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Determination of the available energy,standardized ileal digestibility of amino acids of fermented corn germ meal replacing soybean meal in growing pig diets 被引量:6
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作者 Tengfei He Yuhui Zheng +1 位作者 Xiangshu Piao Shenfei Long 《Animal Nutrition》 SCIE CSCD 2022年第2期259-268,共10页
Three experiments were conducted to compare the digestible(DE),metabolizable energy(ME),and standardized ileal digestibility(SID)of amino acids(AA)in fermented corn germ meal(FCGM)and soybean meal(SBM),and evaluate th... Three experiments were conducted to compare the digestible(DE),metabolizable energy(ME),and standardized ileal digestibility(SID)of amino acids(AA)in fermented corn germ meal(FCGM)and soybean meal(SBM),and evaluate the effects of FCGM replacing SBM in growing pig diets.In Exp.1,18 barrows with initial body weight(BW)of 60.2±3.40 kg were randomly allotted to 3 treatments with 6 replicates per treatment.The control diet used corn as the only energy ingredient,and 2 test diets were made by replacing 25.8%of corn with FCGM or SBM.The DE and ME of FCGM were less(P<0.01)than those of SBM.In Exp.2,18 barrows(59.3±2.52 kg BW)with ileal T-cannulas were randomly allotted to 3 treatments with 6 replicates per treatment.The SID of arginine,tryptophan and proline were greater(P<0.05)and the tyrosine was less(P=0.01)in SBM compared with FCGM.In Exp.3,144 growing pigs(56.1±5.22 kg BW)were randomly allotted to 4 treatments with 6 pens per treatment(3 barrows and 3 gilts per pen).Four diets(FCGM0,FCGM10,FCGM20 and FCGM30)were formulated using FCGM to replace 0%,10%,20%and 30%of SBM,respectively.The ME and SID values of AA of SBM and FCGM were determined by Exp.1 and 2.Results showed that increasing FCGM inclusion quadratically(P<0.05)increased the average daily gain(ADG),average daily feed intake,and the levels of serum immunoglobulin G(IgG)and urea nitrogen,and linearly(P<0.05)increased the serum IgM,the propanoic acid,butyric acid,total volatile fatty acid(VFA)and the Shannon index of microbiota in feces.Besides,the relative abundance of genus Streptococcus in FCGM0,Lactobacillus in FCGM10 and Lachnospiraceae in FCGM30 were increased(P<0.05)compared with other treatments.In conclusion,we recommend replacing 11.80%of SBM with FCGM to obtain the optimal ADG of growing pigs.Moreover,as the ratio of FCGM replacing SBM increased in diet,the immunity,intestinal microbiota and total VFA composition of growing pigs were improved. 展开更多
关键词 available energy Amino acid digestibility Fermented corn germ meal Soybean meal Growing pig
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Generalized Available Potential Energy 被引量:1
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作者 Yong.L.McHall 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1990年第4期395-408,共14页
The kinetic energy generation in either the dry or moist atmosphere may be estimated by the same relationships if we introduce the new concept of generalized available potential energy. The largest magnitude of genera... The kinetic energy generation in either the dry or moist atmosphere may be estimated by the same relationships if we introduce the new concept of generalized available potential energy. The largest magnitude of generalized available potential energy and corresponding reference state of either dry or moist atmosphere are calculated in terms of the mitial conditions and entropy variation of the atmosphere. The obtained relationships are applicable for the statically unstable atmosphere as well. The generalized available potential energy associated with reversible processes reaches the maximum with respect to same initial state. While the generation of kinetic energy in irreversible processes is characterized by sudden changes. When the reference state is assumed to be saturated, we may predict the final temperature and moisture fields corresponding to provided initial state and entropy variation. 展开更多
关键词 Generalized available Potential energy THAN AS
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Surface available gravitational potential energy in the world oceans
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作者 Ruixin Huang Bo Qiu Zhiyou Jing 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第4期40-56,共17页
