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

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.

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Technical Note: The horizontal scale dependence of the cloud overlap parameter α

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-9917-2014 ◽

2014 ◽

Vol 14 (18) ◽

pp. 9917-9922 ◽

Cited By ~ 1

Author(s):

I. Astin ◽

L. Di Girolamo

Keyword(s):

Linear Relationship ◽

Cloud Cover ◽

Scale Dependence ◽

Cloud Fraction ◽

Technical Note ◽

Horizontal Scale ◽

Distributed Cloud ◽

The Relationship ◽

Overlap Parameter ◽

Vertical Correlation

Abstract. The cloud overlap parameter α 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 α tends to increase with an increasing scale. In this Technical Note, we investigate this analytically by considering what happens to α when two grid boxes are merged to give a grid box with twice the area. Assuming that α depends only on scale, then between any two fixed altitudes, there will be a linear relationship between the values of α on 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 α 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 clouds are deeper than would be expected at random (i.e. for exponentially distributed cloud depths).

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An analysis of cloud overlap at a midlatitude atmospheric observation facility

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-5557-2011 ◽

2011 ◽

Vol 11 (12) ◽

pp. 5557-5567 ◽

Cited By ~ 18

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.

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An analysis of cloud overlap at a midlatitude atmospheric observation facility

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-597-2011 ◽

2011 ◽

Vol 11 (1) ◽

pp. 597-625 ◽

Cited By ~ 2

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.

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IMPROVEMENT OF SPRING DURUM WHEAT SELECTION METHODOLOGIES UNDER CLIMATE CHANGE CONDITIONS

Vestnik of the Russian agricultural science ◽

10.30850/vrsn/2019/3/33-36 ◽

1970 ◽

pp. 33-36

Author(s):

А. I. Grabovets ◽

V. P. Kadushkina ◽

S. А. Kovalenko

Keyword(s):

Grain Yield ◽

Durum Wheat ◽

Correlation Coefficient ◽

Harvest Index ◽

Unit Area ◽

Correlation Coefficients ◽

Chemical Mutagenesis ◽

Main Method ◽

The Relationship ◽

Selection Of

With the growing aridity of the climate on the Don, it became necessary to improve the methodology for conducting the breeding of spring durum wheat. The main method of obtaining the source material remains intraspecific step hybridization. Crossings were performed between genetically distant forms, differing in origin and required traits and properties. The use of chemical mutagenesis was a productive way to change the heredity of genotypes in terms of drought tolerance. When breeding for productivity, both in dry years of research and in favorable years, the most objective markers were identified — the size of the aerial mass, the mass of grain per plant, spike, and harvest index. The magnitude of the correlation coefficients between the yield per unit area and the elements of its structure is established. It was most closely associated with them in dry years, while in wet years it decreased. Power the correlation of the characteristics of the pair - the grain yield per square meter - the aboveground biomass averaged r = 0.73, and in dry years it was higher (0.91) than in favorable ones (0.61 - 0.70) , between the harvest and the harvest index - r = 0.81 (on average). In dry years, the correlation coefficient increased to 0.92. Research data confirms the greatest importance of the mass of grain from one ear and the plant in the formation of grain yield per unit area in both dry and wet years. In dry years, the correlation coefficient between yield and grain mass per plant was on average r = 0.80; in favorable years, r = 0.69. The relationship between yield and grain mass from the ear was greater — r = 0.84 and r = 0.82, respectively. Consequently, the breeding significance of the aboveground mass and the productivity of the ear, as a criterion for the selection of the crop, especially increases in the dry years. They were basic in the selection.

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A FORECAST OF PRODUCTIVE LONGEVITY OF HOLSTEIN COWS BY INDIRECT SIGNS

Molochnoe i miasnoe skotovodstvo ◽

10.33943/mms.2020.55.90.006 ◽

2020 ◽

Author(s):

З.С. САНОВА

Keyword(s):

