中国典型地区土壤碳储量研究   总被引：8，自引：2，他引：6       下载免费PDF全文

奚小环  杨忠芳  廖启林  张建新  白荣杰  张秀芝  金立新  王会峰  李敏  夏学齐 《第四纪研究》2010,30(3)

利用多目标区域地球化学调查高精度和高密度土壤碳分布数据,建立"单位土壤碳量",采用指数模型计算方法,取得各地区土壤碳储量数据.按照土壤类型、土地利用分类、生态系统及自然景观等划分方式,按照 0～0.2m,0～1.0m和 0～1.8m不同土壤深度,分析了四川、湖南、吉林、江苏、河北、陕西等代表性地区有机碳储量空间分布特征,进行中国土壤碳储量研究.计算结果表明,全国土壤碳储量分布不均匀.按照 0～1.8m深度比较,成都平原土壤碳储量为1462.9Mt,碳密度为24813t/km2; 吉林平原区碳储量1381.96Mt,碳密度14473t/km2; 湖南洞庭湖区碳储量757.65Mt,碳密度18171t/km2; 江苏省碳储量1468.87Mt,碳密度13802t/km2; 陕西渭河平原碳储量165.47Mt,碳密度12124t/km2; 河北平原区碳储量844.84Mt,碳密度10525t/km2.按照面积加权平均计算,推算出全国多目标区域地球化学调查地区平均碳密度,0～0.2m为3186t/km2,0～1.0m为11646t/km2,0～1.8m为15339t/km2.  相似文献   

黔中气溶胶传输的210 Pb和7 Be示踪:Ⅱ.月及年时间尺度的剖析     

万国江  郑向东  Lee H N  Bai Z G  万恩源  王仕禄  杨伟  苏菲  汤洁  王长生  黄荣贵  刘鹏 《地球科学进展》2010,25(5):505-514

自2001年12月连续逐周在贵阳观风山附近对近地面空气210Pb-7Be浓度和沉降量的观测表明:区域性降水和气温制约近地面空气210Pb具高浓度"U"型年分布;降水量和平流层向下输送影响近地面空气7Be月均浓度的季节性变化;210Pb/7Be月均浓度比率受控于210Pb变化和富7Be气团下沉的影响.观风山与瓦里关山之间因纬度和海拔的关系,7Be比率急剧震荡,显示出海洋性贫7Be气团入侵对观风山地区的明显影响.2002-2008年间贵阳观风山近地面空气210Pb的年均浓度(2.8±0.6)mBq/m3,约为全球若干站点中最高平均浓度值的4倍;而7Be的年均浓度(4.8±0.6)mBq/m3,与全球高海拔站点长期观测的平均值相当,大约为北半球中纬度对流层顶部附近7Be浓度值(18.0 mBq/m3)的1/3.8,显示出低纬度、较高海拔地区的预期水平.2003年,瓦里关山和观风山近地面空气7Be的年均浓度比为3.8,与预期的大气输送和混合作用基本一致.7Be月均浓度的增大趋势反映出受太阳黑子数减少的变化关系,其影响底线大约为4 mBq/m3;7Be年均浓度波动的增大趋势反映出受太阳黑子数降低的可能影响.贵阳观风山降水中7Be和210Pb的体积加权浓度分别为0.72 Bq/L和0.27 Bq/L;年沉降通量分别为0.080 Bq/(cm2·a)和0.031 Bq/(cm2·a).数值模拟显示出全球空气210Pb高浓度区和高沉降通量环带分布,印证了洱海和红枫湖沉积物7Be和157Cs蓄积的模拟结果.  相似文献   

黔中气溶胶传输的210 Pb和7 Be示踪:I.周时间尺度的解释     

万国江  郑向东  Lee H N  Bai Z G  万恩源  王仕禄  杨伟  苏菲  汤洁  王长生  黄荣贵  刘鹏 《地球科学进展》2010,25(5)

