A Method for a Direct Measure of Entrainment and Detrainment

2020 ◽  
Vol 148 (8) ◽  
pp. 3329-3340
Author(s):  
Zhiting Wang
Keyword(s):  
Exchange Rates ◽  
Cloud Model ◽  
Deep Convection ◽  
Correlation Coefficients ◽  
Interface Velocity ◽  
Small Region ◽  
Previous Method ◽  
New Method ◽  
Mass Fluxes ◽  
Free Air

Abstract The entrainment and detrainment rates are important quantities characterizing airmass exchange between clouds and the environment. One of the challenges in calculating the rates is the need to know the velocity vector of the cloud interface in relation to that of the cloud-free air; however, the interface is not well resolved in most cloud model simulations and so the precise value of the vector is not known. Here a new method is described to approximately calculate mass fluxes across the cloud surface in well-resolved simulations of cumulus convection. The method does away with the need to calculate a cloud interface velocity and instead uses gradients of a defined cloud scalar across the cloud interface. As a result, the entrainment and detrainment rates are expressed as an integration over a small region around the cloud interface. The integrand is composed of the total derivative of the cloud scalar. The new method is applied to large-eddy simulations (LES) of a shallow cumulus case and a deep convection case. Compared to a previous method, the approach described here gives 1.5–2 times smaller exchange rates and shows less noise. The smaller exchange rates are explained as the result of differences in how the two methods correct for the advective contribution to variations of cloud volume. Derived two-dimensional distributions of the exchange rates agree well for both methods. Spatial correlation coefficients are about 0.69–0.88 for entrainment and 0.55–0.78 for detrainment.

scholarly journals On interpreting studies of tracer transport by deep cumulus convection and its effects on atmospheric chemistry

2008 ◽  
Vol 8 (20) ◽  
pp. 6037-6050 ◽  
Author(s):  
M. G. Lawrence ◽  
M. Salzmann
Keyword(s):  
Atmospheric Chemistry ◽  
Large Scale ◽  
Deep Convection ◽  
Convective Transport ◽  
Advective Transport ◽  
Tracer Transport ◽  
Transport Models ◽  
Mass Fluxes ◽  
Split Treatment ◽  
The Mean

Abstract. Global chemistry-transport models (CTMs) and chemistry-GCMs (CGCMs) generally simulate vertical tracer transport by deep convection separately from the advective transport by the mean winds, even though a component of the mean transport, for instance in the Hadley and Walker cells, occurs in deep convective updrafts. This split treatment of vertical transport has various implications for CTM simulations. In particular, it has led to a misinterpretation of several sensitivity simulations in previous studies in which the parameterized convective transport of one or more tracers is neglected. We describe this issue in terms of simulated fluxes and fractions of these fluxes representing various physical and non-physical processes. We then show that there is a significant overlap between the convective and large-scale mean advective vertical air mass fluxes in the CTM MATCH, and discuss the implications which this has for interpreting previous and future sensitivity simulations, as well as briefly noting other related implications such as numerical diffusion.

scholarly journals SENTENCE ORDERING USING CLUSTER CORRELATION AND PROBABILITY IN MULTI-DOCUMENTS SUMMARIZATION

2017 ◽  
Vol 10 (2) ◽  
pp. 77
Author(s):  
I Gusti Agung Socrates Adi Guna ◽  
Suci Nur Fauziah ◽  
Wanvy Arifha Saputra
Keyword(s):  
Previous Method ◽  
New Method ◽  
User Evaluation ◽  
Document Summarization ◽  
Chronological Sequence ◽  
Effect Relation ◽  
Cluster Correlation

Most of the document summary are arranged extractive by taking important sentences from the document. Extractive based summarization often not consider the connection sentence.  A good sentence ordering should aware about rhetorical relations such as cause-effect relation, topical relevancy and chronological sequence which exist between the sentences.  Based on this problem, we propose a new method for sentence ordering in multi document summarization using cluster correlation and probability for English documents. Sentences of multi-documents are grouped based on similarity into clusters. Sentence extracted from each cluster to be a summary that will be listed based on cluster correlation and probability. User evaluation showed that the summary result of proposed method easier to understanding than the previous method. The result of ROUGE method also shows increase on sentence arrangement compared to previous method.

