Cross-shelf carbon transport under different greenhouse gas emission scenarios in the East China Sea during winter

Based on Marx-Planck coupled model simulations and in situ hydrography measurements, the volume transport of ocean currents and associated carbon fluxes across the continental margin from the continental shelf to the deep ocean in the East China Sea during winter are estimated. Because cross-shelf currents in the Yellow and East China seas are much stronger in winter than in other seasons and are subducted into the subsurface Kuroshio, the cross-shelf burial of carbon takes place mainly in winter. The analyses show prominent cross-shelf transports during winter in the Yellow and East China seas, with annual mean offshore transport across a section from Taiwan to Cheju at 3.92 Sv(1 Sv=10~6 m~3 s~(-1)). Net transport across the section was0.82 Sv off the shelf, determined by the difference between Taiwan and Cheju strait transports. Net cross-shelf transports of dissolving inorganic carbon(DIC), dissolved organic carbon(DOC), and particulate organic carbon(POC) in winter were 98, 12,and 0.1 million tons, respectively. Under global greenhouse gas emission reduction(RCP4.5) and continuous increase(RCP8.5)scenarios, this cross-shelf transport has an increasing trend. The transports across the Taiwan-Cheju section in winter are predicted to increase by 0.54 and 0.65 Sv from 2006 to 2099, with rates of increase 15.3% and 19.6%, respectively. Associated with the transport increase, the cross-shelf fluxes of DIC, DOC and POC increase by as much as 15.4–25.2%. Cross-shelf carbon fluxes in the East China Sea during winter are evaluated for the first time under the global warming scenarios, showing the importance of cross-shelf transport in the carbon cycle of the China marginal seas.     

智慧规划下的协同编制信息资源平台研究

新兴技术的飞速发展不断改变着规划信息化的应用场景和模式,城市规划需要在工作模式、技术手段与组织方法等多方面进行信息化革新,才能适应城市化转型要求。本文通过对智慧规划的论述和大数据对规划方法影响的分析,并结合广州在总体规划协同编制的信息化实践,提出了时空信息聚合、实时汇聚、智能共享的信息协同解决方案,实现了规划师之间、部门之间的纵向及横向协同,不同层级规划的紧密衔接,汇集多来源、各阶段的工作成果,建设规划编制信息的资源池。     

滑坡监测系统在北长山岛山后村山体滑坡监测中的应用

为有效地监测海岛山体滑坡,找到滑坡的诱发因素,以达到海岛地区防灾减灾的目的。本文以北长山岛为例,针对采石引起的滑坡,利用GPS、三维激光扫描、无人机遥感、位移传感器4种滑坡监测方法,联合建立了北长山岛山后村山体滑坡监测系统。通过对比分析这4种方法发现,在三维激光扫描点云数据密集的滑坡体中、下部选择三维激光扫描获取的滑坡体形态数据,在点云数据稀疏的滑坡体上部选择无人机遥测获取的滑坡体形态数据,精确获取了不同时期滑坡体的挖方量、滑移量;位移传感器获取的实时位移监测数据可得到滑坡体的实时滑移动态,发现在其监测数据突变时滑坡存在滑动的风险。研究还发现采石和降雨是引起山后村滑坡体滑移的两个最重要因素,采石导致滑坡体体积整体减小,降雨导致滑坡体上部拉张加速并引起碎石滑塌。由于监测区环境条件的限制,该系统只能进行滑坡体的表面变形监测。研究成果可为其他海岛滑坡的监测乃至预警提供借鉴和参考。     

复杂路堑高边坡病害治理效果模糊层次评价

双永高速公路K227滑坡由于地形高陡、地质复杂、环境敏感、施工困难等因素成为典型的复杂超高路堑边坡和项目建设及运营养护的关注焦点。为评价该边坡病害治理效果,在长期参与其治理过程的实践、思考、评价和监控基础上,从地形条件、地质条件、环境条件、应力调整和变形控制等方面构建复杂路堑高边坡安全评价指标体系、特征状态量化标准和各评价指标权值。结合模糊综合评判法、专家权威系数修正和最大隶属度原则,建立复杂路堑高边坡安全评估的模糊层次评价模型和评估方法,并与极限平衡法和有限元法计算成果、以及治理前后的现场变形迹象调查和持续性变形监测结果对比分析,对K227滑坡病害治理效果进行综合评判,并证明其是评价复杂路堑高边坡病害治理效果的有效方法。     

