绝对观测时段对地磁基线值观测质量影响的分析研究

基线值的观测质量是综合评价地磁台观测资料质量的一个重要指标。根据肇庆地磁台2007年9月18日进行的连续46组绝对观测数据．分析研究了相应时段基线值的稳定性及精度。研究结果表明,在磁静日的不同时段进行的绝对观测对基线值的稳定性影响较小,基线值观测精度较高。     

不同地震台站水管倾斜仪数据资料对比分析

通过对呼和浩特地震台与包头地震台DSQ型水管倾斜仪的观测环境、仪器安装运行情况及2015—2017年观测资料的观测精度、稳定性、连续性和可靠性等方面进行对比,做出质量评定,运用多种处理方法进行了系统计算和分析。使用维尼迪柯夫调和分析得出M₂波潮汐因子均方差质量指标,得出内在质量精度。应用契比雪夫多项式对年度观测资料拟合分析,从而得出仪器的相对噪声水平,进行两台指标对比分析。对台站地形变观测资料前兆观测系统做出正确的认识和客观的评价,为今后的地震前兆研究和预测具有重要的实际意义。      

大连九龙地磁台观测环境的初步分析

本文从大连九龙地磁台台址勘选、建筑材料磁性检测、台站建设以及观测数据精度等方面着手对大连九龙地磁台的观测环境进行了初步分析。分析结果表明,大连九龙地磁台的观测环境符合地震及前兆数字观测技术规范的要求。     

核旋绝对观测资料的精度分析及检验

在收集河南省及邻省地磁台的核旋绝对观测资料基础上,应用最小二乘法原理进行线性空间相关分析和精度检验。结果表明,三类地磁台核旋观测资料精度较高,F总强度不仅精度高且稳定性好。尤其是郑州-信阳台间各项精度指标均名列前茅,显示出内在质量的优越性。     

回归分析方法在检验地磁内在质量中的应用实例

本文从辽宁省1989、1990两年的地磁资料中,分别随机抽取了各半年同期总场F的资料.采用回归分析方法,计算了各地磁台与对比台的相关系数r和剩余方差s.由r、s结果,分析了它们与观测条件、仪器精度及稳定性、在规定时间内的观测组数之间的关系.对内在质量较高的总场F观测资料,γ的最低取值标准进行评估.     

广东数字化形变观测资料质量评价

通过对广东各数字化形变观测仪器潮汐因子中误差、相位滞后及仪器零漂等参量的计算,对仪器观测资料的连续性、稳定性及观测质量进行了分析和评价.分析结果认为:各台仪器的观测精度基本达到了中国地震局形变Ⅰ类台的标准;地倾斜类观测仪器精度高,稳定性好,尤其是水管倾斜仪的稳定性及精度较高;垂直摆倾斜仪的漂移较大且资料精度较低.伸缩仪...     

新安江地震地倾模拟资料与数字化观测资料的对比分析

简要介绍了新安江地震台JB型金属摆倾斜仪和VS垂直摆倾斜仪这两种模拟与数字地倾斜仪器进行记录的情况,并对模拟记录和数字记录的运行率、相关性、噪声水平、稳定性、观测精度等指标进行对比分析,找出数字化观测与模拟观测的差异,为地震台站进一步搞好数字化观测,提高观测精度提供依据。     

肇庆地磁台磁通门磁力仪对比分析

对2003年肇庆地磁台GM3和Flare-plus磁通门磁力仪的H、D、Z分量观测数据.进行了趋势变化、均值、方差一致性检验以及基线值分析,认为两台磁力仪的观测数据具有同等观测精度和一致的变化趋势,仅均值存在较小的差别,已达到了国内高精度地磁观测的水平.与英国产的Flare-plus磁力仪相比,国产GM3磁力仪的观测精度和稳定性部分性能已达到世界上高精度数字地磁观测仪器的水平,但仪器的总体稳定性,传感器探头受温度影响的程度、仪器零漂等指标还需进一步提高.     

四川四分量钻孔应变观测数据精度评价

利用邱泽华等给出的观测数据和回归分析方法,计算钻孔应变仪四分量元件的相对标定系数,并根据偏差计算自检内精度等指标,对观测数据进行质量评价。选取2017年四川四分量钻孔应变观测台网记录资料,结合四分量钻孔应变仪观测特点,计算并分析应变观测仪相对标定自检内精度,客观评价观测数据精度,结果发现,2017年仁和台四分量钻孔应变数据各月及全年相对标定系数K_i最大,偏差s最小,自检内精度数值最小,表明该台钻孔应变观测数据精度最高。分析认为,相对标定自检内精度可如实反映台站记录资料的可信度,可以更好、更客观地评价台站四分量钻孔应变观测资料质量。     

红山地磁台F值一致性的初步分析

对2007年红山地磁台GM4磁通门磁力仪、FHD质子旋进磁力仪及CZM-2核旋仪的总强度F观测数据,进行了趋势变化、均值、差值以及基线值的对比分析,认为两台数字化仪器F的观测数据具有较高的观测精度和一致的变化趋势,仅均值存在较小的差别,已达到了国内高精度地磁观测的水平.CZM-2核旋仪受人为因素影响较大,仪器精度低.     

