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PREDICTION OF FLOOD SEASON PRECIPITATION IN SOUTHWEST CHINA BASED ON IMPROVED PSO-PLS

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Journal of Tropical Meteorology 2018年第2期24卷 163-175页

作者： WANG Zhi-yi HU Bang-hui yang xiu-qun WANG Xue-zhong WANG Ju HUANG Hong College of Meteorology and Oceanography PLA University of Science and TechnologyNanjing 210001 China School of Atmospheric Sciences Nanjing UniversityNanjing 210023 China Chongqing Meteorological Observatory Chongqing 401147 China

In order to achieve the best predictive effect of the Partial Least Squares(PLS) regression model, Particle Swarm Optimization(PSO) algorithm is applied to automatically filter the optimal subset of a set of candidate factors of PLS regression model in this study. An improved version of the Particle Swarm Optimization-Partial Least Squares(PSO-PLS) regression model is applied to the station data of precipitation in Southwest China during flood *** the PSO-PLS regression method, the prediction of flood season precipitation in Southwest China has been studied. By introducing the precipitation period series of the mean generating function(MGF) extension as an alternative factor, the MGF improved PSO-PLS regression model was also built up to improve the prediction *** selected 10%, 20%, 30% of the modeling samples were used as a test trial; random cross validation was conducted on the MGF improved PSO-PLS regression model. The results show that the accuracy of PSO-PLS regression model and the MGF improved PSO-PLS regression model are better than that of the traditional PLS regression *** training results of the three prediction models with regard to the regional and single station precipitation are considerable, whereas the forecast results indicate that the PSO-PLS regression method and the MGF improved PSO-PLS regression method are much better than the traditional PLS regression method. The MGF improved PSO-PLS regression model has the best forecast performance on precipitation anomaly during the flood season in the southwest of China among three models. The average precipitation(PS score) of 36 stations is 74.7. With the increase of the number of modeling samples, the PS score remained stable. This shows that the PSO algorithm is objective and stable. The MGF improved PSO-PLS regression prediction model is also showed to have good prediction stability and ability.

关键词： precipitation prediction particle swarm optimization partial least squares regression flood season precipitation of Southwest China

华南前汛期降水异常与太平洋海表温度异常的关系

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地球物理学报 2013年第8期56卷 2583-2593页

作者：强学民杨修群南京大学大气科学学院南京210093 解放军理工大学气象海洋学院南京211101

利用近50年华南地区站点逐日降水观测资料和全球大气、海洋分析资料,分析了华南前汛期降水异常的变化特征及其与太平洋海温异常的联系.结果表明,近50年来华南前汛期降水总体呈现减少趋势.影响华南前汛期降水异常的太平洋海温异常型是一... 详细信息

利用近50年华南地区站点逐日降水观测资料和全球大气、海洋分析资料,分析了华南前汛期降水异常的变化特征及其与太平洋海温异常的联系.结果表明,近50年来华南前汛期降水总体呈现减少趋势.影响华南前汛期降水异常的太平洋海温异常型是一个类似于ENSO的西太平洋暖池模态,即显著海温异常区域位于西太平洋暖池.西太平洋暖池区域(120°E—180°E,20°S—20°N)前期冬季海温异常同华南前汛期降水存在显著的负相关关系,是具有预报意义的海温关键区.该关键区海温异常影响华南前汛期降水的可能物理过程是:当前期冬季暖池异常偏暖时,菲律宾周围地区对流活动加强,导致Walker环流及东亚太平洋中低纬局地Hadley环流增强;该异常通过影响东亚-太平洋遥相关波列,使前汛期期间西太平洋副高加强西伸,脊线位置偏北,同时副热带西风急流减弱北退.随着Hadley环流上升支的增强,东亚副热带地区下沉运动也增强了,华南地区对流活动受到抑制.而且由于副高的增强,经过其北侧向华南地区的西南水汽输送辐合也减弱了,因此前汛期降水偏少.冷海温年的情形则相反,华南前汛期降水偏多.近50年来华南前汛期降水总体呈现趋势性减少正是由于前冬西太平洋暖池趋势性增暖所致.

