIES, CANADA

1991 ◽  
Vol 27 (4) ◽  
pp. 527-533 ◽  
Author(s):  
John E. Blake ◽  
Bruce D. McLean ◽  
Anne Gunn
Keyword(s):  
Northwest Territories ◽  
Banks Island ◽  
Free Ranging

Fecundity Comparisons for Various Stocks of Lake Whitefish, Coregonus clupeaformis

1975 ◽  
Vol 32 (3) ◽  
pp. 404-407 ◽  
Author(s):  
M. C. Healey ◽  
C. W. Nicol
Keyword(s):  
Northwest Territories ◽  
Lake Erie ◽  
Fork Length ◽  
Nonlinear Relationship ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Limited Data ◽  
Relative Fecundity ◽  
Great Slave Lake ◽  
The Relationship

We found no significant differences in slope or intercept for the regression of loge fecundity on loge fork length among samples of whitefish from four lakes near Yellowknife in the Northwest Territories. The equation describing the relationship between fecundity and fork length for these populations was:[Formula: see text]Five other populations for which length–fecundity relationships could be calculated had length exponents ranging from 3.20 to 4.38, suggesting a nonlinear relationship between weight and fecundity. Six of the nine populations as well as four others for which limited data were available all had similar relative fecundities. Fish from Buck Lake in Alberta and from Lake Erie had high relative fecundities while fish from Great Slave Lake had low relative fecundity.

Competing Explanations of Split-ticket Voting in American National Elections

2000 ◽  
Vol 28 (3) ◽  
pp. 379-407 ◽  
Author(s):  
FRANCO MATTEI ◽  
JOHN S. HOWES
Keyword(s):  
Small Group ◽  
National Elections ◽  
Congressional Voting ◽  
Party Polarization ◽  
Model Based ◽  
Alternative Approach ◽  
Candidate Evaluations ◽  
Electoral Expectations ◽  
The Relationship

In this article, the authors propose an extension to Fiorina's balancing model based on voters' electoral expectations and test this extension and several implications of the theory. The authors examine the observed pattern of ticket-splitting and find it less consistent with a balancing perspective than with an alternative approach stressing separation between presidential and congressional voting. They also address the relationship between party polarization and ticket-splitting; their results indicate that the occurrence of split ballots does not increase with polarization. A further test identifies respondents with both the sophistication and the motive to engage in balancing behavior. According to this analysis, balancing considerations influence, at most, the very small group of voters whose sophistication and electoral expectations give them the tools and the incentive to pursue balance with a split ballot. Ticket-splitting appears to result far more from incumbency and cross-pressured voters holding candidate evaluations at odds with their partisan learnings.

scholarly journals Towards functional modelling of relationships between the acoustics and perception of vowels

2005 ◽  
Vol 40 ◽  
pp. 133-144
Author(s):  
Hartmut R. Pfitzinger
Keyword(s):  
Steady State ◽  
Sufficient Accuracy ◽  
Acoustic Properties ◽  
Vowel Quality ◽  
Model Based ◽  
Functional Modelling ◽  
The Relationship ◽  
Vowel Height

This paper summarizes our research efforts in functional modelling of the relationship between the acoustic properties of vowels and perceived vowel quality. Our model is trained on 164 short steady-state stimuli. We measured F1, F2, and additionally F0 since the effect of F0 on perceptual vowel height is evident. 40 phonetically skilled subjects judged vowel quality using the Cardinal Vowel diagram. The main focus is on refining the model and describing its transformation properties between the F1/F2 formant chart and the Cardinal Vowel diagram. An evaluation of the model based on 48 additional vowels showed the generalizability of the model and confirmed that it predicts perceived vowel quality with sufficient accuracy.  

scholarly journals Remotely Sensed Water Limitation in Vegetation: Insights from an Experiment with Unmanned Aerial Vehicles (UAVs)

2019 ◽  
Author(s):  
Kelly Easterday ◽  
Chippie Kislik ◽  
Tod E. Dawson ◽  
Sean Hogan ◽  
Maggi Kelly
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Water Content ◽  
Water Deficit ◽  
Water Status ◽  
Field Measurements ◽  
Flying Height ◽  
Plant Water ◽  
Spectral Indices ◽  
Aerial Vehicles ◽  
The Relationship

Unmanned aerial vehicles (UAVs) equipped with multispectral sensors present an opportunity to monitor vegetation with on-demand high spatial and temporal resolution. In this study, we use multispectral imagery from quadcopter UAVs to monitor the progression of a water manipulation experiment on a common shrub, Baccharis pilularis (coyote brush), at the Blue Oak Ranch Reserve (BORR) near San Jose, California. We recorded multispectral data from the plants at several altitudes with nearly hourly intervals to explore the relationship between two common spectral indices, NDVI and NDRE, and plant water content and water potential, as physiological metrics of plant water status, across a gradient of water deficit. An examination of the spatial and temporal thresholds at which water limitations were most detectable revealed that the best separation between levels of water deficit were at higher resolution (lower flying height), and in the morning (NDVI) and early morning (NDRE). We found that both measures were able to identify moisture deficit in plants and distinguish them from control and watered plants; however, NDVI was better able to distinguish between treatments than NDRE and was more positively correlated with field measurements of plant water content than NDRE. Finally, we explored how relationships between spectral indices and water status changed when the imagery was scaled to courser resolutions provided by satellite-based imagery (PlanetScope) and found that PlanetScope data was able to capture the overall trend in treatments but was not able to capture subtle changes in water content. These kinds of experiments that evaluate the relationship between direct field measurements and UAV camera sensitivity are needed to enable translation of field-based physiology measurements to landscape or regional scales.

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