高密度空间采样地震数据特点分析   总被引：3，自引：0，他引：3  

蔡希玲  刘学伟  邓春艳  吕英梅 《应用地球物理》2006,3(1):48-54

中国陆相沉积盆地的地质结构复杂,储层岩性的多变,需要有高精度的勘探方法。高密度空间采样是提高地震勘探精度的一项新技术。本文简要说明了点激发和点接收技术,分析高密度空间采样的野外工作方法,介绍了Gijs j．o．Vermeer提出的对称采样原理,从波场连续性的角度探讨了高密度空间采样技术。重点分析高密度空间采样数据的特点, 即:高密集的初至波有利于近地表结构的调查,可提高静校正的精度;小偏移距、小点距接收增加了浅层的有效覆盖次数,提高浅层反射的成像精度; 对规则噪声可实现无假频采样,室内的噪声分析和噪声压制的精度随着提高;高密度采集使波场连续性增强,使得各种数学变换的精度提高,有利于不同波场的分离。最后指出高密度空间采样地震勘探技术的难点在于室内数据处理,针对海量数据的分析和处理方法还需要进行深入细致的研究工作。  相似文献   

Fine upper crustal structure of Jiashi strong earthquake swarm region in Xinjiang inferred from high resolution seismic refraction profile data     

徐朝繁张先康  段永红杨卓欣酆少英  胡修奇 《地震学报(英文版)》2006,19(1):62-71

Introduction Jiashi-Artux area in southwest Xinjiang is one of the most active earthquake provinces at pre-sent in Chinese mainland. In the last century, about 3/4 strong earthquakes in Chinese mainland hit this area, and especially from January 21 to April 16 in 1997, 7 earthquakes with the magnituderanging from 6.0 to 6.9 occurred in a very small area of 9 km×18 km near Jiashi (ZHU et al, 1998). It has never taken place before in Chinese mainland that a series of strong earthquakes shoo…  相似文献   

A comparative study of geothermal and meteorological records of climate change in Kamchatka     

V. Čermák  J. Šafanda  L. Bodri  M. Yamano  E. Gordeev 《Studia Geophysica et Geodaetica》2006,50(4):675-695

To reconstruct the recent climate history in Kamchatka, a series of repeated precise temperature logs were performed in a number of boreholes located in a broad east-west strip (between 52 and 54°N) in the central part of Kamchatka west of Petropavlovsk-Kamchatski. Within three years more than 30 temperature logs were performed in 10 holes (one up to six logs per hole) to the depth of up to 400 metres. Measured temperature gradients varied in a broad interval 0 to 60 mK/m and in some holes a sizeable variation in the subsurface temperatures due to advective heat transport by underground water was observed. Measured data were compared with older temperature profiles obtained in the early eighties by Sugrobov and Yanovsky (1993). Even when older data are of poorer precision (accuracy of about 0.1 K), they presented valuable information of the subsurface temperature conditions existing 20–25 years ago. Borehole observations and the inverted ground surface temperature histories (GSTHs) used for the paleoclimate reconstruction were complemented with a detailed survey of meteorological data. Namely, the long-term surface air temperature (SAT) and precipitation records from Petropavlovsk station (in operation since 1890) were used together with similar data from a number of local subsidiary meteo-stations operating in Central Kamchatka since 1950. Regardless of extreme complexity of the local meteorological/climate conditions, diversity of borehole sites and calibration of measuring devices used during the whole campaign, the results of the climate reconstruction supported a general warming of about 1 K characteristic for the 20th century, which followed an inexpressive cooler period typical for the most of the 19th century. In the last three to four decades the warming rate has been locally increasing up to 0.02 K/year. It was also shown that the snow cover played a dominant role in the penetration of the climate “signal” to depth and could considerably smooth down the subsurface response to the changes occurred on the surface.  相似文献   

Variations of <Emphasis Type="Italic">δ</Emphasis><Superscript>18</Superscript>O in precipitation from the Muztagata Glacier,East Pamirs     

Li Zhen  Yao Tandong  Tian Lide  Xu Baiqing  Wu Guangjian 《中国科学D辑(英文版)》2006,49(1):36-42

Expeditions to Muztagata (in the eastern Pamirs) during the summer seasons of 2002 and 2003 collected precipitation samples and measured their oxygen isotopes. The δ ¹⁸O in precipitation displays a wide range, varying from −17.40‰ to +1.33‰ in June-September 2002 and from −22.31‰ to +4.59‰ in May-August 2003. The δ ¹⁸O in precipitation correlates with the initial temperature of precipitation during the observing periods. The positive correlation between δ ¹⁸O and temperature suggests that δ ¹⁸O can be used as an indicator of temperature in this region. The δ ¹⁸O values in fresh-snow samples collected from two snow events at different elevations on the Muztagata Glacier show a strong “altitude effect”, with a ratio of nearly −0.40% per 100 m from 5500 m to 7450 m.  相似文献   

