scholarly journals Accumulation and Temperature on The Inland Ice of North Greenland, 1959

1961 ◽  
Vol 3 (30) ◽  
pp. 1017-1044 ◽  
Author(s):  
Chester C. Langway
Keyword(s):  
Snow Accumulation ◽  
Surface Slope ◽  
Empirical Correlations ◽  
Altitude Gradient ◽  
Local Climate ◽  
The Mean ◽  
Inland Ice ◽  
Deep Pits ◽  
North Greenland ◽  
Linear Trends

AbstractTwelve deep pits (5 to 5.5 m.) revealed between 6 and 13 years of snow accumulation. The results show an average net accumulation of 18.5 g./cm.2per year. Accumulation decreases inland at a mean rate of 1.5 g./cm.2per 100 m. rise in elevation. Temperature measurements at 100 m. in all pits give a mean temperature-altitude gradient of 0.77° C. per 100 m. Evidence of melt was observed in all pits, the most pronounced melt occurring in 1954. The mean density reflects the local climate. Other empirical correlations of these data show linear trends that vary systematically with surface slope and local climate.

scholarly journals Accumulation and Temperature on The Inland Ice of North Greenland, 1959

1961 ◽  
Vol 3 (30) ◽  
pp. 1017-1044 ◽  
Author(s):  
Chester C. Langway
Keyword(s):  
Snow Accumulation ◽  
Surface Slope ◽  
Empirical Correlations ◽  
Altitude Gradient ◽  
Local Climate ◽  
The Mean ◽  
Inland Ice ◽  
Deep Pits ◽  
North Greenland ◽  
Linear Trends

AbstractTwelve deep pits (5 to 5.5 m.) revealed between 6 and 13 years of snow accumulation. The results show an average net accumulation of 18.5 g./cm.2 per year. Accumulation decreases inland at a mean rate of 1.5 g./cm.2 per 100 m. rise in elevation. Temperature measurements at 100 m. in all pits give a mean temperature-altitude gradient of 0.77° C. per 100 m. Evidence of melt was observed in all pits, the most pronounced melt occurring in 1954. The mean density reflects the local climate. Other empirical correlations of these data show linear trends that vary systematically with surface slope and local climate.

scholarly journals Snow Accumulation in North Greenland

1958 ◽  
Vol 3 (24) ◽  
pp. 237-248 ◽  
Author(s):  
C. Bull
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
The Mean ◽  
Precipitation Records ◽  
Available Information ◽  
North Greenland

AbstractMeasurements of the annual snow accumulation have been made at many points on a traverse of north Greenland. In lat. 77–78° N. the annual accumulation above 1800 m. was about 13 gm. cm.−2in the years 1948–53 and, in contrast to results which have been obtained further south, did not vary with longitude. In 1953–54 the accumulation was greater. The annual accumulation in north and central Greenland has varied significantly over the last 50 years, but similar variations are not shown in the precipitation records at coastal stations. Using all the available information, the mean annual accumulation on the Greenland Ice Sheet has been calculated as 29±3 gm. cm.−2.

scholarly journals Snow Accumulation in North Greenland

1958 ◽  
Vol 3 (24) ◽  
pp. 237-248 ◽  
Author(s):  
C. Bull
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
The Mean ◽  
Precipitation Records ◽  
Available Information ◽  
North Greenland

AbstractMeasurements of the annual snow accumulation have been made at many points on a traverse of north Greenland. In lat. 77–78° N. the annual accumulation above 1800 m. was about 13 gm. cm.−2 in the years 1948–53 and, in contrast to results which have been obtained further south, did not vary with longitude. In 1953–54 the accumulation was greater. The annual accumulation in north and central Greenland has varied significantly over the last 50 years, but similar variations are not shown in the precipitation records at coastal stations. Using all the available information, the mean annual accumulation on the Greenland Ice Sheet has been calculated as 29±3 gm. cm.−2.

scholarly journals Cambial Activity and Phenology in Three Understory Species along an Altitude Gradient in Mexico

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 506
Author(s):  
Mayte S. Jiménez-Noriega ◽  
Lauro López-Mata ◽  
Teresa Terrazas
Keyword(s):  
Soil Temperature ◽  
Sierra Nevada ◽  
Cambial Activity ◽  
Life Forms ◽  
Dry Season ◽  
Vascular Cambium ◽  
Phenological Stages ◽  
Altitude Gradient ◽  
The Mean ◽  
Trees And Shrubs

The aims of this study were to evaluate the cambial activity and phenology of three species with different life forms (Alchemilla procumbens, Acaena elongata and Ribes ciliatum) along an altitudinal gradient and to establish which environmental variables (light, soil humidity and temperature) had the greatest influence on cambial activity and phenological stages. Over two years, data on phenology, growth and cambium were gathered every four weeks in three to six sites per species in Sierra Nevada, Mexico. The results showed that Ribes is the only species that terminates cambial activity with leaves senescence and is influenced by the minimum soil temperature. The light environment influenced the vegetative stages in Alchemilla (cryptophyte), while in Acaena (hemicryptophyte), the mean soil temperature explained the findings related to leaf area during the dry season and growth along the gradient. In the three species, the reproductive phase dominated for a longer period at higher elevations, especially in Alchemilla. Only Ribes, the phanerophyte, showed a similar cambial activity to other trees and shrubs. Although cambium reactivates during the dry season, no xylogenesis occurs. The three species varied during the time in which vascular cambium was active, and this was dependent on the altitude. Specifically, the variation was more rhythmic in Ribes and switched on and off in Alchemilla. It is likely that, depending on the life form, vascular cambium may be more or less susceptible to one or more climate factors.