Satellite altimetry observations,including the upcoming Surface Water and Ocean Topography mission,provide snapshots of the global sea surface high anomaly field.The common practice in analyzing these surface elevatio... Satellite altimetry observations,including the upcoming Surface Water and Ocean Topography mission,provide snapshots of the global sea surface high anomaly field.The common practice in analyzing these surface elevation data is to convert them into surface velocity based on the geostrophic approximation.With increasing horizontal resolution in satellite observations,sea surface elevation data will contain many dynamical signals other than the geostrophic velocity.A new physical quantity,the available surface potential energy,is conceptually introduced in this study defined as the density multiplied by half of the squared deviation from the local mean reference surface elevation.This gravitational potential energy is an intrinsic property of the sea surface height field and it is an important component of ocean circulation energetics,especially near the sea surface.In connection with other energetic terms,this new variable may help us better understand the dynamics of oceanic circulation,in particular the processes in connection with the free surface data collected through satellite altimetry.The preliminary application of this concept to the numerically generated monthly mean Global Ocean Data Assimilation System data and Archiving,Validation,and Interpretation of Satellite Oceanographic altimeter data shows that the available surface potential energy is potentially linked to other dynamic variables,such as the total kinetic energy,eddy kinetic energy and available potential energy. 展开更多
关键词 satellite altimetry surface available potential energy eddy kinetic energy
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Wave Energy Resource Availability Assessment in the Philippines Based on 30-Year Hindcast Data
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作者 WANG Zhifeng JIANG Dong +1 位作者 DONG Sheng GONG Yijie 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第2期349-364,共16页
With the goal of evaluating the wave and wave energy conditions in the Philippines,the simulated wave nearshore(SWAN)model was used to estimate the wavefield using 30 years of cross-calibrated multi-platform(CCMP)wind... With the goal of evaluating the wave and wave energy conditions in the Philippines,the simulated wave nearshore(SWAN)model was used to estimate the wavefield using 30 years of cross-calibrated multi-platform(CCMP)wind field data(1987-2016).The spatiotemporal patterns of annual and monthly averaged significant wave heights and wave energy in the Philippines were analyzed based on the simulated data.Results showed that they had similar values;in particular,significant wave heights and wave energy were smaller in the south and southwest and higher in the north and northeast.A total of 12 representative points along the Philippine coast were selected to draw wave and wave energy roses.A directional analysis showed that the dominant wave was in the north north-east(NNE),northeast(NE),and east north-east(ENE)directions.Wave energy was mainly distributed in regions with an energy period between 1 and 10 s and significant wave heights between 0 and 4 m.To better utilize wave energy data in the Philippines,this paper studied the available and rich area of wave energy and analyzed the annual and monthly variability index of wave energy in the country.Moreover,the available significant wave heights of wave energy conversion devices(WECs)were set as 0.5-4 m,and the maximum annual average available wave energy occurred in the eastern Philippine Sea area,reaching 13 kW m^(-1).For the safety of WECs,extreme typhoon-induced wave conditions must be considered.Furthermore,the results showed that the maximum significant wave height and mean period over the 50-year return period reached 18 m and 15 s,respectively. 展开更多
关键词 wave energy resource wave energy availability wave climate extreme parameters
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The Energy Budget of a Southwest Vortex With Heavy Rainfall over South China 被引量:17
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作者 傅慎明 孙建华 +1 位作者 赵思雄 李万莉 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2011年第3期709-724,共16页
Energy budgets were analyzed to study the development of an eastward propagating southwest vortex (SWV) associated with heavy rainfall over southern China(11-13 June 2008).The results show that kinetic energy(KE) gene... Energy budgets were analyzed to study the development of an eastward propagating southwest vortex (SWV) associated with heavy rainfall over southern China(11-13 June 2008).The results show that kinetic energy(KE) generation and advection were the most important KE sources,while friction and sub-grid processes were the main KE sinks.There was downward conversion from divergent to rotational wind KE consistent with the downward stretching of SWVs.The Coriolis force was important for the formation and maintenance of the SWV.Convergence was also an important factor for maintenance,as was vertical motion during the mature stage of the SWV and the formation stage of a newly formed vortex(vortex B).The conversion from available potential energy(APE) to KE of divergent wind can lead to strong convection.Vertical motion influenced APE by dynamical and thermal processes which had opposite effects. The variation of APE was related to the heavy rainfall and convection;in this case,vertical motion with direct thermal circulation was the most important way in which APE was released,while latent heat release and vertical temperature advection were important for APE generation. 展开更多
