晚新生代西太平洋古海洋环境演化过程与机制          下载免费PDF全文

李铁刚  秦秉斌  万世明  姚政权  邹建军  刘焱光  乔淑卿  徐兆凯  孙晗杰  南青云  常凤鸣  熊志方 《海洋科学进展》2022,40(4):551-563

晚新生代西太平洋通过水文循环和碳循环两类关键过程,对区域乃至全球气候变化产生深刻的影响。本文从上新世以来西太暖池及其主流系演化、晚第四纪北太平洋中层水演化和白令海峡开合、第四纪中国东部陆架环境演化以及新生代亚太沉积物源-汇过程与碳埋藏等方面,综述了西太平洋古海洋环境演化过程与机制。上新世以来西太暖池与印尼贯穿流的演化过程伴随构造运动而阶段性地发生,但其在轨道时间尺度上演化的细节过程并不清晰,尚未形成系统性认识。北太平洋中层水以及白令海峡开合等关键高纬过程在冰期旋回中发生了显著变化,并与低纬过程之间存在遥相关。第四纪中国东部陆架环境演化主要受控于海平面变化以及与低纬过程相关联的热量与物质传输,在此背景下,中国东部陆架形成了富有机碳的泥质沉积体系。构造隆升和亚洲季风驱动下的亚洲大陆与邻洋的沉积物源-汇过程具有显著的碳汇效应,可能在大气CO₂浓度（${p_{{\rm{C}}{{\rm{O}}_2}}} $）冰期旋回和新生代气候变冷中发挥重要作用。就西太平洋古海洋环境演化过程与机制中若干关键科学问题开展深入和系统研究,不仅可为建立气候变化的低纬驱动理论提供支撑,也可为更好认识我国陆架环境变化规律以及碳汇潜力提供科学依据。  相似文献   

The Acre Basin basement (NW Brazil) and the transition from the intracratonic to retroarc foreland basin system     

Rick Souza de Oliveira  Roberta Mary Vidotti 《Basin Research》2023,35(1):86-119

The understanding of the crustal transition between orogenic zones and cratonic portions in distal regions of foreland basins has received increasing attention, but the analysis is often hampered by the sedimentary cover. Despite the peculiar location of the Acre Basin, specifically between the Amazonian Craton and the sub-Andean zone, local basement studies are still scarce due to lacking seismic data and exploratory wells. Therefore, this work aims to map basement depths, estimate crustal compositions and identify the main depocenters, structures and limits of Acre Basin using an integrated analysis to understand better the region lithospheric evolution, its relationship with the Amazonian Craton and its positioning within the Andean orogeny. For that, we used well, 2D seismic reflection, airborne and ground gravity and magnetic data as well as the EMG2008. Tilt Depth estimates indicate basement depths between 500 and 7800 m and larger sedimentary thicknesses in the northern portion. Additionally, we modelled groups of potential sources between 0.1 and 22 km and Moho depths between 26 and 37 km. Compositionally, the upper crust consists dominantly of meta-sedimentary and low-grade metamorphic rocks and granites, indicating that the sub-Andean and Acre Basins share a similar basement. Thus, there are indications that the basement of the Acre Basin is essentially formed by the Sunsás province in the Amazonian Craton. However, local differences in basement depth, magnetic susceptibility and exploratory potential led to the subdivision into Divisor and Xapuri sub-basins, north and south of the Fitzcarrald Arch, respectively. Finally, it was possible to establish the limits of the Andean orogeny influence in the Acre Basin and delimit the area of the Western Amazon Foredeep installed during the Neogene.  相似文献   

宣痹益气通阳方联合瑞舒伐他汀治疗不稳定型心绞痛患者的疗效评价          下载免费PDF全文

姚胜青  张玄 《应用海洋学学报》2022,38(12):1

目的：观察宣痹益气通阳方联合瑞舒伐他汀治疗阳气虚衰型不稳定型心绞痛（UA）的临床疗效。方法：将126 例阳气虚衰型UA患者随机分为治疗组和对照组,每组各63 例。2组均给予常规西药治疗,对照组再予瑞舒伐他汀钙片治疗,治疗组于对照组基础上再加宣痹益气通阳方治疗,2组均治疗8周。对比2组综合疗效,治疗前后中医证候各项评分及总积分,血脂指标［三酰甘油（TG）、总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）、低密度脂蛋白胆固醇（LDL-C）］,血管内皮功能［血浆内皮素（ET）、一氧化氮（NO）、血管内皮舒张变化率（FMD）］及心血管不良事件（MACE）发生情况。结果：总有效率治疗组为95.24%（60/63）,对照组为84.13%（53/63）,组间比较,差异有统计学意义（P<0.05）;2组治疗后中医证候各项评分及总积分、TG、TC、LDL-C、ET均较治疗前下降,HDL-C、NO、FMD均较治疗前上升,且治疗组下降及上升幅度均大于对照组,差异均有统计学意义（P<0.05）。MACE总发生率治疗组为4.77%（3/63）,对照组为17.46%（11/63）,组间比较,差异有统计学意义（P<0.05）。结论：宣痹益气通阳方联合瑞舒伐他汀钙片治疗阳气虚衰型UA能调节血脂水平,改善血管内皮功能,缓解症状,降低MACE发生风险,具有良好的临床效果。  相似文献   

