南亚高压区Rossby波能量向上穿越对流层顶传播的特征与机制

夏季平流层盛行强东风,Rossby波能量难以从对流层向上传播至平流层,而冬季平流层盛行西风,Rossby波能量容易上传,因此以往对Rossby波能量向平流层传播的研究多考虑冬季的情况.而事实上,因为夏季高原上空南亚高压反气旋环流,并非只有强东风存在,所以Rossby波能量也可能在南亚高压区向上传播,从而影响平流层的温度、风场及大气成分等.因此,本文利用ERA-interim逐日再分析资料,分析了1979—2015年夏季南亚高压区Rossby波能量穿越对流层顶传播的特征与机制.结果表明:Rossby波能量可以从南亚高压西北部的窗口区上传至平流层,最高可到达平流层顶,而在南亚高压的其他部分,Rossby波能量均不能穿越对流层顶上传或穿越对流层顶后无法继续上传.南亚高压西北区Rossby波能量可以穿越对流层顶传播的原因是盛行西风,且西风急流出现的频率很小,同时涡动热量通量异常引起的垂直分量的第一项对其上传有很大贡献.南亚高压东北区也盛行西风,然而Rossby波能量不能向上穿越对流层顶的原因是强西风出现频率较高,且温度脊与高度脊位相相近,不利于上传.南亚高压南部均盛行东风,在平流层中下层均为稳定层结,因此Rossby波能量很难上传.南亚高压西南区在对流层位于青藏高原环流的伊朗高原下沉区附近,层结稳定,并且温度脊超前于高度脊,所以Rossby波能量很难上传.而南亚高压东南区在对流层位于南海-西太平洋热带幅合带,层结不稳定,存在Rossby波能量较弱的上传,达到对流层顶后无法继续上传,该区域温度脊落后于高度脊的温压场配置也为Rossby波能量在对流层内的传播提供了条件.     

RESEARCH ON THE CHARACTERISTICS OF QUATERNARY ACTIVITIES OF SU-XI-CHANG FAULT

Running across the urban areas of Changzhou, Wuxi and Suzhou, the NW-trending Su-Xi-Chang Fault is an important buried fault in Yangtze River Delta. In the respect of structural geomorphology, hilly landform is developed along the southwest side of the Su-Xi-Chang Fault, and a series of lakes and relatively low-lying depressions are developed on its northeast side, which is an important landform and neotectonic boundary line. The fault controlled the Jurassic and Cretaceous stratigraphic sedimentary and Cenozoic volcanic activities, and also has obvious control effects on the modern geomorphology and Quaternary stratigraphic distribution. Su-Xi-Chang Fault is one of the target faults of the project "Urban active fault exploration and seismic risk assessment in Changzhou City" and "Urban active fault exploration and seismic risk assessment in Suzhou City". Hidden in the ground with thick cover layer, few researches have been done on this fault in the past. The study on the activity characteristics and the latest activity era of the Su-Xi-Chang Fault is of great significance for the prevention and reduction of earthquake disaster losses caused by the destructive earthquakes to the cities of Changzhou, Wuxi and Suzhou. Based on shallow seismic exploration and drilling joint profiling method, Quaternary activities and distribution characteristics of the Su-Xi-Chang Fault are analyzed systematically. Shallow seismic exploration results show that the south branch of the Su-Xi-Chang Fault in Suzhou area is dominated by normal faulting, dipping to the north-east, with a dip angle of about 60° and a displacement of 3~5m on the bedrock surface. The north branch of the Su-Xi-Chang Fault in Changzhou area is dominated by normal faulting, dipping to the south, with a dip angle of about 55°~70° and a displacement of 4~12m on the bedrock surface. All breakpoints of Su-Xi-Chang Fault on the seismic exploration profiles show that only the bedrock surface was dislocated, not the interior strata of the Quaternary. On the drilling joint profile in the Dongqiao site of Suzhou, the latest activity of the south branch of Su-Xi-Chang Fault is manifested as reverse faulting, with maximum displacement of 2.9m in the upper part of Lower Pleistocene, and the Middle Pleistocene has not been dislocated by the fault. The fault acts as normal fault in the Pre-Quaternary strata, with a displacement of 3.7m in the Neogene stratum. On the drilling joint profile in the Chaoyang Road site of Changzhou, the latest activity of the north branch of Su-Xi-Chang Fault is manifested as reverse faulting too, with maximum displacement of 2.8m in the bottom layer of the Middle Pleistocene. The fault acts as normal fault in the Pre-Quaternary strata, with a displacement of 10.2m in the bedrock surface. Combining the above results, we conclude that the latest activity era of Su-Xi-Chang Fault is early Middle Pleistocene. The Su-Xi-Chang Fault was dominated by the sinistral normal faulting in the pre-Quaternary period, and turned into sinistral reverse faulting after the early Pleistocene, with displacement of about 3m in the Quaternary strata. The maximum magnitude of potential earthquake on the Su-Xi-Chang Fault is estimated to be 6.0.     