Study on NDVI- T _s space by combining LAI and evapotranspiration     

Han Lijuan  Wang Pengxin  Yang Hua  Liu Shaomin  Wang Jindi 《中国科学D辑(英文版)》2006,49(7):747-754

This paper focuses on interpreting the different spatial relationships between NDVI and T _s, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Temperature-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and T _s are useful for describing, validating and updating land surface models.  相似文献   

δ18O record and temperature change over the past 100 years in ice cores on the Tibetan Plateau     

YAO Tandong  GUO Xuejun  Lonnie Thompson  DUAN Keqin  WANG Ninglian  PU Jianchen  XU Baiqing  YANG Xiaoxin  SUN Weizhen 《中国科学D辑(英文版)》2006,49(1)

The 213 m ice core from the Puruogangri Ice Field on the Tibetan Plateau facilitates the study of the regional temperature changes with its δ18O record of the past 100 years. Here we combine information from this core with that from the Dasuopu ice core (from the southern Tibetan Plateau), the Guliya ice core (from the northwestern Plateau) and the Dunde ice core (from the northeastern Plateau) to learn about the regional differences in temperature change across the Tibetan Plateau. The δ18O changes vary with region on the Plateau, the variations being especially large between South and North and between East and West. Moreover, these four ice cores present increasing δ18O trends, indicating warming on the Tibetan Plateau over the past 100 years. A comparative study of Northern Hemisphere (NH) temperature changes, the δ18O-reflected temperature changes on the Plateau, and available meteorological records show consistent trends in overall warming during the past 100 years.  相似文献   

Relationships between δ18O in summer precipitation and temperature and moisture trajectories at Muztagata, western China   总被引：1，自引：0，他引：1  

YU Wusheng  YAO Tandong  TIAN Lide  LI Zhen  SUN Weizhen  WANG Yu 《中国科学D辑(英文版)》2006,49(1)

Based on summer observations of stable isotope of precipitation at Muztagata, western China, during 2002―2003, this paper presents the relationship between δ18O in precipitation and air temperature, and discusses the effect of moisture transport on δ18O in precipitation. Results show that air temperature correlates positively with δ18O in precipitation, and the temperature effect controls the δ18O of precipitation in this area. The Muztagata region exhibits high δ18O values in summer precipitation, similar to those shown at stations in adjacent regions. According to the results of our model set up to trace the moisture trajectories, the westerlies and local moisture circulation contribute to variations of oxygen isotopes in precipitation. In addition, the impacts of the moisture transport distance, the moisture transport level, and the incursion of the polar air mass also influence the variations of δ18O in precipitation. The moisture origins and transport mechanisms also contribute to the variation of δ18O in precipitation at Muztagata.  相似文献   

东北夏季气温变异的区域差异及其与大气环流和海表温度的关系   总被引：17，自引：2，他引：17       下载免费PDF全文

孙建奇  王会军 《地球物理学报》2006,49(3):662-671

利用1951～2000年中国东北地区23个台站资料，对东北夏季气温的时空分布进行了研究，发现其变化除具有整体的一致性外，东北南部和北部的夏季气温在年际和年代际时间尺度都表现出很大不同，其中北部区域的夏季气温在1987～1988年间发生了一次显著的气候突变. 另外，剔除夏季气温全区一致变化的年份后，南北两区夏季气温与大气环流和海表温度的关系表明：突变前，影响北部和南部冷/热夏季的大气环流形势存在显著的不同，关键海域亦有很大差异：影响南部的为中纬度西太平洋和印度洋部分海域，影响北部的主要为ENSO事件；突变后，两区的夏季气温及相应大气环流和关键海区都趋于一致. 在整个分析时段内，北部夏季气温与东亚夏季风存在显著负相关，而南部的关系则不明显.  相似文献   

利用卫星云图定量分析副热带高压活动的方法及应用     

陈冰廉  林宗桂 《广西气象》2006,27(1):1-3,9

利用数字图像处理方法，设计了一种多重处理的算法，从卫星云图提取定量信息，定量描述副高强度和演变趋势，并应用于预报业务。应用实践表明，这些方法具有客观、定量、自动等优点，在实际使用中可客观定量地跟踪和预报副高演变，对做好广西前汛期暴雨预报有较大的帮助。  相似文献   

多种降阻材料搭配在变电站接地网改造中应用   总被引：20，自引：0，他引：20  

周开春  何明峰 《广西气象》2006,27(3):51-54

在北海市三塘110KV变电站接地网系统改造工程实践中，通过不等长接地体技术及多种将阻材料搭配使用，克服了原接地网接地电阻值增大因素，并对变电站接地网改造和施工工艺进行设计。  相似文献