scholarly journals Climatology of cloud overlap parameter

2017 ◽  
Vol 14 (1) ◽  
pp. 216-225 ◽  
Author(s):  
A.V. Chernokulsky ◽  
◽  
A.V. Eliseev ◽  
Keyword(s):  
Overlap Parameter

scholarly journals The Influence of Automated Machining Strategy on Geometric Deviations of Machined Surfaces

2021 ◽  
Vol 11 (5) ◽  
pp. 2353
Author(s):  
Ján Varga ◽  
Teodor Tóth ◽  
Peter Frankovský ◽  
Ľudmila Dulebová ◽  
Emil Spišák ◽  
...  
Keyword(s):  
Control System ◽  
Surface Quality ◽  
Coordinate Measuring Machine ◽  
Geometric Tolerance ◽  
Geometric Tolerances ◽  
Significant Difference ◽  
Geometric Deviations ◽  
Measuring Machine ◽  
Overlap Parameter ◽  
Total Average

This paper deals with various automated milling strategies and their influence on the accuracy of produced parts. Among the most important factors for surface quality is the automated milling strategy. Milling strategies were generated from two different programs, CAM system SolidCAM, with the help of workshop programming in the control system Heidenhain TNC 426. In the first step, simulations of different toolpaths were conducted. Using geometric tolerance is becoming increasingly important in robotized production, but its proper application requires a deeper understanding. This article presents the measurement of selected planes of robotized production to evaluate their flatness, parallelism and perpendicularity deviations after milling on the coordinate measuring machine Carl Zeiss Contura G2. Total average deviations, including all geometric tolerances, were 0.020 mm for SolidCAM and 0.016 mm for Heidenhain TNC 426. The result is significantly affected by the flatness of measured planes, where the overlap parameter of the tools has a significant impact on the flatness of the surface. With interchangeable cutter plate tools, it is better to use higher overlap to achieve better flatness. There is a significant difference in production time, with SolidCAM 25 min and 30 s, and Heidenhain 48 min and 19 s. In accordance with these findings, the SolidCAM system is more suitable for production.

scholarly journals The impact of atmospheric stability and wind shear on vertical cloud overlap over the Tibetan Plateau

2018 ◽  
Vol 18 (10) ◽  
pp. 7329-7343 ◽  
Author(s):  
Jiming Li ◽  
Qiaoyi Lv ◽  
Bida Jian ◽  
Min Zhang ◽  
Chuanfeng Zhao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Wind Shear ◽  
Cloud Cover ◽  
Atmospheric Stability ◽  
Length Scale ◽  
The Tibetan Plateau ◽  
Total Cloud Cover ◽  
Atmospheric Models ◽  
The Impact ◽  
Overlap Parameter

Abstract. Studies have shown that changes in cloud cover are responsible for the rapid climate warming over the Tibetan Plateau (TP) in the past 3 decades. To simulate the total cloud cover, atmospheric models have to reasonably represent the characteristics of vertical overlap between cloud layers. Until now, however, this subject has received little attention due to the limited availability of observations, especially over the TP. Based on the above information, the main aim of this study is to examine the properties of cloud overlaps over the TP region and to build an empirical relationship between cloud overlap properties and large-scale atmospheric dynamics using 4 years (2007–2010) of data from the CloudSat cloud product and collocated ERA-Interim reanalysis data. To do this, the cloud overlap parameter α, which is an inverse exponential function of the cloud layer separation D and decorrelation length scale L, is calculated using CloudSat and is discussed. The parameters α and L are both widely used to characterize the transition from the maximum to random overlap assumption with increasing layer separations. For those non-adjacent layers without clear sky between them (that is, contiguous cloud layers), it is found that the overlap parameter α is sensitive to the unique thermodynamic and dynamic environment over the TP, i.e., the unstable atmospheric stratification and corresponding weak wind shear, which leads to maximum overlap (that is, greater α values). This finding agrees well with the previous studies. Finally, we parameterize the decorrelation length scale L as a function of the wind shear and atmospheric stability based on a multiple linear regression. Compared with previous parameterizations, this new scheme can improve the simulation of total cloud cover over the TP when the separations between cloud layers are greater than 1 km. This study thus suggests that the effects of both wind shear and atmospheric stability on cloud overlap should be taken into account in the parameterization of decorrelation length scale L in order to further improve the calculation of the radiative budget and the prediction of climate change over the TP in the atmospheric models.

