Advances on Studies of Methane in the Arctic Ocean     

Li Yuhong  Zhan Liyang  Chen Liqi 《地球科学进展》2014,29(12):1355-1361

Methane(CH₄) is an important greenhouse gas, CH₄ concentrations in atmosphere hve increased by 2-3 times since the Industrial Revolution. Considering the huge CH₄ storage in the Arctic Ocean, the fast increasing flux and their consequences are attracting more and more attention. This paper summarized the advances in the study of CH₄ in the Arctic Ocean, especially the distribution pattern and air-sea flux and its biogeochemical cycle in the Arctic Ocean. It also presented the research prospect for the future.  相似文献   

东海和南黄海表层海水中几种挥发性卤代烃的分布和通量研究   总被引：1，自引：0，他引：1  

宋贵生  杨桂朋  陆小兰 《海洋与湖沼》2013,44(1):9-14

以中国近海有代表性的陆架区——东海及南黄海为目标,对东海和南黄海中常见的5种挥发性卤代烃(VHCs)的分布及其海-气通量进行了研究.研究表明,在黄海03断面表层海水中CHCl3、C2HCl3、C2Cl4、CHBrCl2和CHBr2Cl的浓度分别为41(31-54)、53 (23-80)、17 (6.3-23)、23 (7.4-34)和51 (3.1-92) pmol/L,东海表层海水中的浓度分别为25(11-83)、54 (12-95)、39 (9.2-94)、25(5.4-74)和6.4 (1.3-41) pmol/L.由于受人为活动、河流输入和黑潮水入侵的影响,VHCs在水平分布上呈现近岸高、远海低的规律;5种VHCs在表层海水中的浓度与叶绿素a(Chla)存在相关性;这5种化合物在表层海水中没有完全一致的周日变化规律, CHBrCl2和CHBr2Cl的最大值分别在上午10时和下午16时出现,CHCl3、C2HCl3和C2Cl4均在下午13时出现最大值.根据表层海水中CHCl3、C2HCl3和C2Cl4的浓度和文献报道的大气浓度,运用Liss和Salter双层模型,估算得到这3种物质在南黄海的海-气通量分别为76 (1.97-149)、160 (1.07-330)和53 (0.70-119) nmol/(m2·d),在东海的海-气通量为46 (1.65-223)、171 (6.27-495)和135 (3.41-484) nmol/(m2·d),东海和南黄海在冬季是大气CHCl3、C2HCl3和C2Cl4的源.  相似文献   

A pore-throat model based on grain-size distribution to quantify gravity-dominated DNAPL instabilities in a water-saturated homogeneous porous medium     

Khalifa Nsir  Gerhard Schfer 《Comptes Rendus Geoscience》2010,342(12):881-891

A pore-scale network model based on spherical pore bodies and cylindrical pore throats was developed to describe the displacement of water by DNAPL. The pore body size and the pore throat size were given by statistical distributions with user-specified values for the minimum, mean and maximum sizes. The numerical model was applied to a laboratory experiment conducted on a sand-filled glass column. The parameters relative to pore body size and pore throat size that were used in the construction of the equivalent network were derived from the discrete grain-size distribution of the real porous medium. The calculated arrival times of the DNAPL front were compared with those measured using optic fibre sensors placed at different points on the control section of the experimental device. Furthermore, the model simulated DNAPL pressure measured at the entrance section of the system. In general, the numerical results obtained with the model were in good agreement with the actual measurements.  相似文献   

中国天气发生器的降水模拟   总被引：27，自引：0，他引：27  

廖要明  张强  陈德亮 《地理学报》2004,59(5):689-698

天气发生器是气候影响评价研究的重要工具,在气候变化、地球生态系统及极端气候事件发生的风险分析等方面有着广泛的应用。为了建立一个适用于中国广大地区的天气发生器,需要对各种模拟模型及其参数的估计进行深入的研究。其中降水的模拟及其参数的估计是关键,因为气温、辐射等其他气候要素的模拟依赖于降水的发生。本文重点介绍了常用的随机降水模拟模型：两状态一阶马尔科夫链和两参数GAMMA分布。根据中国672个气象站点1961~2000年的逐日降水资料,计算了降水转移概率P (WD)、P (WW) 及GAMMA分布参数ALPHA和BETA,并分析了4个参数在中国各地的空间分布特征与不同地区各参数的季节分布特征。最后根据各地不同月份计算的四个降水模拟参数对中国各地的逐日降水进行模拟,并利用1971~2000年的实测数据对30年模拟结果在统计意义上进行了检验,模拟结果较好。  相似文献   