TRIGONOMETRICAL LEVELLING ACROSS THE INLAND ICE IN NORTH GREENLAND

1956 ◽  
Vol 13 (100) ◽  
pp. 252-261 ◽  
Author(s):  
W. S. B. Paterson ◽  
C. G. M. Slesser
Keyword(s):  
Inland Ice ◽  
North Greenland

scholarly journals Spatial and temporal variability in isotope composition of recent snow in the vicinity of Vostok station, Antarctica: implications for ice-core record interpretation

2002 ◽  
Vol 35 ◽  
pp. 181-186 ◽  
Author(s):  
Alexey A. Ekaykin ◽  
Vladimir Ya. Lipenkov ◽  
Narcisse I. Barkov ◽  
Jean Robert Petit ◽  
Valerie Masson-Delmotte
Keyword(s):  
Isotope Composition ◽  
Ice Core ◽  
Snow Accumulation ◽  
Spatial And Temporal Variability ◽  
Weak Correlation ◽  
Ice Core Record ◽  
Vostok Station ◽  
The Mean ◽  
Mean Annual Air Temperature ◽  
Snow Samples

AbstractContinuous, detailed isotope (δD and δ18O) profiles were obtained from eight snow pits dug in the vicinity of Vostok station, Antarctica, during the period 1984– 2000. In addition, snow samples taken along the 1km long accumulation-stake profile were measured to determine spatial variability in isotope composition of recent snow. the stacked δD time series spanning the last 55 years shows only weak correlation with the mean annual air temperature recorded at Vostok station. Significant oscillations of both snow accumulation and snow isotope composition with the periods 2.5, 5, 20 and, possibly, ~102 years observed at single points are interpreted in terms of drift of snow-accumulation waves of various scales on the surface of the ice sheet.

scholarly journals A Balto-Scandian Middle Cambrian fauna from Peary Land, North Greenland

1988 ◽  
Vol 137 ◽  
pp. 118-118
Author(s):  
T.P Fletcher ◽  
A.K Higgins ◽  
J.S Peel
Keyword(s):  
North America ◽  
Field Work ◽  
First Record ◽  
Geological Survey ◽  
Northern Coast ◽  
Middle Cambrian ◽  
The Pacific ◽  
Cambrian Trilobite ◽  
Inland Ice ◽  
North Greenland

The first record of Middle Cambrian faunas of 'Atlantic' affinity from the Franklinian basin sequence of North Greenland was made by Poulsen (1969) who noted that previously described Greenland faunas were of 'Pacific' type. Field work by the Geological Survey of Greenland during the last decade has established that 'Atlantic' faunas are widespread in more outer shelfsequences along the northern coast of North Greenland while the 'Pacific' faunas occur within inner shelfsequences more to the south, near the margin of the Inland Ice. North Greenland preserves both faunas in dose geographical juxtaposition in only slightly tectonised geological settings. Thus, alatest Middle Cambrian trilobite fauna described by Robison (in press) from the Holm Dal Formation in an area some 40 km south of the presently discussed locality (and more inner shelf) includes a mixture of polymeroids characteristic of the Cedaria Zone of North America and agnostoids characteristic of the Lejopyge laevigata Zone of the Swedish standard zonation.

scholarly journals Snow Accumulation Studies on the Thule Peninsula, Greenland

1968 ◽  
Vol 7 (49) ◽  
pp. 59-76 ◽  
Author(s):  
Steven J. Mock
Keyword(s):  
Regional Scale ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Accumulation Rates ◽  
Surface Slope ◽  
Ice Flow ◽  
Accumulation Pattern ◽  
Flow Phenomena ◽  
Independent Parameters

AbstractData from stake measurements, marker boards and pits along a 136 km trail crossing the Thule peninsula sector of the Greenland ice sheet have been used to determine both the regional and local distribution of snow accumulation, On a regional scale trend surfaces of mean annual accumulation can be adequately predicted from a model using distance from moisture source and elevation as independent parameters. A series of step- or wave-like features break the smooth profile of the ice. sheet and cause profound changes in accumulation rates on a local scale. The accumulation pattern over these features can be predicted from surface slope and departure from regional elevation. Profiles of’ surface and subsurface topography indicate a direct relationship between subsurface hills and step-like features, but cannot be quantitatively accounted for by existing ice-flow theory. Detailed accumulation studies in conjunction with a program of spirit leveling in the vicinity of Camp Century has revealed the development a shallow valley-like feature. Within this feature accumulation rates have increased indicating that it is the result of flow phenomena.