关键词 southwest vortex kinetic energy available potential energy
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Assessment of Several Moist Adiabatic Processes Associated with Convective Energy Calculation 被引量:7
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作者 李耀东 高守亭 刘健文 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2004年第6期941-950,共10页
Several methods dealing with the moist adiabatic process are described in this paper. They are based on static energy conservation, pseudo-equivalent potential temperature conservation, the strict pseudo- adiabati... Several methods dealing with the moist adiabatic process are described in this paper. They are based on static energy conservation, pseudo-equivalent potential temperature conservation, the strict pseudo- adiabatic equation, and the reversible moist adiabatic process, respectively. Convective energy parame- ters, which are closely related to the moist adiabatic process and which re?ect the gravitational e?ects of condensed liquid water, are reintroduced or de?ned, including MCAPE [Modi?ed-CAPE (convective avail- able potential energy)], DCAPE (Downdraft-CAPE), and MDCAPE (Modi?ed-Downdraft-CAPE). Two real case analyses with special attention given to condensed liquid water show that the selection of moist adiabatic process does a?ect the calculated results of CAPE and the gravitational e?ects of condensed liq- uid water are not negligible in severe storms. Intercomparisons of these methods show that static energy conservation is consistent with pseudo-equivalent potential temperature conservation not only in physical properties but also in calculated results, and both are good approximations to the strict pseudo-adiabatic equation. The lapse rate linked with the reversible moist adiabatic process is relatively smaller than that linked with other moist adiabatic processes, especially when considering solidi?cation of liquid water in the reversible adiabatic process. 展开更多
关键词 moist adiabatic processes modified convective available potential energy downdraft con-vective available potential energy modified downdraft convective available potential energy reversible moist adiabatic process liquid water
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Meso-scale available gravitational potential in the world oceans 被引量:2
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作者 FENG Yang WANG Wei HUANG Ruixin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第5期1-13,共13页
The pitfalls of applying the commonly used definition of available gravitational potential energy (AGPE) to the world oceans are re-examined. It is proposed that such definition should apply to the meso-scale proble... The pitfalls of applying the commonly used definition of available gravitational potential energy (AGPE) to the world oceans are re-examined. It is proposed that such definition should apply to the meso-scale problems in the oceans, not the global scale. Based on WOA98 climatological data, the meso-scale AGPE in the world oceans is estimated. Unlike previous results by Oort et al. , the meso-scale AGPE is large wherever there is a strong horizontal density gradient. The distribution of meso-scale AGPE reveals the close connection between the baroclinic instability and the release of gravitational potential energy stored within the scale of Rossby deformation radius. 展开更多
关键词 energy of ocean circulation available potential gravitational energy MESO-SCALE baroclinic instability Rossby deformation radius
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Complete Destruction of Ag Br Emulsion Nuclei BY28Si Ions with 4.5 GeV/Nucleon Energy
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作者 A. Abd EL-Daiem 《Journal of Modern Physics》 2016年第12期1506-1511,共7页
The main experimental characteristics (multiplicity characteristics) of secondary particles have been investigated in interactions of <sup>28</sup>Si with emulsion at 4.5 GeV/c per nucleon at rest of emuls... The main experimental characteristics (multiplicity characteristics) of secondary particles have been investigated in interactions of <sup>28</sup>Si with emulsion at 4.5 GeV/c per nucleon at rest of emulsion, nuclei. The complete destruction of the heavy target nuclei (Ag, Br) has been studied. The average of shower particles is weakly dependent on the target mass whereas the average multiplicity of grey particles is strongly dependent on it. The correlations between the multiplicities of the charged secondaries at different mass number of the projectile and center-of-mass-available energy are investigated. 展开更多
关键词 Multiplicity Characteristics Probability and energy available
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The Diabatic Heating and the Generation of Available Potential Energy: Results from NCEP Reanalysis 被引量:2
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作者 张韬 吴国雄 郭裕福 《Acta meteorologica Sinica》 SCIE 2005年第2期143-159,共17页