Correlation Coefficient ◽

Aging Process ◽

Direct Relationship ◽

Stability Index ◽

Age At First Calving ◽

Group I ◽

Predicted Values ◽

The Stability ◽

Relationship Of ◽

The Relationship

В статье представлены материалы о взаимосвязи продолжительности продуктивного использования коров с характеристикой устойчивости к деградации, с возрастом отела и удоем. В исследованной, разнородной по происхождению, группе животных для прогноза продуктивного периода коров, обусловленного устойчивостью к деградации и возрастом первого отела, пригодно уравнение регрессии, аргументами в котором являются индекс устойчивости, возраст первого отела в первой и второй степенях. Коэффициент корреляции межу предсказанными значениями продуктивного периода и его фактическими величинами в I группе составляет 0,502, во II - 0,604. При этом крайние варианты прогнозируются со статистическими ошибками 5 мес при оценке индекса устойчивости по 2 лактациям и 4,1 мес по 3, а средние варианты, соответственно, 1,6 и 1,51 мес. Индекс устойчивости к процессу старения является важной характеристикой биологических особенностей коров, определяющий их продуктивное долголетие. Его оценка по первым 2 и 3 лактациям имеет прямолинейную связь с продуктивным периодом (r=0,4109 и r=0,5270), соответственно. Зависимость продуктивного периода от возраста первого отела криволинейная — с увеличением возраста первого отела сокращается срок продуктивного использования, при возрасте первого отела более 1400 дней срок продуктивного использования колеблется от 1,33 до 1,41 лактации. Коэффициент корреляции между этими характеристиками коров составляет - 0,2164 в I и - 0,2620 во II группах. The article presents materials about the relationship of the duration of productive use of cows with the characteristic of resistance to degradation, with the age of calving and milk yield. In the studied group of animals, which is heterogeneous in origin, the regression equation is suitable for predicting the productive period of cows due to resistance to degradation and the age of the first calving, the arguments of which are the stability index, the age of the first calving in the first and second degrees. The correlation coefficient between the predicted values of the productive period and its actual values in group I is 0.502, in group II - 0.604. At the same time, the extreme variants are predicted with statistical errors of 5 months when evaluating the stability index for 2 lactations and 4.1 months for 3, and the average variants, respectively, are 1.6 and 1.51 months. The index of resistance to the aging process is an important characteristic of the biological characteristics of cows, which determines their productive longevity. Its estimate for the first 2 and 3 lactations has a direct relationship with the productive period (r=0.4109 and r=0.5270), respectively. The dependence of the productive period age at first calving curvilinear with increasing age at first calving reduces the time to productive use, while age at first calving of more than 1400 days, the period of productive use ranges from 1.33 to 1.41 lactation. The correlation coefficient between these characteristics of cows is-0.2164 in I and-0.2620 in II groups.

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Correlating Capsaicinoid Levels and Physicochemical Proper-ties of Kimchi and Its Perceived Spiciness

Foods ◽

10.3390/foods10010086 ◽

2021 ◽

Vol 10 (1) ◽

pp. 86

Author(s):

So-Ra Yoon ◽

Yun-Mi Dang ◽

Su-Yeon Kim ◽

Su-Yeon You ◽

Mina K. Kim ◽

...

Keyword(s):

Correlation Analysis ◽

Physicochemical Properties ◽

Correlation Coefficient ◽

Partial Correlation ◽

Sugar Content ◽

Amino Acid Content ◽

Titratable Acidity ◽

Free Sugar ◽

Partial Correlation Analysis ◽

The Relationship

Capsaicinoid content, among other factors, affects the perception of spiciness of commercial kimchi. Here, we investigated whether the physicochemical properties of kimchi affect the spicy taste of capsaicinoids perceived by the tasting. High-performance liquid chromatography (HPLC) was used to evaluate the capsaicinoid content (mg/kg) of thirteen types of commercial kimchi. The physicochemical properties such as pH, titratable acidity, salinity, free sugar content, and free amino acid content were evaluated, and the spicy strength grade was determined by selected panel to analyze the correlation between these properties. Panels were trained for 48 h prior to actual evaluation by panel leaders trained for over 1000 h according to the SpectrumTM method. Partial correlation analysis was performed to examine other candidate parameters that interfere with the sensory evaluation of spiciness and capsaicinoid content. To express the specific variance after eliminating the effects of other variables, partial correlations were used to estimate the relationships between two variables. We observed a strong correlation between spiciness intensity ratings and capsaicinoid content, with a Pearson’s correlation coefficient of 0.78 at p ≤ 0.001. However, other specific variables may have influenced the relationship between spiciness intensity and total capsaicinoid content. Partial correlation analysis indicated that the free sugar content most strongly affected the relationship between spiciness intensity and capsaicinoid content, showing the largest first-order partial correlation coefficient (rxy/z: 0.091, p ≤ 0.01).

