西南岩溶地区碳循环观测与模拟研究进展和展望   总被引：1，自引：0，他引：1  

马明国  汤旭光  韩旭军  时伟宇  宋立生  黄静 《地理科学进展》2019,38(8):1196-1205

岩溶地区碳循环具有地表与地下双层结构的相互渗透、有机与无机碳循环的相耦合以及生物与非生物过程的相关联等特征,相对于其他陆地生态系统更为特殊和复杂。中国西南地区是全球最大范围的喀斯特连续出露地区,前期研究结果表明该区域的碳循环路径与过程是基本清晰的,但岩石-土壤-植被-大气-水不同界面间的碳通量及迁移转化机制仍然不明确,亟待开展小流域尺度碳循环各个分量的精细观测,以及区域尺度的碳循环遥感估算和模型模拟工作。论文对西南岩溶地区碳循环观测与模拟研究的进展进行了梳理,在此基础上展望下一步需要重点开展的工作,该研究可以为评估全球气候变化对该地区影响及制定适应对策提供参考。  相似文献   

北京西山寒武纪海相红层的分布与时代     

李明  林宝玉 《地质学报》2022,96(6):1895-1921

本文参照北京西山及国内外寒武系相关地层资料，在古生物学和地层学研究的基础上，对北京西山寒武纪海相红层进行了初步研究。在西山寒武纪地层中，共识别出14层(套)海相红层，分别为：早寒武世下苇甸组1层B∈RB1(沧浪铺期)；早—中寒武世早期3层B∈RB2、B∈RB3及B∈RB4(馒头期—毛庄期)；中寒武世中期3层B∈RB5、B∈RB6及B∈RB7(徐庄期)；中寒武世晚期1层B∈RB8(张夏期)；晚寒武世早期2层B∈RB9、B∈RB10(崮山期)；晚寒武世中期3层B∈RB11、B∈RB12、B∈RB13(长山期)：晚寒武世晚期1层B∈RB14(凤山期)。所有14层海相红层形成于陆表海浅水环境，它们均属陆棚红层。红层分布模式说明，它们的形成与其附近的古陆有关。依据海相红层及其上下层位中所含的三叶虫化石，本文初步论述了各海相红层的大致时代，并与其他地区的同期海相红层进行了对比。此外，本文还讨论了山西东部寒武纪海相红层的层序和全球早寒武世沧浪铺期海相红层的广布事件。  相似文献   

基于MEMS加速度计空投浮标的波浪测量方法试验研究     

刘宁  魏晓辉  王斌  董涛 《海洋科学》2020,44(9):146-153

针对基于MEMS加速度传感器的空投波浪浮标存在采样频率与测波精度低的问题，根据频域衰减积分算法，提出一种相应的波浪测量算法，为了验证该算法测波的准确性，开展了多功能水槽试验研究。该算法旨在将MEMS加速度传感器输出的加速度与姿态角转化为浮标运动的波形，首先将加速度与姿态角信号进行竖向处理获得竖直方向的加速度，再利用离散傅里叶变换将竖向加速度转化为频域内的加速度复数序列，然后引入控制函数减弱低频噪声，经过频域积分、离散傅里叶逆变换、时域积分获得竖直方向的位移，最后通过后处理得到最终的波形。多功能水槽试验采取10中不同波高和周期的工况，对比空投波浪测量浮标与波高仪的测量结果，试验结果表明，浮标的测量误差在10%以内，达到测波标准。  相似文献   

Estimation of forest aboveground biomass from HJ1B imagery using a canopy reflectance model and a forest growth model     

Xinyun Wang  Yige Guo  Jie He  Lingtong Du  Tianhua Hu 《国际地球制图》2018,33(2):148-162

Accurately estimating the spatial distribution of forest aboveground biomass (AGB) is important because of its carbon budget forms part of the global carbon cycle. This paper presented three methods for obtaining forest AGB based on a forest growth model, a Multiple-Forward-Mode (MFM) method and a stochastic gradient boosting (SGB) model. A Li-Strahler geometric-optical canopy reflectance model (GOMS) with the ZELIG forest growth model was run using HJ1B imagery to derive forest AGB. GOMS-ZELIG simulated data were used to train the SGB model and AGB estimation. The GOMS-ZELIG AGB estimation was evaluated for 24 field-measured data and compared against the GOMS-SGB model and GOMS-MFM biomass predictions from multispectral HJ1B data. The results show that the estimation accuracy of the GOMS-MFM model is slightly higher than that of the GOMS-SGB model. The GOMS-ZELIG and GOMS-MFM models are considerably more accurate at estimating forest AGB in arid and semiarid regions.  相似文献   

Decreasing intensity of the last glacial stadials in low latitude terrestrial East Asia inferred by a new observation of pollen records in central Taiwan     