In the existing studies on the atmospheric energy cycle, the attention to thegeneration of available potential energy (APE) is restricted to its global mean value. Thegeographical distributions of the generation of AP... In the existing studies on the atmospheric energy cycle, the attention to thegeneration of available potential energy (APE) is restricted to its global mean value. Thegeographical distributions of the generation of APE and its mechanism of formation are investigatedby using the three-dimensional NCEP/NCAR diabatic heating reanalysis in this study. The results showthat the contributions from sensible heating and net radiation to the generation of zonal andtime-mean APE (G_Z) are mainly located in high and middle latitudes with an opposite sign, while thelatent heating shows a dominant effect on G_Z mainly in the tropics and high latitudes where thecontributions from the middle and upper tropospheres are also contrary to that from the lowtroposphere. In high latitudes, the G_Z is much stronger for the Winter Hemisphere than for theSummer Hemisphere, and this is consistent with the asymmetrical feature shown by the reservoir ofzonal and time-mean APE in two hemispheres, which suggests that the generation of APE plays afundamental role in maintaining the APE in the global atmospheric energy cycle. The samecontributions to the generation of stationary eddy APE (G_(SE)) from the different regions relatedto the maintenance of longitudinal temperature contrast are likely arisen by different physics.Specifically, the positive contributions to G_(SE) from the latent heating in the western tropicalPacific and from the sensible heating over land are dominated by the heating at warm regions,whereas those from the latent heating in the eastern tropical Pacific and from the sensitive heatingover the oceans are dominated by the cooling at cold regions. Thus, our findings provide anobservational estimate of the generation of eddy APE to identify the regional contributions in theclimate simulations because it might be correct for the wrong reasons in the general circulationmodel (GCM). The largest positive contributions to the generation of transient eddy APE (G_(TE)) arefound to be at middle latitudes in the middle and upper tropospheres, where reside the strong localcontributions to the baroclinic conversion from transient eddy APE to transient eddy kinetic energyand the resulting transient eddy kinetic energy. 展开更多
关键词 diabatic heating zonal and time-mean stationary eddy transient eddy generation of available potential energy (APE)
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Precipitation efficiency and its relationship to physical factors 被引量:1
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作者 周玉淑 李小凡 高守亭 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第6期260-265,共6页
The precipitation efficiency and its relationship to physical factors are examined by analyzing a two-dimensional cloud-resolving model simulation during TOGA COARE in this study. The basic physical factors include co... The precipitation efficiency and its relationship to physical factors are examined by analyzing a two-dimensional cloud-resolving model simulation during TOGA COARE in this study. The basic physical factors include convective avail- able potential energy, water-vapor convergence, vertical wind shear, cloud ratio, sea surface temperature, air temperature, and precipitable water. Precipitation efficiencies do not show a close relationship to air temperature nor to sea surface tem- perature nor to precipitable water. The precipitation efficiency increases as the water-vapor convergence rate increases and vertical wind shear weakens, whereas it decreases as the convective available potential energy dissipates and anvil clouds develop. 展开更多
关键词 precipitation efficiency water-vapor convergence convective available potential energy cloud ratio
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Elevational diversity gradients across seed plant taxonomic levels in the Lancang River Nature Reserve: role of temperature, water and the mid-domain effect 被引量:1
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作者 Jie Gao Xing Zhang +2 位作者 Zhifeng Luo Junjie Lan Yanhong Liu 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第4期1110-1116,共7页
