基于中医传承辅助平台探讨禽流感中医兽药规律研究

该文通过中医传承辅助平台挖掘现代文献,探究禽流感中医兽药的处方用药规律,为禽流感中兽药开发提供参考。以“中兽药”“鸡”“禽流感”等为检索词来检索中国期刊全文数据库、万方数据库、维普中文科技期刊全文数据库,检索时间区间为建库至2022年10月。应用EndNote X9进行文献筛选合并,建立治疗禽流感的中医兽药数据库,采用频数分析、聚类分析、关联规则分析等技术研究用药规律。结果表明:248篇文献359味中药中,频次排前10的为金银花、黄芪、甘草、板蓝根、连翘、黄芩、大青叶、鱼腥草、柴胡和黄连;四气出现频次由高到低排序为寒、温、平、凉、热;五味为苦味、甘味、辛味、酸味、咸味;归经为肺、胃、心、脾和肝;功效统计归类前五位为清热药、补虚药、解表药、化痰止咳平喘药以及利水渗湿药。关联分析中发现,金银花-板蓝根二组合药物出现频次最高,但置信度最高为板蓝根-连翘-金银花三组合药物。聚类分析中,发现三组合中黄芪、金银花、甘草、鱼腥草、板蓝根组合出现频次最高,为133次。可见,中药治疗禽流感类疾病具有一定的规律,其治疗以清热类为主,以“板蓝根-连翘-金银花”为核心药组,佐以补虚类、解表类等,可为治疗禽流感中兽药新药开发提供参考。

Analysis of the Winter Cloud-to-Ground Lightning Activity and Its Synoptic Background in China during 2010-20

Cloud-to-ground(CG)lightning data and the ECMWF ERA-Interim reanalysis dataset are analyzed to gain insight into the spatiotemporal distribution and synoptic background of winter-season CG flashes between December 2010 and February 2020 in China.We identify three Winter Lightning Frequent Areas(WLAs):the southwest side of the Yunnan-Guizhou Plateau(WLA1),the east side of the Yunnan-Guizhou Plateau(WLA2),and the Poyang Lake Plain(WLA3).The CG lightning flashes most frequently occur at local midnight and have a monthly peak in February.The CG lightning in WLA1 is mostly generated in non-frontal weather;however,the lightning in WLA2 and WLA3 mostly occurs in frontal systems.The frontal circulation situation is divided into four typical types:transversal trough after high pressure,low vortex,confrontational convergence,and asymptotic convergence.In all typical weather patterns,the lightning occurs downstream of a 500 hPa trough and is accompanied by a southwesterly low-level jet.The convective parameters of winter thunderstorms differ greatly from those of summer thunderstorms.The maximum convective available potential energy(MCAPE)and K-index(KI)are more useful metrics than convective available potential energy(CAPE)and Showalter index(SI)during winter.This study further deepens the understanding of the distribution characteristics of winter CG lightning in China,which motivates further research to improve the ability of winter thunderstorm prediction.

Asymmetric Distribution of Convection in Tropical Cyclones over the Western North Pacific Ocean

Forecasts of the intensity and quantitative precipitation of tropical cyclones（TCs） are generally inaccurate, because the strength and structure of a TC show a complicated spatiotemporal pattern and are affected by various factors. Among these, asymmetric convection plays an important role. This study investigates the asymmetric distribution of convection in TCs over the western North Pacific during the period 2005–2012, based on data obtained from the Feng Yun 2（FY2）geostationary satellite. The asymmetric distributions of the incidence, intensity and morphology of convections are analyzed.Results show that the PDFs of the convection occurrence curve to the azimuth are sinusoidal. The rear-left quadrant relative to TC motion shows the highest occurrence rate of convection, while the front-right quadrant has the lowest. In terms of intensity, weak convections are favored in the front-left of a TC at large distances, whereas strong convections are more likely to appear to the rear-right of a TC within a 300 km range. More than 70% of all MCSs examined here are elongated systems, and meso-β enlongated convective systems（MβECSs） are the most dominant type observed in the outer region of a TC. Smaller MCSs tend to be more concentrated near the center of a TC. While semi-circular MCSs [MβCCSs, MCCs（mesoscale convective complexes）] show a high incidence rate to the rear of a TC, elongated MCSs [MβECSs, PECSs（persistent elongated convective systems）] are more likely to appear in the rear-right quadrant of a TC within a range of 400 km.

