大尺度雁列断层粘滑运动数值模拟     

王时  王想  陈定发  马广庆  王思思  董博 《地震地磁观测与研究》2018,39(6):23-30

通过ANSYS软件建立二维雁列断层模型，采用粘弹性力学参数，建立摩擦系数接触单元，模拟10万年时间大尺度雁列走滑断层活动（地震相关活动），分析挤压条件下的断层活动特征，研究结果表明：①断层时空区域不同，所受应力也不同，接近贯通区域重合地区所受应力较大，粘滑运动剧烈，由贯通区域向断层两侧逐渐延伸，所受应力依次减小；②摩擦系数越小，地震发生频率越高，地震运动周期越短，则位错量相对较小，易发生震级较小地震；摩擦系数越大，地震发生频率越低，地震运动周期越长，则位错量相对较大，易发生震级较大地震；③给定的边界挤压速率越大，地震发生频率越高，地震运动周期越短，则位错量增大，易发生震级较大地震。  相似文献   

SMAP卫星海表盐度产品的检验与校正     

秦思思  王辉  朱江  万莉颖  张宇  王昊运 《海洋学报(英文版)》2020,39(3):148-158

In this study, sea surface salinity(SSS) Level 3(L3) daily product derived from soil moisture active passive(SMAP)during the year 2016, was validated and compared with SSS daily products derived from soil Moisture and ocean salinity(SMOS) and in-situ measurements. Generally, the root mean square error(RMSE) of the daily SSS products is larger along the coastal areas and at high latitudes and is smaller in the tropical regions and open oceans. Comparisons between the two types of daily satellite SSS product revealed that the RMSE was higher in the daily SMOS product than in the SMAP, whereas the bias of the daily SMOS was observed to be less than that of the SMAP when compared with Argo floats data. In addition, the latitude-dependent bias and RMSE of the SMAP SSS were found to be primarily influenced by the precipitation and the sea surface temperature(SST). Then, a regression analysis method which has adopted the precipitation and SST data was used to correct the larger bias of the daily SMAP product. It was confirmed that the corrected daily SMAP product could be used for assimilation in high-resolution forecast models, due to the fact that it was demonstrated to be unbiased and much closer to the in-situ measurements than the original uncorrected SMAP product.  相似文献   

Consistency grammar for 3D indoor model checking     

Shayan Nikoohemat  Abdoulaye A. Diakit  Ville Lehtola  Sisi Zlatanova  George Vosselman 《Transactions in GIS》2021,25(1):189-212

Indoor 3D models are digital representations of building interiors reconstructed from scanned data acquired by laser scanners, digital depth (RGBD) cameras, and CAD drawings. Consequently, there is noise in the source data and a notable variety in the methods used to treat the noise and to process these data into reconstructed models. Alas, the correctness of these reconstructions and thus their suitability for a given application are uncertain. There is a lack of a robust base logic that would allow for controlling the consistency of these (automatically) generated models. Fortunately, correctness criteria are well‐defined through existing international standards. Hence, we propose a conceptual framework based on formal grammars to check the semantic, geometric, and topological consistency of a reconstructed 3D model. The proposed method proceeds in three steps to validate the model: (1) correctness checking of individual components; (2) consistency verification of instances’ interactions; and (3) model consistency check for targeted applications. Our method identifies the components in the model that violate the given rules derived from the current standards and expert knowledge. Ultimately, we propose a quantified formulation of our method that may be straightforwardly integrated into industrial‐level model checkers. The approach is independent of level of details and reconstruction method.  相似文献   

无人船在水下地形测量应用中的可靠性分析及工艺流程优化     

杨少愚  孙睿英  任思思 《测绘与空间地理信息》2021,44(z1):233-236

随着科学技术的不断发展,人们对水下地形测量的精度需求越来越高.无人船搭载单波束测深仪通过集成计算机与测量设备实施水下地形测量,已逐渐成为内陆浅水区域水下测量的主要技术手段.本文通过与传统水下测量模式进行对比,分析GPS-RTK在无验潮模式下进行水下测量的原理及优势,并对其可靠性进行了验证,阐述了如何更加有效地将无人船测量技术应用到实际生产当中.  相似文献   

Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services     

Kohei OGAWA  Edward VERBREE  Sisi ZLATANOVA  Naohiko KOHTAKE  Yoshiaki OHKAMI 《地球空间信息科学学报》2011,14(2):109-118

Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.  相似文献   

Development of a soil moisture‐based distributed hydrologic model for determining hydrologically based critical source areas          下载免费PDF全文

Sisi Li  Margaret Gitau  David Bosch  Bernard A. Engel  Liang Zhang  Yun Du 《水文研究》2017,31(20):3543-3557

A simple grid cell‐based distributed hydrologic model was developed to provide spatial information on hydrologic components for determining hydrologically based critical source areas. The model represents the critical process (soil moisture variation) to run‐off generation accounting for both local and global water balance. In this way, it simulates both infiltration excess run‐off and saturation excess run‐off. The model was tested by multisite and multivariable evaluation on the 50‐km² Little River Experimental Watershed I in Georgia, U.S. and 2 smaller nested subwatersheds. Water balance, hydrograph, and soil moisture were simulated and compared to observed data. For streamflow calibration, the daily Nash‐Sutcliffe coefficient was 0.78 at the watershed outlet and 0.56 and 0.75 at the 2 nested subwatersheds. For the validation period, the Nash‐Sutcliffe coefficients were 0.79 at the watershed outlet and 0.85 and 0.83 at the 2 subwatersheds. The per cent bias was less than 15% for all sites. For soil moisture, the model also predicted the rising and declining trends at 4 of the 5 measurement sites. The spatial distribution of surface run‐off simulated by the model was mainly controlled by local characteristics (precipitation, soil properties, and land cover) on dry days and by global watershed characteristics (relative position within the watershed and hydrologic connectivity) on wet days when saturation excess run‐off was simulated. The spatial details of run‐off generation and travel time along flow paths provided by the model are helpful for watershed managers to further identify critical source areas of non‐point source pollution and develop best management practices.  相似文献   

Development of a distributed hydrological model to facilitate watershed management     

Sisi Li  Margaret Gitau  Bernard A. Engel  Yun Du  Carlington Wallace 《水文科学杂志》2017,62(11):1755-1771

To facilitate precise and cost-effective watershed management, a simple yet spatially and temporally distributed hydrological model (DHM-WM) was developed. The DHM-WM is based on the Mishra-Singh version of the curve number method, with several modifications: The spatial distribution of soil moisture was considered in moisture updating; the travel time of surface runoff was calculated on a grid cell basis for routing; a simple tile flow module was included as an option. The DHM-WM was tested on a tile-drained agricultural watershed in Indiana, USA. The model with the tile flow module performed well in the study area, providing a balanced water budget and reasonable flow partitioning. The daily coefficient of determination and Nash-Sutcliffe coefficient were 0.58 and 0.56, for the calibration period, and 0.63 and 0.62 for the validation period. The DHM-WM also provides detailed information about the source areas of flow components, the travel time and pathways of surface runoff.