It remains unclear whether the elevational diversity gradients observed in seed plants across different taxonomic levels (family, genus, and species) are driven by the same macro-environmental variables. In this stu... It remains unclear whether the elevational diversity gradients observed in seed plants across different taxonomic levels (family, genus, and species) are driven by the same macro-environmental variables. In this study, seed plant elevational distribution data from the Lancang River Nature Reserve (Yunnan, China) were used to investigate spatial patterns in diversity and their environ- mental correlates, comparing across taxonomic levels. Environmental variables included energy availability, climate seasonality and environmental heterogeneity. All taxonomic levels (family, genus, and species) were found to have strong elevational richness gradients, with the strength of the gradient weakening at higher taxonomic levels. Spatial patterns in richness were explained by a combination of contemporary environmental variables and the mid-domain effect at all taxonomic levels. The independent effects of temperature- and precipitation-related variables were similar in explaining geographical patterns of family, genus and species richness. Energy, seasonality and heterogeneity variables influenced seed plant spatial richness at different taxonomic levels in similar ways. 展开更多
关键词 Elevational diversity gradients Lancang River Nature Reserve energy availability Climate seasonality Environmental heterogeneity
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The Effect of Surface Friction on the Development of Tropical Cyclones
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作者 方娟 汤剑平 伍荣生 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2009年第6期1146-1156,共11页
When tropical cyclones (hereafter referred as TCs) are over the ocean, surface friction plays a dual role in the development of TCs. Prom the viewpoint of water vapor supply, frictional convergence and Ekman pumping... When tropical cyclones (hereafter referred as TCs) are over the ocean, surface friction plays a dual role in the development of TCs. Prom the viewpoint of water vapor supply, frictional convergence and Ekman pumping provide a source of moisture for organized cumulus convection and is propitious to the spin-up of TCs. On the other hand, surface friction leads to a dissipation of kinetic energy that impedes the intensification of TCs. Which role is dominant in the developing stage of TCs is a controversial issue. In the present work, the influence of surface friction on the growth of TCs is re-examined in detail by conducting two sets of numerical experiments initialized with different cyclonic disturbances. Results indicate that, because of the inherent complexities of TCs, the impact of surface friction on the evolution of TCs can not be simply boiled down to being positive or negative. In the case that a TC starts from a low-level vortex with a warm core, surface friction and the resultant vertical motion makes an important contribution to the convection in the early developing stage of the TC by accelerating the build-up of convective available potential energy (CAPE) and ensuring moisture supply and the lifting of air parcels. This effect is so prominent that it dominates the friction-induced dissipation and makes surface friction a facilitative factor in the spin-up of the TC. However, for a TC formed from a mesoscale convective vortex (MCV) spawned in a long-lasting mesoscale convective system (MCS), the initial fields, and especially the low-level humidity and cold core, enable the prerequisites of convection (i.e., conditional instability, moisture, and lifting), to be easily achieved even without the help of boundary-layer pumping induced by surface friction. Accordingly, the reliance of the development of TCs on surface friction is not as heavy as that derived from a lowlevel vortex. The positive effect of surface friction on the development of TCs realized through facilitating favorable conditions for convection is nearly cancelled out by the friction-induced dissipation. However, as SST is enhanced in the latter case, the situation may be changed, and different development speeds may emerge between model TCs with and without surface friction considered. In short, owing to the fact that TC development is a complicated process affected by many factors such as initial perturbations, SST, etc., the importance of surface friction to the intensification of TCs may vary enormously from case to case. 展开更多
关键词 surface friction tropical cyclone boundary-layer pumping convective available potential energy
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Construction of the Forecast System of Classified Severe Convection Weather in Qinghai Province Based on Ingredients-based Method
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作者 Qin GUAN Xinfu YAO +3 位作者 Qingping LI Jinhai LI Yao HU Bianbian ZHANG 《Meteorological and Environmental Research》 CAS 2022年第5期47-55,共9页
