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| 1 | OBSERVATION AND MODEL ANALYSES OF POSITIVE CLOUD-TO-GROUND LIGHTNING IN MESOSCALE CONVECTIVE SYSTEMS显示文摘The analyses of spatial and temporal characteristics of positive cloud-to-ground(CG)lightning for four mesoscaleconvective systems and two severe local convective systems in 1989 and 1990 show that positive CG flash rate usuallyhas two peak values.The major peak occurs during the developing stage of the storm and most of the positive CGflashes originate at the lower part of the storm.The minor occurs during the dissipative stage of the storm and most ofthe positive CG flashes originate at the upper part of the storm,especially in the region of the wind divergence in thestorm anvil.The positive CG flash rate is almost an order of magnitude larger in the developing stage than in thedissipative stage.The appearing time of the peak of negative CG flash rate is in accordance with that of the valley of pos-itive CG flash rate.The higher the intensity of the radar echo,the higher the positive CG flash rate.Most of the positive CG flashes oc-cur when the weak echo area is larger,and mostly originate in the region where the radar echo intensity is about 10dBzand in the back region of the moving storms.The spatial distribution of the positive CG flashes is much more dispersivethan that of the negative.The mesoscale analysis reveals a bipolar lightning pattern.The mean bipole--length reaches itsminimum during the mature stage of the storm and reaches the maximum during the developing stage of the storm.The vertical distribution of the charge density is calculated by a one-dimensional charging model.Then,we discussthe producing condition of the positive CG lightning and forming cause of charge structure mentioned above. | Yan Muhong Guo Changming Qie Xiushu Ge Zhengmo Zhang Guangshu Lanzhou Institute of Plateau Atmospheric Physics,Academia Sinica,Lanzhou 730000 | 1992 | Acta meteorologica Sinica1992，6，4： | 16 |
| 2 | Indoor imitation experimental study on driving factors of rainfall-runoff process显示文摘The driving actions of rainfall-runoff process can be attributed to two aspects. The first is the influence of precipitation process, and the second is that of the ground pad. The re- search results of 179 indoor experiments conducted to imitate rainfall-runoff process indicate that both precipitation duration and intensity play important roles in affecting confluence lag time, which is obviously inconsistent with the traditional hypotheses. The nonlinear relationship is of great significance to the confluence curve especially when the precipitation duration is less than the total confluence time or the precipitation intensity is small. Therefore it can be concluded that the unit hydrograph (UH) can be applied to rainfall-runoff process imitation in the humid areas in the south China region. However, the UH application should be strictly modified in accordance with precipitation conditions in the arid and semiarid region of north China where the precipitation duration is short and the intensity is unstable. It will be hard to get ideal imitation results if the UH is applied blindly without considering specific conditions in the north China region. This also explains the unsatisfactory imitation results caused by using various hydrological models in the north China region. When the precipitation duration is short, and the watershed has not reached total watershed concentration, the characteristics of confluence change greatly, which reflects the actual situation in the north China region. Therefore necessary nonlinear corrections should be made when UH is applied. If the duration is longer than the total confluence time and the balance between pondage and discharge is stricken, the imitation research results will be applicable to both rainfall-runoff relation with longer duration in the south China region and the basic theoreti- cal research on runoff generation and concentration. On conditions of adequate rainfall, peak discharge is in linear relationship with intensity, but has nothing to do with the ground pad. There is a negative linear relationship between intensity and time to peak . The amount of pondage capacity in a catchment is in linear relationship with intensity and peak discharge, with obvious influence by the ground pad status and interception, and it has nothing to do with the position of interceptions. | ZHANG Shifeng1, LIU Changming 1, XIA Jun1, TAN Ge 1, LI Lin1, LIU Caitang1, ZHOU Changqing 1 & GUO Lei2 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2. College of Water Resources and Hydropower Engineering, Wuhan University, Wuhan 430072, China | 2005 | Science China Earth Sciences2005，48，3： | 3 |
