scholarly journals Improvements in the Subgrid-Scale Representation of Moist Convection in a Cumulus Parameterization Scheme: The Single-Column Test and Its Impact on Seasonal Prediction

2007 ◽  
Vol 135 (6) ◽  
pp. 2135-2154 ◽  
Author(s):  
Young-Hwa Byun ◽  
Song-You Hong
Keyword(s):  
Large Scale ◽  
Meridional Circulation ◽  
Random Selection ◽  
The Other ◽  
Moist Convection ◽  
Subgrid Scale ◽  
Convection Scheme ◽  
Single Column ◽  
Convective Momentum Transport ◽  
Selection Of

Abstract This study describes a revised approach for the subgrid-scale convective properties of a moist convection scheme in a global model and evaluates its effects on a simulated model climate. The subgrid-scale convective processes tested in this study comprise three components: 1) the random selection of cloud top, 2) the inclusion of convective momentum transport, and 3) a revised large-scale destabilization effect considering synoptic-scale forcing in the cumulus convection scheme of the National Centers for Environmental Prediction medium-range forecast model. Each component in the scheme has been evaluated within a single-column model (SCM) framework forced by the Tropical Ocean Global Atmosphere Coupled Ocean–Atmosphere Response Experiment data. The impact of the changes in the scheme on seasonal predictions has been examined for the boreal summers of 1996, 1997, and 1999. In the SCM simulations, an experiment that includes all the modifications reproduces the typical convective heating and drying feature. The simulated surface rainfall is in good agreement with the observed precipitation. Random selection of the cloud top effectively moistens and cools the upper troposphere, and it induces drying and warming below the cloud-top level due to the cloud–radiation feedback. However, the two other components in the revised scheme do not play a significant role in the SCM simulations. On the other hand, the role of each modification component in the scheme is significant in the ensemble seasonal simulations. The random selection process of the cloud top preferentially plays an important role in the adjustment of the thermodynamic profile in a manner similar to that in the SCM framework. The inclusion of convective momentum transport in the scheme weakens the meridional circulation. The revised large-scale destabilization process plays an important role in the modulation of the meridional circulation when this process is combined with other processes; on the other hand, this process does not induce significant changes in large-scale fields by itself. Consequently, the experiment that involves all the modifications shows a significant improvement in the seasonal precipitation, thereby highlighting the importance of nonlinear interaction between the physical processes in the model and the simulated climate.

A Stochastic Unified Convection Scheme (UNICON). Part I: Formulation and Single-Column Simulation for Shallow Convection

2020 ◽  
Vol 77 (2) ◽  
pp. 583-610 ◽  
Author(s):  
Jihoon Shin ◽  
Sungsu Park
Keyword(s):  
Similarity Theory ◽  
Domain Size ◽  
Cloud Base ◽  
Moist Convection ◽  
Shallow Convection ◽  
Power Law Distribution ◽  
Convection Scheme ◽  
Multivariate Gaussian Distribution ◽  
Single Column ◽  
Mean And Variance

Abstract By extending the previously developed unified convection scheme (UNICON), we develop a stochastic UNICON with convective updraft plumes at the surface randomly sampled from the correlated multivariate Gaussian distribution for updraft vertical velocity w^ and thermodynamic scalars ϕ^, of which standard deviations and intervariable correlations are derived from the surface-layer similarity theory. The updraft plume radius R^ at the surface follows a power-law distribution with a specified scale break radius. To enhance computational efficiency, we also develop a hybrid stochastic UNICON consisting of n bin plumes and a single stochastic plume, each of which mainly controls the ensemble mean and variance of grid-mean convective tendency, respectively. We evaluated the stochastic UNICON using the large-eddy simulation (LES) of the Barbados Oceanographic and Meteorological Experiment (BOMEX) shallow convection case in a single-column mode. Consistent with the assumptions in the stochastic UNICON, the LES w^ and ϕ^ at the surface follow approximately the half- and full-Gaussian distributions, respectively. LES showed that a substantial portion of the variability in ϕ^ at the cloud base stems from the surface, which also supports the concept of stochastic UNICON that simulates various types of moist convection based on the dry stochastic convection launched from the surface. Overall, stochastic UNICON adequately reproduces the LES grid-mean thermodynamic states as well as the mean and variance of ϕ^, including their dependency on the domain size and R^. A sensitivity test showed that the perturbations of ϕ^ as well as R^ at the surface are important for the correct simulation of the grid-mean thermodynamic states.