Collaborative Study of the Spectrophotometric Determination of Phosphatase Activity in Milk Utilizing a New Alkaline Phosphatase Assay System

1972 ◽  
Vol 55 (3) ◽  
pp. 498-503
Author(s):  
D H Kleyn ◽  
C L Huang
Keyword(s):  
Systematic Error ◽  
Collaborative Study ◽  
Correlation Coefficients ◽  
New Method ◽  
Statistical Comparison ◽  
Alkaline Phosphatase Assay ◽  
Phosphatase Assay ◽  
Method Analysis ◽  
Quantitative Procedure

Abstract A quantitative procedure (modified new method) has been studied that employs phenolphthalein monophosphate as the substrate and dialysis of released phenolphthalein followed by subseqvient measurement of the dialysate in a spectrophotometer at 550 nm. Nine collaborators evaluated 6 unknown samples of milk containing various levels of rawmilk, in triplicate, by the modified new method and the Scharer modified spectrophotometric method. Analysis of variance revealed that the random error of the modified new method was almost twice that of the Scharer technique, while the systematic error of the modified new method was only about ¼ that of the latter method. Two-sample charts indicated that the systematic error of the modified new method was less than that of the Scharer method; this was verified by a statistical comparison which showed that the total analytical error was much lower for the modified new method. A linear relationship was found between the 2 methods by 5 of the collaborators; the correlation coefficients ranged from 0.993 to 0.999. Based on these results, the method has been adopted as official first action for the analysis of milk.

scholarly journals Possible Effects of Collisional Breakup on Mixed-Phase Deep Convection Simulated by a Spectral (Bin) Cloud Model

2005 ◽  
Vol 62 (6) ◽  
pp. 1917-1931 ◽  
Author(s):  
Axel Seifert ◽  
Alexander Khain ◽  
Ulrich Blahak ◽  
Klaus D. Beheng
Keyword(s):  
Cloud Model ◽  
Deep Convection ◽  
Sensitivity Study ◽  
Mixed Phase ◽  
Convective Clouds ◽  
Hebrew University ◽  
Raindrop Size ◽  
Convective Cells ◽  
Rain Rates ◽  
Rain Formation

Abstract The effects of the collisional breakup of raindrops are investigated using the Hebrew University Cloud Model (HUCM). The parameterizations, which are combined in the new breakup scheme, are those of Low and List, Beard and Ochs, as well as Brown. A sensitivity study reveals strong effects of collisional breakup on the precipitation formation in mixed-phase deep convective clouds for strong as well as for weak precipitation events. Collisional breakup reduces the number of large raindrops, increases the number of small raindrops, and, as a consequence, decreases surface rain rates and considerably reduces the speed of rain formation. In addition, it was found that including breakup can lead to a more intense triggering of secondary convective cells. But a statistical comparison with observed raindrop size distributions shows that the parameterizations might systematically overestimate collisional breakup.

Parameter identification of nonlinear rotor-bearing system based on improved kriging surrogate model

2016 ◽  
Vol 23 (5) ◽  
pp. 794-807 ◽  
Author(s):  
Fang Han ◽  
Xinglin Guo ◽  
Changki Mo ◽  
Haiyang Gao ◽  
Peijun Hou
Keyword(s):  
Evolutionary Algorithm ◽  
Surrogate Model ◽  
Computation Time ◽  
Previous Method ◽  
New Method ◽  
Structure Parameters ◽  
Kriging Surrogate Model ◽  
Rotor Bearing ◽  
Robustness To Noise ◽  
Bearing System

This paper presents a new method which can identify the structure parameters (such as the bearing parameters, the nonlinear rub-impact parameters, and so on) of a nonlinear rotor-bearing system. Based on an improved kriging surrogate model and evolutionary algorithm (IKSMEA), the new method can provide more accurate results with less computation time. The initial kriging surrogate model (KSM) is constructed by the samples of varying structure parameters and their response values. According to the identified process, a multi-point addition criterion is proposed and more appropriate predicted points are added to update the KSM. Numerical studies and experimental validation of a nonlinear rotor-bearing system are performed. Comparing to the previous method (KSM and evolutionary algorithm), the new method satisfies the condition of convergence with less updating steps and increased robustness to noise. The identified results indicate that the IKSMEA can identify the nonlinear rotor system more effectively and accurately.

scholarly journals New Similarity of Triangular Fuzzy Number and Its Application

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Xixiang Zhang ◽  
Weimin Ma ◽  
Liping Chen
Keyword(s):  
Collaborative Filtering ◽  
Fuzzy Number ◽  
Recommendation System ◽  
Fuzzy Numbers ◽  
Comprehensive Evaluation ◽  
Cloud Model ◽  
Triangular Fuzzy Number ◽  
New Method ◽  
Triangular Fuzzy Numbers

The similarity of triangular fuzzy numbers is an important metric for application of it. There exist several approaches to measure similarity of triangular fuzzy numbers. However, some of them are opt to be large. To make the similarity well distributed, a new method SIAM (Shape’s Indifferent Area and Midpoint) to measure triangular fuzzy number is put forward, which takes the shape’s indifferent area and midpoint of two triangular fuzzy numbers into consideration. Comparison with other similarity measurements shows the effectiveness of the proposed method. Then, it is applied to collaborative filtering recommendation to measure users’ similarity. A collaborative filtering case is used to illustrate users’ similarity based on cloud model and triangular fuzzy number; the result indicates that users’ similarity based on triangular fuzzy number can obtain better discrimination. Finally, a simulated collaborative filtering recommendation system is developed which uses cloud model and triangular fuzzy number to express users’ comprehensive evaluation on items, and result shows that the accuracy of collaborative filtering recommendation based on triangular fuzzy number is higher.

