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Search Results: 1 - 10 of 279620 matches for " <br>包云轩 "
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Numerical simulation of the migration parameters of the Brown Planthopper,Nilaparvata lugens (St(a)l)

BAO Yun-Xuan,<br>
生态学报 , 2005,
Abstract: Based on the data of the insect trap catches, the entomological radar surveying, and the weather observations in the China, some processes by which the northward and southward migrations through China of the Brown Planthopper Nilaparvata lugens (BPH) occur during July and October in 1991 were picked out. These processes have been investigated with an advanced mesoscale numerical weather-forecasting model, MM5 (V3.2) and the 3D windborne trajectories of BPH's migration were simulated. Some parameters, such a...
Influence of Low-level Jets on the great events of BPH's migration northward in China

Bao Yun Xuan,<br>,谢杰,向勇,徐希燕,刘宇
生态学报 , 2009,
Abstract: Low level jet (LLJ) is an ideal passageway for the long-distance migrations of Nilaparvata lugens (Stal)′s populations. In order to explore the effect of LLJ on BPH′s migrations northward, we have conducted a synthetic analysis of the Chinese BPH′s lighting catches in 2007 and done some case studies in combination with the respective weather data. Our results indicate: (1) the LLJ as a large-scale weather system in Eastern Asia, played an important role in the great migrations northward of Chinese BPH′s populations in 2007 linking the pest sources and the destination of the migrant populations; (2) the tempo-spatial distribution and strength change of LLJ had a significant impact on the landing times, landing scopes, landing heads of BPH′s populations, and the selection of the main landing regions; (3) the prediction of that the brown planthoppers immigrated into the main landing regions carried by LLJ by a trajectory-backward approach is consistent with LLJ dynamic explanation; (4) the downstream of LLJ played a key role in the distribution of the BPH′s landing areas.
Risk division on winter wheat suffering from spring wet damages in Jiangsu Province

WU Hongyan,GAO Ping,XU Weigen,BAO Yunxuan,<br>吴洪颜,高苹,徐为根,
生态学报 , 2012,
Abstract: Spring wet damage has brought a serious impact to the growth and yield of winter wheat in the southern China. Efficient risk divisions of wet damages shall play an important role on the safe production of winter wheat. In this paper, some meteorological factors such as ten-day precipitation, ten-day sunshine time, and ten-day rainfall days were selected to reflect the characteristic of wet damage occurrence in spring and the data of these factors in all springs of 49 years (from 1960 to 2008) were used to analyze the relationship between them and the climate yield of winter wheat in Jiangsu Province. The results were followed as: (1) In Jiangsu Province, the change of the above factors in the springs have been significantly associating with the fluctuation of the climatic yield. (2) The path analysis showed that the ten-day precipitation and ten-day sunshine time were the two direct factors influencing on the climatic yield of winter wheat but the ten-day rainfall days had indirect impact on it. (3) Q index was used to distinguish the wet years form the years of other types and establish an integrated risk exponential model about the wet damage of winter wheat combined with the occurrence frequency of wet damages and the drop percentage in winter wheat yield. (4)The established risk exponential model were applied to evaluate the risks of winter wheat suffering from wet damage in the different regions of Jiangsu Province and divide the regions of different risk grades. Consequently, some measures of prevention from the wet damage were put forward and it will provide a scientific basis for the prevention from wet disasters and mitigate the loss of the winter wheat production in Jiangsu Province.
Numerical Simulations of a Highly Complex Fog Event on Shanghai-Nanjing Expressway

