中国区域碳循环研究进展与展望   总被引：26，自引：2，他引：24  

戴民汉  翟惟东  鲁中明  蔡平河  蔡卫君  洪华生 《地球科学进展》2004,19(1):120-130

中国陆地和海洋生态系统的区域碳循环在全球碳循环过程中占有重要地位。目前,中国陆地生态系统在全球碳循环中的地位和作用已有比较深入的研究,而中国边缘海系统碳循环研究相对薄弱。简要回顾中国碳循环（以现代过程的描述为主）的研究动态,重点阐述中国边缘海碳循环研究概况及CO2的海-气交换、有机碳循环、颗粒有机碳的输出、河流的输运等海洋碳循环过程的关键科学问题。在汇总补充及数据更新的基础上勾画了中国区域碳循环框架。我们认为,中国的区域碳循环过程尚有诸多未知量和不确定性,缺乏把陆、海、气作为一个系统的综合研究,海洋生态系统碳循环研究尤其需要加强。中国边缘海的碳循环研究应当围绕CO2的汇源过程这一碳循环的中心问题,深入开展边缘海碳的生物地球化学及其与大气CO2的耦合作用等方面的研究。  相似文献   

西藏雅鲁藏布江成矿区矿产资源评价新进展   总被引：29，自引：5，他引：24  

李光明  杨家瑞丁俊 《地质通报》2003,22(9):699-703

雅鲁藏布江成矿区位于青藏高原腹地,目前是中国西部地区地质工作程度极低的地区之一,但成矿条件十分有利。近年来中国地质调查局在该成矿区部署的“雅鲁藏布江成矿区铜多金属资源调查评价”项目取得了一些重要进展,目前已控制了4个大型铜矿床、1个大型铅锌矿床、3个大型富铁矿床的雏形,新提出了一批可供进行预查或普查的新矿产地,中国西部又一大型铜、铁、多金属矿产资源基地的前景在西藏已经初步显现。  相似文献   

Variation of stress during the rupture process of the 1995 M_L=4.1 Shacheng, Hebei, China, earthquake sequence     

Chen Xue-zhong  Xu Xiang-tong  Zhai Wen-jie 《地震学报(英文版)》2005,18(3):297-302

According to the rupture dynamics of earthquakes, variations of the apparent stress and the difference between the static stress drop and the dynamic stress drop during the rupture of earthquakes are analyzed for the July 20, 1995 M _L=4.1 Shacheng, Hebei, China, earthquake sequence. Results obtained show that the apparent stress for main-shock is about 5 MPa, and the average apparent stress for aftershocks 0.047 MPa. During the rupture of the main-shock, the dynamic stress drop is approximately 1.6 times greater than the static stress drop with the difference of nearly 2.7 MPa. The dynamic stress drop is less than the static stress drop for all aftershocks with the average difference of −0.75 MPa. Therefore, when the mainshock occurs the final stress on the focal fault is higher than the dynamic frictional stress, corresponding to that the fault is abruptly locked. When the aftershocks occur the final stress on the focal fault is lower than the dynamic frictional stress, corresponding to that the fault overshoots. It can be seen from the above results that there could be some differences in the physic processes between the mainshock and the aftershocks. Contribution No. 05FE3013, Institute of Geophysics, China Earthquake Administration.  相似文献   

Determination of naphthenic acids in crude oil by chemical ionization mass spectrometry     

吕振波田松柏  翟玉春丁毅 庄丽宏 《中国地球化学学报》2005,24(1):67-72

Naphthenic acids in petroleum are considered a class of biological markers. Their potential use in source correlation and as an indicator of biodegradation was reported in the past ( Dzidic et al. ,1988 ; Behar and Albrecht, 1984). Due to their highly complicated properties, detailed characterization of the acids is difficult. A method based on positive ion CI (chemical ionization) mass spectrometry using isobutane reagent gas to produce ( M 15)^ ions was applied to the analysis of naphthenic acid esters. Since the complex mixture of naphthenic acids cannot be separated into individual components, only the determination of relative distribution of acids classified in terms of hydrogen deficiency was possible. The identities and relative distribution of fatty and mono-, di-, tri-, and higher polycyclic acids were obtained from the intensities of the ( M 15 )^ ions according to z-series formula CπH2π 2 O2 of naphthenic acids. The components are characterized on the basis of group type and carbon number distributions. A comparison of the FAB and CI results showed that the group type distributions obtained bv both methods agree surprisingly well.The results indicated this method is simple, rapid and easy to operate. The geochemical implication of naphthenic acids was investigated by using a set of well-characterized crude oil samples. It is found that the naphthenic acid distribution can be used as a fingerprint for oil-oil and oil-source correlations.  相似文献   