Psychology of Scientist: XXX. Credibility of Psychologists: An Empirical Study

1970 ◽  
Vol 27 (3) ◽  
pp. 835-838 ◽  
Author(s):  
Leonard D. Goodstein ◽  
Karen Lee Brazis
Keyword(s):  
Empirical Study ◽  
Empirical Research ◽  
Random Selection ◽  
The Other ◽  
Affective Reactions ◽  
Negative Findings ◽  
Professional Psychologists ◽  
The Many ◽  
Selection Of

In order to evaluate the effects of bias among psychologists, two virtually identical abstracts of presumably empirical research in the area of astrology were prepared, one with positive findings and the other with negative findings. The data collected by mail from a random selection of professional psychologists indicated that those Ss receiving the negative abstract rated the study as better designed, more valid, and as having more adequate conclusions than those receiving the positive abstract. The many emotionally charged spontaneous comments included with the responses suggests that strong affective reactions are involved, as well as prejudgments.

Once again about the hapax grammar: Epigenetic Linguistics

2020 ◽  
Vol 3 (1) ◽  
pp. 23-27
Author(s):  
Dan Faltýnek ◽  
Ľudmila Lacková ◽  
Hana Owsianková
Keyword(s):  
Large Scale ◽  
Random Selection ◽  
Epigenetic Marks ◽  
Selection Of ◽  
Epigenetic Processes ◽  
National Corpus ◽  
Hapax Legomena

AbstractIn this article, we deal with the similarity between epigenetic marks in DNA and hapax legomena in language; based on the so-called hapaxes, a grammar description is designed. We reflect hapax analysis of Czech language provided by Novotná (2013) and avoid random selection of the corpus. For this reason, we analyze a corpus of 12 authentic books from 12 authors who elaborated the theme “What’s new in…” concerning their field of science, assigned by Nová beseda publishing. By analyzing a middle-sized corpus, we expected results similar to those of large-scale national corpus (see Novotná 2013). We chose to classify hapaxes into different categories in comparison to Novotná, yet the results show similar language productive categories. This kind of language potentiality seems to be analogical to epigenetic processes in biology, which is briefly introduced.

scholarly journals The ‘Prostration Hemerology’ Revisited: An Everyman’s Manual at the King’s Court

2015 ◽  
Vol 105 (2) ◽  
Author(s):  
Enrique Jiménez ◽  
Selim F. Adalı
Keyword(s):  
British Museum ◽  
Random Selection ◽  
The Other ◽  
University Museum ◽  
Unpublished Manuscripts ◽  
The University ◽  
Selection Of

Abstract:The ‘Prostration Hemerology’, with its seemingly random selection of dates and plethora of unparalleled prescriptions – such as the towing of boats upstream, the kissing of ecstatics, and the impregnating of street women –, is one of the most peculiar hemerologies in Alasdair Livingstone’s recent anthology of the genre. This article attempts a new reconstruction of the text which differs from Livingstone’s in several respects. To this end it uses eight previously unpublished manuscripts, identified in the collections of the Ancient Orient Museum of the Istanbul Archaeological Museums, the University Museum (Philadelphia), and the British Museum. Thanks to these and the collation of the other five tablets used by Livingstone, an almost complete reconstruction of the text is now possible. It reveals itself to be an influential hemerology: as well as being widely cited by scholars at the Assyrian court, it was extensively quoted in later hemerological compilations.

Shallow Meridional Circulations in the Tropical Atmosphere

2008 ◽  
Vol 21 (14) ◽  
pp. 3453-3470 ◽  
Author(s):  
Chidong Zhang ◽  
David S. Nolan ◽  
Christopher D. Thorncroft ◽  
Hanh Nguyen
Keyword(s):  
Large Scale ◽  
Meridional Circulation ◽  
Indian Subcontinent ◽  
Meridional Flow ◽  
Trade Wind ◽  
Seasonal Cycles ◽  
Tropical Atmosphere ◽  
Moist Convection ◽  
Meridional Overturning ◽  
Deep Moist Convection

Abstract A shallow meridional circulation (SMC) in the tropical atmosphere features a low-level (e.g., 700 hPa) flow that is in the opposite direction to the boundary layer monsoon or trade wind flow and is distinct from the meridional flow above. Representations of the SMC in three global reanalyses show both similarities and astonishing discrepancies. While the SMC over West Africa appears to be the strongest, it also exists over the eastern Atlantic and eastern Pacific Oceans, and over the Indian subcontinent, with different strength and structure. All SMCs undergo marked seasonal cycles. The SMCs are summarized into two types: one associated with the marine ITCZ and the other with the summer monsoon. The large-scale conditions for these two types of SMCs are similar: a strong meridional gradient in surface pressure linked to surface temperature distributions and an absence of deep moist convection. The processes responsible for these conditions are different for the two types of SMCs, as are their structures relative to moist convection, associated precipitation, and deep meridional overturning circulations. It is suggested that discrepancies among the representations of the SMC in the three global reanalyses stem from different treatment of physical parameterizations, especially for cumulus convection, in the models used for the data assimilation.