认识环境核素在不同地域空气中的浓度分布和沉降到地表环境的通量对气溶胶污染物全球扩散模型的建立和验证、沉积过程示踪和沉积计年、流域侵蚀示踪参比,以及生态系统受天然辐照的评价等多个领域都是关键的依据.自2001年以来在贵阳观风山等地逐周连续采样,对近地面空气和降水中210Pb和7Be浓度的观测结果表明:①因气象条件变化,近地面空气210mPb和7Be周浓度具有2～6周变幅不等的短周期波动.210Pb空气浓度在年内的总趋势呈现出受气温变化的总体影响和降水的短暂调控;而7Be空气浓度出现连续不断的峰-谷交替.②两核素在近地面空气周浓度的低值同步,210Pb/7Be比率较高(≥0.8),显示出海洋性贫210Pb-7Be气团的入侵影响;它们高的周浓度也同步耦合,比率较低(≤0.7),显示出高层大气富7Be气团的输入.③210Pb和7Be的周降水浓度及水-气分配系数在秋末春季较高,而春末-秋季明显偏低.周降水浓度随同期空气浓度呈增高趋势,其季节分界分别为0.2 Bq/L和1 Bq/L;而Kd值随同期空气浓度增大呈降低趋势.210Pb和7Be的降水沉降主要分布在每年的春夏季;周沉降量随同期降水量呈增大趋势,7Be增大的斜率约为210Pb的3倍;当近于零降水时,它们在降水中的初始比率约为2.5.它们出现高或者较高的周降水沉降都伴随当周或邻周空气浓度的急剧下降;降水中210Pb/7Be比率主要分布在≤0.5,并与空气中210Pb/7Be比率基本同步,显示出两核素被降水清洗的效率基本相近.④2008年冰冻极端天气过程中,210Pb-7Be空气浓度同步低谷并存在气溶胶低浓度与高比活度耦合.⑤观风山7Be周空气浓度显示低纬度、较高海拔地区的预期水平;短周期波动反映强下沉气流和低海拔上升气团影响分别在观风山和瓦里关山的滞后性.  相似文献   

2008年汶川8.0级地震的发震构造:沿龙门山断裂带新生的地壳深部断裂     

徐杰  高祥林  周本刚  计凤桔  张进  白玉柱  陈国光 《地学前缘》2010,17(5):117

在区域地质构造研究中,龙门山断裂带也称为龙门山褶皱-冲断带或推覆构造带。许多研究者认为,2008年汶川8级地震的发震构造是这条断裂带或其中央映秀—北川断裂。笔者在深入分析龙门山断裂带的构造演化和岩石圈结构构造特征的基础上,着重探讨8级地震的发震构造,提出不同的认识。龙门山断裂带经历了松潘—甘孜造山带的前陆褶皱-冲断带(T3-J)、造山带(K-E)和青藏高原边缘隆起带(N-Q)3个动力学条件不同的演化阶段,在前两个阶段断裂带递进发展,第三阶段断裂带则被改造。从三维空间看,龙门山断裂带位于松潘—甘孜地块东南缘的上地壳内,并被推覆到扬子陆块上;而松潘—甘孜地块的中—下地壳和岩石圈地幔发生韧性增厚,而且向扬子陆块壳下俯冲,从而使浅、深部构造在垂向上形成"吞噬"扬子地块的"鳄鱼嘴"式结构。虽然在平面上汶川8级地震的主余震分布与映秀—北川断裂一致,但从剖面上看其震源所构成的震源破裂体位于龙门山断裂带之下的扬子陆块内。这种不一致性表明,8级地震的发震构造不是龙门山断裂带,而是扬子陆块内新生的高角度断裂,其走向基本与龙门山断裂带一致。推测这一震源断裂的形成过程是:当松潘—甘孜地块向东南推挤时,其前缘"鳄鱼嘴"构造咬合并错断被吞噬的扬子陆块部分,形成具有右旋逆平移性质的新断裂,导致汶川8级地震的发生。  相似文献   

