|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Short-Term Dynamic Radar Quantitative Precipitation Estimation Based on Wavelet Transform and Support Vector Machine显示文摘Currently,Doppler weather radar in China is generally used for quantitative precipitation estimation(QPE)based on the Z–R relationship.However,the estimation error for mixed precipitation is very large.In order to improve the accuracy of radar QPE,we propose a dynamic radar QPE algorithm with a 6-min interval that uses the reflectivity data of Doppler radar Z9002 in the Shanghai Qingpu District and the precipitation data at automatic weather stations(AWSs)in East China.Considering the time dependence and abrupt changes of precipitation,the data during the previous 30-min period were selected as the training data.To reduce the complexity of radar QPE,we transformed the weather data into the wavelet domain by means of the stationary wavelet transform(SWT)in order to extract high and low-frequency reflectivity and precipitation information.Using the wavelet coefficients,we constructed a support vector machine(SVM)at all scales to estimate the wavelet coefficient of precipitation.Ultimately,via inverse wavelet transformation,we obtained the estimated rainfall.By comparing the results of the proposed method(SWTSVM)with those of Z=300×R1.4,linear regression(LR),and SVM,we determined that the root mean square error(RMSE)of the SWT-SVM method was 0.54 mm per 6 min and the average Threat Score(TS)could exceed 40%with the exception of the downpour category,thus remaining at a high level.Generally speaking,the SWT-SVM method can effectively improve the accuracy of radar QPE and provide an auxiliary reference for actual meteorological operational forecasting. | Changjiang ZHANG Huiyuan WANG Jing ZENG Leiming MA Li GUAN | 2020 | Journal of Meteorological Research2020，34，2： | 4 |
| 2 | Impacts of TRMM SRR assimilation on the numerical prediction of tropical cyclone显示文摘Impacts of the four-dimensional variation (4DVAR) assimilation of Tropical Rainfall Measuring Mission (TRMM)/TMI surface rainfall rate (SRR) on the initialization and simulation of TC Danas in 2001 are studied. A number of sensitivity experiments are designed to evaluate the performance of assimilation during the particular stage when Danas developed from a tropical depression towards a typhoon, as well as an abrupt turning. Under the dynamic and thermodynamic constraints of meso-scale model and the 4DVAR, the TRMM SRR data are directly assimilated in high horizontal resolution (18 km). On the basis of the adjustment of initial model field, 4DVAR of TRMM SRR considerably improved the depiction of TC’s structure and rainfall. The same explanation can also be given to the enhancement of simulation on TC’s intensity and track. In comparison with the popular idea of twice steps of SRR assimilation, namely, 4DVAR plus 1DVAR, the retrieval error is expected to be avoided in the procedure of direct 4DVAR. In addition, the TRMM SRR 4DVAR within a high-resolution model can take into account as much information as observed and is expected to be performed in operational use if the observed rainfall data are routinely available. | MA Leiming QIN Zenghao DUAN Yihong LIANG Xudong WANG Dongliang | 2006 | Acta Oceanologica Sinica2006，25，5： | 3 |
| 3 | All-optical logic devices based on black arsenic-phosphorus with strong nonlinear optical response and high stability显示文摘The Kerr nonlinearity in two-dimensional(2D)nanomaterials is emerging as an appealing and intriguing research area due to their prominent light processing,modulation,and manipulation abilities.In this contribution,2D black arsenic-phosphorus(B-AsP)nanosheets(NSs)were applied in nonlinear photonic devices based on spatial self-phase modula-tion(SSPM)method.By applying the Kerr nonlinearity in 2D B-AsP,an all-optical phase-modulated system is proposed to realize the functions of“on”and“off”in all-optical switching.By using the same all-optical phase-modulated system,another optical logic gate is proposed,and the logical“or”function is obtained based on the 2D B-AsP NSs dispersions.Moreover,by using the SSPM method,a 2D B-AsP/SnS_(2) hybrid structure is fabricated,and the result illustrates that the hybrid structure possesses the ability of the unidirectional nonlinear excitation,which helps in obtaining the function of spatial asymmetric light propagation.This function is considered an important prerequisite for the realization of diode functionalization,which is believed to be a factor in important basis for the design of isolators as well.The initial investig-ations indicate that 2D B-AsP is applicable for designing optical logical devices,which can be considered as an import-ant development in all-optical information processing. | Leiming Wu Taojian Fan Songrui Wei Yijun Xu Ye Zhang Dingtao Ma Yiqing Shu Yuanjiang Xiang Jun Liu Jianqing Li Krassimir Panajotov Yuwen Qin Han Zhang | 2022 | Opto-Electronic Advances2022，5，1： | 3 |
| 4 | Intelligent fractional-order integral sliding mode control for PMSM based on an improved cascade observer显示文摘In this paper,an intelligent fractional-order integral sliding mode control(FOISMC)strategy based on an improved cascade observer is proposed.First,an FOISMC strategy is designed to control a permanent magnet synchronous motor.It has good tracking performance,is strongly robust,and can effectively reduce chattering.The proposed FOISMC strategy associates strong points of the integral action(which can eliminate steady-state tracking errors)and the fractional calculus(which is flexible).Second,an improved cascade observer is proposed to detect the rotor information with a smaller observation error.The proposed observer combines an adaptive sliding mode observer and an extended high-gain observer.In addition,an improved variable-speed grey wolf optimization algorithm is designed to enhance controller parameters.The effectiveness of the strategy is tested using simulations and an experiment involving model uncertainty and external disturbance. | Lingfei XIAO Leiming MA Xinhao HUANG | 2022 | Frontiers of Information Technology & Electronic Engineering2022，23，2： | 3 |
