地震烈度仪数据传输协议     

黄文辉  吴永权  吴叔坤  苏柱金  欧阳龙斌 《地震地磁观测与研究》2017,38(5):155-158

中国地震烈度速报与预警系统建设即将全面启动,面对未来地震预警系统中大量地震烈度仪的接入,为了方便数据的传输、汇集、共享、使用和管理,设计一种地震烈度仪数据传输协议。本文介绍烈度仪数据传输协议设计思想和特点,并给出一种参考实现,重点表述各个模块的功能和逻辑关系。  相似文献   

黑潮近岸分支流在2017年9月与2019年9月差异的研究     

燕杰  侯一筠  刘泽 《海洋与湖沼》2021,52(4):813-822

通过对比2017年9月和2019年9月的温盐大面观测数据,发现东海陆架上黑潮近岸分支流的路径在两次观测中存在显著差异。2019年9月黑潮近岸分支流中上游的路径相较2017年9月明显的东向偏移,造成黑潮次表层水入侵东海近岸海域的强度较弱。为了探究黑潮近岸分支流的上述显著年际差异的原因,利用卫星高度计数据和再分析风场数据,通过分析大面观测同期的绝对海表动力高度、地转流场以及海表风场的差异,阐述了黑潮近岸分支流路径产生显著年际差异的动力机制。2019年8—9月东海海表较2017年8—9月盛行更强的西南向沿岸季风,强的西南向沿岸风通过埃克曼输运促使水体向岸堆积并在近岸区域沿岸西南向堆积。因此, 2019年8—9月东海近岸海域的跨岸方向压力梯度与2017年8—9月相比较小而沿岸压力梯度则较大。2019年8—9月,受压力梯度分布的影响,东海近岸海域产生西南向的沿岸地转流和离岸地转流。其中西南向的沿岸地转流会在底部生成离岸的底埃克曼流,离岸底埃克曼流和离岸地转流共同抑制了黑潮近岸分支流的向岸入侵。这导致2019年9月黑潮近岸分支流的路径向东偏移,黑潮次表层水入侵浙江近海及长江口区域的强度随之减弱。通过分析研究实际观测案例,阐述了风影响黑潮近岸分支流入侵东海近岸海域的动力机制,同时明确指出海表风场会从黑潮近岸分支流的中上游区域改变其路径,进而对黑潮入侵东海近岸海域产生重要影响。  相似文献   

浙江省梅汛期洪涝灾情分析和预测   总被引：1，自引：0，他引：1       下载免费PDF全文

张文坚  庄锡潮  王镇铭  王卫红 《气象》2001,27(2):32-35

通过所构设的雨涝强度、雨涝影响面积等统计量来估计灾情，有较高的正确率，能估计出极端情况，为灾害评估工作提供了新的思路。  相似文献   

Potential wind erosion rate response to climate and land‐use changes in the watershed of the Ningxia–Inner Mongolia reach of the Yellow River,China, 1986–2013          下载免费PDF全文

Heqiang Du  Tao Wang  Xian Xue 《地球表面变化过程与地形》2017,42(13):1923-1937

Climate and land‐use changes could strongly affect wind erosion and in turn cause a series of environmental problems. Thus, the objective of this study was to assess potential wind erosion rate (PWER) response to climate and land‐use changes in the watershed of the Ningxia–Inner Mongolia Reach of the Yellow River (NIMRYR), China. The watershed of NIMRYR suffers from serious wind erosion hazards, and over recent decades, wind erosion intensity and distribution has changed, following climate and land‐use changes. To understand these processes in the NIMRYR watershed, the Integrated Wind Erosion Modelling System (IWEMS) and the Revised Wind Erosion Equation (RWEQ) were used to calculate the PWER under different climate conditions and land‐use scenarios, and to assess the influences of climate and land‐use changes on the PWER. The results show the PWER in the whole watershed had a significant declining trend from 1986 to 2013. The results of the relationship among PWER, climate change, and land‐use changes showed that climate change was the dominant control on the PWER change in this watershed. Compared to the period 1986–1995, the average PWER decreased 23.32% and 64.98% as a result of climate change in the periods 1996–2005 and 2006–2013, respectively. In contrast with climate change, the effects of land‐use changes on the average PWER were much lower, and represented a change in PWER of less than 3.3% across the whole watershed. The study method we used could provide some valuable reference for wind erosion modelling, and the research results should help climate and land‐use researchers to develop strategies to reduce wind erosion. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Variation in reach‐scale thalweg‐migration intensity in a braided reach of the lower Yellow River in 1986–2015          下载免费PDF全文