关键词：华南前汛期降水异常西太平洋暖池海表温度异常

Oxidation behavior of 4774DD1 Ni-based single-crystal superalloy at 980℃ in air

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China Foundry 2024年第2期21卷 116-124页

作者： Yu Fang Ya-zhou Li Qiang yang qun-gong He xiu-fang Gong Qian Duan Hai-yang Song Fu Wang Qiong-yuan Zhang Hong Zeng State Key Laboratory of Long-Life High Temperature Materials Dongfang Turbine Co.Ltd.Deyang 618000SichuanChina State Key Laboratory for Manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

The oxidation behavior of a novel Ni-based single-crystal 4774DD1 superalloy for industrial gas turbine applications was investigated by the isothermal oxidation at 980℃ and discontinuous oxidation weight gain *** phase constitution and morphology of surface oxides and the characteristics of the crosssection oxide film were analyzed by XRD,SEM and *** show that the oxidation kinetics of the 4774DD1 superalloy follows the cubic law,indicating its weak oxidation resistance at this *** the oxidation time increases,the composition of the oxide film evolves as following:One layer consisting of a bottom Al_(2)O_(3)sublayer and an upper(Al_(2)O_(3)+NiO)mixture sublayer after oxidized for 25 ***,two layers composed of an outermost small NiO discontinuous grain layer and an internal layer for 75 *** internal layer is consisted of the bottom Al_(2)O_(3)sublayer,an intermediate narrow CrTaO_(4)sublayer,and an upper(Al_(2)O_(3)+NiO)mixture *** two layers comprising an outermost relative continuous NiO layer with large grain size and an internal layer as the oxidation time increases to 125 *** internal layer is composed of the upper(Al_(2)O_(3)+NiO)mixture sublayer,an intermediate continuous(CrTaO_(4)+NiWO_(4))mixture sublayer,and a bottom Al_(2)O_(3)***,three layers consisting of an outermost(NiAl2O_(4)+NiCr2O_(4))mixture layer,an intermediate(CrTaO_(4)+NiWO_(4))mixture layer,and a bottom Al_(2)O_(3)layer for 200 h.

关键词： nickel-base single crystal superalloy oxidation kinetics oxide film microstructure mechanism

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华南前汛期开始和结束日期的划分

地球物理学报 2008年第5期51卷 1333-1345页

作者：强学民杨修群解放军理工大学气象学院

本文利用48年(1957～2004年)中国站点逐日降水资料和同期NCEP/NCAR逐日再分析资料,研究了华南前汛期的开始和结束时间的划分问题.首先,选择了研究华南前汛期问题的区域和代表站点,然后对降水量、水汽(可降水量,水汽通量,水汽通量散度)... 详细信息

本文利用48年(1957～2004年)中国站点逐日降水资料和同期NCEP/NCAR逐日再分析资料,研究了华南前汛期的开始和结束时间的划分问题.首先,选择了研究华南前汛期问题的区域和代表站点,然后对降水量、水汽(可降水量,水汽通量,水汽通量散度)、垂直速度和假相当位温等物理量的演变特征进行分析,发现:前汛期起、止前后上述要素均有阶段性的突变.其中4月第1候(19候)是华南前汛期的开始,可降水量、水汽通量和假相当位温等增加显著,对流开始活跃,水汽通量散度也由辐散变为辐合,降水量明显增加.但4月份总体雨量不强,主要为锋面降水.5月份随夏季风爆发,水汽继续增加,对流活跃,进入季风降水阶段;夏季风降水盛期时段主要集中在6月份.6月第4候(34候)前汛期结束,各降水指标骤减.然后根据降水和环流指标,提出了华南前汛期开始和结束日期的划分标准,定义了逐年的开始和结束日期.最后对华南前汛期开始期之前、之后以及结束期之前、之后的大气环流背景做了对比分析.指出,前汛期开始前,环流形势有利于华南地区增暖增湿;开始期以后则有利于冷空气南下,造成连续降水,使华南进入前汛期.而前汛期的结束,则是由于东亚大气环流的季节调整,尤其是西太平洋副热带高压的第一次北跳所造成的.