唐山震区上地壳平均波速比分析

收集河北地震台网记录的唐山震区2012-2016年ML≥1.0地震,选取震源深度5-10km、波形信噪比较高的波形数据,拾取直达P波、S波震相到时,利用和达法计算平均波速比,并分析研究区平均波速比水平分布特征与时变特征,结果表明:唐山震区上地壳平均波速比约为1.71,且水平分布呈区域化特征,反映了研究区复杂的地壳结构。研究区内3次ML≥4.0地震前,波速比曲线均呈较显著的下降-低值-回升形态,表明该区平均波速比变化可能具有一定地球物理异常特征。     

Advances in urban information extraction from high-resolution remote sensing imagery

The study of urban area is one of the hottest research topics in the field of remote sensing. With the accumulation of high-resolution(HR) remote sensing data and emerging of new satellite sensors, HR observation of urban areas has become increasingly possible, which provides us with more elaborate urban information. However, the strong heterogeneity in the spectral and spatial domain of HR imagery brings great challenges to urban remote sensing. In recent years, numerous approaches were proposed to deal with HR image interpretation over complex urban scenes, including a series of features from low level to high level, as well as state-of-the-art methods depicting not only the urban extent, but also the intra-urban variations. In this paper, we aim to summarize the major advances in HR urban remote sensing from the aspects of feature representation and information extraction. Moreover, the future trends are discussed from the perspectives of methodology, urban structure and pattern characterization, big data challenge, and global mapping.     

三峡水库和长江中下游通江湖泊(洞庭湖和鄱阳湖)草鱼、鲢的孵化日期及早期生长特征

三峡水库以及上游江段形成的河—库生态系统与长江中下游洞庭湖和鄱阳湖的江湖生态系统都是四大家鱼的重要栖息地,有相似性也有差异.2017年7—8月在三峡水库、洞庭湖和鄱阳湖利用地笼、虾笼、高网和迷魂阵采集草鱼和鲢幼鱼样本,观测耳石日轮,分析三峡水库和通江湖泊草鱼和鲢幼鱼的繁殖时间和早期生长特征及差异,探讨相应的保护措施.结果显示,三峡水库、洞庭湖和鄱阳湖采集草鱼幼鱼的孵化日期分别为4月24日—5月25日、5月21日—6月26日和5月4日—5月28日;鲢幼鱼的孵化日期分别为4月10日—6月12日、5月25日—6月19日和5月9日—6月12日.三峡水库、洞庭湖和鄱阳湖草鱼样本的体长增长率分别为1.04、1.84和1.64 mm/d,微耳石的沉积率分别为3.41、5.41和4.77μm/d;鲢幼鱼的体长增长率分别为1.10、2.87和1.96 mm/d,微耳石沉积率分别为2.96、7.17和4.57μm/d.洞庭湖草鱼和鲢的体长增长率和耳石沉积率均显著大于三峡水库;鄱阳湖鲢的体长增长率和耳石沉积率均显著大于三峡水库,而草鱼的体长增长率和耳石沉积率则与三峡水库没有显著差异.结果表明,三峡水库蓄水后长江中游干流草鱼和鲢的繁殖时间明显滞后;洞庭湖和鄱阳湖的草鱼和鲢幼鱼生长更快.目前,长江全面禁渔正在逐步实施,预期将对恢复鱼类资源起到重要的作用.除了全面禁渔之外,还建议保护和修复鱼类栖息地;减少江湖阻隔,灌江纳苗;增殖放流亲鱼;开展生态调度,促进鱼类繁殖.     