scholarly journals Linearization of a Simple Moist Convection Scheme for Large-Scale NWP Models

2005 ◽  
Vol 133 (6) ◽  
pp. 1655-1670 ◽  
Author(s):  
Jean-François Mahfouf
Keyword(s):  
Large Scale ◽  
Temporal Integration ◽  
Preliminary Evaluation ◽  
Moist Convection ◽  
Convection Scheme ◽  
Surface Precipitation ◽  
Cloud Properties ◽  
Convection Schemes ◽  
Linearized Scheme ◽  
Linearization Errors

Abstract A simple Kuo-type convection scheme with an improved closure based on moist enthalpy accession (Kuo symmetric) has been linearized for the tangent-linear (TL) and adjoint (AD) versions of the Global Environmental Multiscale (GEM) model. The nonlinear scheme exhibits a reasonable behavior in terms of heating and moistening rates when evaluated in stand-alone mode over a set of deep convective profiles. A preliminary evaluation of a straightforward linearization in the global TL model has revealed the existence of noise that leads to an unacceptable solution after 12 h of integration. By neglecting several terms in the linearization (detrainment rate and cloud properties), the temporal evolution of humidity analysis increments is improved by including this simplified linearized convection scheme in the TL model. The behavior of the linearized scheme has also been compared favorably to the linearized version of the European Centre for Medium-Range Weather Forecasts (ECMWF) mass-flux convection scheme. When examining the validity of the TL approximation for surface precipitation, it appears that linearization errors are large for both stratiform and convective rainfall (rms errors are about twice the mean absolute perturbed precipitation). These errors are not reduced when considering accumulated rain rates instead of instantaneous quantities. However, the occurrence of “on–off” processes is reduced by a temporal integration of rain. This could make the variational assimilation of accumulated precipitation rates easier. Finally, errors coming from internal nonlinearities are slightly larger than those produced by discontinuities. This confirms the interest for improving the linearity of nonlinear convection schemes for applications in variational contexts.

scholarly journals A Parameterization of Convective Dust Storms for Models with Mass-Flux Convection Schemes

2015 ◽  
Vol 72 (6) ◽  
pp. 2545-2561 ◽  
Author(s):  
Florian Pantillon ◽  
Peter Knippertz ◽  
John H. Marsham ◽  
Cathryn E. Birch
Keyword(s):  
Conceptual Model ◽  
Mass Flux ◽  
Large Scale ◽  
Dust Storms ◽  
Cold Pool ◽  
Moist Convection ◽  
Convection Scheme ◽  
Scale Models ◽  
Strong Winds ◽  
Convection Schemes

Abstract Cold pool outflows, generated by downdrafts from moist convection, can generate strong winds and therefore uplift of mineral dust. These so-called haboob convective dust storms occur over all major dust source areas worldwide and contribute substantially to emissions in northern Africa, the world’s largest source. Most large-scale models lack convective dust storms because they do not resolve moist convection, relying instead on convection schemes. The authors suggest a parameterization of convective dust storms to account for their contribution in such large-scale models. The parameterization is based on a simple conceptual model, in which the downdraft mass flux from the convection scheme spreads out radially in a cylindrical cold pool. The parameterization is tested with a set of Met Office Unified Model runs for June and July 2006 over West Africa. It is calibrated with a convection-permitting run and applied to a convection-parameterized run. The parameterization successfully produces the extensive area of dust-generating winds from cold pool outflows over the southern Sahara. However, this area extends farther to the east and dust-generating winds occur earlier in the day than in the convection-permitting run. These biases are caused by biases in the convection scheme. It is found that the location and timing of dust-generating winds are weakly sensitive to the parameters of the conceptual model. The results demonstrate that a simple parameterization has the potential to correct a major and long-standing limitation in global dust models.

Microbiological Sampling of Carcasses by Excision or Swabbing

2000 ◽  
Vol 63 (2) ◽  
pp. 167-173 ◽  
Author(s):  
C. O. GILL ◽  
T. JONES
Keyword(s):  
Escherichia Coli ◽  
Fold Increase ◽  
Random Selection ◽  
The Other ◽  
Sampling Techniques ◽  
Cotton Wool ◽  
E Coli ◽  
Beef Carcasses ◽  
The Mean ◽  
Selection Of