Jie Li  Junqiang Xia  Meirong Zhou  Shanshan Deng  Xiaolei Zhang 《地球表面变化过程与地形》2017,42(13):1952-1962

Thalweg migration of an alluvial river plays a key role in channel evolution, which may influence the effect of existing river training works and biodiversity on floodplains, and cause losses in riparian land and property. The braided reach of the Lower Yellow River underwent continuous channel aggradation during the period from 1986 to 1999, and then remarkable channel degradation in 1999–2015 owing to the state of operation of the Xiaolangdi Reservoir in 1999. Here we quantify associated thalweg migration changes and identify the key influencing factor in the braided reach. Thalweg‐migration distances and intensities at section‐ and reach‐scales were calculated during the past 30 years from 1986 to 2015, in order to investigate the characteristics of thalweg migration in the reach. There was a 47% reduction in the reach‐scale thalweg‐migration distance and a 35% reduction in the corresponding migration intensity after the reservoir operation. It is also revealed that fluvial erosion intensity is a dominant factor in controlling the thalweg migration, based on the investigation into various influencing factors in the study reach. The thalweg‐migration intensity of the braided reach can be expressed as a power function of the previous four‐year average fluvial erosion intensity. The calculated thalweg‐migration intensities in 1986–2015 using the proposed relation generally agree with the observed data. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

An approach to analysing plot scale infiltration and runoff responses to rainfall of fluctuating intensity   总被引：1，自引：0，他引：1       下载免费PDF全文

David Dunkerley 《水文研究》2017,31(1):191-206

Simulated rainfall of fluctuating intensity was applied to runoff plots on bare dryland soils in order to explore a new method for analysing the non‐steady‐state responses of infiltration and overland flow. The rainfall events all averaged 10 mm/h but included intensity bursts of up to 70 mm/h and lasting 5–15 min, as well as periods of low intensity and intermittency of up to 25 min. Results were compared with traditional steady‐state estimates of infiltrability made under simulated rainfall sustained at a fixed intensity of 10 mm/h. Mean event infiltration rate averaged 13.6% higher under fluctuating intensities, while runoff ratios averaged only 63% of those seen under constant intensity. In order to understand the changing soil infiltrability, up to three affine Horton infiltration equations were fitted to segments of each experiment. All equations had the same final infiltrability f_c, but adjusted values for coefficients f₀ (initial infiltrability) and K_f (exponential decay constant) were fitted for periods of rainfall that followed significant hiatuses in rainfall, during which subsurface redistribution allowed near‐surface soil suction to recover. According to the fitted Horton equations, soil infiltrability recovered by up 10–24 mm/h during intra‐event rainfall hiatuses of 15 to 20‐min duration, contributing to higher overall event infiltration rates and to reduced runoff ratios. The recovery of infiltrability also reduced the size of runoff peaks following periods of low intensity rainfall, compared with the predictions based on single Horton infiltration equations, and in some cases, no runoff at all was recorded from late intensity peaks. The principal finding of this study is that, using a set of affine equations, the intra‐event time variation of soil infiltrability can be tracked through multiple intensity bursts and hiatuses, despite the lack of steady‐state conditions. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

1975年海城M_S7.3地震强地面运动模拟          下载免费PDF全文

赵宏阳  陈晓非 《地球物理学报》2017,60(7):2707-2715

地震强地面运动预测对工程的抗震设计,地震危害性分析以及减轻特定地区可能发生的大地震所造成的灾害具有重要的作用.本文根据辽宁省海城地区的地质资料和发生于1975年2月4日辽宁省海城市的M_S7.3地震资料,分别构造了海城地区的地下速度结构和海城地震的震源模型,并且使用可以准确描述地形起伏的曲线网格有限差分方法计算了海城地震的波场传播过程.通过对计算得到的波场快照、合成理论地震图以及地震烈度的分析表明：（1）震源模型、地下的速度结构和地形起伏对海城地震的波场传播模拟具有重要的影响,它们所产生的近断层效应、方向性效应和盆地效应明显;（2）通过计算得到的海城地震的理论烈度分布与通过震后调查得到的烈度分布大体符合,验证了本文所构造的震源模型和速度结构的合理性.  相似文献   