冬季中东急流对中国西南地区覆冰形成的影响

采用西南地区 (25°N～35°N, 95°E～110°E) 96个常规气象观测站1961年1月1日～2009年12月31日逐日气象要素资料, 利用同时满足地面日最低气温在-10～1 ℃、 相对湿度大于80%、 日照时数小于等于2个小时这三个条件, 计算1月中国西南地区覆冰日数。利用NCEP/NCAR再分析格点资料, 分析大气环流特征。结果表明: 强覆冰年时欧亚地区500 hPa高度距平场为 “北高南低”、 中高纬地区 “西高东低”、 中低纬地区“西低东高” 的形势, 乌拉尔山高压脊、 里海东部低压槽、 副热带高压均偏强, 有利于冷暖空气在西南地区强烈交汇, 是西南地区形成覆冰的基本条件; 冬季中东急流强, 则有利于西南地区覆冰的形成, 相关最好的区域位于四川—云南—贵州三省交界处、 贵州省大部分地区、 云南省北部与西藏东南部交界处、 陕西省西南部以及川西二郎山附近, 这些均是最易发生严重覆冰的区域; 500 hPa中亚低槽活动, 将中东急流变化与西南地区覆冰强弱紧密的联系了起来; 前期12月北大西洋百慕大群岛附近海表温度的异常偏低是1月中东急流异常偏强的重要影响因素。     

An investigation of the effects of wave state and sea spray on an idealized typhoon using an air-sea coupled modeling system

In this study, the impact of atmosphere-wave coupling on typhoon intensity was investigated using numerical simulations of an idealized typhoon in a coupled atmosphere-wave-ocean modeling system. The coupling between atmosphere and sea surface waves considered the effects of wave state and sea sprays on air-sea momentum flux, the atmospheric low-level dissipative heating, and the wave-state-affected sea- spray heat flux. Several experiments were conducted to examine the impacts of wave state, sea sprays, and dissipative heating on an idealized typhoon system. Results show that considering the wave state and sea-spray-affected sea-surface roughness reduces typhoon intensity, while including dissipative heating intensifies the typhoon system. Taking into account sea spray heat flux also strengthens the typhoon system with increasing maximum wind speed and significant wave height. The overall impact of atmosphere-wave coupling makes a positive contribution to the intensification of the idealized typhoon system. The minimum central pressure simulated by the coupled atmosphere-wave experiment was 16.4 hPa deeper than that of the control run, and the maximum wind speed and significant wave height increased by 31% and 4%, respectively. Meanwhile, within the area beneath the typhoon center, the average total upward air-sea heat flux increased by 22%, and the averaged latent heat flux increased more significantly by 31% compared to the uncoupled run.     

东亚冬季风指数的分类和比较

在回顾了2009年以前定义过的冬季风指数的基础上,按照定义要素的不同,进行了分类及序列延长计算,并将现有的冬季风指数分为海陆气压差类(4个)、高压特征类(3个)、风场特征类(9个)、环流特征类(4个)和综合类(2个)。研究了这些冬季风指数的年际及年代际变化趋势及其周期变化,分析了各指数之间的相关性,以及冬季风指数对中国冬季大陆气温变化的指示性。结果表明:东亚冬季风存在缓慢减弱的变化趋势,主要呈现出准6a,准11a和准17a的周期振荡特征。同类别指数之间的相关性要优于不同类别的。东亚冬季风指数与中国冬季大陆气温相关性普遍好的地区主要在河套及内蒙古中部、华南和东南沿海、四川盆地等。     

灌木植被分布区阻力特性理论及试验研究

为探明河道灌木植被分布区阻水规律，对灌木植被主干、分枝产生的水流阻力特性及其定量特征进行研究。提出原型植被体积修正系数和灌木植被水力半径确定方法，理论推导灌木植被阻力系数计算公式，并结合水槽试验建立植被阻力系数与植被水力半径为特征长度的植被雷诺数之间的关系式。研究结果表明：引入原型植被体积修正系数和灌木植被水力半径使灌木植被阻力计算更为准确；植被阻力系数与植被雷诺数之间呈指数函数关系，随植被雷诺数的增加呈单调减小的趋势，与水槽试验结果吻合很好。     

闽江口溶解态镉、铜、铅的行为及其与营养盐的关系

研究了１９９０年６月和１０月闽江口溶解态镉、铜、铅的行为及其与营养盐的关系。结果表明，在６月和１０月镉呈添加行为，铜呈保守行为，而铅呈除去行为、镉的添加主要源自浮游生物碎屑的再矿化作用，而铅的去除受非生物无机过程控制。     

多波束测深系统声线跟踪方法对比分析

多波束测深系统的声学原理和海水的不均匀性,使得声波在传播过程中发生声线的折射现象,对波束测点位置的计算带来较大误差。针对多波束数据后处理常用的几种声线跟踪方法,通过模型分析,仿真实验,对比分析得出了各个方法的优缺点,估计了各种跟踪方法的模型精度,证明等效声速法与常梯度法应用价值较高。