scholarly journals Methodological Development of the Conditional Sampling Method. Part I: Sensitivity to Statistical and Technical Characteristics

2005 ◽  
Vol 114 (3) ◽  
pp. 615-640 ◽  
Author(s):  
A.K. Fotiadi ◽  
F. Lohou ◽  
A. Druilhet ◽  
D. Ser�a ◽  
Y. Brunet ◽  
...  
Keyword(s):  
Sampling Method ◽  
Conditional Sampling ◽  
Methodological Development

scholarly journals A Joint Probability Density–Based Decomposition of Turbulence in the Atmospheric Boundary Layer

2018 ◽  
Vol 146 (2) ◽  
pp. 503-523 ◽  
Author(s):  
Maria J. Chinita ◽  
Georgios Matheou ◽  
João Teixeira
Keyword(s):  
Probability Density ◽  
Vertical Velocity ◽  
Large Scale ◽  
Sampling Method ◽  
Joint Probability ◽  
Convective Cloud ◽  
Conditional Sampling ◽  
Large Eddy Simulation Model ◽  
Joint Probability Density ◽  
Cloud Core

Abstract In convective flows, vertical turbulent fluxes, covariances between vertical velocity and scalar thermodynamic variables, include contributions from local mixing and large-scale coherent motions, such as updrafts and downdrafts. The relative contribution of these motions to the covariance is important in turbulence parameterizations. However, the flux partition is challenging, especially in regions without convective cloud. A method to decompose the vertical flux based on the corresponding joint probability density function (JPD) is introduced. The JPD-based method partitions the full JPD into a joint Gaussian part and the complement, which represent the local mixing and the large-scale coherent motions, respectively. The coherent part can be further divided into updraft and downdraft parts based on the sign of vertical velocity. The flow decomposition is independent of water condensate (cloud) and can be applied in cloud-free convection, the subcloud layer, and stratiform cloud regions. The method is applied to large-eddy simulation model data of three boundary layers. The results are compared with traditional cloud and cloud-core decompositions and a decaying scalar conditional sampling method. The JPD-based method includes a single free parameter and sensitivity tests show weak dependence on the parameter values. The results of the JPD-based method are somewhat similar to the cloud-core and conditional sampling methods. However, differences in the relative magnitude of the flux decomposition terms suggest that an objective definition of the flow regions is subtle and diagnosed flow properties like updraft characteristics depend on the sampling method. Moreover, the flux decomposition depends on the thermodynamic variable and convection characteristics.

An Investigation of the Conditional Sampling Method Used to Estimate Fluxes of Active, Reactive, and Passive Scalars

1996 ◽  
Vol 35 (10) ◽  
pp. 1835-1845 ◽  
Author(s):  
Gabriel G. Katul ◽  
Peter L. Finkelstein ◽  
John F. Clarke ◽  
Thomas G. Ellestad
Keyword(s):  
Sampling Method ◽  
Conditional Sampling ◽  
Passive Scalars

Controls on trace gas exchange observed by a conditional sampling method

1998 ◽  
Vol 32 (19) ◽  
pp. 3265-3274 ◽  
Author(s):  
J.B. Moncrieff ◽  
I.J. Beverland ◽  
D.H. ÓNéill ◽  
F.D. Cropley
Keyword(s):  
Gas Exchange ◽  
Sampling Method ◽  
Trace Gas ◽  
Conditional Sampling

An Empirical Analysis of the Obtrusiveness of and Participants' Compliance with the Electronically Activated Recorder (EAR)

2007 ◽  
Vol 23 (4) ◽  
pp. 248-257 ◽  
Author(s):  
Matthias R. Mehl ◽  
Shannon E. Holleran
Keyword(s):  
Empirical Analysis ◽  
Sampling Method ◽  
Daily Life ◽  
Assessment Method ◽  
Data Confidentiality ◽  
Short Term ◽  
Naturally Occurring ◽  
Two Samples ◽  
Audio Recorder ◽  
Term Monitoring

Abstract. In this article, the authors provide an empirical analysis of the obtrusiveness of and participants' compliance with a relatively new psychological ambulatory assessment method, called the electronically activated recorder or EAR. The EAR is a modified portable audio-recorder that periodically records snippets of ambient sounds from participants' daily environments. In tracking moment-to-moment ambient sounds, the EAR yields an acoustic log of a person's day as it unfolds. As a naturalistic observation sampling method, it provides an observer's account of daily life and is optimized for the assessment of audible aspects of participants' naturally-occurring social behaviors and interactions. Measures of self-reported and behaviorally-assessed EAR obtrusiveness and compliance were analyzed in two samples. After an initial 2-h period of relative obtrusiveness, participants habituated to wearing the EAR and perceived it as fairly unobtrusive both in a short-term (2 days, N = 96) and a longer-term (10-11 days, N = 11) monitoring. Compliance with the method was high both during the short-term and longer-term monitoring. Somewhat reduced compliance was identified over the weekend; this effect appears to be specific to student populations. Important privacy and data confidentiality considerations around the EAR method are discussed.

Sign in / Sign up

Export Citation Format

Share Document