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Innovative Correlation Coefficient Measurement with Fuzzy Data

Mathematical Problems in Engineering ◽

10.1155/2016/9094832 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11

Author(s):

Berlin Wu ◽

Chin Feng Hung

Keyword(s):

Mathematics Achievement ◽

Correlation Coefficient ◽

Empirical Studies ◽

Correlation Coefficients ◽

Interval Data ◽

Fuzzy Data ◽

Pearson’S Correlation Coefficient ◽

Coefficient Measurement ◽

The Relationship ◽

Fuzzy Interval

Correlation coefficients are commonly found with crisp data. In this paper, we use Pearson’s correlation coefficient and propose a method for evaluating correlation coefficients for fuzzy interval data. Our empirical studies involve the relationship between mathematics achievement and other projects.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-7329-2018 ◽

2018 ◽

Vol 18 (10) ◽

pp. 7329-7343 ◽

Cited By ~ 8

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.

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

10.5194/acp-2017-642 ◽

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.

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HUBUNGAN PERSEPSI TENTANG PROFESI FISIOTERAPI DENGAN MOTIVASI BELAJAR MAHASISWA AKADEMI FISIOTERAPI UKI

Jurnal Dinamika Pendidikan ◽

10.33541/jdp.v10i3.630 ◽

2018 ◽

Vol 10 (3) ◽

pp. 226

Author(s):

Maksimus Bisa

Keyword(s):

Regression Analysis ◽

Linear Regression ◽

Correlation Analysis ◽

Correlation Coefficient ◽

Linear Regression Analysis ◽

Motivation To Learn ◽

Simple Linear Regression ◽

Level 1 ◽

Relationship Of ◽

The Relationship

ABSTRACTThis study is descriptive analitik, aims to describe the relationship of perceptions about the physiotherapy profession with the motivation to learn students of the Academy of Physiotherapy UKI. Data collection through questionnaires to students of Physiotherapy Academy UKI level 1, 2, and 3 with a sample of 53 students, then give a score of each statement of questionnaire.The result of correlation analysis shows that p = 0,584> Î± (0,05) ho is accepted, so there is no significant relationship between the two variables. To measure the closeness and intensity of the relationship between the two variables, test of correlation coefficient and simple linear regression. The result of correlation coefficient test (r) obtained by -0,077, lies below the value of -0.30 (very weak) thus can be said there is no relation between perception about physiotherapy profession with motivation learn student Akfis UKI. Result of linear regression analysis obtained equation: Y = 73,52 + (-0,088) X. This means that every 1 point decrease of perception value will influence motivation value equal to 0,088 times.Keywords: Perception, motivation, physiotherapy profession, and learning achievement. ABSTRAKPenelitian ini bersifat deskriptif analitik, bertujuan untuk mendeskripsikan hubungan persepsi tentang profesi fisioterapi dengan motivasi belajar siswa Akademi Fisioterapi UKI. Pengumpulan data melalui kuesioner kepada siswa Fisioterapi Academy UKI tingkat 1, 2, dan 3 dengan sampel sebanyak 53 siswa, kemudian memberikan skor masing-masing kuesioner pernyataan. Hasil analisis korelasi menunjukkan bahwa p = 0,584> Î± (0,05) ho diterima, sehingga tidak ada hubungan yang signifikan antara kedua variabel tersebut. Untuk mengukur kedekatan dan intensitas hubungan antara kedua variabel tersebut, uji koefisien korelasi dan regresi linier sederhana. Hasil uji koefisien korelasi (r) diperoleh sebesar -0,077, berada di bawah nilai -0,30 (sangat lemah) sehingga dapat dikatakan tidak ada hubungan antara persepsi tentang profesi fisioterapi dengan motivasi belajar siswa Akfis UKI. Hasil analisis regresi linier diperoleh persamaan: Y = 73,52 + (-0,088) X. Artinya setiap 1 titik penurunan nilai persepsi akan mempengaruhi nilai motivasi sebesar 0,088 kali.Kata kunci: Persepsi, motivasi, profesi fisioterapi, dan prestasi belajar.

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