| 5 | Improving the Extreme Rainfall Forecast of Typhoon Morakot(2009) by Assimilating Radar Data from Taiwan Island and China's Mainland显示文摘This study examined the impact of an improved initial field through assimilating ground-based radar data from China's Mainland and Taiwan Island to simulate the long-lasting and extreme rainfall caused by Morakot(2009). The vortex location and the subsequent track analyzed through the radial velocity data assimilation(VDA) are generally consistent with the best track. The initial humidity within the radar detecting region and Morakot's northward translation speed can be significantly improved by the radar reflectivity data assimilation(ZDA). As a result, the heavy rainfall on both sides of Taiwan Strait can be reproduced with the joint application of VDA and ZDA. Based on sensitivity experiments, it was found that, without ZDA, the simulated storm underwent an unrealistic inward contraction after 12-h integration, due to underestimation of humidity in the global reanalysis, leading to underestimation of rainfall amount and coverage. Without the vortex relocation via VDA, the moister(drier) initial field with(without) ZDA will produce a more southward(northward) track, so that the rainfall location on both sides of Taiwan Strait will be affected. It was further found that the improvement in the humidity field of Morakot is mainly due to assimilation of high-value reflectivity(strong convection) observed by the radars in Taiwan Island, especially at Kenting station. By analysis of parcel trajectories and calculation of water vapor flux divergence, it was also found that the improved typhoon circulation through assimilating radar data can draw more water vapor from the environment during the subsequent simulation, eventually contributing to the extreme rainfall on both sides of Taiwan Strait. | Xuwei BAO Dan WU Xiaotu LEI Leiming MA Dongliang WANG Kun ZHAO Ben Jong-Dao JOU | 2017 | Journal of Meteorological Research2017，31，4： | 3 |
| 6 | Improving the behavior of the cumulus parameterization for tropical cyclone prediction : Convection trigger显示文摘 | Ma Leiming Tan Z- M | 2009 | Atmos Res2009，92，： | 1 |
| 7 | Heme oxygenase-1 is induced by thyroid hormone and involved in thyroid hormone preconditioning-induced protection against renal warm ischemia in rat显示文摘 | Fei Li Shuyan Lu Ruixia Zhu Zhongxin Zhou Lingdi Ma Leiming Cai Zhiyuan Liu | 2011 | Molecular and Cellular Endocrinology2011，，1： | 1 |
| 8 | Improving the behavior of the cu- mulus parameterization for tropical cyclone prediction Convec tion trigger 显示文摘 | Ma Leiming Tan Zhemin | 2009 | Atmos Res2009，92，： | 1 |
| 9 | Purification of four strains of endophytic fungi from Astragalus and their optimized liquid fermentations显示文摘This study was designed to isolate endophytic fungi from A. mongholicus(growing in northeast China) to determine whether they can produce bioactive metabolites. Four strains of endophytic fungi(strains 16, 17, 23 and 75) were successfully isolated from A. mongholicus using the surface disinfection method. According to ITS-rDNA sequences analysis, strains 16 and 75 were identified as Fusarium oxysporum, and strains 17 and 23 were identified as Bionectria ochroleuca. We applied the Box-Behnken design(BBD) to optimize the liquid fermentation conditions and obtain the maximum cell dry weight(CDW) yield. Optimal parameters were obtained under the following experimental conditions: temperature of 28°C, potato dextrose agar(PDA) liquid medium of 80 mL and rotation speed of 150 rpm. The four isolated endophytic fungi did not produce astragalosides I–IV, flavonoids or polysaccharides. Isolation of additional species of endophytic fungi from A. mongholicus and determination of their capacity to produce biologically active substances are subjects in need of further research. | Wei Ma Xiubo Liu Jiao Jiao Leiming Zhang Weichao Ren Ling Ma Xiangjun Kong Ning Zhang Xiwu Zhang | 2014 | Journal of Forestry Research2014，25，3： | 1 |
| 10 | Formation and Development of a Mountain-induced Secondary Center inside Typhoon Morakot(2009)显示文摘The structural evolution of Typhoon Morakot(2009) during its passage across Taiwan was investigated with the WRF model. When Morakot approached eastern Taiwan, the low-level center was gradually filled by the Central Mountain Range(CMR), while the outer wind had flowed around the northern tip of the CMR and met the southwesterly monsoon to result in a strong confluent flow over the southern Taiwan Strait. When the confluent flow was blocked by the southern CMR, a secondary center(SC) without a warm core formed over southwestern Taiwan. During the northward movement of the SC along the west slope of the CMR, the warm air produced within the wake flow over the northwestern CMR was continuously advected into the SC, contributing to the generation of a warm core inside the SC. Consequently, a well-defined SC with a warm core, closed circulation and almost symmetric structure was produced over central western Taiwan, and then it coupled with Morakot's mid-level center after crossing the CMR to reestablish a new and vertically stacked typhoon. Therefore, the SC inside Morakot was initially generated by a dynamic interaction among the TC's cyclonic wind, southwesterly wind and orographic effects of the CMR, while the thermodynamic process associated with the downslope adiabatic warming effect documented by previous studies supported its development to be a well-defined SC. In summary, the evolution of the SC in this study is not in contradiction with previous studies, but just a complement, especially in the initial formation stage. | Xuwei BAO Leiming MA Jianyong LIU Jie TANG Jing XU | 2018 | Advances in Atmospheric Sciences2018，35，9： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员