Based on the data of the cases of severe convection weather such as hail,thunderstorm(thunderstorm gale)and short-time heavy precipitation in recent 10 years,the spatial and temporal distribution characteristics of di... Based on the data of the cases of severe convection weather such as hail,thunderstorm(thunderstorm gale)and short-time heavy precipitation in recent 10 years,the spatial and temporal distribution characteristics of different types of severe convection weather were analyzed.The results show that the frequency of severe convection weather tended to increase,of which short-time heavy precipitation and thunderstorm weather rose,and hail and thunderstorm gale weather decreased.Severe convection weather began to extend in late spring and early autumn.Typical cases were selected to analyze the evolution mechanism,and the conceptual models of severe convective weather caused by cold advection forcing,warm advection forcing and baroclinic frontogenesis were obtained.The key predictors for the potential prediction of severe convection weather were proposed,such as CAPE(convective available potential energy)for hail weather,UH index(maximum ascending helicity)for thunderstorm gale and PWV(precipitable water vapor)for short-time heavy precipitation.ERA5 data were used to get the forecast threshold of the key factor of classified severe convection weather,and it was verified that the threshold was available.Meanwhile,the causes of the error of failure cases were analyzed.For instance,the larger deviation of CAPE was caused by the 2 m deviation of temperature.Supplementary correction method and threshold were given to provide a reference for the objective forecast and early warning of severe convection weather. 展开更多
关键词 Classified strong convection Convective available potential energy Rising helicity Atmospheric precipitable water THRESHOLD
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Effects of the Soil Heat Flux Estimates on Surface Energy Balance Closure over a Semi-Arid Grassland 被引量:6
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作者 岳平 张强 +2 位作者 牛生杰 成华 王西育 《Acta meteorologica Sinica》 SCIE 2011年第6期774-782,共9页
Soil heat flux is important for surface energy balance (SEB), and inaccurate estimation of soil heat flux often leads to surface energy imbalance. In this paper, by using observations of surface radiation fluxes and... Soil heat flux is important for surface energy balance (SEB), and inaccurate estimation of soil heat flux often leads to surface energy imbalance. In this paper, by using observations of surface radiation fluxes and soil temperature gradients at a semi-arid grassland in Xilingguole, Inner Mongolia, China from June to September 2008, the characters of the SEB for the semi-arid grassland were analyzed. Firstly, monthly averaged diurnal variations of SEB components were revealed. A 30-min forward phase displacement of soil heat flux (G) observed by a fluxplate at the depth of 5-em below the soil surface was conducted and its effect on the SEB was studied. Secondly, the surface soil heat flux (Gs) was computed by using harmonic analysis and the effect of the soil heat storage between the surface and the fluxplate on the SEB was examined. The results show that with the 30-min forward phase displacement of observed G, the slope of the ordinary linear regression (OLR) of turbulent fluxes (H+LE) against available energy (Rn G) increased from 0.835 to 0.842, i.e., the closure ratio of SEB increased by 0.7%, yet energy imclosure of 15.8% still existed in the SEB. When Gs, instead of G was used in the SEB equation, the slope of corresponding OLR of (H+LE) against (Rn-Gs) reached 0.979, thereby the imelosure ratio of SEB was reduced to only 2.1%. 展开更多
关键词 soil heat flux surface energy balance harmonic analysis turbulent fluxes available energy
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Energy Budgets on the Interactions between the Mean and Eddy Flows during a Persistent Heavy Rainfall Event over the Yangtze River Valley in Summer 2010 被引量:10
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作者 傅慎明 汪汇洁 +1 位作者 孙建华 张元春 《Journal of Meteorological Research》 SCIE CSCD 2016年第4期513-527,共15页
In this study,a persistent heavy rainfall event(PHRE) that lasted for around 9 days(from 0000 UTC 17 to0000 UTC 26 June 2010) and caused accumulated precipitation above 600 mm over the Yangtze River valley,was rea... In this study,a persistent heavy rainfall event(PHRE) that lasted for around 9 days(from 0000 UTC 17 to0000 UTC 26 June 2010) and caused accumulated precipitation above 600 mm over the Yangtze River valley,was reasonably reproduced by the advanced research WRF model.Based on the simulation,a set of energy budget equations that divided the real meteorological field into the mean and eddy flows were calculated so as to understand the interactions between the precipitation-related eddy flows and their background circulations(BCs).The results indicated that the precipitation-related eddy flows interacted with their BCs intensely during the PHRE.At different layers,the energy cycles showed distinct characteristics.In the upper troposphere,downscaled energy cascade processes appeared,which favored the maintenance of upper-level eddy flows;whereas,a baroclinic energy conversion,which reduced the upper-level jet,also occurred.In the middle troposphere,significant upscaled energy cascade processes,which reflect the eddy flows' reactionary effects on their BCs,appeared.These effects cannot be ignored with respect to the BCs' evolution,and the reactionary effects were stronger in the dynamical field than in the thermodynamical field.In the lower troposphere,a long-lived quasi-stationary lower-level shear line was the direct trigger for the PHRE.The corresponding eddy flows were sustained mainly through the baroclinic energy conversion associated with convection activities.Alongside this,the downscaled energy cascade processes of kinetic energy,which reflect the direct influences of BCs on the precipitation-related eddy flows,were also favorable.A downscaled energy cascade of exergy also appeared in the lower troposphere,which favored the precipitation-related eddy flow indirectly via the baroclinic energy conversion. 展开更多