Estimating the Correlated Observation-Error Characteristics of the Chinese FengYun Microwave Temperature Sounder and Microwave Humidity Sounder

In operational data assimilation systems, observation-error covariance matrices are commonly assumed to be diagonal.However, inter-channel and spatial observation-error correlations are inevitable for satellite radiances. The observation errors of the Microwave Temperature Sounder(MWTS) and Microwave Humidity Sounder(MWHS) onboard the FengYun-3A(FY-3A) and FY-3B satellites are empirically assigned and considered to be uncorrelated when they are assimilated into the WRF model's Community Variational Data Assimilation System(WRFDA). To assimilate MWTS and MWHS measurements optimally, a good characterization of their observation errors is necessary. In this study, background and analysis residuals were used to diagnose the correlated observation-error characteristics of the MWTS and MWHS. It was found that the error standard deviations of the MWTS and MWHS were less than the values used in the WRFDA. MWTS had small inter-channel errors, while MWHS had significant inter-channel errors. The horizontal correlation length scales of MWTS and MWHS were about 120 and 60 km, respectively. A comparison between the diagnosis for instruments onboard the two satellites showed that the observation-error characteristics of the MWTS or MWHS were different when they were onboard different satellites. In addition, it was found that the error statistics were dependent on latitude and scan positions.The forecast experiments showed that using a modified thinning scheme based on diagnosed statistics can improve forecast accuracy.

Evaluation of lightning-induced overvoltage on a 10 kV distribution line based on electromagnetic return-stroke model using finite-difference time-domain

Accurate simulation of lightning-induced overvoltage for overhead distribution lines is helpful to prevent lightning trip accidents.An electromagnetic return-stroke model was used to represent lightning and then a 3D finite-difference time-domain(FDTD)method was adopted to simulate the lightning-induced overvoltage on a distribution line without a field-line coupling model.How lightning-induced overvoltage behave for different ground conductivity and varying distance between the distribution line and the lightning channel was analysed.The results showed that the overvoltage waveforms at the centre point of the line corresponding to lightning strikes on the lossy ground and an ideal ground(σ=∞)were similar;however,the peak amplitudes of the waveform were affected by soil conductivity at a close distance.The relationship between magnitude of the overvoltage and distance can be described by a second-order exponential decay equation.Finally,the overvoltage calculated using the proposed model was compared with those obtained based on Agrawal's model and measurements made using the newly developed intelligent insulator on site.From these comparisons,it could be concluded that the FDTD method with the electromagnetic return-stroke model produces reasonably accurate results of the attenuated oscillation waveform,which can better reproduce the overvoltage on operational distribution lines.

Maintenance and Sudden Change of a Strong Elevated Ducting Event Associated with High Pressure and Marine Low-Level Jet

Capture of a strong elevated ducting event,especially its maintenance and sudden change,is of great value to airborne radar to achieve its beyond-the-line-of-sight detection.However,the knowledge is not easily accessible over the open ocean and hence very rare.During the Air–Sea Interaction Survey(ASIS)over the western North Pacific(WNP)in May 2016,a strong elevated ducting event with a long-life period and sudden change in its evolution was observed.Measurements from the ASIS,images from the Himawari-8 satellite,reanalysis data from the ECMWF,and Weather Research and Forecasting(WRF)model,were used to analyze the maintenance and sudden change of this strong ducting event,together with the model performance on simulating it.The results showed that the maintenance of strong elevated ducts,with their tops ranging from 750 to 1050 m and average strength of approximately 38 M units,was caused by a strong dry air mass capping over the wet marine atmospheric boundary layer(MABL),together with the subsidence inversion associated with high pressure.The WRF model performs well in simulating them.However,a sudden increase in duct height with a slight decrease of strength was recorded by the subsequent GPS radiosonde,which was finally contributed to the mechanical turbulent inversion and hydrolapse associated with the marine low-level jet(MLLJ).The height of the maximum horizontal wind speed(Umh)of the MLLJ corresponds well with the bottom of the trapping layer.However,these jet-relevant ducts are generally weak and it is difficult to accurately simulate them by using the mesoscale numerical model,since the wind-shear produced eddies are too small to be properly parameterized.

Future Changes in the Impact of North Pacific Midlatitude Oceanic Frontal Intensity on the Wintertime Storm Track in CMIP5 Models

The storm track and oceanic front play an important role in the midlatitude air–sea interaction.In this study,future changes in the impact of the North Pacific midlatitude oceanic frontal intensity on the wintertime storm track are projected based on climate model outputs from the Coupled Model Intercomparison Project Phase 5(CMIP5).The performance of 13 CMIP5 models is evaluated,and it is found that a majority of these models are capable of reproducing the northward intensification of the storm track in response to the strengthened oceanic front.The ensemble means of outputs from six best models under three Representative Concentration Pathway(RCP)scenarios(RCP2.6,RCP4.5,and RCP8.5)are compared with the results of the historical simulation,and future changes are projected.It is found that the impact of the oceanic frontal intensity on the storm track tends to get stronger and extends further westward in a warming climate,and the largest increase appears in the RCP8.5 run.Further analysis reveals that the stronger impact of the oceanic front on the storm track in the future may be partially attributed to the greater oceanic frontal impact on the near-surface baroclinicity,which is mainly related to the intensified oceanic frontal impact on the meridional potential temperature gradient under the climate change scenario.However,this process can hardly explain the increasing impact of the oceanic front on the upstream of the storm track.

