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121.
122.
汪宝山 《高原山地气象研究》2000,20(4)
用通报年份的前期相关因子和历年比较,通过相似与不相似系数的计算,客观的找出前期天气形势演变的最相似年份,如果预报因子和预报对象存在着因果关系,就可通过相似年份制作天气预报. 相似文献
123.
Jianming Zhu Baoshan Zheng Zhongliang Wang Huayun Xiao Dajun Mao Hongcan Su 《中国地球化学学报》2000,19(2):161-166
Within the range of 0.01 km mini-landscape in Yutangba, Enshi, Hubei Province, the content of Se in corn is very high. The average Se contents in root, stem, leaf and seed of corn were estimated to be 4.36±3. 27mg/kg, 3.08±2.24 mg/kg, 9.74±7.62mg/kg, and 8.07±5.02mg/kg, respectively. The research results show that there is a significantly positive correlation between corn selenium and soil selenium, and thus according to the distribution of Se in corn, three subregions can be divided in Yutangba. The content of selenium in corn is controlled by that of soil. A little variation in selenium content in soil will lead to a considerable corresponding variation in corn. So it is deduced that the organs that contain relatively high Se in plants may be used as a sensitive selenium indicator of Se levels in the environment. 相似文献
124.
频率-波数域方法的发展及其在台阵数据分析中的应用 总被引:1,自引:0,他引:1
频率-波数域分析(Frequency-wavenumber analysis,简称F-K analysis)是一种常用的台阵数据处理方法,在地震学等领域具有良好的应用效果。本文通过介绍F-K分析的基本原理及各种改进的F-K分析方法,并结合实例综述了其在台阵数据分析中的几种应用,包括检测微弱信号源、分析噪声特征、提取面波频散曲线、台阵设计这4方面;通过对这些研究的回顾,本文总结了该研究领域的新进展及需要注意的问题,并对F-K成像新的应用前景进行了分析和展望。 相似文献
125.
基于云计算的九分量噪声互相关函数计算及其在China Array密集台阵数据的应用 总被引:1,自引:0,他引:1
提出一种基于云计算的九分量噪声互相关函数的计算方法,可以利用弹性的云计算服务,实现海量噪声互相关函数计算的分解和加速。本文将此技术应用于"中国地震科学台阵探测——南北地震带北段"674个宽频带台站2014~2015年的三分量连续记录,获取了所有台站间的九分量噪声互相关函数。总体计算共完成了约22万条台站对路径上近14.9亿条单天互相关函数的计算,整体平均耗时约为10.2h,完成等量计算,传统计算模式需要耗时近6个月,基于云计算的NCF计算技术实现了近400倍的加速,并可以弹性地扩充。分析了所得九分量噪声互相关函数中瑞利面波的ZH振幅比,并与天然地震中瑞利面波的振幅比进行了比较,验证了计算结果的可靠性。基于云计算的噪声互相关函数计算方法,为利用现代计算技术处理海量数据提供了重要参考。 相似文献
127.
Large volume airgun arrays have been widely used in exploring and monitoring underground structures for nearly a decade. Nowadays, large volume airgun arrays adopt the synchronous excitation mode, and source characteristics are controlled by the source signal of a single airgun, which to some extent limits its application. In order to realize the asynchronous excitation of the airgun array, we developed a new firing system for the airgun array, and carried out a field experiment in the Binchuan Fixed Airgun Signal Transmission station to study the influences of the asynchronous excitation on the source signal. The experimental results show that:the newly developed airgun array firing system can ignite the airguns according to the setting time series with high precision. By designing the excitation time series, the asynchronous excitation can enhance the energy of airgun source signal at 3-5Hz, and reduce the energy of pressure pulse wave at 6-18Hz. The signal detection capability of the asynchronous excitation with time series mode is equivalent to the synchronous excitation. 相似文献
128.
The distribution of heavy metal in surface soils and their uptake by plants along roadside slopes in longitudinal range gorge region,China 总被引:1,自引:1,他引:0
Metal distributions (Cd, Cr, Cu, Ni, Pb and Zn) in the soils and plants were investigated in roadside surface soils and grass
herbage collected from two study sites adjacent to Mangshi–Ruili and Dali–Baoshan highways. At each study site, soil and plant
samples were collected along two roadside slopes with distances of 5, 10, 20, 50, 100, and 200 m away from the highway. Results
show that the enrichment of heavy metals in the surface soils and plants along the road is caused by the highway, and it decreases
with the increasing distance from the road. Metal concentrations in the soils and plants along the downslope are higher than
those in the upslope along the road. The six types of metals investigated in this research mainly distributed within 200 m
from the highway. Four types of relationships between metal uptake by plants from soils and the distance were found and their
clear distinctions of Cr, Cu, Pd, Ni and Zn uptake by plants were also investigated. 相似文献
129.
湿地景观格局变化研究进展 总被引:45,自引:1,他引:44
湿地是自然界最富生物多样性的生态景观,具有重要的生态功能。湿地景观格局是各种生态过程综合作用的结果,具有高度的景观异质性,对景观的功能和过程有着显著的影响。湿地生态系统是世界上受威胁最为严重的生态系统之一,在自然因素和人类活动的影响下发生了大面积的转化或丧失。本文从湿地景观格局研究方法、面积变化、景观类型转化、驱动力以及动态模型、湿地景观格局指数以及湿地景观格局与气候变化之间的关系等方面综述了湿地景观格局变化的研究进展,指出湿地景观格局变化及其生态效应和高原湿地景观格局变化与气候变化之间的关系是未来研究的重点领域。 相似文献
130.
Zhaoling Zhang Shiliang Liu Shikui Dong Wei Fu Baoshan Cui 《Frontiers of Earth Science》2009,3(4):389-396
The construction of roads has direct and indirect impacts on soil erosion, with spatio-temporal variations existing among
different levels of road zones. Aiming to quantitatively analyze the soil loss, this paper explored the relationship between
the erosion of soil and its distance from the road in Fengqing county, Southwest China in 1987 and 2004, respectively. The
average soil erosion was calculated and expressed with grid map using universal soil loss equation (USLE) model based on GIS
and RS. Along the different levels of roads classified as trunk, county, town, village and unpaved road, the buffer zones
were subdivided into five stripes, each of which was 200 meters wide. The average soil erosion modulus of each buffer zone
was also counted. Results show that the soil loss decreases with increasing distance to the road except rare trunk roads in
the region. In addition, the declined intensity varies with the different levels of roads. Soil erosion was more serious along
the lower level road than the higher ones. And soil erosion was more severe for all levels of roads in 1987 than those in
2004 because much more rainfalls affected the situation of soil erosion in 1987. 相似文献