改良黄土汤联合奥美拉唑钠治疗急性非静脉曲张性上消化道出血55例          下载免费PDF全文

任小军  罗云 《应用海洋学学报》2022,38(12):9

目的：观察改良黄土汤联合奥美拉唑钠治疗急性非静脉曲张性上消化道出血(ANVUGIB)脾胃虚弱证的临床疗效。方法：将105 例ANVUGIB脾胃虚弱证患者随机分为治疗组和对照组。对照组50 例采用奥美拉唑钠治疗,治疗组55 例在对照组治疗的基础上加用改良黄土汤治疗。观察2组的综合疗效、止血效果、止血时间、输血量及血清白细胞介素-10(IL-10)水平。结果：总有效率治疗组为94.55%（52/55）,对照组为82.00%（41/50）,组间比较,差异有统计学意义（P<0.05）。治疗组在治疗12、24、48、72 h的止血成功率均高于对照组,止血时间均短于对照组（均P<0.05）。2组治疗72 h血清IL-10均较治疗前下降,且治疗组低于对照组（P<0.01或P<0.05）。结论：改良黄土汤联合奥美拉唑钠治疗ANVUGIB脾胃虚弱证可提高止血有效率,减轻机体炎症反应。  相似文献   

Augmenting forest inventory attributes with geometric optical modelling in support of regional susceptibility assessments to bark beetle infestations     

《International Journal of Applied Earth Observation and Geoinformation》2013

Assessment of the susceptibility of forests to mountain pine beetle (Dendroctonus ponderosae Hopkins) infestation is based upon an understanding of the characteristics that predispose the stands to attack. These assessments are typically derived from conventional forest inventory data; however, this information often represents only managed forest areas. It does not cover areas such as forest parks or conservation regions and is often not regularly updated resulting in an inability to assess forest susceptibility. To address these shortcomings, we demonstrate how a geometric optical model (GOM) can be applied to Landsat-5 Thematic Mapper (TM) imagery (30 m spatial resolution) to estimate stand-level susceptibility to mountain pine beetle attack. Spectral mixture analysis was used to determine the proportion of sunlit canopy and background, and shadow of each Landsat pixel enabling per pixel estimates of attributes required for model inversion. Stand structural attributes were then derived from inversion of the geometric optical model and used as basis for susceptibility mapping. Mean stand density estimated by the geometric optical model was 2753 (standard deviation ± 308) stems per hectare and mean horizontal crown radius was 2.09 (standard deviation ± 0.11) metres. When compared to equivalent forest inventory attributes, model predictions of stems per hectare and crown radius were shown to be reasonably estimated using a Kruskal–Wallis ANOVA (p < 0.001). These predictions were then used to create a large area map that provided an assessment of the forest area susceptible to mountain pine beetle damage.  相似文献   

国家西部测图工程标准化研究与实践     

苏山舞  殷红梅  于荣花 《测绘科学》2013,38(2):38-40

标准研制是西部测图工程的重要工作内容,为工程的顺利开展、实施提供技术依据和质量保障。本文介绍西部测图工程标准化工作,以测什么、怎么测、如何表达三个问题为视点研究制定西部测图工程内部标准——生产技术规定,提出在大型测绘工程标准化工作中解决三个问题的技术要点,设计标准化工作视图,用以指导工程标准制定及实施。  相似文献   

Dynamical Control of Pacific Oceanic Low-frequency Variability on Western Boundary and Marginal Seas     

Lixin Wu  Zhengyu Liu 《地球物理与天体物理流体动力学》2013,107(3):201-222

The adjustment of sea surface height (SSH) around the coasts of the Japan/East Sea (JES) and the South China Sea (SCS) basins subjected to extratropical Pacific Oceanic low frequency variability is studied using a Kelvin-planetary wave model and a high resolution numerical model. It is found that the modulation of SSH around the coast of Japan is mainly determined by slow adjustment of planetary waves, which radiate from the west coast of Honshu and Hokkaido due to the coastal Kelvin wave. In contrast, the SSH modulation around the cost of the South China Sea basin is mainly determined by the coastal Kelvin wave, which transfers the anomalous SSH into the SCS via the Luzon Strait and out via the Mindoro Strait. The planetary waves radiating from the west coast of Palawan establish a nearly uniform SSH anomaly in the southern part of the SCS, bounded by an eastward jet at the latitude of the Mindoro Strait. Along the western boundary, SSH anomaly decreases almost linearly toward the south, in accordance with the changing local deformation radius. In these two marginal seas, the mean subtropical Pacific gyre circulation enhances SSH modulation induced by extratropical Pacific low frequency variability. Overall, the SSH adjustment in the JES and the SCS predicted by the analytical model agrees well with the numerical model simulation. Application of this model to interaction between these marginal seas and the open ocean is discussed.  相似文献   