Direct/indirect effects of aerosols and their separate contributions to Typhoon Lupit(2009):Eyewall versus peripheral rainbands

As a typhoon approaches the continent,the position where anthropogenic aerosols penetrate,the convection competition between the eyewall and peripheral rainbands,and the separate contributions of direct aerosol-radiation interactions(ARI)and indirect aerosol-cloud interactions(ACI),yield uncertainties in the convection intensification area and hence the typhoon intensity.Typhoon Lupit(2009)was simulated using the Weather Research and Forecasting Model with Chemistry(WRF-Chem)to investigate and isolate the direct and indirect effects of aerosols on the intensity,convection,and precipitation of the typhoon.Three simulations(CTL,CLEAN,and CTLARIOFF)were designed,representing a polluted case(CTL,considering the ingestion of anthropogenic aerosols with ARI and ACI),a clean maritime case(CLEAN,mainly with sea salt aerosols),and a polluted case without aerosol radiative forcing(CTLARIOFF,as per CTL but without ARI).The results showed that anthropogenic aerosols could penetrate into both the peripheral rainbands and the eyewall when the typhoon was approaching the Asian continent.Owing to the representation of the real aerosol scenario,the simulated typhoon intensity weakened and was closer to observed values in the CTL experiment.The ARI dominated over ACI with the opposite effects.Specifically,the ACI mainly enhanced the formation of ice-phase hydrometeors within the upper level of the eyewall with more freezing latent heat releases,leading to an invigoration of eyewall convection.These excess ice-phase particles melted after they descended into the warm layer below the 0°C level,which accelerated the accretion of cloud droplets by raindrops(Pcacr)and hence the mixed phase precipitation process in the eyewall.The dynamic feedback induced by the ACI enhanced the boundary layer inflow and the upper layer outflow,supporting the maintenance of strong eyewall convection and intensification of the typhoon.Inversely,the ARI heated the distant periphery low-level atmosphere at an altitude of 1-2 km by the absorbing polluted aerosols.The heated air,driven by the radial inflow,firstly went through the periphery rainbands of the typhoon and invigorated convection there due to the low-level warming.Then,the enhanced periphery convection inhibited the further transport of warm moist air into the eyewall,resulting in weakening of the eyewall convection and hence typhoon intensity.In sum,for the polluted scenario,as the typhoon approached the continent,ARI played a dominant role over ACI.The WRF-Chem model with full consideration of aerosol-cloud-radiation interactions is advantageous in terms of reliably simulating typhoon intensity and precipitation distribution.

Mature typhoon “cloud gyro” model and numerical simulation study

Due to the coarse temporal resolution of the best track databases for typhoons,some small-scale characteristics of typhoon motion have been neglected.In order to reveal the fine features of typhoon motion,the dense cloud within the radius of maximum wind(RMW)of mature typhoons,defined as a“cloud gyro”that simultaneously spins around its own rotational axis and precesses around the vertical axis,is approximated to a rigid body.Based on the principles of gyrodynamics,the derived mathematical model of a typhoon track indicates that typhoon movement is composed of translational motion governed by the steering flow and superimposed precessional motion that manifests as the inherent characteristics of typhoon tracks,especially with the external torque.High temporal resolution numerical simulation of a real case verifies the conclusion of this study,which is that the smaller the RMW,the larger the tangential wind speed or the larger the external torque,and the more obviously precessional motion manifests.

Enhancing Tropical Cyclone Intensity Estimation from Satellite Imagery through Deep Learning Techniques

This study first utilizes four well-performing pre-trained convolutional neural networks(CNNs) to gauge the intensity of tropical cyclones(TCs) using geostationary satellite infrared(IR) imagery.The models are trained and tested on TC cases spanning from 2004 to 2022 over the western North Pacific Ocean.To enhance the models performance,various techniques are employed,including fine-tuning the original CNN models,introducing rotation augmentation to the initial dataset,temporal enhancement via sequential imagery,integrating auxiliary physical information,and adjusting hyperparameters.An optimized CNN model,i.e.,visual geometry group network(VGGNet),for TC intensity estimation is ultimately obtained.When applied to the test data,the model achieves a relatively low mean absolute error(MAE) of 4.05 m s~(-1).To improve the interpretability of the model,the SmoothGrad combined with the Integrated Gradients approach is employed.The analyses reveal that the VGGNet model places significant emphasis on the distinct inner core region of a TC when estimating its intensity.Additionally,it partly takes into account the configuration of cloud systems as input features for the model,aligning well with meteorological principles.The several improvements made to this model's performance offer valuable insights for enhancing TC intensity forecasts through deep learning.