Groups of 25 carcasses were obtained by random selection of carcasses at the end of each of eight commercial processes for the dressing or cooling of carcasses. Samples were collected from six groups of pig or beef carcasses by excision or swabbing with sponge, gauze, or cotton wool, with one sample obtained by each of the four methods from a separate, randomly selected site on each carcass. Total aerobic counts, coliforms, and Escherichia coli from each sample were enumerated. Values for the mean log10, log10 mean, and log10 total numbers recovered were calculated for each set of total aerobic counts. Those statistics indicated that the numbers of bacteria recovered by excision or swabbing with sponge or gauze were similar, while the numbers recovered by swabbing with cotton wool were at the lower end of or below the range of the numbers recovered by the other methods. The numbers of coliforms or E. coli recovered from carcasses by sampling areas up to 100 cm2 were too few for the estimation of log mean numbers. Sampling of two groups of carcasses by swabbing with gauze indicated that each 10-fold increase in the area sampled, from 10 to 1,000 cm2, approximately doubled the number of samples from which coliforms or E. coli were recovered. Sampling of six groups of carcasses from one process indicated that the sizes of swabs and volumes of diluent used for processing swabs did not have to be increased proportionally to the area of carcass surface sampled to recover numbers of E. coli proportional to the sampled area. It therefore appears that carcass sampling techniques can be varied widely without compromising the recovery of bacteria, and that the relative efficiencies with which bacteria are recovered by different techniques can be assessed by sampling each carcass in a group of 25 by each of the methods to be compared.

scholarly journals Effects of Convective Processes on GCM Simulations of the Madden–Julian Oscillation

2010 ◽  
Vol 23 (2) ◽  
pp. 352-377 ◽  
Author(s):  
Liping Deng ◽  
Xiaoqing Wu
Keyword(s):  
General Circulation ◽  
Climate Model ◽  
General Circulation Models ◽  
Madden Julian Oscillation ◽  
State University ◽  
Moist Convection ◽  
Iowa State University ◽  
Convection Scheme ◽  
Convective Momentum Transport ◽  
Tropical Climates

Abstract Weak temporal variability in tropical climates such as the Madden–Julian oscillation (MJO) is one of major deficiencies in general circulation models (GCMs). The uncertainties in the representation of convection and cloud processes are responsible for these deficiencies. With the improvement made to the convection scheme, the Iowa State University (ISU) GCM, which is based on a version of the NCAR Community Climate Model, is able to simulate many features of MJO as revealed by observations. In this study, four 10-yr (1979–88) ISU GCM simulations with observed sea surface temperatures are analyzed and compared to examine the effects of the revised convection closure, convection trigger condition, and convective momentum transport (CMT) on the MJO simulations. The modifications made in the convection scheme improve the simulations of amplitude, spatial distribution, eastward propagation, and horizontal and vertical structures, especially for the coherent feature of eastward-propagating convection and the precursor sign of convective center. The revised convection closure plays a key role in the improvement of the eastward propagation of MJO. The convection trigger helps produce less frequent but more vigorous moist convection and enhance the amplitude of the MJO signal. The inclusion of CMT results in a more coherent structure for the MJO deep convective center and its corresponding atmospheric variances.

The Effect of Imposed Drying on Parameterized Deep Convection

2009 ◽  
Vol 66 (7) ◽  
pp. 2085-2096 ◽  
Author(s):  
Adam H. Sobel ◽  
Gilles Bellon
Keyword(s):  
Relaxation Time ◽  
Boundary Conditions ◽  
Large Scale ◽  
Deep Convection ◽  
Lower Troposphere ◽  
The Other ◽  
Specific Humidity ◽  
Middle Troposphere ◽  
Single Column ◽  
Gross Moist Stability

Abstract This paper examines the influence of imposed drying, intended to represent horizontal advection of dry air, on parameterized deep convection interacting with large-scale dynamics in a single-column model framework. Two single-column models, one based on the NASA Goddard Earth Observing System general circulation model version 5 (GEOS5) and the other developed by Bony and Emanuel, are run in weak temperature gradient mode. Drying is imposed by relaxation of the specific humidity field toward zero within a specified vertical layer. The strength of the drying is controlled by specifying either the relaxation time scale or the vertically integrated drying tendency; results are insensitive to which specification is used. The two models reach very different solutions for the same boundary conditions and model configuration. Even when adjustments to the boundary conditions and model parameters are made to render the precipitation rates similar, large differences in the profiles of relative humidity and large-scale vertical velocity persist. In both models, however, drying in the middle troposphere is more effective, per kg m−2 s−1 (or W m−2) of imposed drying, in suppressing precipitation than is drying in the lower troposphere. Even when compared at equal relaxation time (corresponding to weaker net drying in the middle than lower troposphere), middle-tropospheric drying is comparably effective to lower-tropospheric drying. Upper-tropospheric drying has a relatively small effect on precipitation, although large drying in the upper troposphere cannot be imposed as a steady state because of the lack of moisture there. Consistent with the other model differences, the gross moist stabilities of the two models are quite different and vary somewhat differently as a function of imposed drying, but in both models the gross moist stability increases as the drying is increased when it is less than around 30 W m−2 and located in the middle troposphere. For lower-tropospheric drying, the gross moist stability either decreases with increased drying or increases more slowly than for middle-tropospheric drying.

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