非地转湿Q矢量在台风暴雨预报中的应用试验     

张亚洲  邵邹  邓文彬  赵文斌 《气象与减灾研究》2011,(4):23-29

利用NCEP/NCAR全球格点资料和TRMM卫星资料,采用改进后的非地转湿Q矢量,对0908号台风“莫拉克”引起的台湾南部特大暴雨过程进行预报应用试验.试验结果表明:(1) 850hPa高度层的非地转湿Q矢量散度及水汽通量散度分布可以预报未来24 h暴雨的落区及其雨带的分布,暴雨发生在Q矢量散度梯度大值区靠近辐合区域,...  相似文献   

An assessment of arctic sea ice concentration retrieval based on “HY-2” scanning radiometer data using field observations during CHINARE-2012 and other satellite instruments     

SHI Lijiang  LU Peng  CHENG Bin  KARVONEN Juha  WANG Qimao  LI Zhijun  HAN Hongwei 《海洋学报(英文版)》2015,(3)

A retrieval algorithm of arctic sea ice concentration (SIC) based on the brightness temperature data of “HY-2” scanning microwave radiometer has been constructed. The tie points of the brightness tempe...  相似文献   

Analysis of Water Resources Carrying Capacity of the “Belt and Road” Initiative Countries based on Virtual Water Theory     

ZHENG Xin  XU Zengrang 《资源与生态学报(英文版)》2019,10(6):574-583

Most countries along the route of the “Belt and Road” initiative are faced with a shortage of water resources. However, successful implementation of the initiative depends on water availability to support economic and social development. We designed a water resources carrying capacity evaluation index system, assigned grades and weights to each evaluation index and calculated a water resources carrying index for the 65 countries along the route. We used virtual water theory to analyze China’s net virtual water import from key bulk agricultural products through international trade. For more than half of the countries along the route, their water resources will be unable to support the economic development that will be necessary for fulfilling the goals of the Initiative. As a country with insufficient water resources carrying capacity, China is a net virtual water importer in the virtual water trade. This virtual water trade can improve China’s water resources support capacity, and ensure China’s water and food security for the future.  相似文献   

“五江一河”的洪水特征及其对跨流域调水量的制约——三评“红旗河工程”构想     

赵希涛  魏乐军 《地球学报》2020,41(1):91-105

在上文阐明"五江一河"径流量的年际变化及各节点具体径流量要比"红旗河工程"构想少得多的基础上,本文依据前人资料和成果,进一步阐述这些河流的径流量,在年内分配的不均匀性与洪水特征,及其对跨流域调水量的制约作用。研究表明:"五江一河"在11月到翌年4月,径流量只占全年总径流量的12.09%~21.84%,月均只有2.01%~3.64%,为冬、春季枯水期。其径流量只比拟调水比例20%或21%的月均值1.67%或1.75%略多。如此之少的水量,只能维系流域内的生态、生产及生活用水,而不能跨流域调水。何况"红旗河"中、下游在冬季结冰期也难以进行调水。每年6月份到9月份的4个月,"五江一河"径流量占全年径流量的53.3%~88.3%,甚至8月份的月径流量可达全年总径流量的17.8%~29.6%,属于汛期。根据径流量的实际数据,一年当中可供调水时间段只有丰水与平水期的6个月或汛期的3~4个月,要比"红旗河工程"构想的全年调水的时间大大缩短。在可资跨流域调水的每年5—10月份的时间窗口中,如果按原构想的月均调水流量占年径流量的比例1.67%(按20%计)或1.75%(按21%计)进行调水,则"五江一河"的年调水总量仅为153.25×10^8m^3(按20%计)或161.50×10^8m^3(按21%计)。仅为原构想调水量600亿m^3的1/4,充其量不足27%。在丰水与平水期的6个月中实现年径流量20%或21%的年调水比例,就意味将月调水比例从占年径流量的1.67%或1.75%增加为3.33%或3.50%。这样,"五江一河"的年调水总量可达到306.50×10^8m^3或323.00×10^8 m^3。此调水方案,导致调水河道截面积或工程规模增加一倍,但调水量也只有原构想的大约一半或至多54%。如果将调水目标强行设定为600亿m^3,那么"五江一河"的调水比例将提高到占年径流量的27.1%(南水北调西线工程开展前),或除金沙江和雅砻江之外的其它调水河流的39.0%(南水北调西线工程完成后),"红旗河"的建设规模势必大大增加,这也意味着工程难度大大增加,意味着工程建设与运行成本大大增加,意味着洪水、地震与地质灾害的危险性大大增加。"五江一河"实际可调水量比"红旗河"构想严重减少,使人不禁会对"红旗河"工程立论的科学基础和科学依据提出质疑。  相似文献   

Digital mapping of coastal boulders – high-resolution data acquisition to infer past and recent transport dynamics     

Fabian Boesl  Max Engel  Rodrigo C. Eco  JaN B. Galang  Lia A. Gonzalo  Francesca Llanes  Eva Quix  Helmut Brückner 《Sedimentology》2020,67(3):1393-1410