关键词：华南前汛期开始期和结束期锋面降水季风降水大气环流的季节调整副高北跳

Centroid Hom-associative Algebras and Centroid Hom-Lie Algebras

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Acta Mathematica Sinica,English Series 2024年第4期40卷 935-961页

作者： Yu xiu BAI Leonid A.BOKUT Yu qun CHEN Ze Rui ZHANG Department of Mathematics Teaching Guangzhou Civil Aviation CollegeGuangzhou 510403P.R.China Sobolev Institute of Mathematics Novosibirsk 630090Russia Novosibirsk State University Novosibirsk 630090Russia School of Mathematical Sciences South China Normal UniversityGuangzhou 510631P.R.China

In this article,we construct free centroid hom-associative algebras and free centroid hom-Lie *** also construct some other relatively free centroid hom-associative algebras by applying the Gr?bner-Shirshov basis theory for(unital)centroid hom-associative ***,we prove that the"Poincaré-Birkhoff-Witt theorem"holds for certain type of centroid hom-Lie algebras over a field of characteristic 0,namely,every centroid hom-Lie algebra such that the eigenvectors of the mapβlinearly generates the whole algebra can be embedded into its universal enveloping centroid hom-associative algebra,and the linear basis of the universal enveloping algebra does not depend on the multiplication table of the centroid hom-Lie algebra under consideration.

关键词： Centroid hom-Lie algebra centroid hom-associative algebra Gr?bner-Shirshov basis

Subseasonal Variations of Wintertime North Pacific Evaporation,Cold Air Surges and Water Vapor Transport

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Subseasonal Variations of Wintertime North Pacific Evaporati...

北太平洋副热带高压年际变异与ENSO循环之间的选择性相互作用

第35届中国气象学会年会

作者： REN Xuejuan yang xiu-qun HU Haibo School of Atmospheric Sciences Nanjing University

This study addresses subseasonal variations of oceanic evaporation（E） over the North Pacific during winter,and the connection with the cold air surges（CAS） and atmospheric water vapor transport using the OAFlux and ERA-Interim daily *** performing an empirical orthogonal function（EOF） analysis,two dominant modes of subseasonal evaporation anomaly（E?） are identified:a zonally wave-train like pattern（EOF1）,and an east positive–west negative dipolar pattern（EOF2） in the midlatitude *** analyses yield the following conclusions.（1） The Siberian high（SH）-related CAS has a crucial role in generation of the EOF1 mode of E?.When the dry and cold airmass passes the warm Kuroshio current and its extension（KOE） region,the increased air–sea temperature and moisture differences and intensified wind speed lead to the above-normal oceanic E,and vice versa.（2） The Aleutian low（AL）-related CAS contributes to the EOF2 mode of E?.The intensified AL transports dramatically colder and drier airmass toward the KOE region,and slightly warmer and wetter one toward the west coast of North America,leading to the east positive–west negative structure of E? in the midlatitude basin.（3）A quasi-linear relationship exists between E? and divergent water vapor transport anomalies over the KOE ***（negative） E? is generally accompanied by anomalous vapor source（sink）.（4） The divergent water vapor transport anomalies associated with the two EOFs are preliminarily decided by their individual lower-level wind fields anomalies,and secondly by the meridional inhomogeneity of subseasonal specific humidity *** effects on precipitation over the pan-North Pacific region are also discussed.

关键词： oceanic evaporation cold air surges atmospheric water vapor transport subseasonal time scale

来源： cnki会议评论

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地球物理学报 2010年第7期53卷 1543-1553页

作者：李熠杨修群谢倩南京大学大气科学学院南京210093 解放军理工大学气象学院南京211101

利用NCEP/NCAR大气再分析资料以及Hadley中心海表温度资料,针对北太平洋副热带高压(简称副高)的完整系统,通过分析超前于ENSO事件的海平面副高年际异常特征及其对ENSO事件的触发作用以及ENSO事件对500 hPa副高和海平面副高的滞后影响,... 详细信息

