山东滨州市冰雹天气分型和预报方法研究     

王培涛  王凤娇  张婷婷 《沙漠与绿洲气象(新疆气象)》2019,(3):33-40

利用山东滨州市7个国家气象站与61个人影作业站点观测资料,结合高空观测及探空、ECMWF再分析等资料,对2001—2011年滨州降雹时空分布特征、天气系统和物理量特征、降雹形势分型和预报方法进行研究。得出:(1)降雹日数年均8.6次,总体呈现明显下降的年际变化特征;4—10月可降雹,6—7月降雹最多;降雹主要出现在14时—翌日02时;北部沿海相对较多。(2)降雹形势主要有5种类型:冷涡型降雹、低槽型降雹、横槽型降雹、西北气流型降雹、其他小范围降雹。根据冷涡中心位置冷涡型划分为两个关键区;低槽型可分为前倾槽、阶梯槽、较深低槽、与中低纬度共同作用的槽;横槽型降雹范围广、破坏性大;西北气流型存在连续性。(3)4类13种物理量具有不同分布特征和变异系数,均具有较好的代表性。不同月份、不同降雹影响程度和影响系统,物理量具有较明显差别。(4)0℃层高度在1370~5331m时,7种物理量可用于预报冰雹,K≥17℃、T850-500≥25℃、LI≤2℃、SRH≥0.1m^2·s^-2、SSI≥240、SWEAT≥100、Cape≥2J·kg^-1时可能降雹。6月、7—8月和其它月分别有3种、1种、3种物理量指标组合可用于预报冰雹,物理量的组合和数值有差异。  相似文献   

CONSONORM_HG: a new method of norm calculation for mid‐ to high‐grade metamorphic rocks          下载免费PDF全文

L. Mathieu  S. Trépanier  R. Daigneault 《Journal of Metamorphic Geology》2016,34(1):1-15

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Ecological classification of European transitional waters in the North-East Atlantic eco-region     

Cristina Galván  José Antonio Juanes  Araceli Puente 《Estuarine, Coastal and Shelf Science》2010

A new methodology to classify European North-East Atlantic transitional waters into ecological types has been developed based on the most important hydrological and morphological features that are likely to determine the ecology of aquatic systems in transitional waters. Hydrological indicators help identifying if a transitional water area is dominated by fresh or sea water and/or by intertidal or subtidal areas, while morphological indicators allow an estimation of the complexity of the transitional water and the diversity of the habitats involved. Twelve transitional waters of the southern Bay of Biscay were classified using this methodology and the five hydro-morphological types obtained were validated with benthic macro-invertebrate data. Transitional waters with a complex morphology showed the highest values of species diversity, while those with a smaller tidal influence showed lower species diversity. The ‘Scrobicularia’ and ‘Abra’ assemblages, previously identified in the study area, were found to be related to different types of transitional waters. The ‘Abra’ assemblage only appeared in estuaries with a complex morphology and dominated by tidal influences, while the ‘Scrobicularia’ assemblage was detected in all the transitional waters except for a single coastal lagoon. This classification of transitional waters may therefore be useful to establish the biological reference conditions needed for European Directives.  相似文献   

Capabilities of the bathymetric Hawk Eye LiDAR for coastal habitat mapping: A case study within a Basque estuary   总被引：1，自引：0，他引：1  

Guillem Chust  Maitane Grande  Ibon Galparsoro  Adolfo Uriarte  Ángel Borja 《Estuarine, Coastal and Shelf Science》2010

The bathymetric LiDAR system is an airborne laser that detects sea bottom at high vertical and horizontal resolutions in shallow coastal waters. This study assesses the capabilities of the airborne bathymetric LiDAR sensor (Hawk Eye system) for coastal habitat mapping in the Oka estuary (within the Biosphere Reserve of Urdaibai, SE Bay of Biscay, northern Spain), where water conditions are moderately turbid. Three specific objectives were addressed: 1) to assess the data quality of the Hawk Eye LiDAR, both for terrestrial and subtidal zones, in terms of height measurement density, coverage, and vertical accuracy; 2) to compare bathymetric LiDAR with a ship-borne multibeam echosounder (MBES) for different bottom types and depth ranges; and 3) to test the discrimination potential of LiDAR height and reflectance information, together with multi-spectral imagery (three visible and near infrared bands), for the classification of 22 salt marsh and rocky shore habitats, covering supralittoral, intertidal and subtidal zones. The bathymetric LiDAR Hawk Eye data enabled the generation of a digital elevation model (DEM) of the Oka estuary, at 2 m of horizontal spatial resolution in the terrestrial zone (with a vertical accuracy of 0.15 m) and at 4 m within the subtidal, extending a water depth of 21 m. Data gaps occurred in 14.4% of the area surveyed with the LiDAR (13.69 km²). Comparison of the LiDAR system and the MBES showed no significant mean difference in depth. However, the Root Mean Square error of the former was high (0.84 m), especially concentrated upon rocky (0.55–1.77 m) rather than in sediment bottoms (0.38–0.62 m). The potential of LiDAR topographic variables and reflectance alone for discriminating 15 intertidal and submerged habitats was low (with overall classification accuracy between 52.4 and 65.4%). In particular, reflectance retrieved for this case study has been found to be not particularly useful for classification purposes. The combination of the LiDAR-based DEM and derived topographical features with the near infrared and visible bands has permitted the mapping of 22 supralittoral, intertidal and subtidal habitats of the Oka estuary, with high overall classification accuracies of between 84.5% and 92.1%, using the maximum likelihood algorithm. The airborne bathymetric Hawk Eye LiDAR, although somewhat limited by water turbidity and wave breaking, provides unique height information obscured from topographic LiDAR and acoustic systems, together with an improvement of the habitat mapping reliability in the complex and dynamic coastal fringe.  相似文献   

