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 An analysis of cloud overlap at a midlatitude atmospheric observation facility

2011 ◽  
Vol 11 (1) ◽  
pp. 597-625 ◽  
Author(s):  
L. Oreopoulos ◽  
P. M. Norris
Keyword(s):  
Correlation Coefficient ◽  
Seasonal Variations ◽  
Rank Correlation ◽  
Separation Distance ◽  
Cloud Fraction ◽  
Vertical Resolution ◽  
Value Differences ◽  
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 observational facility. Two facets of overlap are investigated: cloud fraction overlap, expressed in terms of a parameter "alpha" indicating the relative contributions of maximum and random overlap, and overlap of horizontal distributions of condendsate, 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 that emerges under the assumption that overlap parameters decay exponentially with separation distance. Both cloud fraction overlap and condensate overlap show significant seasonal variations with a clear tendency for overlap to be closer to maximum for summer months. A tendency for more maximum overlap is also observed as the size of the domain used to define cloud fractions increases. These dependencies are significantly weaker for rank correlations. Hitherto unexplored overlap parameter dependencies are investigated by analyzing mean parameter value 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 a tendency exists for random cloud fraction overlap to be generally in sync with more random overlap of condensate ranks.

scholarly journals Technical Note: The horizontal scale-dependence of the cloud overlap parameter alpha

2014 ◽  
Vol 14 (7) ◽  
pp. 9801-9813 ◽  
Author(s):  
I. Astin ◽  
L. Di Girolamo
Keyword(s):  
Correlation Coefficient ◽  
Cloud Cover ◽  
Scale Dependence ◽  
Cloud Fraction ◽  
Technical Note ◽  
Horizontal Scale ◽  
Distributed Cloud ◽  
The Relationship ◽  
Overlap Parameter ◽  
Vertical Correlation

Abstract. The cloud overlap parameter alpha relates the combined cloud fraction between two altitude levels in a grid box to the cloud fraction as derived under the maximum and random overlap assumptions. In a number of published studies in this and other journals it is found that alpha tends to increase with increasing scale. In this technical note, we investigate this analytically by considering what happens to alpha when two grid boxes are merged to give a grid box with twice the area. Assuming that alpha depends only on scale then, between any two fixed altitudes, there will be a linear relationship between the values of alpha at the two scales. We illustrate this by finding the relationship when cloud cover fractions are assumed to be uniformly distributed, but with varying degrees of horizontal and vertical correlation. Based on this, we conclude that alpha increases with scale if its value is less than the vertical correlation coefficient in cloud fraction between the two altitude levels. This occurs when the cloud are deeper than would be expected at random (i.e. for exponentially distributed cloud depths). However, the degree of scale-dependence is controlled by the horizontal correlation coefficient in the cloud fraction between adjacent grid boxes, being greatest when this correlation is zero. Trivially, there is no scale-dependence when this correlation is one. The observed, generally strong, scale-dependence would thus indicate that the horizontal correlation is small.

Note on Use of phi as a Simplified Partial Rank Correlation Coefficient

1966 ◽  
Vol 18 (3) ◽  
pp. 973-974 ◽  
Author(s):  
Richard W. Johnson
Keyword(s):  
Correlation Coefficient ◽  
Rank Correlation ◽  
Partial Rank Correlation

Use of phi as a simplified partial rank correlation coefficient is described and illustrated.

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.

scholarly journals The relationship between the effectiveness of performing technical elements and indicators of static and dynamic balance in young acrobats 6-7 years old

2021 ◽  
Vol 7 (4) ◽  
pp. 58-68
Author(s):  
T. Chernykh ◽  
V. Mulyk ◽  
K. Mulyk ◽  
А. Skaliy ◽  
А. Ostrowski ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Dynamic Equilibrium ◽  
Dynamic Balance ◽  
Rank Correlation ◽  
Young Athletes ◽  
Spearman’S Rank Correlation ◽  
Spearman’S Rank Correlation Coefficient ◽  
Initial Stage ◽  
Equilibrium Test ◽  
The Relationship