Sq发电机电流的UT变异性及其地面磁场的重建

本文用不同经度的7对中低纬台站水平磁场分量H,求得1965年随世界时（UT）变化的S_q指数（一种描述S_q电离层发电机电流强度的地磁指数）.结果表明,S_q发电机电流不仅有显著的逐日变化,而且有很大的UT变化.UT变化主要表现在电流总强度的强弱和电流涡焦点纬度移动两方面,这意味着决定发电机过程的太阳潮汐风场和电离层电导率随UT而变.用求得的S_q指数重新构造出的S_q变化与观测值符合得较好,它不仅显示出S_q幅度逐日变化的特点,而且还能复现出S_q形态的某些逐日变异性.     

城镇化对极端降水的影响及其贡献率研究——以太湖平原地区为例

城镇化背景下极端降水事件频发,洪涝灾害问题日益突出,探讨城镇化对极端降水的影响已成为热点与难点问题.本文以长江下游太湖平原地区为例,基于区内40个雨量站长序列的逐日资料(1976-2015年),结合城镇化下土地利用/覆被和社会经济等数据,对比分析了不同城镇化阶段极端降水相关指标的时空变化规律,并定量评估不同城镇化水平对...     

The performance of benthic indicators of ecological change in Adriatic coastal lagoons: throwing the baby with the water?

The ecological quality of 127 stations from six Adriatic coastal lagoons was assessed using a suite of biotic indices: H', d, 1-lambda', Delta(*), Delta(+), W, AMBI, BOPA and FINE. The analysis indicated the difficulties in deriving and using the existing indices from benthic communities in highly variable environmental conditions in coastal lagoons. Different metrics rendered different results: the use of H' resulted in the classification of all stations as "Moderate/Poor/Bad", whereas BOPA classified the majority of the stations as "Good/High". Using Delta(+), most of the stations resulted as "Not anthropogenically impacted", while the W-statistics gave 82 stations as "Undisturbed" and 45 as "Moderately/Grossly disturbed". AMBI classified 55 stations as "High/Good" and 72 as "Moderate/Poor/Bad", whereas those were 32 and 95 with FINE, respectively. The latter, which was developed just for Italian coastal lagoons, was the most conservative among the indices studied. Yet, it showed the highest correlation with the species/abundance matrix. Using indices developed for coastal waters in lagoons can give the distorted indication that the water body is degraded, when it might be just a natural, low diversity, high abundance community, i.e. a lagoonal community. Moreover, the outcome of the use of a certain index has a financial dimension such that lagoons misclassified as being "poor status" will then require expensive remediation measures. For the lagoons studied, there is probably an adequate quality and quantity of benthic data available for making management decisions, but this study highlights the limits of the existing indices for lagoonal ecosystems. The challenge for the next future is to couple long term conservation of the natural environment with the highly productive activities carried out in lagoonal ecosystems.     

地电扰动指数GEI研究

本文应用中国大陆地区11个地电场台站5.5年（2012-01-01—2017-05-31）中磁静日和磁扰日的观测数据,并联系地电场变化敏感响应地下介质非均匀性和空间电磁活动的特点,发展了地电扰动指数,即消除静日地电变化的幅值比地电指数（GEI）.对比各台站的地电指数与地磁指数,87.43%的单台地电指数D与单台地磁指数K在数值上完全相同或相差1,93.75%的单台平均地电指数Ds与单台平均地磁指数[K+0.5]（四舍五入）相同或仅相差1,说明地电指数能用于量化界定地电扰动水平,如同地磁指数量化界定磁扰水平.地电指数将服务于地球电磁环境监测、科学研究等领域,同时也可以用来评估地电场观测数据的质量.     

浅谈新疆测震台网传输链路的改造

要做到IP到台站有很多种方式可选,根据新疆测震台网各台站的现状列举了7类不同的数据传输方式,这些数据传输方式在新疆测震台网中均得到应用,也都达到IP到台站的目的.分别对这些数据传输链路的原理及优缺点进行阐述,并结合目前各台站具体情况作链路适用性的相关分析,希望能够对其他省局台网的台站通信链路设计、改造起到参考.     