第四纪华容隆起构造活动、成因及动力机制   总被引：9，自引：0，他引：9  

柏道远  李长安  王先辉  周柯军  马铁球  彭云益  李纲  陈渡平 《地质科学》2010,45(2):411-427

第四纪华容隆起位于江汉—洞庭盆地中部。通过地表观察和第四系钻孔对华容隆起及周缘地貌、第四纪断裂和沉积进行调查,恢复华容隆起构造升降特征与过程,进而探讨华容隆起的成因及其构造活动的动力机制。研究表明:早更新世-中更新世中期华容隆起与周缘凹陷一道沉降,同时前者受周边正断裂控制相对后者有抬升,中更新世晚期一道抬升,晚更新世—全新世构造稳定或弱沉降。第四纪期间华容隆起总体表现为明显的构造沉降。以上表明第四纪华容隆起主要由前第四纪盆—山地貌分异造成,其次与第四纪期间相对周缘凹陷抬升有关。上述地质特征以及区域第四纪地质资料,表明早更新世-中更新世中期江汉—洞庭盆地为断陷盆地,中更新世晚期—全新世转变为坳陷盆地。就华容隆起第四纪构造活动的动力机制进行了探讨并提出:1)早更新世-中更新世中期江汉—洞庭盆地断陷沉降与地幔上隆背景下的深部物质迁出有关。2)中更新世晚期以来的构造活动可能与深部物质蠕移运动的回返以及板块尺度的物质运动和挤压作用有关。3)江汉—洞庭盆地的整体性沉降导致盆地中部的华容隆起以沉降为主;华容隆起特殊的地壳物质结构可能导致深部物质更难向外迁移,使其相对周缘凹陷有抬升。  相似文献   

Eight new quasars discovered by the Guoshoujing Telescope (LAMOST) in one extragalactic field     

Xue-Bing Wu  Zhen-Dong Jia  Zhao-Yu Chen  Wen-Wen Zuo  Yong-Heng Zhao  A-li Luo  Zhong-Rui Bai  Jian-Jun Chen  Hao-Tong Zhang  Hong-Liang Yan  Juan-Juan Ren  Shi-Wei Sun  Hong Wu  Yong Zhang  Ye-Ping Li  Qi-Shuai Lu  You Wang  Ji-Jun Ni  Hai Wang  Xu Kong  Shi-Yin Shen 《中国天文和天体物理学报》2010,10(8)

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Using comprehensive and sequential vegetation classification system to predict the influence of climate change on vegetation succession of alpine grassland of Qinghai Plateau     

Hongmei Li  Yushou Ma  Yanfang Bai 《Frontiers of Earth Science》2010,4(1):99-104

Distribution of grassland vegetation is highly associated with climatic conditions and varied with climatic change. The tendency of climatic changes on Qinghai Plateau was analyzed, based on the meteorological data from 1961 to 2007 collected from 50 meteorological stations distributed throughout the whole plateau. The vegetation distribution of alpine grassland under past and future climatic change was estimated by using the approach of Comprehensive and Sequential Classification system. Results show that the climate varied greatly before and after 1987. The temperature increased 0.16°C/10a before 1987 and 0.64°C/10a after 1987. The precipitation increased 0.14 mm/10a before 1987 and 3.92 mm/10a after 1987. There were 12 types of grassland vegetation between 1961 and 1987, while there were 11 types of grassland vegetation between 1988 and 2007 on the Plateau. When climatic warming continued with CO₂ doubling in the future, the vegetation of alpine grassland will shrink into nine types.  相似文献   

地震勘探技术在新疆准东煤田的应用     

刘兴金  陈召曦  白锦琳 《中国煤炭地质》2010,(6):59-62

新疆准东煤田主要煤层为赋存于中侏罗系西山窑组地层中的B煤组煤层,受区域构造和沉积环境的影响,该煤组煤层存在分叉合并、露头、缺失、火烧等地质现象,煤层结构比较复杂。以准东煤田西山窑组地层中的B煤组煤层为例,介绍了上述地质现象在地震时间剖面上的表现特征及解释原则,并采用地震反演技术对该区煤层厚度及煤层结构进行了解释,其精度与实际揭露相比,吻合程度较高。  相似文献   

