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Synoptic and mesoscale study of a severe convective outbreak with the nonhydrostatic Global Environmental Multiscale (GEM) model 总被引：1，自引：0，他引：1
A. Erfani A. Méthot R. Goodson S. Bélair K.-S. Yeh J. Côté R. Moffet 《Meteorology and Atmospheric Physics》2003,82(1-4):31-53
Summary ?A nonhydrostatic 4-km version of the Global Environmental Multiscale (GEM) model, with detailed microphysics included, was
used to forecast the initiation, development, and structure of a tornado-producing supercell storm that occurred near Pine
Lake (Alberta, Canada) on 15 July 2000. Examination of observations and comparison with conceptual models indicate that this
storm is a good example of supercell storms that regularly produce summertime severe weather over Alberta.
It was found that the high-resolution model was able to reproduce the early initiation of convective activity along the Rocky
Mountains foothills, as well as the rapid northeastward propagation towards the Pine Lake area and the subsequent intensification
into a supercell storm. The general structures of the forecasted convective system correspond well with conceptual representations
of such events. Overall, this high-resolution forecast of the Pine Lake supercell storm was a significant improvement over
the current operational version of the GEM model (24 km), which was not able to intensify the foothills’ convection into a
supercell storm. Finally, it was found that the nonhydrostatic version of the model produces better trajectory and propagation
speed of the convective system, as compared with the hydrostatic one.
Received March 20, 2001; revised August 24, 2001 相似文献
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J. Mailhot J. A. Milbrandt A. Giguère R. McTaggart-Cowan A. Erfani B. Denis A. Glazer M. Vallée 《Pure and Applied Geophysics》2014,171(1-2):209-229
Environment Canada ran an experimental numerical weather prediction (NWP) system during the Vancouver 2010 Winter Olympic and Paralympic Games, consisting of nested high-resolution (down to 1-km horizontal grid-spacing) configurations of the GEM–LAM model, with improved geophysical fields, cloud microphysics and radiative transfer schemes, and several new diagnostic products such as density of falling snow, visibility, and peak wind gust strength. The performance of this experimental NWP system has been evaluated in these winter conditions over complex terrain using the enhanced mesoscale observing network in place during the Olympics. As compared to the forecasts from the operational regional 15-km GEM model, objective verification generally indicated significant added value of the higher-resolution models for near-surface meteorological variables (wind speed, air temperature, and dewpoint temperature) with the 1-km model providing the best forecast accuracy. Appreciable errors were noted in all models for the forecasts of wind direction and humidity near the surface. Subjective assessment of several cases also indicated that the experimental Olympic system was skillful at forecasting meteorological phenomena at high-resolution, both spatially and temporally, and provided enhanced guidance to the Olympic forecasters in terms of better timing of precipitation phase change, squall line passage, wind flow channeling, and visibility reduction due to fog and snow. 相似文献
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Application of water pinch technology for water and wastewater minimization in aluminum anodizing industries 总被引：1，自引：1，他引：0
S. M. Khezri Ph.D. F. Lotfi M.Sc. S. Tabibian M.Sc Z. Erfani M.Sc. 《International Journal of Environmental Science and Technology》2010,7(2):281-290
This study aims to describe the application of water pinch technology in industrial water consumption management in aluminum anodizing industry. Water pinch analysis is a systematic technique for designing, optimization and retrofitting of energy, mass and water recovery networks. The selection of different operations existing in an industry has an important role in correctness of application of pinch technology. Water usages in anodizing industry are various, but researches have been shown that, it has the best efficiency on the selection of rinsing chambers to pinch technology. There are different methods in pinch technology mostly based on mass transfer of single or multiple contaminants. In this research, a new method is used to select effective contaminant to be applied to pinch analysis. This research is based on Mann and Liu’s method in single contaminant. But “the guide for classification of raw water, wastewater and recycled water for industrial and recreation” is chosen to use a complex of index contaminants as a single contaminant. This method is very simple and applicable for various industrial processes. By an index contaminant like total dissolved solids, the water usage reduced about 6.7 %. Using pinch technology and this new approach in three rinsing chambers, water usage reduced about 14.4 %. 相似文献
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The study started by Cabo and Brandenberger (J. Cosmol. Astropart. Phys. 2:15, 2009) about the Dilaton mean field stabilization thanks to the effective potential generated by the existence of massive fermions, is here extended. Three loop corrections are evaluated in addition to the previously calculated two loop terms. The results indicate that the Dilaton vacuum field tends to be fixed at a high value close to the Planck scale, in accordance with the need for predicting Einstein gravity from string theory. The mass of the Dilaton is evaluated to be also a high value close to the Planck mass, which implies the absence of Dilaton scalar signals in modern cosmological observations. These properties arise when the fermion mass is chosen to be either at a lower bound corresponding to the top quark mass, or alternatively, at a very much higher value assumed to be in the grand unification energy range. One of the three 3-loop terms is exactly evaluated in terms of Master integrals. The other two graphs are however evaluated in their leading logarithm correction in the perturbative expansion. The calculation of the non leading logarithmic contribution and the inclusion of higher loops terms could made more precise the numerical estimates of the vacuum field value and masses, but seemingly are expected not to change the qualitative behavior obtained. The validity of the here employed Yukawa model approximation is argued for small value of the fermion masses with respect to the Planck one. A correction to the two loop calculation done in the previous work is here underlined. 相似文献
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This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling (SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance (harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths. 相似文献
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The accuracy and efficiency of the modelling techniques utilized to model the nonlinear behavior of structural components is a significant issue in earthquake engineering. In this study, the sufficiency of three different modelling techniques that can be employed to simulate the structural behavior of columns is investigated. A fiber-based finite length plastic hinge (FB-FLPH) model is calibrated in this study. In order to calibrate the FB-FLPH model, a novel database of the cyclic behavior of hollow steel columns under simultaneous axial and lateral loading cycles with varying amplitudes is used. By employing the FB-FLPH model calibrated in this study, the interaction of the axial force and the bending moment in columns is directly taken into account, and the deterioration in the cyclic behavior of these members is implicitly considered. The superiority of the calibrated FB-FLPH modelling approach is examined compared with the cases in which conventional fiber-based distributed plasticity and concentrated plasticity models are utilized. The efficiency of the enumerated modelling techniques is probed when they are implemented to model the columns of a typical special moment frame in order to prove the advantage of the FB-FLPH modelling approach.
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