适应数值模式垂直坐标的GPS掩星反演资料稀疏化方案          下载免费PDF全文

马旭林  郭欢  和杰  周勃旸  李琳琳 《大气科学学报》2019,42(3):380-389

GPS掩星反演大气温湿资料具有高垂直分辨率、高精度、受云和降水影响小等优点,针对GRAPES同化预报系统,发展设计了一种既考虑预报模式高度-地形追随垂直坐标不均匀分层特点,又结合掩星反演资料特性的新适应性垂直稀疏化方案。通过个例试验和批量试验,探索了该适应性稀疏化方案对分析预报质量的影响。试验结果表明:选取合适的稀疏参数,新稀疏化方案的GPS掩星反演资料对背景场的调整更加有效,分析场质量更高;位势高度、比湿、温度和风场等预报场的均方根误差均更小;适应性稀疏化方案对改善台风路径预报具有积极作用。批量试验则进一步证实了适应性稀疏化方案对分析场质量有明显的改善作用。  相似文献   

Stable isotopic signatures of the modern land snail Eremina desertorum from a low-latitude (hot) dry desert—A study from the Petrified Forest,New Cairo,Egypt     

《Chemie der Erde / Geochemistry》2015,75(1):65-72

This study was conducted on recent desert samples—including (1) soils, (2) plants, (3) the shell, and (4) organic matter from modern specimens of the land snail Eremina desertorum—which were collected at several altitudes (316–360 m above sea level) from a site in the New Cairo Petrified Forest. The soils and shell_{E. desertorum} were analyzed for carbonate composition and isotopic composition (δ¹⁸O, δ¹³C). The plants and organic matter_{E. desertorum} were analyzed for organic carbon content and δ¹³C. The soil carbonate, consisting of calcite plus minor dolomite, has δ¹⁸O values from −3.19 to −1.78‰ and δ¹³C values −1.79 to −0.27‰; covariance between the two values accords with arid climatic conditions. The local plants include C3 and C4 types, with the latter being dominant. Each type has distinctive bulk organic carbon δ¹³C values: −26.51 to −25.36‰ for C3-type, and −13.74 to −12.43‰ for C4-type plants.The carbonate of the shell_{E. desertorum} is composed of aragonite plus minor calcite, with relatively homogenous isotopic compositions (δ¹⁸O_mean = −0.28 ± 0.22‰; δ¹³C_mean = −4.46 ± 0.58‰). Most of the δ¹⁸O values (based on a model for oxygen isotope fractionation in an aragonite-water system) are consistent with evaporated water signatures. The organic matter_{E. desertorum} varies only slightly in bulk organic carbon δ¹³C values (−21.78 ± 1.20‰) and these values suggest that the snail consumed more of C3-type than C4-type plants. The overall offset in δ¹³C values (−17.32‰) observed between shell_{E. desertorum} carbonate and organic matter_{E. desertorum} exceeds the value expected for vegetation input, and implies that 30% of carbon in the shell_{E. desertorum} carbonate comes from the consumption of limestone material.  相似文献   

电感耦合等离子体发射光谱法测定硼硅酸盐玻璃中的硼等常见元素   总被引：2，自引：1，他引：1  

郭中宝  张艳妮  代铮  王潇 《岩矿测试》2015,34(1):55-59

硼硅酸盐玻璃中的硼、钙、镁、铝、铁、钛、硅等常见元素普遍采用各元素分别测定的方式进行分析,分析效率很低;而且硼的测定普遍采用容量法,当B2O3含量低于1%时,容量法测定误差较大。本文以KOH熔融的方式消解样品,采用电感耦合等离子体发射光谱法(ICP-AES)进行分析。通过实验研究了KOH用量和不同称样量对B2O3测定结果的影响。结果表明,KOH用量在3 g以上时有较好的熔样效率和熔样效果,称样量低于0.4 g对B2O3测定结果无明显影响,考虑到其他元素的测定,确定了KOH用量优选3 g,称样量优选0.1 g。在此条件下,测定B2O3等常见元素的精密度(RSD,n=6)≤2%,加标回收率在96.0%~105.6%之间,除Si O2测定误差较大外,其他元素的测定结果均令人满意。本方法确定的B2O3的定量限为0.067%,且对于B2O3最高含量达到16%的测定结果也令人满意,因此可测定B2O3含量的范围至少为0.067%~16%。当样品中的B2O3含量高于4%时,方法准确度和精密度与国家标准分析方法(容量法)相当;当B2O3含量低于1%时,方法准确度和精密度都优于容量法。与现有报道相比,本方法显著拓宽了B2O3的测定范围,并具有良好的准确度,而且在B2O3准确测定的同时,也实现了Ca、Mg、Al、Fe、Ti的定量分析和Si的半定量分析,大大提高了分析效率,可以实现硼硅酸盐玻璃中B2O3等常见元素的准确快速分析。  相似文献   

Networking,context and firm-level innovation: Cooperation through the regional filter in Norway     