日侧极光弧的发光强度与沉降电子能谱的相关关系          下载免费PDF全文

丘琪  杨惠根  陆全明  胡泽骏 《地球物理学报》2017,60(2):489-498

本文利用中国北极黄河站多波段全天空极光观测数据,选取稳定的日侧极光弧,统计研究了极光强度比I_(557.7)/I_(630.0)与极光发光强度I_(557.7)的相关关系.发现I_(557.7)在午前暖点和午后热点区附近出现极大值,分别为2.2kR和2.9 kR;而I_(630.0)在磁正午出现极大值,为1.5kR.当I_(557.7)从0.1kR增加到10kR时,极光强度比I_(557.7)/I_(630.0)也由0.2增加到9.结合DMSP卫星探测的沉降粒子能谱数据,找到17个DMSP卫星穿越黄河站上空极光弧的事件,共穿越40条极光弧.得到了沉降电子的平均能量正比于极光强度比I_(557.7)/I_(630.0),沉降电子的总能通量正相关于极光强度I_(557.7)的关系式.利用该关系式反演所有极光弧的电子能谱,发现在午前和午后扇区,产生极光弧的沉降电子主要来源于等离子体片边界层;在高纬出现强度较弱的弧,对应等离子体幔区域.在磁正午附近,沉降电子的平均能量较低,极光弧处于低纬一侧,粒子源区主要是低纬边界层.  相似文献   

A wind tunnel investigation of particle segregation,ripple formation and armouring within sand beds of systematically varied texture          下载免费PDF全文

Cheryl McKenna Neuman  ottO Bédard 《地球表面变化过程与地形》2017,42(5):749-762

This paper reports on a wind tunnel investigation of particle segregation, ripple formation and surface armouring within sand beds of systematically varied particle size distribution, from coarsely skewed to bimodal. By design, the system was closed with no external inputs of mass from an external particle feed. Particles too coarse to travel in saltation for the given range in wind speed were dyed red in order to distinguish them in optical images from finer sand particles, which could be entrained into the unidirectional airflow. A 3D laser scanner measured the changing bed topography at regular time intervals during 18 experiments involving varied combinations of wind speed and bed texture. Image classification techniques were used to investigate the coincident self‐organization of the two populations of particles, as distinguished by their colour. As soon as saltation commenced, some of the red particles segregated into thin discontinuous patches. Particle trapping and sheltering on these rough patches was strongly favoured, causing them to grow preferentially. During the earliest stages of formation, bedform growth coincided with: (i) rapid coarsening of the surface texture; and (ii) the merging of proto‐ripple ‘crests’ to generate larger rhythmic bedforms of lower frequency. Consistent with previous work, ripple size was observed to increase under stronger winds when not exceeding the threshold for entrainment of the coarse‐mode or red particles from the crest. With declining rates of mass transport and particle segregation as the bed surface armoured, and the consequent deceleration of ripple propagation through to the end of each experiment, all surfaces eventually attained a steady‐state morphometry. At saturation, the largest ripples developed on beds having the lowest initial concentration of red particles. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

高烈度区大跨刚构-连续梁桥地震响应分析   总被引：1，自引：1，他引：0       下载免费PDF全文

魏鑫  卫星  李明清 《地震工程学报》2017,39(6):1005-1010

为研究大跨刚构-连续梁桥在高烈度地区的地震响应,选取羊记沟左线大桥为工程背景,利用Midas软件建立多个有限元模型,考虑纵、横桥向的水平地震波输入,比较反应谱与时程分析结果,获得结构动力响应特点,为大跨刚构-连续梁桥的抗震设计提供参考依据。结果表明:刚构-连续体系仅单墩刚构时不宜采用反应谱分析,高烈度地区桥梁进行地震响应时程分析时,选用与场地适应的地震波的同时,应考虑采用本地地震参数转化人工波作为地震激励源。桥墩不等高时,可通过改变墩截面形状及其与主梁连接方式调节内力分布,避免矮墩刚度大导致的内力集中。  相似文献