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邹璇  唐卫明  施闯  刘经南 《大地测量与地球动力学》2014,34(1):78-83

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玄松柏  申重阳  邢乐林  李辉 《大地测量与地球动力学》2014,34(1):24-27

???????????????????????????????????????α??????????????????????α????????????????????????????????2001-2006?????????????21.8 mm/a?????????????????????????????????????????????Ч???2009??????????????????????????????????6.6 mm/a????????????????  相似文献   

Seasonal variations in the water residence time in the Bohai Sea using 3D hydrodynamic model study and the adjoint method     

Luo  Chongxin  Lin  Lei  Shi  Jie  Liu  Zhe  Cai  Zhongya  Guo  Xinyu  Gao  Huiwang 《Ocean Dynamics》2021,71(2):157-173

Ocean Dynamics - The Bohai Sea is a large, semi-enclosed bay of China with a transport timescale of more than 1 year. Residence time (RT) is an important indicator used to determine the...  相似文献   

小行星引力场综述     

郭茜  鄢建国  杨轩  金炜桐  李斐 《地球物理学进展》2021,36(1):1-7

近年来小行星探测已成为各航天大国的热点,小行星引力场对研究其内部结构、组成成分、早期演化和探测器轨道设计、着陆等方面有着极其重要的作用.随着小行星探测数据的不断更新、探测任务的增多和观测技术改进,针对小行星引力场的研究也在不断增多并产生新的进展.目前获取小行星引力场的方法主要为利用探测器飞掠过程中得到的轨道跟踪数据反演引力场及根据小行星形状模型正演引力场两种方法.本文对这两种方法进行介绍,通过回顾几个取得较大进展的小行星探测任务,综述截至目前小行星引力场模型的发展现状,分析各个研究模型的优缺点,并对小行星引力场的发展进行展望.  相似文献   

Numerical investigation of the effect of seasonal variations of depthof-closure on shoreline evolution     

Xuan Tinh Nguyen  Minh Thanh Tran  Hitoshi Tanaka  Trung Viet Nguyen  Yuta Mitobe  Cong Dien Duong 《国际泥沙研究》2021,36(1):1-16

The current study presents the effects of seasonal variations in the depth-of-closure(Dc)on shoreline evolution using a numerical,one-line shoreline model.Beach erosion of the southern beach of the Nha Trang Coast,which is located in south central of Vietnam,is selected as the study area.This study area is immensely influenced by the tropical monsoon climate that has a clear pattern of large waves in the northeast monsoon season and calm waves in the non-monsoon season.The analysis of the long-term measured shoreline variations from a video-camera system has found a strong correlation of these variations to the monsoon-dominated wave characteristics in the Nha Trang Bay.Therefore,a new approach for determining the depth-of-closure with consideration of the seasonal wave climate changes is purposed in the current study.By implementing this new approach into a numerical,one-line shoreline model,it is found that the seasonal variations of Dc appear to better describe the periodical shoreline evolution due to the monsoon-dominated wave characteristics for the Nha Trang Coast.Such important findings are considered to commonly apply for monsoon-dominated coastal regions in general.These findings are useful information not only for scientific readers but also for the coastal authorities and managers in order to make better countermeasure plans against this kind of erosion mechanism in the future.  相似文献   

基于高空气球平台的下投探空:系统研发和青藏高原实验          下载免费PDF全文

Jinqiang Zhang  Hongbin Chen  Yunfei Du  Wenzheng Shao  Runping Zeng  Keping Zhu  Yi Liu  Yuejian Xuan 《大气和海洋科学快报》2021,14(3):30-35

为提高复杂地理环境和极端天气条件下的大气廓线探测能力,本文自主研发了基于平流层高空气球平台的下投探空系统,并在青藏高原开展探测评估实验.该系统主要由下投探空舱,携带降落伞的下投探空仪,下投施放装置,数据接收通讯天线和GPS模块等组成.下投探空仪测量数据通过卫星通信链路和无线电信号实时发送至数据接收机存储处理.2020年青藏高原实验中8枚下投探空仪全部成功施放,提供了合理有效的大气廓线探测数据.后续会进一步提高下投探空仪传感器性能,全面评估其探测准确性和精度.  相似文献   