利用NCEP/NCAR大气再分析资料以及Hadley中心海表温度资料,针对北太平洋副热带高压(简称副高)的完整系统,通过分析超前于ENSO事件的海平面副高年际异常特征及其对ENSO事件的触发作用以及ENSO事件对500 hPa副高和海平面副高的滞后影响,结果表明了北太平洋副热带高压年际变异和ENSO循环之间存在选择性相互作用.即在大多数情况下,一方面,前期海平面副高减弱会导致热带西太平洋表面西风异常,通过海洋平流过程触发El Nino事件在夏季发生发展,在秋冬季成熟;而另一方面,El Nino事件在秋冬季发展成熟后,增强了赤道中太平洋的对流性热源,通过对异常热源的动力响应,同期和次年夏季500 hPa副高增强,又通过增强的Hadley环流作用,副热带地区下沉运动增强,从而使得次年夏季海平面副高增强,增强的海平面副高又有利于触发下一个La Nina事件.副高年际变异和ENSO循环之间相互作用的选择性主要取决于副高异常是否接近于赤道以及ENSO事件本身的持续性.这种相互作用有利于在热带太平洋海气系统产生准两年振荡.

关键词：北太平洋副热带高压 ENSO 相互作用

Optimizing FeCoNiCrTi high-entropy alloy with hydrogen pumping effect to boost de/hydrogenation performance of magnesium hydride

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Rare Metals 2024年第7期43卷 3273-3285页

作者： Meng-Chen Song Fu-Ying Wu Yi-qun Jiang xiu-Zhen Wang Hu Zhao Li-Xin Chen Liu-Ting Zhang School of Energy and Power Instrumental Analysis CenterJiangsu University of Science and TechnologyZhenjiang 212003China Max Planck Institute for Iron Research 40237DuisseldorfGermany School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore State Key Laboratory of Silicon Materials Department of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China

The exploration of efficient,long-lived and cost-effective transition metal catalysts is highly desirable for the practical hydrogen storage of magnesium hydride(MgH_(2)) in sustainable energy ***,FeCoNiCrTi high-entropy alloy(HEA) nanosheets were prepared via a facile wet chemical ball milling strategy and they were introduced into MgH_(2) to boost the hydrogen storage *** refined HEA exhibited superior catalytic activity on MgH_(2).In contrast to additive-free MgH_(2),the initial desorption temperature of the constructed MgH_(2)-HEA composite was reduced from 330.0 to 198.5℃ and a remarkable 51% reduction in the dehydrogenation activation energy was ***,the MgH_(2)-HEA composite only required one-twentieth time of that consumed by pure MgH_(2) to absorb 5.0 wt% of H_(2) at 225℃.The synergy between the "hydrogen pumping" effect of Mg_2Ni/Mg_2NiH_4 and Mg_2Co/Mg_2CoH_5 couples,as well as the good dispersion of Fe,Cr and Ti on the surface of MgH_(2) contributed to the enhanced de/hydrogenation performance of the MgH_(2)-HEA *** study furnishes important steering for the design and fabrication of multiple transition metal catalysts and may push the commercial application of magnesium-based hydrides one step forward.

关键词： Hydrogen storage Magnesium hydride High-entropy alloys Catalysis

局地零平面位移对非均匀地表有效空气动力学参数的影响

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物理学报 2013年第14期62卷 234-239页

作者：钟时杨修群郭维栋南京大学大气科学学院南京210093

利用最新提出的非均匀地表有效空气动力学参数联合计算方案,研究了三种非均匀地表情况下局地零平面位移对有效粗糙度和有效零平面位移影响的统计特征.结果表明,局地零平面位移对有效粗糙度有增幅作用,随着局地零平面位移的增加,有效粗... 详细信息

利用最新提出的非均匀地表有效空气动力学参数联合计算方案,研究了三种非均匀地表情况下局地零平面位移对有效粗糙度和有效零平面位移影响的统计特征.结果表明,局地零平面位移对有效粗糙度有增幅作用,随着局地零平面位移的增加,有效粗糙度也相应增大,但局地零平面位移对有效粗糙度的增幅作用随地表粗糙变率增加而略有减小;有效零平面位移随局地零平面位移的增加而增加,但总小于线性加权平均值,且随着地表粗糙变率的增大,有效零平面位移却有所减小.

关键词：非均匀地表局地零平面位移有效粗糙度有效零平面位移