近58年福泉日照时数变化特征分析

本文利用福泉市气象站1961-2018年的日照时数数据,应用线性趋势发、M-K突变分析法,对福泉市日照资料序列进行分析,结果表明：近58年福泉市年日照时数呈现减少的趋势,突变出现2000年。月分布上只有2月是增加的趋势,其余月份日照时数呈现减少的趋势。     

中国降水的季节性

本文使用一套基于中国气象局所属的2416个台站数据所得的高分辨降水资料,对1961~2013年中国降水季节性进行了研究。就全国平均而言,各季节降水占全年降水百分率最高的为夏季（56.5%）,春季（19.3%）和秋季（18.9%）次之,冬季（5.3%）最少;针对不同地区,各季节降水百分率存在很大差异,例如华南春季降水最多、东北至高原一线秋季降水大于春季降水。春、夏两季降水百分率高值（低值）区域略呈现出降水百分率减少（增多）趋势,秋季整体上略微减少,冬季则显著增加;季节降水百分率的变率整体表现为夏季大而冬季小,其西部的变率与地形为显著负相关,东部变率的大值区位置随季节变化;秋冬两季的降水百分率变率有显著增加,各季节不同地区变率的变化趋势存在明显差异。     

庞西垌地区地球化学异常圈定方法讨论

庞西垌地区位于钦杭成矿带南段,是主要的贵金属、有色金属成矿区。区内构造复杂,岩浆活动频繁。基于庞西垌地区水系沉积物测量数据,以Au、Ag元素含量为例,分别利用传统统计学方法、趋势面法和分形方法计算其异常下限值,并圈定地球化学异常。通过对3种方法计算过程及应用效果的对比,分析了3种方法应用于本研究区的效果,进而揭示了复杂地质背景下,最适用于圈定地球化学异常的方法。     

Identification of trends in rainfall,rainy days and 24 h maximum rainfall over subtropical Assam in Northeast India

Trends in rainfall, rainy days and 24 h maximum rainfall are investigated using the Mann-Kendall non-parametric test at twenty-four sites of subtropical Assam located in the northeastern region of India. The trends are statistically confirmed by both the parametric and non-parametric methods and the magnitudes of significant trends are obtained through the linear regression test. In Assam, the average monsoon rainfall (rainy days) during the monsoon months of June to September is about 1606 mm (70), which accounts for about 70% (64%) of the annual rainfall (rainy days). On monthly time scales, sixteen and seventeen sites (twenty-one sites each) witnessed decreasing trends in the total rainfall (rainy days), out of which one and three trends (seven trends each) were found to be statistically significant in June and July, respectively. On the other hand, seventeen sites witnessed increasing trends in rainfall in the month of September, but none were statistically significant. In December (February), eighteen (twenty-two) sites witnessed decreasing (increasing) trends in total rainfall, out of which five (three) trends were statistically significant. For the rainy days during the months of November to January, twenty-two or more sites witnessed decreasing trends in Assam, but for nine (November), twelve (January) and eighteen (December) sites, these trends were statistically significant. These observed changes in rainfall, although most time series are not convincing as they show predominantly no significance, along with the well-reported climatic warming in monsoon and post-monsoon seasons may have implications for human health and water resources management over bio-diversity rich Northeast India.     

Spatial Variation of Sea Level Trend Along the Bangladesh Coast

The Bangladesh coast is threatened by rising sea level due to various factors. The results based on the analysis of past 22 years of tidal data of the Bangladesh coast reveal that the annual mean tidal level in the eastern Bangladesh coast is rising at an alarmingly high rate of 7.8 mm/year, which is almost twice the observed rate in the western region. This type of sea level trend seems to be the result of changing local conditions like increased precipitation and land subsidence during the recent decades. It seems that the higher rate of land subsidence in the eastern Bangladesh coast is the main causative factor for the steeper sea level trends there. The differential sea level trends show that the subsidence component in the sea level rise may be as high as 4 mm/year in the eastern Bangladesh coast. However, this needs to be verified with actual geological observations.     

我国海洋溢油事故特征与趋势分析

文章通过对1971—2011年期间发生在我国沿海海域内溢油量在50t以上的海洋溢油事故数据的收集调查,分析了海洋溢油事故的年际变化、事故原因、油品种类、事故发生地区、事故等级等的统计特征。结果表明:1971—2011年我国50t以上海洋溢油事故共发生81起,溢油总量为49 667t;碰撞是造成海洋溢油事故的最主要原因,占总溢油次数的48.2%;污染物类型主要为燃油、原油和柴油;广东省和山东省是发生溢油事故的大省;特别重大溢油事故发生频率为0.32次/a。     

1998年1月10日张北-尚义6.2级地震前昌平地震台应变资料的异常变化分析

分析了昌平地震台体应变、线应变及差应变等观测资料在１９９８ 年１ 月１０日张北尚义６ ．２ 级地震前的异常变化．结果表明：该次地震前昌平台的应变观测资料出现了明显的趋势异常;体应变的异常时间与震级有较好的相关性;差应变资料显示了短临异常;由线应变资料计算的主应变方向在地震前逐渐向震中偏转; Ｍ２ 波潮汐因子也出现了明显的异常变化     

宁波庄市井水位异常变化的地震前兆信息分析

着重分析了近年来庄市井水位在贡海地震区３次ＭＳ〉５．０地震前的异常特征。通过分析得到的认识是,该井水侠在５．０级以上地震前大都存在０．５ａ以上的趋势异常和年变规律的变化,震前１－２个月出现较丰富的短临前兆信息,如水位固体潮畸变,日潮差波幅增大,阶跃等微动态变化。     

青海强震等间距特征研究及未来强震趋势预测

利用塑性力学和地震力学以及前人的研究结果,提出了一种新的地震等间距特征机理的解释方法,认为地夺等间距特征的成因是中、下地壳的滑移网同上部地壳的相互作用。其动力源为环太平洋地震带和欧亚地震带的联合作用。利用青海强震分布的等间跨特征对未来可能发生强震的地点进行趋势预测。     

张家口地震台连续重力异常分析

张家口地震台gPhone连续重力观测仪潮汐因子自2016年6月出现持续下降的趋势变化,累计变化量达到7×10-3。分析重力残差曲线,异常出现时同期残差数据未出现同步变化;将去零漂前后潮汐因子的变化情况进行对比分析,发现潮汐因子变化趋势一致,排除仪器调零影响;针对新建楼房可能引起的重力变化,建立了重力正演模型,计算结果显示,新建楼房的荷载变化仅能引起0.31微伽的重力变化,表明新建楼房对重力观测的影响较弱。综合分析认为,此次出现的重力潮汐因子下降趋势异常可能为前兆异常,需加强跟踪分析。