scholarly journals Local Climate Zone Classification Scheme Can Also Indicate Local-Scale Urban Ventilation Performance: An Evidence-Based Study

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 776 ◽  
Author(s):  
Ziqi Zhao ◽  
Lidu Shen ◽  
Liguang Li ◽  
Hongbo Wang ◽  
Bao-Jie He
Keyword(s):  
Wind Speed ◽  
Classification Scheme ◽  
Local Scale ◽  
Evidence Based ◽  
Weather Station ◽  
Local Climate ◽  
Mean Wind Speed ◽  
The Mean ◽  
Ventilation Performance ◽  
Local Climate Zone

Studies on urban ventilation indicate that urban ventilation performance is highly dependent on urban morphology. Some studies have linked local-scale urban ventilation performance with the local climate zone (LCZ) that is proposed for surface temperature studies. However, there is a lack of evidence-based studies showing LCZ ventilation performance and affirming the reliability of using the LCZ classification scheme to demonstrate local-scale urban ventilation performance. Therefore, this study aims to analyse LCZ ventilation performances in order to understand the suitability of using the LCZ classification scheme to indicate local-scale urban ventilation performance. This study was conducted in Shenyang, China, with wind information at 16 weather stations in 2018. The results indicate that the Shenyang weather station had an annual mean wind speed of 2.07 m/s, while the mean wind speed of the overall 16 stations was much lower, only 1.44 m/s in value. The mean wind speed at Shenyang weather station and the 16 stations varied with seasons, day and night and precipitation conditions. The spring diurnal mean wind was strong with the speeds of 3.56 m/s and 2.21 m/s at Shenyang weather station and the 16 stations, respectively. The wind speed (2.21 m/s at Shenyang weather station) under precipitation conditions was higher than that (1.75 m/s at Shenyang weather station) under no precipitation conditions. Downtown ventilation performance was weaker than the approaching wind background, where the relative mean wind speed in the downtown area was only 0.53, much less than 1.0. The downtown ventilation performance also varied with seasons, day and night and precipitation conditions, where spring diurnal downtown ventilation performance was the weakest and the winter nocturnal downtown ventilation performance was the strongest. Moreover, the annual mean wind speed of the 16 zones decreased from the sparse, open low-rise zones to the compact midrise zones, indicating the suitability of using LCZ classification scheme to indicate local-scale urban ventilation performance. The high spatial correlation coefficients under different seasons, day and night and precipitation conditions, ranging between 0.68 and 0.99, further affirmed that LCZ classification scheme is also suitable to indicate local-scale urban ventilation performance, despite without the consideration of street structure like precinct ventilation zone scheme.

scholarly journals On the mean anomaly and the mean longitude in tests of post-Newtonian gravity

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
Lorenzo Iorio
Keyword(s):  
Binary Systems ◽  
Central Body ◽  
Semimajor Axis ◽  
Newtonian Gravity ◽  
Atmospheric Drag ◽  
Tests Of General Relativity ◽  
Orbital Configuration ◽  
The Mean ◽  
Tests Of Gravity ◽  
Linear Trends

Abstract The distinction between the mean anomaly $${\mathcal {M}}(t)$$M(t) and the mean anomaly at epoch $$\eta $$η, and the mean longitude l(t) and the mean longitude at epoch $$\epsilon $$ϵ is clarified in the context of a their possible use in post-Keplerian tests of gravity, both Newtonian and post-Newtonian. In particular, the perturbations induced on $${\mathcal {M}}(t),\,\eta ,\,l(t),\,\epsilon $$M(t),η,l(t),ϵ by the post-Newtonian Schwarzschild and Lense–Thirring fields, and the classical accelerations due to the atmospheric drag and the oblateness $$J_2$$J2 of the central body are calculated for an arbitrary orbital configuration of the test particle and a generic orientation of the primary’s spin axis $$\varvec{{\hat{S}}}$$S^. They provide us with further observables which could be fruitfully used, e.g., in better characterizing astrophysical binary systems and in more accurate satellite-based tests around major bodies of the Solar System. Some erroneous claims by Ciufolini and Pavlis appeared in the literature are confuted. In particular, it is shown that there are no net perturbations of the Lense–Thirring acceleration on either the semimajor axis a and the mean motion $$n_{\mathrm{b}}$$nb. Furthermore, the quadratic signatures on $${\mathcal {M}}(t)$$M(t) and l(t) due to certain disturbing non-gravitational accelerations like the atmospheric drag can be effectively disentangled from the post-Newtonian linear trends of interest provided that a sufficiently long temporal interval for the data analysis is assumed. A possible use of $$\eta $$η along with the longitudes of the ascending node $$\Omega $$Ω in tests of general relativity with the existing LAGEOS and LAGEOS II satellites is suggested.

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