Purpose: to determine the relationship between the performance of basic elements and indicators of static and dynamic balance in the training process of young acrobats 6-7 years. Material and methods. The study involved 16 young acrobats at the stage of initial training (age 6-7 years). All parents of the participants gave written consent for the participation of children in the study. The study involved testing the technique of performing basic elements of sports acrobatics and assessing the static and dynamic balance of young athletes. The relationship between (swallow, shoulder blade, forward squat, wheel (sideways overturning), bridges) and static and dynamic equilibrium tests was determined. Spearman's rank correlation coefficient method was used as a method of statistical analysis. Results. It is established that the largest relationship between the performance of basic elements and static balance in the basic exercises of young acrobats have: Romberg's test with the elements "Swallow", "Stand on the shoulders", "Bridge"; Biryuk test with elements "Swallow", "Wheel", "Bridge"; balance "Swallow" with elements "Swallow", "Wheel"; static equilibrium test with the elements "Swallow", "Rack on the shoulders", "Rolling forward with a squat", "Wheel". Reliable values ​​of the correlation coefficient were established between the tests of dynamic balance and the basic elements of sports acrobatics in young athletes 6-7 years, namely: "Swallow", "Flip forward with a squat", "Wheel" and "Bridge". The analysis of special tests of static and dynamic balance in mastering the basic elements of acrobatics at the first stage of long-term training makes it possible to use them to determine the level of coordination capabilities of young athletes and further improve the use of acrobatic exercises. Conclusions. A reliable relationship between the performance of basic exercises and indicators of static and dynamic balance in young acrobats at the initial stage of training. It is shown that the level of static and dynamic balance is of great importance for the assimilation and improvement of basic elements of technology by young acrobats 6-7 years. Static and dynamic balance tests can be used to individually build training programs and young acrobats. It is shown that sports acrobatics is a significant means of developing the balance of children 6-7 years.

scholarly journals The association between parameters of oral mucosal immunity and 25-hydroxyvitamin D in patients with rampant caries

2022 ◽  
Vol 20 (4) ◽  
pp. 32-38
Author(s):  
A. S. Putneva ◽  
T. M. Karavaeva ◽  
M. V. Maksimenya ◽  
P. P. Tereshkov ◽  
M. N. Mishchenko ◽  
...  
Keyword(s):  
Plasma Level ◽  
Correlation Coefficient ◽  
Rank Correlation ◽  
Control Group ◽  
Hydroxyvitamin D ◽  
Spearman’S Rank Correlation ◽  
Spearman’S Rank Correlation Coefficient ◽  
25 Hydroxyvitamin D ◽  
Tgf Β1 ◽  
Rampant Caries

Aim. To determine the saliva level of immunoregulatory proteins in patients with rampant caries and 25-hydroxyvitamin D (25(OH)D) deficiency and evaluate the association of their concentration with 25(OH)D plasma level.Materials and methods. The study was performed in two groups. The experimental group included 15 patients aged 20–22 years with rampant caries and the 25(OH)D plasma level of < 20 ng / ml. The control group encompassed 15 healthy age-matched volunteers with the 25(OH)D plasma level of 20–100 ng / ml. The concentrations of B7.2 (CD86), free active TGF-β1, CTLA-4, PD-1, Tim-3, LAG-3, IGFBP-4, and ICAM-1 were assessed using flow cytometry. The levels of LL-37 and secretory immunoglobulin A (sIgA) were measured using ELISA. The Spearman’s rank correlation coefficient was used to reveal a correlation between the indicated proteins and the 25(OH)D plasma level.Results. A decrease in B7.2 (CD86), PD-1, Tim-3, sIgA, and LL-37 and elevation of IGFBP-4 and ICAM-1 saliva levels were detected in patients with rampant caries and 25-hydroxyvitamin D deficiency. A positive Spearman’s rank correlation coefficient was revealed between plasma 25(OH)D and saliva levels of free active TGF-β1, CTLA4, B7.2 (CD86), LL-37, and sIgA. A negative correlation was revealed between 25(OH)Dand ICAM-1.Conclusion. 25(OH)D deficiency in patients with rampant caries is associated with decreased levels of B7.2 (CD86), PD-1, Tim-3, sIgA, and LL-37 and elevated levels of IGFBP-4 and ICAM-1 in the saliva. 

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