| 3 | CNN-BiLSTM-Attention Model in Forecasting Wave Height over South-East China Seas显示文摘Though numerical wave models have been applied widely to significant wave height prediction,they consume massive computing memory and their accuracy needs to be further improved.In this paper,a two-dimensional(2D)significant wave height(SWH)prediction model is established for the South and East China Seas.The proposed model is trained by Wave Watch III(WW3)reanalysis data based on a convolutional neural network,the bidirectional long short-term memory and the attention mechanism(CNNBiLSTM-Attention).It adopts the convolutional neural network to extract spatial features of original wave height to reduce the redundant information input into the BiLSTM network.Meanwhile,the BiLSTM model is applied to fully extract the features of the associated information of time series data.Besides,the attention mechanism is used to assign probability weight to the output information of the BiLSTM layer units,and finally,a training model is constructed.Up to 24-h prediction experiments are conducted under normal and extreme conditions,respectively.Under the normal wave condition,for 3-,6-,12-and 24-h forecasting,the mean values of the correlation coefficients on the test set are 0.996,0.991,0.980,and 0.945,respectively.The corresponding mean values of the root mean square errors are measured at 0.063 m,0.105 m,0.172 m,and 0.281 m,respectively.Under the typhoon-forced extreme condition,the model based on CNN-BiLSTM-Attention is trained by typhooninduced SWH extracted from the WW3 reanalysis data.For 3-,6-,12-and 24-h forecasting,the mean values of correlation coefficients on the test set are respectively 0.993,0.983,0.958,and 0.921,and the averaged root mean square errors are 0.159 m,0.257 m,0.437 m,and 0.555 m,respectively.The model performs better than that trained by all the WW3 reanalysis data.The result suggests that the proposed algorithm can be applied to the 2D wave forecast with higher accuracy and efficiency. | Lina Wang Xilin Deng Peng Ge Changming Dong Brandon J.Bethel Leqing Yang Jinyue Xia | 2022 | Computers, Materials & Continua2022，，10： | 2 |
| 4 | Changes in Soil Nutrients of Farmland with Different Cultivation Years of Panax ginseng显示文摘Through analyzing the soil organic matters(N,P,K) of farmland cultivated with different years of Panax ginseng,this paper studied the changes in soil nutrients of farmland with different vertical depths and cultivation years of P.ginseng.Results indicated that the vertical structure was obvious in soil nutrients of farmland with different cultivation years of P.ginseng;in most cases,the soil nutrient content gradually declined with the fibrous roots of P.ginseng spreading downward;the soil electrical conductivity(EC),total nitrogen(TN),total phosphorus(TP),total potassium(TK),available nitrogen,available phosphorus were manifested as surface layer > root layer > bottom layer,while the available potassium was manifested as surface soil and bottom layer > root layer;the soil pH changed in the range of 5.69-6.22,suitable for growth of P.ginseng.It is expected to provide theoretical basis for improvement of soil nutrients of farmland with cultivation of P.ginseng. | Changming GE Xin WANG Aixuan WU Yun LU Hongyan ZHAO Renzhe PIAO | 2017 | Asian Agricultural Research2017，9，12： | 0 |
| 5 | Effect of Spent Mushroom Substrate on Physical and Chemical Properties and Enzymic Activity of Rice显示文摘In order to explore the substitution substrate for rice seedling on upland fields,this paper uses spent mushroom substrate to study the physical and chemical properties of substrate,enzymic activity and number of tillers during the cultivation of rice seedling on upland fields.The results show that at the three stages of rice seedling cultivation( two-leaf stage,three-leaf stage,four-leaf stage),the content of organic matter and EC in spent mushroom substrate is higher than in the control soil,p H is within the range suitable for the growth of rice,and other nutrients( total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus) are slightly different in different periods;except phosphatase,there are significant differences in urease,catalase and sucrase between spent mushroom substrate and the control soil; the number of tillers under spent mushroom substrate is larger than under the control. | Hairu YU Xue LI Xin ZHANG Changming GE Renzhe PIAO Meishan LI Zongjun CUI Hongyan ZHAO | 2016 | Asian Agricultural Research2016，8，6： | 0 |
| 6 | Effects of Agitating Intensity on Anaerobic Digestion Performance of Corn Straw Silage显示文摘Anaerobic fermentation can increase biomass energy use efficiency of crop straws and realize win-win of energy and environment.This paper explored the biogas generation performance of anaerobic digestion of cow dung liquid as nitrogen source in three different levels of stirring intensity at 30℃ constant temperature condition. Through p H value,biogas production,chemical oxygen demand( COD),methane content,volatile fatty acid( VFA),principal component analysis( PCA) and modified Gompertz model,effects of agitating intensity on anaerobic digestion performance of corn straw silage were evaluated. Results indicate that the COD removal rate of three agitating intensity levels is higher than 85%,and p H value is about 6.5; the cumulative biogas production after 20 days is 2h > 4h > 1h of agitating; in the49 th day,the biogas production is 1.9 Lat 30 min /2h,1.7 L at 30 min /4 h,and 1. 6 Lat 30 min / h; the maximum biogas production rate is 30 min /2h > 30 min /4h > 30 min / h; and the maximum methane production rate is 30 min /4h > 30 min /2h > 30 min / h; in the same energy consumption,the biogas production at 30 min /4h is higher than 1h. In conclusion,overall analysis of energy consumption and economic factors indicate that 30 min /4 h agitating intensity is more suitable for straw biogas fermentation project. This study is expected to provide theoretical foundation for biogas fermentation project. | Xin ZHANG Xue LI Benyue ZHANG Changming GE Renzhe PIAO Weidong WANG Hongyan ZHAO Zongjun CUI | 2016 | Asian Agricultural Research2016，8，9： | 0 |
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