scholarly journals An analysis of cloud overlap at a midlatitude atmospheric observation facility

2011 ◽  
Vol 11 (12) ◽  
pp. 5557-5567 ◽  
Author(s):  
L. Oreopoulos ◽  
P. M. Norris
Keyword(s):  
Correlation Coefficient ◽  
Seasonal Variations ◽  
Rank Correlation ◽  
Domain Size ◽  
Separation Distance ◽  
Cloud Fraction ◽  
Vertical Resolution ◽  
Clear Tendency ◽  
Systematic Relationships ◽  
Overlap Parameter

Abstract. An analysis of cloud overlap based on high temporal and vertical resolution retrievals of cloud condensate from a suite of ground instruments is performed at a mid-latitude atmospheric observation facility. Two facets of overlap are investigated: cloud fraction overlap, expressed in terms of a parameter "α" indicating the relative contributions of maximum and random overlap, and overlap of horizontal distributions of condensate, expressed in terms of the correlation coefficient of condensate ranks. The degree of proximity to the random and maximum overlap assumptions is also expressed in terms of a decorrelation length, a convenient scalar parameter for overlap parameters assumed to decay exponentially with separation distance. Both cloud fraction overlap and condensate overlap show significant seasonal variations with a clear tendency for more maximum overlap in the summer months. More maximum overlap is also generally observed when the domain size used to define cloud fractions increases. These tendencies also exist for rank correlations, but are significantly weaker. Hitherto unexplored overlap parameter dependencies are investigated by analyzing mean parameter differences at fixed separation distance within different layers of the atmospheric column, and by searching for possible systematic relationships between alpha and rank correlation. We find that for the same separation distance the overlap parameters are significantly distinct in different atmospheric layers, and that random cloud fraction overlap is usually associated with more randomly overlapped condensate ranks.

scholarly journals The impact of atmospheric dynamics on vertical cloud overlap over the Tibetan Plateau

2017 ◽  
Author(s):  
Jiming Li ◽  
Qiaoyi Lv ◽  
Bida Jian ◽  
Min Zhang ◽  
Chuanfeng Zhao ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Wind Shear ◽  
Cloud Cover ◽  
Atmospheric Stability ◽  
Separation Distance ◽  
Atmospheric Dynamics ◽  
The Tibetan Plateau ◽  
Total Cloud Cover ◽  
The Impact ◽  
Overlap Parameter

Abstract. The accurate representation of cloud vertical overlap in atmospheric models is particularly significant for predicting the total cloud cover and for the calculations related to the radiative budget in these models. However, it has received too little attention due to the limited observation, especially over the Tibetan Plateau (TP). In this study, 4 years (2007–2010) of data from the CloudSat cloud product and collocated ERA-Interim reanalysis product were analyzed to examine the seasonal and zonal variations of cloud overlap properties over the TP region, and evaluate the effect of atmospheric dynamics on cloud overlap. Unique characteristics of cloud overlap over the TP have been found. The statistical results show that the random overlap assumption slightly underestimates the total cloud coverage for discontinuous cloud layers over the TP, whereas the overlap parameter α for continuous cloud sharply decrease from maximum to random overlap with an increase of layer distance, eventually trending towards a minimal overlap (e.g., negative α values) as the cloud layer separation distance exceeds 1.5 km. Compared with the global averaged cloud overlap characteristics, the proportion of minimal overlap over the TP is significant high (about 41 %). It may be associated with the unique topographical forcing and thermos-dynamical environment of the TP. As a result, we propose a valid scheme for quantifying the degree of cloud overlap over the TP through a linear combination of the maximum and minimum overlap, and further parameterize decorrelation length scale L as a function of wind shear and atmospheric stability. Compared with other parameterizations, the new scheme reduces the bias between predicted and observed cloud covers. These results thus indicate that effects of wind shear and atmospheric stability on cloud overlap should both be taken into account in the parameterization of overlap parameter to improve the simulation of total cloud cover in models.