The geometric signature: Quantifying landslide-terrain types from digital elevation models   总被引：11，自引：0，他引：11  

Richard J. Pike 《Mathematical Geology》1988,20(5):491-511

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Isotopic compositional Characteristics of Terrigenous Natural Gases in China   总被引：1，自引：1，他引：1  

沈平  徐永昌 《中国地球化学学报》1993,12(1):14-24

The C and H isotopic compositions of the methane in more than 160 gas samples from 10 basins in China are presented in this paper.The natural gases are classified as four types: biogenic gas ,bio-thermocatalytic transitional gas, gas associated with condensate oil ,and coal-type gas. The isotopic compositions of these gases closely related to the depositional basins, the types of organic matter,the stages of thermal evolution and the genetic characteristics of different gas reservoirs.Studies of the C and H isotopic compositions of terrigenous natural gases will provide valua-ble information on the prospecting and development of natural gases of different genetic types.  相似文献   

造盆作用及成矿盆地的历史动力综合分类建议   总被引：3，自引：0，他引：3  

陈国达 《地球科学进展》1993,8(3):30-36

本文把历史分析方法与动力分析方法两种分折方法结合起来,提出了一个综合的盆地分类方案。按历史动力综合分类,造盆作用及盆地可划分为三大类:大洋壳型、雏陆壳(过渡壳)型及大陆壳型大壳型中可细分为活动区型及稳定区型。雏陆壳型包括前地槽型及地槽前期型。大陆壳型中计有地槽后期型、地台型和地洼型。  相似文献   

Summary of the fossil record of pinnipeds of Japan, and comparisons with that from the eastern North Pacific     

Shigeo  Miyazah Hideo  Horkawa Naoki  Kohno Kiyoharu  Hirota Masaichi  Kimura Yoshkazu  Hasegawa Yukimitsu  Tomida Lawrence G.  Barnes Clayton E.  Ray 《Island Arc》1994,3(4):361-372

Abstract The fossil pinniped record of the North Pacific Ocean includes both Phocidae and Otariidae ( sensu lato ), extends from the Late Oligocene to the Late Pleistocene, is taxonomically diverse, and is constantly becoming more complete owing to additional important discoveries. The earliest and most diverse fossil pinnipeds in the North Pacific are otariids, the phocids not appearing until the latest Pliocene. The theoretical center of otariid pinniped evolutionary history has been considered by some to be in the eastern North Pacific. New materials from the western North Pacific, however, including representatives of the subfamilies Enaliarctinae, Imagotariinae, Odobeninae and Otariinae, indicate that pinniped evolutionary patterns were basin-wide phenomena, and that a more complete record undoubtedly would reveal numerous trans-Pacific distributions. This would be expected considering the distributions of living species. The paucity of fossil Phocidae and their absence from pre-Pliocene deposits are consistent with theories that the family primarily evolved outside the North Pacific.  相似文献   

矿物分类和识别的人工神经网络模型     

蔡煜东  宫家文 《矿物学报》1994,14(1):56-60

本文提出矿物分类和识别的人工神经网络模型，并选取一组标样－我国沉积碳酸盐型锰矿中菱锰矿作为研究对象，识别效率达１００％。结果表明，该模型性能良好，可望成为矿物识别的有效手段。  相似文献   

土地类型系列制图的几个理论问题   总被引：1，自引：0，他引：1  

蔡运龙 《地理研究》1994,13(1):76-83

实际存在的不同尺度地域分异规律是土地类型系列制图的客观基础。多种尺度制图构成的土地类型系列制图可以全面揭示区域土地类型的形成因素、分布规律和空间结构特征,也为不同层次土地规划管理之间的相互补充、协调提供了重要基础。  相似文献