辽宁冬季城市空气质量分布状况综合研究   总被引：5，自引：0，他引：5       下载免费PDF全文

马雁军  刘宁微  王扬锋 《气象与环境学报》2007,23(3):15-18

利用2006年12月辽宁14个城市的大气环境现状监测资料和沈阳、鞍山、抚顺、本溪4城市可吸收入颗粒物(PM10,PM2.5和PM1)的监测资料,对辽宁冬季各城市的空气质量分布状况进行了综合研究。结果表明:辽宁14个城市的冬季空气质量分布状况为优、良和轻微污染3个等级,其中铁岭、营口和辽阳的空气质量有28 d为良及以上等级;空气质量级别为轻微污染日数最多的城市是本溪,共计12 d;其次是葫芦岛、沈阳、鞍山、抚顺、盘锦、阜新,共计7—10 d。各城市的首要污染物是PM10。由于冬季燃煤量的增加,沈阳、鞍山、抚顺和本溪4城市PM2.5日平均浓度值的超标率为77.4%—90.3%。  相似文献   

多环芳烃来源与分布及迁移规律研究概述   总被引：14，自引：0，他引：14  

韩菲 《气象与环境学报》2007,23(4):57-61

概述了多环芳烃的来源,就近年来多环芳烃(PAHs)在大气、土壤、植被和水体沉积物中分布与迁移规律的研究成果进行了综述,并展望了未来PAHs研究方向。  相似文献   

Selection of Test and Reference Areas for the Indian Deepsea Environment Experiment (INDEX)     

Rahul Sharma  B. Nagender Nath 《Marine Georesources & Geotechnology》2000,18(3):177-187

The Indian Deepsea Environment Experiment (INDEX) was conducted in the Central Indian Ocean Basin, to assess the effects of a simulated disturbance on the marine ecosystem and to collect data to predict the effects of large-scale mining. To select the Test and Reference areas for benthic disturbance, detailed studies were carried out for a better understanding of the topgraphic undulations and nodule distribution in five preselected areas of 10 ×10 nautical miles each. Flat topography was one of the important considerations for selection of the areas, because this would allow further dispersion of sediment plume and offer easier maneuverability of the benthic disturber. Relatively low nodule abundances were also preferred, to prevent clogging of the suction device used for resuspension of sediment. On the basis of morphological analysis and nodule distribution, two areas, T1 and A1, were selected as the best suited pair for the disturbance and monitoring experiment.  相似文献   

关于香港人口的分布与其土地利用问题的意见   总被引：2，自引：0，他引：2  

叶汇  林慧玲 《热带地理》2000,20(1):12-15

概述了香港人口分布和土地利用现状的特点 ,根据香港的土地利用特点 ,结合香港地势图分析 ,全区的土地利用以城市用地为主 ,主要利用沿海冲积 -海积平原和坡地。文中针对高台地和斜坡地利用提出一些新意见 ,务求全体香港市民不受滑坡的威胁。  相似文献   

Davis二倍数规律与Zipf三参数模型的等价性证明——关于城市规模分布法则的一个理论探讨   总被引：5，自引：0，他引：5  

陈彦光  刘继生 《地理科学进展》1999,18(3)

本文从城市规模分布的Ｄａｖｉｓ 二倍数规律（２ｎ 规律：ａｉ＝ ａｉ＋ ｎ·２ｎ,ｆｉ＝ ｆｉ＋ ｎ·２－ ｎ）中推导出具有一般意义的三参数Ｚｉｐｆ模型：Ｐ（ｒ）＝ Ｃ（ｒ－ α）－ ｄｚ,揭示了２ｎ 规律隐含的分形几何性质, 论证了２ｎ 法则为Ｚｉｐｆ维数ｄｚ＝ １ 时的特殊情形, 并将２ｎ 规律推广到具有普遍意义的δｎ 规律, 给出了Ｚｉｐｆ维数及分维与邻级倍数δ的数值关系：ｄｚ＝ １／Ｄ＝ ｌｎ２／ｌｎδ。最后从三个方面对文中的理论成果进行了实证分析。  相似文献   

Distribution of Landslides in Baoshan City, Yunnan Province, China   总被引：1，自引：1，他引：0  

GAO Yuxin  XU Chong  TIAN Yingying  MA Siyuan  SHEN Lingling  LU Yongkun  RAN Hongliu 《中国地震研究》2020,34(1):50-63

Using Google Earth software as a platform, this study has established an integrated database of both old and new landslides in Baoshan City, Yunnan Province, China, and analyzed their development characteristics together with distribution rules, respectively. Based on the results, a total of 2 427 landslides occurred in the study area, including 2 144 new landslides and 283 old landslides, with a total area of about 104.8 km². The new landslides are mostly in small-scales with an area less than 10 000 m², while the area of individual old landslide is mostly larger than 10 000 m². By analyzing the relationship between the two types of landslides and eight impact factors (i.e., elevation, slope angle, slope aspect, slope position, lithology, fault, regional Peak Ground Acceleration (PGA), and average annual rainfall), the different individual influencing factors, distribution regularities and mechanisms of the two types of landslides are revealed. In detail, the main influencing factors of new landslides are elevation, slope angle, slope aspect, slope position, lithology, regional PGA and average annual rainfall, while the influencing factors of old landslides are mainly elevation, slope angle, and lithology. This study provides basic data and support for landslide assessment and further disaster reduction in Baoshan City. Besides, it also provides new constraints in deeply understanding the effect of different topographic and geological conditions, historical earthquakes, rainfall and other factors on the occurrence mechanisms of both new landslides and old landslides.  相似文献