《Geoforum》2015

The paper assesses the role for innovation of one aspect which has been generally overlooked by evolutionary economic geography: context. It analyses how context shapes the impact of collaboration on firm-level innovation for 1604 firms located in the five largest city regions of Norway. Specifically, the analysis shows how the benefits to firms of collaborating within regional, national, and international innovation networks are affected by the knowledge endowments of the region within which the firm is located. Using a logit regression analysis, we find, first, that only national and international networking have a significant positive impact on the likelihood of innovation (the former only for process innovation), whereas the regional knowledge endowments have no direct effect. Second, regional cooperation is particularly effective in regions with high investments in R&D, whereas international cooperation is important in regions with an educated workforce – and regional and national collaboration may be ineffective in such cases. We conclude that, in the case of Norway, context is essential in determining the capacity of firms to set up networks and innovate. Regions with an educated workforce can use the resulting absorptive capacity to successfully assimilate knowledge being diffused through global pipelines from faraway places. However, this absorptive capacity is likely to be heavily filtered if regional firms mainly rely on internal connections within Norway.  相似文献   

Evaluation of the relative roles of global versus local sedimentary controls on Middle to Late Pleistocene formation of continental margin strata,Canterbury Basin,New Zealand          下载免费PDF全文

Tania Villaseñor  John M. Jaeger  Kathleen M. Marsaglia  Greg H. Browne 《Sedimentology》2015,62(4):1118-1148

Determining the relative influence of eustasy versus local sedimentary processes on strata formation is a fundamental challenge in the study of continental margin stratigraphy. In this paper, the relative contribution of these factors on continental margin evolution during the Middle to Late Pleistocene is evaluated using samples from Integrated Ocean Drilling Program Expedition 317. Core‐logging, biostratigraphy and quantitative X‐ray diffraction mineralogy are used to delineate continental shelf sedimentary systems. Major lithological unconformities bound stratigraphic sequences that contain recurring compositional patterns and that resemble other examples of Middle to Upper Pleistocene sequences. However, a preliminary chronology suggests that sequence boundary formation cannot be linked ‘one to one’ with eustatic cycles and therefore these sequences can contain multiple ca 100 ka eustatic cycles. Smaller amplitude, higher frequency transitions in sediment composition are interpreted as stratigraphic sequences driven by more rapid perturbations in the interplay of accommodation and sediment supply; their stratigraphy is variable in time and across the shelf, suggesting a strong influence of local sedimentary forcing in their formation. Changes in sediment composition after the Middle Pleistocene Transition indicate that sediment transfer from onshore sources in the glaciated Southern Alps to the middle‐shelf occurred over a single 100 ka glacio‐eustatic cycle, with an additional 100 ka lag before the mineralogical signal was preserved on the outer‐shelf. This phenomenon is coincident with rapid shelf progradation in this basin, suggesting a causal relation between across‐shelf sediment transport and margin progradation. This is one of very few studies that provide insights at the core scale into the processes driving continental margin evolution during the Middle to Late Pleistocene. This work shows that compositional changes in mud‐dominated successions can lead to a sequence stratigraphic interpretation and the identification of high‐frequency sequences, which may not be possible using a conventional stratigraphic approach.  相似文献   

Sedimentology,three‐dimensional geobody reconstruction and carbon dioxide origin of Pleistocene travertine deposits in the Ballık area (south‐west Turkey)          下载免费PDF全文

Hannes Claes  Jeroen Soete  Koen Van Noten  Hamdy El Desouky  Marcelle Marques Erthal  Frank Vanhaecke  Mehmet Özkul  Rudy Swennen 《Sedimentology》2015,62(5):1408-1445

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Structural style in a young flexure-induced oblique extensional system,north-western Bonaparte Basin,Australia     

《Journal of Structural Geology》2015

In the north-western Bonaparte Basin (North West Shelf of Australia) Neogene to Recent flexure-induced extension superimposed obliquely over the Mesozoic rift structures. Thus, the area offers a good opportunity to investigate the dynamics and architecture of oblique extension fault systems. Analysis of basin-scale 2D and 3D seismic data along the Vulcan sub-basin shows that Neogene deformation produced a new set of extensional, en échelon faults, at places accompanied by the reactivation of the Mesozoic faults. The pre-existing Mesozoic structures strongly control the distribution of the Neogene-Recent deformation, both at regional and local scales. Main controls on the Neogene-Recent fault style, density and segmentation/linkage include: (1) the orientation of the underlying Mesozoic structures, (2) the obliqueness of the younger extension relative to the rift-inherited faults, and (3) the proximity to the Timor Trough. Three types of vertical relationships have been observed between Mesozoic and Neogene-Recent faults. Hard linkages seems to develop when both fault systems trend parallel, therefore increasing risks for trap integrity. It is suggested that the orientation of maximum horizontal stress (S_Hmax) relative to the Mesozoic faults, forming hydrocarbon traps, is critical for their potential seal/leak behaviour. Stratigraphic growth across the faults indicates that main fault activity occurred during the Plio-Pleistocene, which corresponds to the timing of tectonic loading on Timor Island and the development of lithospheric flexure. Synchronism of normal faulting with flexural bending suggests that extensional deformation on the descending Australian margin accompanied the formation of the Timor Trough.  相似文献   