Über des magnetische Verhalten von Cs2MYbF6 (M = Na, K, Rb) und Cs2NaYbBr6 / On the Magnetic Behaviour of Cs2MYbF6 (M = Na, K, Rb) and Cs2NaYbBr6

1979 ◽  
Vol 34 (12) ◽  
pp. 1507-1511
Author(s):  
Werner Urland
Keyword(s):  
Crystal Field ◽  
Ground State ◽  
Magnetic Behaviour ◽  
Magnetic Data ◽  
Temperature Range ◽  
Angular Overlap Model ◽  
The Individual ◽  
Overlap Model ◽  
Overlap Parameter

Abstract The magnetic behaviour of Cs2MYbF6 (M = Na, K, Rb) and Cs2NaYbBr6 has been studied in the temperature range between 3.5 and 251.3 K. The magnetic data are interpreted by means of a previously developed model in which the influence of the crystal field is theoretically described by the angular overlap model. The obtained values of the angular overlap parameter eσ(R) for the individual compounds are discussed and compared with each other. The energy values of the crystal-field levels of the 2F7/2 ground state are calculated.

Positron Lifetime Spectroscopy on Controlled Pore Glass Porosimetry and Pore Size Distribution

2008 ◽  
Vol 607 ◽  
pp. 169-172 ◽  
Author(s):  
Stefan Thränert ◽  
D. Enke ◽  
G. Dlubek ◽  
Reinhard Krause-Rehberg
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Mean Free Path ◽  
Infinite Length ◽  
Positron Annihilation Lifetime ◽  
Controlled Pore Glass ◽  
Pore Glass ◽  
Positron Lifetime Spectroscopy ◽  
Overlap Parameter

Positron annihilation lifetime spectroscopy (PALS) is used to study a series of controlled pore glasses (CPG). The lifetime spectra were decomposed into four components using the routine LifeTime, version 9.0 (LT9). The largest lifetime τ4, which is attributed to the annihilation of ortho-positronium (o-Ps) localized at mesopores, varied at 300 K between 21 and 131 ns. The size of mesopores (mean free path), D, was determined by N2 adsorption and Hg intrusion techniques to vary between 1.8 and 56 nm. It is shown that the Tao-Eldrup model extended to cylinders of infinite length and diameter d = D describes well the experiment for an overlap parameter δ fitted to be δ = 0.193 nm. The spectra were also analyzed allowing a distribution of o-Ps lifetimes. A method is developed to calculate the pore size distribution n(d) from the τ4 distribution. This method is of particular interest since PALS is very sensitive to pores being too small to be exactly analyzed by conventional porosimetry.

scholarly journals Influence of the overlap parameter on the convergence of the ptychographical iterative engine

2008 ◽  
Vol 108 (5) ◽  
pp. 481-487 ◽  
Author(s):  
Oliver Bunk ◽  
Martin Dierolf ◽  
Søren Kynde ◽  
Ian Johnson ◽  
Othmar Marti ◽  
...  
Keyword(s):  
Overlap Parameter

CHAOS IN COUPLED ROTATORS

1993 ◽  
Vol 04 (02) ◽  
pp. 375-383
Author(s):  
STEFANO RUFFO
Keyword(s):  
High Temperature ◽  
Model System ◽  
High Dimensional ◽  
Temperature Threshold ◽  
Ergodic Hypothesis ◽  
Time Averages ◽  
Dynamics Simulations ◽  
Overlap Parameter ◽  
Temperature Side ◽  
Coupled Rotators

We show that time averages of physical observables agree with ensemble averages provided chaos is present and widespread in a model system of coupled rotators. Slow relaxation is present both at low and at high temperature, where chaos is weak and inefficient. A 1.5 dimensional Hamiltonian describes the high dimensional motion quite well and allows the introduction of a Chirikov overlap parameter. A Gibbsian calculation of this parameter predicts the high temperature threshold to the statistical regime. The onset of nonlinearity is instead the mechanism which leads to the statistical regime on the low temperature side. This result should prove of interest for understanding and controlling the relaxation to equilibrium of molecular dynamics simulations. Moreover it indicates that perhaps the ergodic hypothesis is a too strong requirement.

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