夏季西北太平洋大气环流异常及其与热带印度洋-太平洋海温变化的关系   总被引：5，自引：0，他引：5       下载免费PDF全文

晏红明  李清泉  袁媛  李崇银 《地球物理学报》2013,56(8):2542-2557

本文分析了夏季西北太平洋大气环流异常特征及其与海温变化的关系,发现夏季西北太平洋异常反气旋/气旋(WNPAC/WNPC)是西北太平洋地区对流层中低层存在的重要大气环流异常现象,与东亚-西北太平洋低纬度至高纬度的经向PJ波列及欧亚中高纬度东西纬向波列的变化有关,通过与中高纬度环流变化的联系,对东亚及欧亚中高纬度气候有重要影响.夏季WNPAC/WNPC与热带海温变化的关系存在明显的不对称性,显著的WNPAC一般出现在El Niño衰减年夏季,与前期El Niño成熟年冬季的赤道东太平洋暖海温异常和El Niño衰减年春夏季印度洋海盆尺度的暖海温异常有明显的正相关关系,进一步表明了WNPAC在El Niño事件影响夏季气候中的重要桥梁作用;而夏季显著的WNPC与前期和同期热带海温变化的关系存在明显的不确定性,主要与夏季热带印度洋和赤道中东太平洋之间东暖西冷的热力差异异常引起的孟加拉湾-赤道西太平洋西风异常有关.进一步分析WNPAC/WNPC与海温变化关系不对称的可能原因,发现El Niño和La Niña衰减年夏季热带印度洋和太平洋海温变化所引起的印-太之间海温(热力)差异的一致性特征可能是导致WNPAC/WNPC与海温变化关系不对称的主要原因.  相似文献   

A method for groundwater prospect zonation in data poor areas using remote sensing and GIS: a case study in Kalikavu Panchayath of Malappuram district,Kerala, India     

《International Journal of Digital Earth》2013,6(2):155-170

Abstract

The present study was an attempt to delineate potential groundwater zones in Kalikavu Panchayat of Malappuram district, Kerala, India. The geo-spatial database on geomorphology, landuse, geology, slope and drainage network was generated in a geographic information system (GIS) environment from satellite data, Survey of India topographic sheets and field observations. To understand the movement and occurrence of groundwater, the geology, geomorphology, structural set-up and recharging conditions have to be well understood. In the present study, the potential recharge areas are delineated in terms of geology, geomorphology, land use, slope, drainage pattern, etc. Various thematic data generated were integrated using a heuristic method in the GIS domain to generate maps showing potential groundwater zones. The composite output map scores were reclassified into different zones using a decision rule. The final output map shows different zones of groundwater prospect, viz., very good (15.57% of the area), good (43.74%), moderate (28.38%) and poor (12.31%). Geomorphic units such as valley plains, valley fills and alluvial terraces were identified as good to excellent prospect zones, while the gently sloping lateritic uplands were identified as good to moderate zones. Steeply sloping hilly terrains underlain by hard rocks were identified as poor groundwater prospect zones.  相似文献   

Pore Water Pressure as a Trigger of Shallow Landslides in the Western Ghats of Kerala,India: Some Preliminary Observations from an Experimental Catchment     

《自然地理学》2013,34(4):374-386

The Western Ghats mountain chain of Kerala, India, is prone to landslides mainly caused by anthropogenic disturbances and very high rainfall amounts. Here, some initial observations on the apparent relationship among pore water pressure fluctuations, rainfall characteristics, and landslide initiation are presented based on monitoring in an experimental catchment in the upper Tikovil River basin. On June 21 and 22, 2007, continuous rain fell for over 10 hours with a total precipitation of 147 mm, causing three shallow landslides in the catchment. Measurements using piezometers in three hollows of the catchment indicate that the rain spell resulted in the development of high pore water pressure from the beginning of the storm that persisted through the time of occurrence of shallow landslides. The pore water pressure patterns in these monitored hollows are possible representatives of the pore water pressure pattern in the hollows where the landslides initiated. This similarity of response pattern enables such data to be used for the calibration and validation of physically based slope hydrology models coupled with slope stability models.  相似文献