关键词 persistent heavy rainfall kinetic energy available potential energy scale interaction Yangtze and Huaihe River valley
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Relationships Between Estimated Hourly Energy Balance and Body Composition in Professional Cheerleaders
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作者 Moriah P.Bellissimo Ashley D.Licata +2 位作者 Anita Nucci Walter Thompson Dan Benardot 《Journal of Science in Sport and Exercise》 2019年第1期69-77,共9页
Purpose We sought to describe and examine the interrelationships between energy intake,body composition,and estimated energy balance.Methods Using self-reported hourly food intake and formula-based energy expenditure(... Purpose We sought to describe and examine the interrelationships between energy intake,body composition,and estimated energy balance.Methods Using self-reported hourly food intake and formula-based energy expenditure(EE)protocols,19 female profes-sional cheerleaders(mean age 25.4 years)were assessed to obtain energy balance(EB)for a typical training day.Energy intake(EI)was predicted using the USDA Food Composition Database SR27,and EE was predicted using the Harris-Benedict equation plus a MET-based relative intensity activity scale.Body composition was predicted using a multi-current,8-mode segmental bioelectrical impedance analysis system.Hourly and daily EB was calculated from EI and EE data.Results Subjects reported a 24 h EI significantly below(P<0.001)the unadjusted predicted energy requirement(1482 kcal vs.2199 kcal,respectively),resulting in an average negative net EB of−720 kcal.Carbohydrate intake was significantly below the minimum recommended level(3.1 g/kg vs.6 g/kg,P<0.001)while protein and fat intakes met the recommended levels.Higher fat intake(g/kg)was significantly associated with a higher EI kcal/kg(r=0.726;P<0.001),which was sig-nificantly associated(r=−0.55;P=0.01)with a lower body fat percent(BF%).Using the median of BF%(20.9)as the cut point,participants with fewer hours in a negative EB had lower BF%(P=0.043)and those with lower BF%spent more time in an EB of±300 kcal(P=0.013).Conclusions These athletes reported low energy intakes that resulted in large EB deficits and/or more hours in a negative EB,which could be counterproductive for achieving a lean body composition overtime. 展开更多
关键词 ATHLETE energy availability energy deficit RED-S Restrictive diet NUTRITION
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Environmental Influences on the Intensity Change of Tropical Cyclones in the Western North Pacific 被引量:7
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作者 储惠芸 伍荣生 《Acta meteorologica Sinica》 SCIE 2013年第3期335-343,共9页
The atmospheric and oceanic conditions are examined during different stages of the lifecycle of western North Pacific tropical cyclones (TCs), with the intention to understand how the environment affects the intensi... The atmospheric and oceanic conditions are examined during different stages of the lifecycle of western North Pacific tropical cyclones (TCs), with the intention to understand how the environment affects the intensity change of TCs in this area. It is found that the intensification usually occurs when the underlying sea surface temperature (SST) is higher than 26℃. TCs usually experience a rapid intensification when the SST is higher than 27.5℃ while lower than 29.5℃. However, TCs decay or only maintain its intensity when the SST is lower than 26℃. The intensifying TCs usually experience a low-to-moderate vertical wind shear (2-10 m s-l). The larger the vertical wind shear, the slower the TCs strengthen. In addition, the convective available potential energy (CAPE) is much smaller in the developing stage than in the formation stage of TCs. For the rapidly intensifying TCs, the changes of SST, CAPE, and vertical wind shear are usually small, indicating that the rapid intensification of TCs occurs when the evolution of the environment is relatively slow. 展开更多
关键词 tropical cyclone sea surface temperature convective available potential energy vertical windshear
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Cold Air Activities in July 2004 and Its Impact on Intense Rainfalls over Southwest China 被引量:1
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作者 陈艳 丁一汇 《Acta meteorologica Sinica》 SCIE 2007年第3期302-319,共18页