中国区域逐日融合降水数据集与国际降水产品的对比评估   总被引：12，自引：3，他引：9  

宇婧婧  沈艳  潘旸  熊安元 《气象学报》2015,73(2):394-410

中国国家气象信息中心基于2400多个国家级台站观测日降水量和CMORPH卫星反演降水产品,采用概率密度匹配和最优插值相结合的两步数据融合方法,研制了中国区域1998年以来的0.25°×0.25°分辨率的逐日融合降水产品(CMPA_Daily)。通过该数据集与广泛应用于中国天气气候领域的两种国际上降水融合产品TRMM 3B42(Tropical Rainfall Measuring Mission, 3B42)和GPCP(Global Precipitation Climatology Project, 1 degree daily)的对比评估,考察CMPA_Daily产品的质量,评价其能否合理体现中国降水的天气气候特征。首先利用2008—2010年5—9月独立检验数据定量对比了CMPA_Daily、TRMM 3B42和GPCP 三种降水产品的误差,结果表明,在误差的时间变化和空间分布上,CMPA_Daily均具有最高的相关系数和最小的平均偏差及均方根误差,TRMM 3B42其次,GPCP的误差相对较大。CMPA_Daily只低估了大暴雨,TRMM 3B42低估了大雨以上量级的降水,而GPCP低估了除小雨以外的所有降水。CMPA_Daily产品因融入了更多的站点观测信息,不论在中国东部沿海,还是中西部地形复杂区,其精度均优于TRMM 3B42和GPCP产品,即使在站点稀疏的青藏高原地区,CMPA_Daily降水量也更加接近站点观测,呈现明显的高相关。CMPA_Daily与独立检验数据的高相关在地形起伏时效果也较稳定,TRMM和GPCP的相关系数则随着地形变化幅度陡变而非常明显地降低。进一步通过对比分析各降水产品1998—2012年的气候平均降水特征表明,3种资料对中国区域气候平均降水量、降水强度、频率分布以及年际变化的总体描述基本一致,因有效融入了更多的中国站点观测信息,不论降水空间分布还是降水量,CMPA_Daily与地面观测均最为接近,在中国的中东部大部分地区对降水的估计精度明显更高,而在站点分布较稀疏的青藏高原地区,CMPA_Daily的降水分布型与TRMM、GPCP卫星融合资料类似,较地面站点插值产品更能体现出合理的降水分布。对中国强降水事件监测对比表明,CMPA_Daily产品可以更加准确地描述降水的强度变化,细致刻画降水空间分布,在把握降水小尺度特征上具有明显的优势,体现出高分辨率、高精度降水产品的特点。  相似文献   

基于FLAC3D数值模拟的老采空区剩余沉降量分析计算—以山东枣庄安博化工项目为例     

臧浩  种衍飞  冯堂武  于树宾  张昌龙 《山东国土资源》2015,31(7)

空区的剩余沉降值计算是采空区地质灾害危险程度一种定量分析的方法,利用FLAC3D直接模拟早期采煤形成的老采空区塌陷状态,计算出老采空区的剩余沉降量。以山东枣庄安博化工项目为例,首先采用物探、钻探手段探测老采空区深度、顶板塌落与破碎状况以及地质地层信息,其次结合岩心试验地质材料参数结果进行FLAC3D模拟,计算自重作用下采空区剩余沉降量,以及加载建筑后老采空区剩余沉降值,对比了传统概率积分法计算沉降值,结果基本一致,说明计算方法是可靠的。最后分析加载应力与破碎带剩余沉降值的数量关系。为老采空区土地稳定性评估以及剩余沉降量的计算方法提供科学依据与借鉴。  相似文献   

南粤古驿道历史建筑数字化保护与VR场景构建     

万飞  刘子旋  谭明 《测绘通报》2021,(2):108-111

南粤古驿道遗留了众多文化遗产,具有较高的历史、艺术、科学价值,但历史建筑损坏较为严重。为推进南粤古驿道活化利用,本文采用精细三维建模技术与虚拟现实（VR）技术实现了南粤古驿道的数字化保护。首先对南粤古驿道遗址进行了分析,然后从数据采集、点云数据处理、几何模型加工、纹理贴图等方面阐述对历史遗迹进行精细三维建模和VR场景构建的流程和方法。为提高点云数据处理效率,提出了基于遗传算法的欧氏聚类点云分割算法。应用结果表明,本文构建的精细三维模型及VR场景能有效还原南粤古驿道历史建筑,为古驿道与古街巷、古村落、红色革命遗址等文化自然景观的保护提供了新的思路。  相似文献