BAO Yunxuan,DING Qiuji,YUAN Chengsong,YAN Mingliang,<br>,丁秋冀,袁成松,严明良
大气科学 , 2013,
Abstract: The objective of this study is to ascertain the engendering causes and evolving patterns of dense fog weather processes on expressways and to reveal their mechanisms of influencing visibility during transportation. Observed fog data from the automatic weather monitoring system (AWMS) along the Shanghai-Nanjing Expressway in China and that from conventional meteorological stations covering areas near the same region were collected and analyzed for a typical complex fog event that occurred over the expressway on November 7, 2009. Based on analysis of actual weather conditions during the fog event, the Weather Research and Forecasting Model for Version 3.1 (WRF3.1), a non-hydrostatic mesoscale numerical forecasting model with high spatial and temporal resolutions, was used in conjunction with National Centers for Environmental Prediction (NCEP) 0.5°×0.5° meteorological reanalysis data to simulate a typical fog event. Numerical simulations of several physical variables were verified from the observed data of the fog event data of AWMS. The dynamic and thermodynamic conditions engendering this complex fog event in addition to moisture levels were analyzed. The following were the main conclusions: (1) The atmospheric circulation conditions in Jiangsu Province and its contiguous regions were stable before and during the heavy fog event. These regions were affected by the southeastern stream at the southwestern side of an anti-cyclone system over the Yellow Sea. Moreover, a weak surface wind present during the entire fog process provided favorable dynamic conditions for engendering heavy fog. (2) The simulated distribution areas of the fog masses depicted by the liquid water content (LWC) agreed with observation data. (3) The simulated visibilities were very close to the observed AWMS visibility data. (4) The mixed fog event occurred during 18:00 (BST) November 7 to 08:00 (BST) November 8, 2009. The embryo of this heavy fog event was a local patchy fog that was converted into radiation fog under the influence of radiation cooling. Then, a warm and humid air advection mass from the surface of the East Sea moved southeast and entered into the southern part of Jiangsu Province to create an advection fog mass. This mass combined with the earlier radiation fog to form a complex fog mass from the dual effects of radiation cooling and advection cooling, enabling large-scale expansion. (5) The warming of the surface caused by short-wave radiation after sunrise was the main reason for the rapid dissipation of the fog body.
Case studies on the landing mechanisms of the brown planthoppers Nilaparvata lugens (St(a)l)

HU Gao,BAO Yun-Xuan,WANG Jian-Qiang,ZHAI Bao-Ping,<br>胡高,,王建强,翟保平
生态学报 , 2007,
Abstract: 应用MM5中尺度数值模拟模式和GRADS气象图形软件,对1999年6月22日~7月2日一次褐飞虱迁飞降落过程及其大气背景场进行了个例研究,并侧重对灵川、东至、徽州3个站点的降虫机制做了分析。结果表明:(1)此次迁飞过程有两个明显的降虫区:天柱.灵川.贺县一线范围内(降虫区Ⅰ)和三都-天柱-黔阳-修水-东至-徽州-奉贤-线(降虫区Ⅱ);(2)低空急流为褐飞虱北迁提供了运载气流,降虫区位于降水区边缘;(3)地形降水胁迫害虫降落是降虫区Ⅰ褐飞虱降落的主要原因,梅雨锋降水导致了褐飞虱集中降落在降虫区Ⅱ;(4)虫源的空间分布差异和不同的天气条件导致了东至、徽州地区不同的降虫分布。
Atmospheric water vapor conditions of Cnaphalocrocis medinalis outbreak in 2003

WANG Cuihua,BAO Yunxuan,WANG Jianqiang,ZHAI Baoping,XIANG Yong,<br>王翠花,,王建强,翟保平,向勇
应用生态学报 , 2006,
Abstract: To reveal the influence of atmospheric water vapor conditions on the outbreak of Cnaphalocrocis medinalis in 2003, the geographic distributions of the pest per 667 m^2 of China on June 16th, July 21st, and September 1st, 2003 were analyzed under the support of ArcGIS, and the air relative humidity and water vapor flux fields on 850,925 and 1 000 hPa that had the greatest influence on the pest immigration were selected to do simulation and objective analysis. The results showed that the transferring status of water vapor and the distribution of relative humidity on the upper air had significant indicative meanings for the immigration. In the regions of C. medinalis outbreak, the air relative humidity on each layer from the ground to 850 hPa was higher than 50%. The shorter the distance to the landing region of C. medinalis, the higher the humidity was, while the shorter the distance to the taking-off region, the lower this humidity was. 850 hPa was the main layer of water vapor transferring during C. medinalis migration, and the key pathway of the migration. On this height, the direction of water vapor transferring was basically concurrent with that of C. medinalis migration.
热带气象学报 , 2014,
Abstract: 由于光能利用率(lightuseefficiency,lue)随环境的变化关系十分复杂,现有的lue估算植被初级生产力(gpp)和净初级生产力(npp)的模型过于粗糙简单,而通过遥感直接估计lue会更加可靠。研究表明,光化学反射植被指数(pri)与lue有很好的相关性,故pri在利用遥感估计lue方面具有极大的潜力。但是,很多研究也发现了pri-lue的关系受到许多因素的干扰。为了探究多角度高光谱对光化学反射植被指数估算光能利用率的影响,分析了各观测日的光化学反射植被指数变化情况及其与实测光能利用率的关系。结果表明:在主平面的4个观测日都表现出后向的pri值大于前向的pri值,均表现出当光谱仪探头从后向散射方向向着前向散射方向变化时,pri值逐渐变小然后随着天顶角的变大而变大;在光合作用的外部条件和内部环境不受影响的情况下,prosail模型在主平面前向散射方向的中等角度(45°和60°)与后向散射方向的小角度(-15°和-30°)可以较好模拟出单一植被覆盖条件下水稻冠层植被的反射光谱。
Potential establishment areas of Solenopsis invicta in China:A prediction based on GIS