The severe rainfall events in the mid-summer of July 2004 and the roles of cold air in the formation of heavy precipitation are investigated by using daily observational precipitation data of China and NCEP/NCAR reana... The severe rainfall events in the mid-summer of July 2004 and the roles of cold air in the formation of heavy precipitation are investigated by using daily observational precipitation data of China and NCEP/NCAR reanalysis. The results show that the severe rainfalls in Southwest China are closely related to the cold air activities from the mid-high latitudes, and the events take place under the cooperative effects of mid-high latitude circulation and low latitude synoptic regimes. It is the merging of a cold vortex over mid-latitudes with the northward landing typhoon and eastward Southwest China Vortex, as well as the abrupt transformation from a transversal trough into an upright one that causes three large alterations of mid-high atmospheric circulation respectively in the early and middle ten days of this month. Then, the amplitude of long waves soon magnifies, leading to the unusual intrusion of cold air to low-latitude areas in the mid-summer. Meanwhile, the warm and humid southwest summer monsoon is quite active. The strong interactions of cold air and summer monsoon over Southwest China result in the large-scale convective rainfalls on the southern side of cold air. With regard to the activities of cold air, it can influence rainfalls in three prominent ways. Firstly, the incursion of upper-level cold air is often accompanied by partial southerly upper-level jet. The ascending branch of the corresponding secondary circulation, which is on the left front side of the jet center, provides the favorite dynamic upward motion for the rainfalls. Secondly, the southward movement of cold air contributes to the establishment of atmospheric baroclinic structure, which would lead to baroclinic disturbances. The atmospheric disturbances associated with the intrusion of cold air can destroy the potential instability stratification, release the convective available potential energy (CAPE) and finally cause convective activities. In addition, the advection processes of dry and cold air at the upper level along with the advection of humid and warm air at the lower level are rather significant for the reestablishment of potential instability in the precipitation area, which is one of the crucial factors contributing to persistent rainfalls. 展开更多
关键词 cold air Southwest China strong rainfall CAPE (convective available potential energy
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Sensitivity of Lake-Effect Convection to the Lake Surface Temperature over Poyang Lake in China
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作者 Haibo ZOU Shanshan WU Jiusheng SHAN 《Journal of Meteorological Research》 SCIE CSCD 2022年第2期342-359,共18页
In this study, high-resolution weather research and forecasting(WRF) simulations are used to explore the sensitivity of lake-effect convection over Poyang Lake(PL) to the change of lake surface temperature(LST). A con... In this study, high-resolution weather research and forecasting(WRF) simulations are used to explore the sensitivity of lake-effect convection over Poyang Lake(PL) to the change of lake surface temperature(LST). A control experiment(CTR) with climate mean LST(303 K) is compared with six sensitivity experiments(CTR-1/2/3K and CTR+1/2/3K) in which the LSTs are set based on the mean LST difference of 6 K between the maximum and minimum. The results show that the CTR experiment reasonably reproduces the lake-effect convection, and the lake-effect convection in sensitivity experiments is significantly influenced by the LST. With the increase of LST, the initiation time of the lake-effect convection is advanced gradually, while the initiation location moves PL from its shore.The lake-effect convection strengthens(weakens) in the increase-temperature CTR+1/2/3K(decrease-temperature CTR-1/2/3K) experiments, but the lake-effect convection does not monotonically strengthen with the LST, for the strongest one occurring in the CTR+1K experiment. The corresponding diagnostic analysis shows that the upward sensible heat flux and latent heat flux over PL increase with the LST, resulting in the enhancement of the lake-land breeze and the enlargement of the convective available potential energy(CAPE). This is the main reason for the changes in the initiation time and location, as well as the intensity of lake-effect convection in different experiments.In addition, the non-monotonous variation of the level of free convection, which is mainly induced by the non-monotonous variation of the lifting condensation level, is responsible for the non-monotonous variation of the lake-effect convection intensity with the LST. 展开更多
关键词 Poyang Lake lake-effect convection lake breeze convective available potential energy(CAPE) level of free convection(LFC)
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