Changes in daily temperature and precipitation extremes in the Yellow River Basin, China

Spatiotemporal changes in climatic extremes in the Yellow River Basin from 1959 to 2008 were investigated on the basis of a suite of 27 climatic indices derived from daily temperature and precipitation data from 75 meteorological stations with the help of the Mann–Kendall test, linear regression method and GIS technique. Furthermore, the changes in the probability distribution of the extreme indices were examined. The results indicate: (1) The whole basin is dominated by significant increase in the frequency of warm days and warm nights, and dominated by significant decrease in the frequency of cold days and cold nights. Although trends in absolute temperature indices show less spatial coherence compared with that in the percentile-based temperature indices, overall increasing trends can be found in Max Tmax (TXx), Min Tmax (TXn), Max Tmin (TNx) and Min Tmin (TNn). (2) Although the spatial patterns and the number of stations with significant changes for threshold and duration temperature indices are also not identical, general positive trends in warm indices (i.e., summer days (SU25), tropical nights (TR20), warm spell duration indicator and growing season length) and negative trends in cold indices (i.e., frost days, ice days and cold spell duration indicator) can be found in the basin. Annual nighttime temperature has increased at a faster rate than that in daytime temperature, leading to obvious decrease in diurnal temperature range. (3) The changes in precipitation indices are much weaker and less spatially coherent compared with these of temperature indices. For all precipitation indices, only few stations are characterized by significantly change in extreme precipitation, and their spatial patterns are always characterized by irregular and insignificant positive and negative changes. However, generally, changes in precipitation extremes present drying trends, although most of the changes are insignificant. (4) Results at seasonal scale show that warming trends occur for all seasons, particularly in winter. Different from that in other three seasons, general positive trends in max 1-day precipitation (Rx1DAY) and max 5-day precipitation (Rx5DAY) are found in winter. Analysis of changes in probability distributions of indices for 1959–1983 and 1984–2008 indicate a remarkable shift toward warmer condition and a less pronounced tendency toward drier condition during the past decades. The results can provide beneficial reference to water resource and eco-environment management strategies in the Yellow River Basin for associated policymakers and stakeholders.     

The spatial–temporal variation of dry and wet periods in Iran based on comparing SPI and RDI indices

Drought is a natural hazard which can cause harmful effects on water resources. To monitor drought, the use of an indicator and determination of wet and dry period trend seem to have an important role in quantifying the drought analysis. In this paper, in addition to the comparison of Reconnaissance Drought Index (RDI) and Standardized Precipitation Index (SPI), based on the most appropriate probability distribution function, it was tried to examine the trends of dry and wet periods based on the mentioned indices. Accordingly, the meteorological data of 30 synoptic stations in Iran (1960–2014) was used and the trend was analyzed using the Mann–Kendall test by eliminating the effect of any significant autocorrelation coefficients at 95% confidence level (modified Mann–Kendall). Comparing results between the time series of RDI and SPI drought indices based on statistical indicators (RMSE?<?0.434, R²?>?0.819 and T-statistic?<?0.419) in all studied stations revealed that the behavior of the two indices was roughly the same and the difference between them was not significant. The trend analysis results of RDI and SPI indices based on modified Mann–Kendall test showed that the variation of dry and wet periods was decreasing in most of the studied stations (five cases were significant). In addition, the results of the trend line slope of dry and wet periods related to the drought indices in the studied area indicated that the slope was negative for SPI and RDI indices in 70% and 50% of stations, respectively.     

城市化对北京气象站极端气温指数趋势变化的影响

利用5个乡村气象站和北京气象站(简称北京站)1960～2008年日最高、最低气温资料,比较分析了北京地区城市和乡村极端气温指数年、季节的时间变化以及城市化对北京站各极端气温指数趋势变化的影响.结果表明:1960～2008年北京站霜冻日数、冷夜日数、冷昼日数和平均日较差均显著减少,暖夜日数、暖昼日数、平均最高气温和平均最...     

Derivation and test of ionospheric activity indices from real-time ionosonde observations in the European region

New ionospheric activity indices are derived from automatically scaled online data from several European ionosonde stations. These indices are used to distinguish between normal ionospheric conditions expected from prevailing solar activity and ionospheric disturbances caused by specific solar and atmospheric events (flares, coronal mass ejections, atmospheric waves, etc.). The most reliable indices are derived from the maximum electron density of the ionospheric F 2-layer expressed by the maximum critical frequency foF 2. Similar indices derived from ionospheric M(3000)F 2 values show a markedly lower variability indicating that the changes of the altitude of the F 2-layer maximum are proportionally smaller than those estimated from the maximum electron density in the F 2-layer. By using the ionospheric activity indices for several stations the ionospheric disturbance level over a substantial part of Europe (34°N–60°N; 5°W–40°E) can now be displayed online.     

云南地区地壳介质各向异性-快剪切波偏振特性

通过对云南遥测地震台网2000年1月1日——2003年12月31日4年资料的分析， 使用剪切波分裂SAM综合分析方法，获得了云南地区10个数字地震台站的快剪切波偏振结果. 结果表明， 云南地区大部分台站的快剪切波偏振优势方向主要为近N——S或NNW方向； 位于活动断裂上的台站的快剪切波偏振优势方向与活动断裂的走向一致；与GPS主压应变方向一致，与区域主压应力方向基本一致；少数台站的快剪切波偏振较为复杂，或与活动断裂的走向及GPS主压应变方向不一致. 这样的台站总是位于几个断裂的交会处，反映了复杂的断裂背景和复杂的应力分布特征. 快剪切波偏振优势方向代表了原地最大主压应力方向，受到区域应力场和断裂分布等多种因素的控制.