云南中甸纳帕海古环境演化的有机碳同位素记录

中甸纳帕海位于云贵高原横断山脉腹地,其成因与碳酸岩类地层长期溶蚀有关,在丰水期和枯水期纳帕海的水位相差很大,枯水期常形成浅水池沼,因而造成枯水期和丰水期水生植被的发育状况有很大的差异,枯水期由于水生植物（飘浮和挺水植物）发育,造成总有机碳和氢指数的增加,有机碳同位素偏负,丰水期出现相反的演化趋势,进一步轮推表明在暖干的气候条件下纳帕海极易形成枯水位,在冷湿的气候下可维持相对高的水位,古环境重建表明纳帕海在大约32kaBP和15kaBP出现环境的重大于变迁,32-15kaBP出现高湖面。     

基于三维激光扫描的堆积体滑坡变形机理及阈值模型试验研究

为分析白龙江流域舟曲段江顶崖滑坡的变形演化机理及其阈值,设计降雨条件下的大型堆积体滑坡物理模型试验,采用FARO FocusS 350三维激光扫描仪进行滑坡数据采集、处理,获取滑坡在不同降雨工况的点云模型数据,对比分析不同降雨工况下滑坡宏观及局部特征点的变化情况。研究表明：滑坡模型表面出现持续、快速、变化鲜明的整体变形特征,伴随出现滑坡模型中、前部横向、纵向的张拉裂缝,表明在非饱和渗流影响下,堆积体滑坡模型的基质吸力降低、孔隙水压力以及滑坡体重力荷载增加,导致滑坡模型临近失稳;根据滑坡模型宏观变形情况,其变形演化过程可划分为：初始变形阶段、等速变形阶段和加速变形阶段,3个不同变形阶段坡体宏观变形各自有其特点。通过对试验阶段的变形特征分析,设立了滑坡变形速率阈值,分别为0.01 m/h、0.02 m/h、0.2 m/h。基于三维激光扫描技术坡体监测,结合坡体变形宏观和局部分析的优势,在保证高精度监测、采集、处理的同时,得到坡体的整体变形和位移。     

秋季太湖水下光场结构及其对水生态系统的影响

水生态系统中光能的分配很大程度上决定了水生态系统的结构和功能,利用2007年11-12月太湖水体光学特性和组分浓度数据,对秋季太湖水下光场结构特征和水体组分光竞争能力的表征光学量(漫衰减系数、平均余弦)和影响因素(吸收系数比重)进行了分析研究.结果表明,秋季太湖水下辐照度呈现单峰分布,最高值为583nm左右:根据Kd可将黄质和非色素物质主导程度的强弱分为弱、较强、强三个等级;Kd(PAR)平均值为4.61±1.54m-1,水体真光层厚度平均值为1.11±0.35m;太湖水下光场的光能主要分布在青光和黄绿光波长范围内,约占总能量的60%,蓝光和红光波长范围内的能量约占30%,这样的光谱结构有利于铜绿微囊藻和斜生栅藻的生长.     

海南省海水鱼养殖产业现状调研与对策研究

文章基于“结构-行为-绩效”（SCP）范式,从市场结构、市场行为和市场绩效3个方面分析海南省的海水鱼养殖产业。发现：海水鱼养殖业属于原子型市场结构,市场集中度较低,龙头企业竞争力不足;总体进入壁垒较低,市场进入难度较小;种苗产业链分工和定价随机性强,鱼卵价格出现经常性短期波动;海水养殖业资源配置效率较低,许多企业面临环保督察、经营管理、人力资源等诸多危机,产业技术进步贡献度不足。因此,提出如下建议：海南海水鱼养殖业需要在兼顾生态文明建设的前提下,政府需要制定长远的渔业发展规划;加快推进行业的分工与专业化的生产;通过兼并、强强联合加快推进规模经济,进一步提高产品附加值,提高产业综合竞争力。     

基于坐标系选取与椭球元素确定建立城市坐标系的研究

为了使GNSS测量成果更好地服务于城市建设,并保持与原有数据的一致性,需将其归算至城市坐标系.本文阐述了城市坐标系建立的方法理论,总结了将GNSS测量成果归算至城市坐标系的一般步骤,并利用GNSS实测数据进行验证与分析,提出了一些合理化的建议,为GNSS测量成果归算至城市坐标系提供参考和借鉴.