《Journal of Asian Earth Sciences》2013

The cold intensity of the last glacial stadials corresponding to marine isotope stage (MIS) 5d (or 5b), MIS 4 and MIS 2 in terrestrial East Asia monsoon area is not discussed much due to the paucity of long continuous pollen records. A palynological study of drilling cores from three closely-linked intramontane basins (Toushe, Sun-moon Lake and Yuchi) in central Taiwan provides a history of shifting altitudinal vegetation zones in surrounding mountains during late Quaternary climate changes. By integrating these records, we found that the alpine conifer forest approached its lowest altitude, about 614 m, during the earliest stadial (≒MIS 5d or 5b), and 745 m during the early stadial (≒MIS 4) based on records of Yuchi Basin and Sun-moon Lake. In addition, the pollen records of Toushe Basin and Sun-moon Lake show more temperate conditions for the late stadial (≒MIS 2) than the early stadial (≒MIS 4). This leads to an interpretation of a decreasing intensity of stadials during the last glaciation, which might follow the regional insolation amplitude. Such a decreasing trend in coldness during the last glacial stadials does not exist in the record for the South China Sea which reflects a different sensitivity and response to climatic forcings between terrestrial and marine.  相似文献   

Carbonate platform growth and demise offshore Central Vietnam: Effects of Early Miocene transgression and subsequent onshore uplift     

《Journal of Asian Earth Sciences》2013

Miocene carbonate platforms cover a large part of the Central Vietnamese South China Sea margin. Early carbonate deposition took place on two regional platforms separated by a narrow depression developed along the trace of the East Vietnam Boundary Fault Zone. West of the East Vietnam Boundary Fault Zone, the Tuy Hoa Carbonate Platform fringes the continental margin between Da Nang and Nha Trang. Here, platform growth initiated during the Early Miocene and continued until Middle Miocene time when regional uplift led to subaerial exposure, termination of platform growth and karstification. East of the fault zone, the Triton Carbonate Platform was also initiated during the Early Miocene. Carbonate growth thrived during Early and part of Middle Miocene time and a thick, clean Lower and Middle Miocene carbonate succession cover the Triton Horst and the Qui Nhon Ridge. During the Middle Miocene, partial drowning resulted in the split-up of the Triton Carbonate Platform. Repeated partial drowning events throughout the Middle and Late Miocene resulted in westwards retreat of platform growth and eventual platform drowning and termination of carbonate deposition. Modern carbonate growth continues on isolated platforms hosting the Paracel Islands farther seawards. The onset of widespread carbonate deposition largely reflects the Early Miocene transgression of the area linked with early post-rift subsidence and the opening of the South China Sea. The mid-Neogene shift in carbonate deposition is interpreted as a consequence of regional uplift and denudation of central and south Indochina starting during Middle Miocene time when the Tuy Hoa Carbonate Platform became subaerially exposed. Stressed carbonate growth conditions on the Triton Carbonate Platform probably resulted from increased inorganic nutrient input derived from the uplifted mainland, possibly enhanced by deteriorated climatic conditions and rapid sea-level fluctuations promoting platform drowning.  相似文献   

基于无人机高光谱特征的红树林种群识别研究     

周在明  陈本清  徐冉  方维 《海洋学报》2021,43(9):137-145

红树林种群的组成和分布对于红树林生态系统的保护和恢复至关重要。本研究以漳江口红树林保护区为研究对象,通过获取无人机高光谱影像,进行光谱特征分析、光谱微分变换和包络线去除,提取了911组17个光谱特征参数,通过逐步判别分析筛选出13个用于决策树构建的特征参数,最终通过C5.0决策树模型获得了研究区红树林种群的分布状况。结果表明,漳江口红树林保护区植被种群呈现自上到下不同类型的分布情况,研究区上部以桐花树和秋茄混合类型为主,中间区域呈现白骨壤、桐花树和秋茄三者共生的现状,研究区下部则以白骨壤分布为主,伴生有少量的秋茄。通过混淆矩阵计算,得到研究区总体分类精度为 87.95%,Kappa系数为 83.81%,具有较好的精度。研究结果可为区域红树林湿地保护提供数据支撑,为红树林种群识别研究提供方法参考。  相似文献   

Other contents     

《Applied Geochemistry》1999,14(8):I

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Assessment and prioritization of soil erosion triggering factors using analytical hierarchy process and Taguchi method   总被引：1，自引：0，他引：1  

Mehdi Hayatzadeh  Vahid Moosavi  Ramyar Aliramaee 《国际泥沙研究》2023,38(3):396-404

The main aims of this study are assessing some factors which affect the soil erosion process and evaluating the results of an analytical hierarchy process(AHP) method using the Taguchi method. Firstly, the weights for those factors and levels affecting soil erosion were determined by the AHP method. The determination of weights was based on the opinions of academic researchers, experts, middle managers,and members of the Soil and Water Research Centers in Iran. Secondly, an L32 Taguchi orthogona...  相似文献   

青藏高原地球物理与大陆动力学研究的新进展   总被引：2，自引：0，他引：2       下载免费PDF全文

李秋生  高原  王绪本  赵俊猛 《地球物理学报》2020,63(3):789-801

岩石圈地球物理探测、深部结构成像与各向异性等研究是青藏高原大陆动力学研究的基础.近年来,随着深部地球物理探测技术和反演成像技术的进步,信息提取与细节分辨能力不断提升,青藏高原壳幔结构、碰撞和隆升动力学、资源与地质灾害的深部机制等研究进展显著.本专辑收录33篇论文,主要分布在深部结构与地球物理探测、地震各向异性与变形、断裂性质与地震活动等三个主要研究领域.本文重点围绕这些论文,对近年来青藏高原地球物理研究进展进行综述.  相似文献