Contamination and potential mobility assessment of heavy metals in urban soils of Hangzhou,China: relationship with different land uses   总被引：1，自引：0，他引：1  

S. G. Lu  S. Q. Bai 《Environmental Earth Sciences》2010,60(7):1481-1490

Concentration and distribution of heavy metals (Cd, Cu, Pb and Zn) in urban soils of Hangzhou, China, were measured based on different land uses. The contamination degree of heavy metals was assessed on the basis of pollution index (PI), integrated pollution index (IPI) and geoaccumulation index (I _geo). The 0.1 mol l⁻¹ HCl extraction procedure and gastric juice simulation test (GJST) were used to evaluate the potential mobility and environmental risk of heavy metals in urban soils. The average concentration of Cd, Cu, Pb and Zn in urban soils was measured at 1.2 (with a range of 0.7–4.6), 52.0 (7.4–177.3), 88.2 (15.0–492.1) and 206.9 (19.3–1,249.2) mg kg⁻¹, respectively. The degree of contamination increased in the order of industrial area (IA) > roadside (RS) > residential and commercial areas (RC) > public park and green areas (PG). The PIs for heavy metals indicated that there is a considerable Cd, Cu, Pb and Zn pollution, which originate from traffic and industrial activities. The IPI of these four metals ranged from 1.6 to 11.8 with a mean of 3.5, with the highest IPI in the industrial area. The assessment results of I _geo also supported that urban soil were moderately contaminated with Cd and to a lesser extent also with Cu, Pb and Zn. The IP and I _geo values reveal the pollution degree of heavy metal was the order of Cd > Pb > Zn ≈ Cu. It was shown that mobility and bioavailability of the heavy metals in urban soils increased in the order of Cd > Cu > Zn ≈ Pb. Owing to high mobility of Cd and Cu in the urban soils, further investigations are needed to understand their effect on the urban environment and human health. It is concluded that industrial activities and emissions from vehicles may be the major source of heavy metals in urban contamination. Results of this study present a rough guide about the distribution and potential environmental and health risk of heavy metals in the urban soils.  相似文献   

Oxygen consumption and ammonia-N excretion of Meretrix meretrix in different temperature and salinity     

Tang Baojun  Liu Baozhong  Yang Hongsheng  Xiang Jianhai 《中国海洋湖沼学报》2005,23(4):469-474

Effects of temperatures and salinities on oxygen consumption and ammonia-N excretion rate of clamMeretrix meretrix were studied in laboratory from Oct. 2003 to Jan. 2004. Two schemes were designed in incremented temperature at 10, 15, 20, 25°C at 31.5 salinity and in incremented salinity at 16.0, 21.0, 26.0, 31.5, 36.0, and 41.0 at 20°C, all for 8–10 days. From 10 to 25°C, both respiration and excretion rate were increased. One-way ANOVA analysis demonstrated significant difference (P<0.01) in physiological parameters in this temperature range except between 15 and 20°C. The highestQ ₁₀ thermal coefficient value (12.27) was acquired between 10 and 15°C, and about 1 between 15 and 20°C, indicatingM. meretrix could well acclimate to temperature changes in this range. Salinity also had significant effects on respiration and excretion rate (P<0.05). The highest values of respiration and excretion rate ofM. meretrix were recorded at 16.0 salinity (20°C). These two physiological parameters decreased as salinity increased until reached the minimumQ ₁₀ value at 31.5 (20°C), then again, these parameters increased with increasing salinity from 31.5 to 41.0.M. meretrix can catabolize body protein to cope with osmotic pressure stress when environmental salinity is away from its optimal range. No significant difference was observed between 26.0 and 36.0 in salinity (P>0.05), suggesting that a best metabolic salinity range for this species is between 26.0 and 36.0. This work is supported by National High-Tech R & D Program of China. (863 Program) (2002AA603014).  相似文献