江淮流域持续性强降水期间西太副高位置变异与非绝热加热的关系   总被引：5，自引：3，他引：5  

王黎娟  陈璇  管兆勇  何金海 《热带气象学报》2011,27(3):327-335

采用NCEP/NCAR逐日再分析资料及全国740站逐日降水资料,讨论了江淮流域持续性强降水期间西太平洋副高位置变动特征及其与非绝热加热的关系.通过个例合成研究发现:副高位置变异与强降水持续期间大气非绝热加热关系密切.强降水持续期间,副高北侧的江淮流域和西侧的孟加拉湾北部地区均存在强烈的视热源和视水汽汇.强降水发生前3 ...  相似文献   

方斑东风螺3个选育世代遗传多样性和遗传结构的微卫星分析     

梁园  付敬强  沈铭辉  骆轩  游伟伟  柯才焕 《海洋科学》2022,46(10):85-93

采用12个多态性微卫星标记对方斑东风螺(Babylonia areolata)泰国选育系TF₄~TF₆连续3代选育群体的遗传多样性与遗传结构进行了分析。3个群体的多态信息含量分别为0.730、0.717和0.708,均高于0.5,表现出较高的多态性。平均等位基因数(A)、有效等位基因数(A_e)、观测杂合度(H_o)、期望杂合度(H_e)和Shannon’s信息指数(I)的变化范围分别为11.667~12.583、6.334~6.915、0.658~0.672、0.737~0.787和1.837~2.003,整体呈降低趋势,但差异并不显著(P>0.05)。分子方差分析结果显示,群体间的遗传变异仅占总变异的0.95%;群体间的遗传分化系数(F_st)介于0.00569~0.01324,处于低等分化水平(F_st<0.05)。主坐标分析和STRUCTURE分析结果显示,3个群体呈现出相似的遗传背景和遗传结构。以上研究结果表明,经过连续多代的人工选育,方斑东风螺选育群体保持着较高的遗传多样性水平,遗传变异和遗传分化水平较低,遗传结构趋于稳定,仍具有较高的遗传选育潜力。  相似文献   

RELATIONSHIP BETWEEN RESORT LIFE CYCLE AND RESIDENTS＇ PERCEPTION AND ATTITUDE -A Case Study of Putuo Mountain     

YANGXiao-zhong LULin ZHANGGuang-sheng LUSong XUANGuo-fu 《中国地理科学(英文版)》2004,14(1):90-96

The change in residents‘ perception and attitude and resort life cycle are the basic problems in the course of resort evolution. This thesis sets up the dynamic model of residents‘perception and attitude, analyzes the linkage between residents‘ perception and attitude and the influential factors of resort life cycle, and finally, with a case study of Putuo Mountain, preliminarily discusses the relationship between resort life cycle and residents‘perception and attitude. The research findings show that, although within development stage of life cycle, Putuo Mountain has already presented some signs of mature stage. The on-the-spot survey also indicates that, the local residents‘ positive perception is stronger than their negative perception. But compared with residents in some other coastal resorts such as Haikou and Sanya, negative perception of residents in Putuo Mountain is more evident, as the result of the smaller tourism carrying capacity in Putuo Mountain. There are some influential factors that have great impact on tourism carrying capacity in Putuo Mountain: tourist-resident number ratio, residents‘ benefit-cost ratio and characteristics of tourism resources. And the less influential factors are residents‘ demographic character, tourist behavioral character and cultural differences between local residents and tourists. Therefore, effective measures should be taken to adjust the structure of tourism product for the purpose of expanding tourism carrying capacity, lowering its pressure, lessening residents‘ environmental cost and enhancing their positive perception, which is the most essential prerequisite for the maturation of life cycle in Putuo Mountain.  相似文献   

Residues of selected antibiotics in water and mud from shrimp ponds in mangrove areas in Viet Nam   总被引：1，自引：0，他引：1  

Le TX  Munekage Y 《Marine pollution bulletin》2004,49(11-12):922-929

In recent years, antibiotics have been used widely in intensive shrimp culture and this may lead to their contamination of the environment. Surveys on residues of trimethoprim (TMP), sulfamethoxazole (SMX), norfloxacin (NFXC) and oxolinic acid (OXLA) in water and mud in shrimp ponds in mangrove areas were conducted in the north as well as in south of Viet Nam in July and August, 2002. The results show that these antibiotics are found in all samples in both shrimp ponds and surrounding canals. The highest concentrations of TMP, SMX, NFXC and OXLA are 1.04, 2.39, 6.06, and 2.50 ppm in water samples; and 734.61, 820.49, 2615.96, 426.31 ppm (based on wet mud weight), respectively. The comparison of antibiotics residues between study sites and types of shrimp ponds will be discussed in this paper. The results also suggest that antibiotics residues may cause harmful effect on ecosystems in the study sites.  相似文献