降雨入渗对非饱和土边坡稳定性的影响   总被引：2，自引：0，他引：2  

黄光明 《中国煤田地质》2005,17(Z1):78-79

降雨往往是引起边坡失稳的主要促发因素.根据某算例,采用极限平衡分析方法,讨论了土体的初始体积含水率、降雨的强度、降雨时间对边坡稳定性的影响程度.  相似文献   

对地质勘查单位发展的几点看法探讨     

翟刚 《中国煤田地质》2005,17(Z1):127-127

分析了地质勘查单位的现状及存在问题,提出了地质勘查单位走市场化道路,掌握竞争力,依托优势加快发展,不断探索深化改革的新路子.  相似文献   

区域气候模拟中多种对流参数化方案的比较研究   总被引：32，自引：7，他引：25  

潘劲松  翟国庆  高坤 《大气科学》2002,26(2):206-220

利用区域气候模式RegCM2,选择Betts-Miller、Kuo-Anthes和Grell3种积云对流参数化方案,进行了1991年和1994年5～7月2个个例的东亚季风区区域气候模拟试验,重点分析比较了3种参数化方案对降水总量分布、主要降水时段、雨带南北变动和基本气象要素场的模拟能力,并相对实测降水和基本要素的观测分析进行了统计检验.通过对比,发现Betts方案的模拟能力明显优于其他两种方案.  相似文献   

西双版纳地区稻田甲烷的排放通量   总被引：4，自引：0，他引：4  

杨光明  武文明  沙丽清 《山地学报》2007,25(4):461-468

2005年,采用静态箱(暗箱)-气相色谱法对云南西双版纳热带地区单季稻田甲烷(CH4)排放进行田间原位观测。试验设置了三个处理,即无氮肥对照处理(NN)、低氮施肥处理(LN)和高氮施肥处理(HN),氮肥(尿素和复合肥)水平分别为0 kg/(N.hm2)、150 kg/(N.hm2)和300 kg/(N.hm2)。结果表明在水稻生长期CH4排放通量的季节变化峰值出现在拔节孕穗期,且只有1个典型的排放峰。NN、LN和HN处理的CH4季节平均排放速率分别为6.69±0.37 mg/(m2.h)、7.19±0.43 mg/(m2.h)和6.04±0.31 mg/(m2.h)。不同氮肥用量对CH4排放通量的影响规律不明显。各处理的CH4排放通量与温度的相关关系不同,与稻田水深均无显著的相关关系。  相似文献   

Longmu Co-Shuanghu plate suture and evolution records of paleo-Tethyan oceanic in Qiangtang area,Qinghai-Tibet plateau     

Li Cai  Zhai Qingguo  Dong Yongsheng  Zeng Qinggao  Huang Xiaopeng 《Frontiers of Earth Science》2007,1(3):257-264

Three Late Triassic plate sutures, namely, the Longmu Co-Shuanghu suture, Kunlun-Qinling suture and Xijinwulan-Jinshajiang suture, have been recognized on the Qinghai-Tibet plateau. Data show that the last two sutures have no essential elements of the northern boundary of Gondwana. This paper briefly introduces the facts of the existence of the paleo-Tethys Ocean in the Longmu Co-Shuanghu suture, i.e., the ages and natures of Early Paleozoic ophiolites, Permian ophiolites, Devonian-Permian radiolarian cherts, accretionary relics of different natures, two types of tectonic mélange zones and ophiolites. The starting time of paleo-Tethys Ocean in Qiangtang may be traced back to the Early Paleozoic and the records about the oceanic basin evolution lasted from the Late Devonian to Late Triassic. It is thought that the Longmu Co-Shuanghu suture was the site for the extinction of the paleo-Tethys Ocean on Qinghai-Tibet plateau and an important window for the reconstruction and inversion of the early-stage formation and evolution of the Qinghai-Tibet plateau, as well as the northern boundary of Gondwana wich the geoscience community has paid attention to in the past few decades. Translated from Geological Bulletin of China, 2007, 26(1): 13–21 [译自: 地质通报]  相似文献   

流动VLBI终端系统的技术改造与升级     

乔少敏唐颖哲  刘光明 《测绘科学与工程》2007,27(1):41-45

本文介绍了流动VLBI终端系统的技术改造与升级情况以及MK5A数据系统的构成与工作原理，论述了实现BBC系统本振步长、BBC滤波器带宽和带宽增益补偿以及流动VLBI数据系统等方面的技术改造与升级的原理和方法，最后介绍了应用结果。  相似文献