Determination of Soil and Terrain Conditions from the Vegetation Cover (Using the Volga-Akhtubinsk Floodplain as an Example)

1995 ◽  
pp. 142-146
Author(s):  
L. S. Rodman
Keyword(s):  
Vegetation Cover

The influence of climate on pool inception in boreal fens

Botany ◽  
2015 ◽  
Vol 93 (10) ◽  
pp. 637-649 ◽  
Author(s):  
Yann Arlen-Pouliot ◽  
Serge Payette
Keyword(s):  
Vegetation Cover ◽  
Little Ice Age ◽  
Tree Mortality ◽  
Ice Age ◽  
Climatic Forcing ◽  
Influence Of Water ◽  
Physical Degradation ◽  
Pool Formation ◽  
Massive Tree

Fens are one of the two most important peatland types of the boreal biome. The fen surface is often made of contrasted microenvironments, pools and strings, distributed in a geometric arrangement known as patterned fen. The fens are under the influence of varying water regimes causing the formation of pools, a process that we named aqualysis. The term refers to the physical degradation of the vegetation cover under the influence of water ponding. It is proposed here that pool inception is among a set of differential responses of peatland ecosystems to changes in hydrology caused by climate. In this study, we have evaluated the influence of climate on pool inception using the spatiotemporal distribution of trees found dead in pools of four boreal fens of northwestern Quebec. Tree-ring dating of tree mortality allowed the determination of the most recent and synchronized periods of pool formation in the studied fens. Most trees died over the last centuries, particularly after 1750 AD. The demographic pattern of tree establishment and mortality highlights a climatic forcing linked to the Little Ice Age oscillation opposing less humid events facilitating tree colonization succeeded by more humid events causing massive tree death and pool inception. We conclude that peatland aqualysis is among the processes controlled by climate contributing to the dynamics of patterned fens through pool formation.

Multispectral Radiometry for the Determination of the Vegetation Cover Conditions

1992 ◽  
Author(s):  
M. Mazanek ◽  
Z. Peceny ◽  
J. Janik ◽  
T. Cesky ◽  
C. Rumler
Keyword(s):  
Vegetation Cover

scholarly journals A Comparison of the Influence of Vegetation Cover on the Precision of an UAV 3D Model and Ground Measurement Data for Archaeological Investigations: A Case Study of the Lepelionys Mound, Middle Lithuania

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5303
Author(s):  
Algimantas Česnulevičius ◽  
Artūras Bautrėnas ◽  
Linas Bevainis ◽  
Donatas Ovodas
Keyword(s):  
Vegetation Cover ◽  
Large Scale ◽  
3D Model ◽  
Three Dimensional ◽  
Measurement Data ◽  
Aerial Photographs ◽  
Herbaceous Vegetation ◽  
Ground Measurement ◽  
The Impact

The aim of this research was to conduct a comparative analysis of the precision of ground geodetic data versus the three-dimensional (3D) measurements from unmanned aerial vehicles (UAV), while establishing the impact of herbaceous vegetation on the UAV 3D model. Low (up to 0.5 m high) herbaceous vegetation can impede the establishment of the anthropogenic roughness of the surface. The identification of minor surface alterations, which enables the determination of their anthropogenic origin, is of utmost importance in archaeological investigations. Vegetation cover is regarded as one of the factors influencing the identification of such minor forms of relief. The research was conducted on the Lepelionys Mound (Prienai District Municipality, Lithuania). Ground measurements were obtained using Trimble GPS, and UAV “Inspire 1” was used for taking aerial photographs. Following the data from the ground measurements and aerial photographs, large scale surface maps were drawn and the errors in the measurement of the position of the isolines were compared. The results showed that the largest errors in the positional measurements of fixed objects were conditioned by the height of grass. Grass with a height of up to 0.1 m resulted in discrepancies of up to 0.5 m, whereas grass that was up to 0.5 m high led to discrepancies up to 1.3 m high.

Determination of vegetation cover fraction by inversion of a four-parameter model based on isoline parametrization

2007 ◽  
Vol 111 (4) ◽  
pp. 553-566 ◽  
Author(s):  
Abdelaziz Kallel ◽  
Sylvie Le Hégarat-Mascle ◽  
Catherine Ottlé ◽  
Laurence Hubert-Moy
Keyword(s):  
Vegetation Cover ◽  
Model Based

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

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