CHEN Chen,GONG Weirong,HU Baishi,ZHOU Guoliang,BAO Yunxuan,LIU Fengquan,<br>陈晨,龚伟荣,胡白石,周国梁,,刘凤权
应用生态学报 , 2006,
Abstract: Based on geographic information system (GIS), the potential establishment areas of Solenopsis invicta Buren in China were predicted. The days above threshold temperature and the number of degree-days were used as main determining factors, while annual precipitation and altitude were used as limiting factors. By using the Kriging spatial interpolation function in GIS software, the potential establishment area was divided into four categories, i.e., most suitable, suitable, mildly suitable, and unsuitable. The most suitable area was in the greater part of Guangdong, central and southern Guangxi, small part of southern Yunnan, Hainan, Taiwan, Hong Kong, and Macao, suitable area was in southern Yunnan, northern Guangxi and Guangdong, southern Henan, western Anhui, greater part of Zhejiang, central and eastern Hubei, Chongqing, Hunan, Jiangxi, and Fujian, mildly suitable area was in the greater parts of Anhui and Henan, central and eastern Hebei and Shandong, Beijing, Tianjian, central and northern Jiangsu, northwestern Zhejiang and Hubei, southern Shanxi, eastern Sichuan, central and western Guizhou, and small part of central Yunnan, and unsuitable area was in the greater parts of northwest, northeast, and north China.
Numerical Simulation and Diagnostic Analysis of a Heavy Fog Process in Shanghai-Nanjing Expressway

YAN Ming-liang,MIAO Qi-long,YUAN Cheng-song,BAO Yun-xuan,WAN Xiao-yan,<br>严明良,缪启龙,袁成松,,万小雁
高原气象 , 2011,
Abstract: 利用新一代中尺度数值预报模式WRF和NCEP 1°×1°再分析资料, 对2007年10月26日发生在沪宁高速公路区域的一次大雾天气过程进行了数值模拟, 同时采用沪宁高速公路自动气象监测站的实时资料对模拟效果进行了验证, 发现WRF模式较成功地模拟了此次大雾过程。结果表明: (1)此次大雾是一次典型的辐射雾, 其形成主要原因之一是成雾之前的降水过程给近地层大气带来了充足的水汽, 空气相对湿度达到90%以上, 雾区内近地层基本上为弱的水汽辐合区; (2)弱的负涡度场有利于气流下沉, 在垂直方向上可以确保湿空气不外流; (3)地面辐射冷却和低空冷平流是此次大雾形成、 发展和维持的重要因素, 地面辐射冷却在热力条件中起主导作用, 冷平流作用远小于地面辐射冷却作用。
气象科学 , 2012, DOI: 10.3969/2012jms.0057
Abstract: 利用沪宁高速公路实时监测数据,筛选出30个典型高温天气过程,应用wrf模式对其进行了数值模拟。在对输出结果作统计分析后,提取了沪宁高速公路高温天气的几个数值预警指标,建立了梅村、河阳两站的高温预报模型。研究表明:(1)利用wrf模式对沪宁高速公路沿线的高温天气过程进行模拟是可行的;(2)提取的沪宁高速公路高温数值预警指标有:前一日14时的地表温度ts≥40℃、地面潜热通量fl≥350w·m-2、近地面相对湿度hr≤60%、当日08时的地面感热通量fs为负值且绝对值≥70w·m-2、地面水平风速vs≤3m·s-1,当各项指标同时满足时,可预报当日会出现35℃以上的高温;(3)采用多元线性回归方法分别建立了梅村和河阳站的高温天气预报模型,经检验所建模型预报准确率较高。
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