Coastal boulder fields provide clues to long-term frequency-magnitude patterns of coastal flooding events and have the potential to play an important role in coastal hazard assessment. Mapping boulders in the field is time and labour-intensive, and work on intertidal reef platforms, as in the present study, is physically challenging. By addressing coastal scientists who are not specialists in remote sensing, this contribution reports on the possibilities and limitations of digital applications in boulder mapping in Eastern Samar, Philippines, where recent supertyphoons Haiyan and Hagupit induced high waves, coastal flooding and boulder transport. It is demonstrated how satellite imagery of sub-metre resolution (from Pléiades and WorldView-3 imagery) enables efficient analysis of transport vectors and distances of larger boulders, reflecting variation in latitudes of both typhoon tracks and approaching angles of typhoon-generated waves. During the investigated events, boulders with a-axes of up to 8 m were clearly identified to have been shifted for up to 32 m, mostly along the seaward margin of the boulder field. It is, however, hard to keep track of smaller boulders, and the length of a-axes and b-axes including their orientation is often impossible to map with sufficient accuracy. Orthophotographs and digital surface models created through the application of an unmanned aerial vehicle and the ‘Structure from Motion’ technique provide ultra-high-resolution data, and have the potential to not only improve the results of satellite image analysis, but also those from field mapping and may significantly reduce overall time in the field. Orthophotographs permit unequivocal mapping of a-axes and b-axes including their orientation, while precise values for c-axes can be derived from the respective digital surface models. Volume of boulders is best inferred from boulder-specific Structure from Motion-based three-dimensional models. Battery power, flight speed and altitude determine the limits of the area covered, while patches shielded by the boulders are difficult to resolve. For some tasks, field mapping remains mandatory and cannot be replaced by currently available remote sensing tools: for example, sampling for rock type, density and age dating, recording of lithological separation of boulders from the underlying geological unit and of geomorphic features on a millimetre to decimetre-scale, or documentation of fine-grained sediment transport in between the boulders in supratidal settings. In terms of future events, the digital products presented here will provide a valuable reference to track boulder transport on a centimetre to decimetre-scale and to better understand the hydrodynamics of extreme-wave events on a fringing reef coastline.  相似文献   

台风激发的第二类地脉动特征及激发模式分析   总被引：3，自引：1，他引：2       下载免费PDF全文

郑露露  林建民  倪四道  祝捍皓  郑红 《地球物理学报》2017,60(1):187-197

0.003~1 Hz频段的地脉动主要来源于海浪运动与固体地球的耦合作用,台风引起的强烈海浪运动往往可使地脉动能量显著增强.由于涉及大气-海洋-固体地球三个圈层之间的复杂动量传递与耦合过程,迄今为止,关于台风激发地脉动的具体源区位置及激发机制尚存在争议.本文选取日本、中国东南沿海及台湾地区的地震台站波形连续记录,研究了2008年台风"森拉克"和"黑格比"激发地脉动的时频特征,开展相应数值模拟,并与观测数据进行了对比分析研究.结果表明台风激发第二类地脉动存在两种主要模式:(1)近岸源区激发,即台风引起波浪入射至海岸反射并与后续来波相互作用形成驻波作用于海底而激发;(2)台风中心附近源区激发,即台风中心移动过程中不同时期激发的同频率波浪相向传播、相互作用产生驻波作用于海底而激发,源区位置主要集中于台风中心左后方.此外,结合波浪再分析数据、台风风场特征,我们进一步对第二类地脉动激发过程中的影响因素进行了分析,发现:第一种模式激发的地脉动与近岸源区波浪场强度、观测点至源区距离及台风中心至海岸线距离等因素相关;而第二种模式激发的地脉动则主要受台风中心附近波浪场的频率成分与传播方向影响.  相似文献   

1992-2014年河北省流动重力资料整理     

张娜  龚燕民  苏树朋  李博 《地震地磁观测与研究》2017,38(2):112-119

系统整理河北省1992-2014年流动重力资料，利用LGADJ数据处理软件，对每期重力数据进行单期平差、多期整体平差计算，改正历史遗留问题，利用差分结果绘制145幅流动重力等值线差分图，通过具体异常点位及重力变化分析，得出：①地震前重力场变化强度与震级大小存在相关性；②流动重力观测资料地震前具有较为明显的前兆异常反应；③地震均发生在重力变化的“0”等值线附近地区。  相似文献   

基于遗传—神经网络方法的广西台风灾害评估模型研究     

李艳兰  金龙  史旭明  陈丹 《气象与环境学报》2021,37(3):139-144

选取1981—2018年影响广西且灾情记录比较完整的86个台风样本,基于台风灾害伤亡人数、直接经济损失划分灾情等级,选取致灾因子,利用遗传算法与神经网络相结合的方法建立广西台风灾害评估模型。结果表明：选取的台风灾害致灾因子与台风灾情等级之间具有显著的相关性,构建的遗传—神经网络集合预报模型对台风灾情预估效果较好,训练样本拟合一致率为86.1%,测试样本预报准确率为71.4%,其中严重和较重的台风灾情等级预报结果与实况基本一致,较轻等级的预报准确率达83.3%。  相似文献   

台风移速突变的诊断分析及路径预报     

仲荣根 《海洋湖沼通报》1994,(2):149-154

本文利用台风移动方程对作用在台风上的各力进行了诊断分析：主要力是气压梯度力和地转偏向力，二者同量级，其他各力约小１－３个量级；当台风加速移动时，气压梯度力小于地转编向力；减速移动时，气压梯度力大于地转偏向力。用预报方程计算得到的台风路径与实际台风路径在趋势上近于一致，预报误差约为２００ｋｍ。  相似文献   

南极海冰与西北太平洋台风     

张林  薛振和 《海洋预报》1996,13(1):34-40

本文利用最大熵谱分别计算了南极４个区海冰和西北太平洋台风发生频数的变化周期，并对前３年的南极海冰强弱和当年的台风发生频率数进行了逐月时间序列相关分析。  相似文献