scholarly journals Convective Initiation in an Idealized Cloud Model Using an Updraft Nudging Technique

2012 ◽  
Vol 140 (11) ◽  
pp. 3699-3705 ◽  
Author(s):  
Jason Naylor ◽  
Matthew S. Gilmore
Keyword(s):  
Boundary Layer ◽  
Cloud Model ◽  
Deep Convection ◽  
Convective Initiation ◽  
Modeling Studies ◽  
Convective Inhibition ◽  
Cloud Modeling

Abstract Previous cloud modeling studies have noted difficulty in producing strong, sustained deep convection in environments with convective inhibition and/or midlevel dryness when the thermal bubble technique is used to initiate convection. This difficulty is also demonstrated herein, using 113 supercell proximity soundings—most of which contain capping inversions and some amount of convective inhibition. Instead, by using an updraft nudging initiation technique, substantially more supercells result and for a longer period. Additionally, the number of supercell-producing cases is maximized when updraft nudging is applied for only the first 15 min of cloud time near the top of the boundary layer instead of longer/shorter periods or when nudging is applied near the surface.

Determination of Alkalinity of Reclaimed Rubber

1931 ◽  
Vol 4 (2) ◽  
pp. 273-280
Author(s):  
Henry F. Palmer ◽  
George W. Miller
Keyword(s):  
Previous Method ◽  
New Method ◽  
End Point ◽  
Alkaline Material

Abstract A new method is given for determining the relative alkalinity of reclaimed rubber. The extraction of the alkaline material is based on a digestion of the sample in a mixture of ethanol, benzene, and water. The method is compared with the previous method described by the authors in 1928. The experimental figures given show that the new method gives results which are dependable, and approximately four times as accurate as the previous method. The higher degree of accuracy is due to the elimination of much of the personal error, the extraction of a larger percentage of alkaline material, and a more accurate titration end point. The purpose of this paper is to present a method for determining the relative alkalinity of reclaimed rubber which, in the authors??? opinion, has certain advantages over other methods in use at present.

Ecological Environment Evaluation of Coal Mining Area Based on Cloud Model

2012 ◽  
Vol 433-440 ◽  
pp. 1372-1376
Author(s):  
Dan Li ◽  
Da Peng Fan ◽  
Chun You Dong
Keyword(s):  
Coal Mining ◽  
Cloud Model ◽  
Mining Area ◽  
New Method ◽  
Ecological Environment ◽  
Coal Mining Area

In order to solve the universal uncertainty in ecological environment evaluation of coal mining area, the cloud model is proposed. Theory of cloud model is introduced; a new method of coal mineral area ecological environment evaluation based on cloud model is presented and its effectiveness is tested by example. Testified by the experiment, results of evaluation are intuitionist with more details, and approach to the fact better.

scholarly journals Off-line algorithm for calculation of vertical tracer transport in the troposphere due to deep convection

2012 ◽  
Vol 12 (8) ◽  
pp. 20239-20289 ◽  
Author(s):  
D. A. Belikov ◽  
S. Maksyutov ◽  
M. Krol ◽  
A. Fraser ◽  
M. Rigby ◽  
...  
Keyword(s):  
Transport Model ◽  
Deep Convection ◽  
Cumulus Cell ◽  
Reanalysis Data ◽  
Convective Precipitation ◽  
Cumulus Convection ◽  
Tracer Transport ◽  
Chemical Transport Model ◽  
Reanalysis Dataset ◽  
Mass Fluxes

Abstract. A modified cumulus convection parametrisation scheme is presented. This scheme computes the mass of air transported upward in a cumulus cell using conservation of moisture and a detailed distribution of convective precipitation provided by a reanalysis dataset. The representation of vertical transport within the scheme includes entrainment and detrainment processes in convective updrafts and downdrafts. Output from the proposed parametrisation scheme is employed in the National Institute for Environmental Studies (NIES) global chemical transport model driven by JRA-25/JCDAS reanalysis. The simulated convective precipitation rate and mass fluxes are compared with observations and reanalysis data. A simulation of the short-lived tracer 222Rn is used to further evaluate the performance of the cumulus convection scheme. Simulated distributions of 222Rn are validated against observations at the surface and in the free troposphere, and compared with output from models that participated in the TransCom-CH4 Transport Model Intercomparison. From this comparison, we demonstrate that the proposed convective scheme can successfully reproduce deep cloud convection.

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