水库诱发地震地下水监测网建设的若干问题探讨

根据国内外已发生的水库诱发地震的基本特点,结合三峡工程诱发地震地下水监测网与金沙江下游水电工程地下水监测网建设的经验及我国地震地下水动态观测网建设与运行中得到的科学认识,探讨了水库诱发地震的地下水监测井网建设中的布网区及其范围、观测井间距确定、观测井位置选择、观测含水层选择与观测井深度和结构设计等若干技术问题.     

Characteristics of water isotopes and hydrograph separation during the wet season in the Heishui River, China

Runoff generation and dynamics is an important issue in watershed and water resource management, but the mechanism in large scale is unclear and site-dependent. For this reason, spatial variations of δD and δ¹⁸O of river water and their sources within large-area of the Heishui Valley of the upper Yangtze River in western China were investigated during the wet season. A total 117 river water samples were collected at 13 sampling sites located at the junction of the principal river course and its tributaries. The results showed no spatial variations of either δD or δ¹⁸O values existed among tributary sampling sites A, B, E, F, H and I during the wet season, and significantly spatial variation occurred between tributary sampling sites A, B, E, F, H, I and site K; which indicated different proportions of rain entering river water should lead to spatial variation of water isotopes. The hydrograph separation analysis, based on the isotope data of river water, meltwater and rain water samples, showed the contribution of snow and glacier meltwater varied from 63.8% to 92.6%, and that of rain varied from 7.4% to 36.2%; which meant that snow and glacier meltwater was the main supplying water source of baseflow in the Heishui Valley. And the roles of glacier and snow meltwater should be significantly noticed in water resource management in this alpine valley at the rim of the Tibetan Plateau.     

Study on seismic numerical model on the Chinese mainland and its vicinity

IntroductionSeismicprocessisextremelycomplicatedjustashasbeenprovedbytheeallhquakepredictionpractice.Thecomplexityofseismicprocessmainlydisplaystheinhomogeneityofseismicspace-timedistribution.Therearealotoffactorscausingthecomplexity,includingthemediumofseismicsource,themechanicalprocessofseismicsource,mutualeffectofgroupseismicactivity,andsoon.Studyontheseismicactivitylawstillremainsinalowlevel,especiallyintheaspectofseismicoccurrenceprocess.Manyscholarstrytostudytheseismicactivebehavioringr…     

一种ENC数据在空间信息平台下的转换方法

通过解析电子航海图(electronic navigational chart,ENC)的数据空间组织结构与数据模型,提出一种利用数据存储方式建设ENC专题数据库的方法,这种存储方式解决了多物标类多属性的统一存储问题,简化了数据的存储结构.同时,基于设计的ENC数据解析与读取方法,结合ENC动态符号化技术,在空间信息平...     

Dynamic land use change simulation using cellular automata with spatially nonstationary transition rules

The dynamic relationships between land use change and its driving forces vary spatially and can be identified by geographically weighted regression (GWR). We present a novel cellular automata (GWR-CA) model that incorporates GWR-derived spatially varying relationships to simulate land use change. Our GWR-CA model is characterized by spatially nonstationary transition rules that fully address local interactions in land use change. More importantly, each driving factor in our GWR model contains effects that both promote and resist land use change. We applied GWR-CA to simulate rapid land use change in Suzhou City on the Yangtze River Delta from 2000 to 2015. The GWR coefficients were visualized to highlight their spatial patterns and local variation, which are closely associated with their effects on land use change. The transition rules indicate low land conversion potential in the city’s center and outer suburbs, but higher land conversion potential in the inner near suburbs along the belt expressway. Residual statistics show that GWR fits the input data better than logistic regression (LR). Compared with an LR-based CA model, GWR-CA improves overall accuracy by 4.1% and captures 5.5% more urban growth, suggesting that GWR-CA may be superior in modeling land use change. Our results demonstrate that the GWR-CA model is effective in capturing spatially varying land transition rules to produce more realistic results, and is suitable for simulating land use change and urban expansion in rapidly urbanizing regions.     

基于MODIS数据的北疆积雪黑碳和雪粒径反演及时空变化分析

积雪是地球上反射率较高的自然表面,对于中高纬度地区的水文和能量收支平衡发挥着重要作用。表层积雪中的黑碳和雪粒径变化可以显著影响积雪反照率,造成积雪对太阳辐射吸收的变化,进而对区域气候变化和水文循环产生反馈作用。利用遥感技术对季节性积雪表层黑碳和雪粒径进行定量评估,可以获取时空上连续系统的雪表黑碳浓度和雪粒径变化情况,这也是许多气候和水文模型的输入因子。以中国主要季节性积雪区北疆为研究区,基于MODIS（Moderate Resolution Imaging Spectroradiometer）数据的3（0.47 μm）、2（0.86 μm）和5（1.24 μm）波段,采用SGSP（Snow Grain Size and Pollution Amount）算法反演2000-2018年积雪期的雪表黑碳浓度和雪粒径,并结合地面观测数据对于反演结果进行了精度验证,综合分析北疆雪表黑碳浓度和雪粒径时空变化趋势。结果显示,SGSP算法能够同时反演雪表黑碳浓度和雪粒径,并且验证结果表明纯雪像元上反演结果具有较好的精度;2000-2018年北疆雪表年均黑碳浓度和年均雪粒径都随时间变化呈现微弱下降趋势;受地理位置和局部污染源的影响,北疆积雪黑碳浓度空间分布复杂,天山北坡经济带平均黑碳浓度最高,伊犁地区平均黑碳浓度最低,雪粒径的空间分布显示塔城地区平均雪粒径最大,伊犁地区最小。     

铀矿石和环境固体样品中210Po的测量

铀矿石和固体环境样品用Ｎａ２Ｏ２,ＮａＯＨ在６５０°Ｃ快速熔融后,用ＨＣｌ中和到ｐＨ值近似为９,以Ｆｅ（ＯＨ）３载带２１０Ｐｏ,调ＨＣｌ酸度为０．２－０．４ｍｏｌ／Ｌ,用抗坏血酸保护镀片,在７０°Ｃ时自镀３ｈ,２１０Ｐｏ的回收率可达９７．８±１．４％。产生的硅胶不影响测量结果。     

Investigation of the hydrate reservoir production under different depressurization modes

Abstract

Large reserves of natural gas hydrates exist, and the depressurization method has the greatest potential for gas hydrate reservoir recovery. Currently, the most commonly adopted depressurization simulation method is a constant bottom-hole pressure production scheme. This study proposes a new depressurization mode with decreasing bottom-hole pressure. The production characteristic was numerically investigated using this method. The results show the following: (1) As the depressurization exponent (n) decreases, the development effect improves, and production indexes including cumulative gas production/dissociation and gas-water ratio increase. However, the reservoir energy consumption is higher and the hydrate reformation is more severe. (2) Compared to the proposed depressurization mode, the hydrate production index of the constant bottom-hole pressure production (n?=?0) is better. However, the hydrate reservoir energy consumption is higher and the hydrate reformation is more severe using constant bottom-hole pressure production. (3) To achieve a balance between production and reservoir energy consumption during depressurization production, the bottom-hole pressure should be controlled by selecting a suitable depressurization exponent between n_min and n_max, which can be determined through numerical simulations.     

宏观尺度下基岩海岸岸线分形机制研究--以中国基岩海岸为例

在跟踪国际、国内海岸线分形研究进展的基础上,以中国基岩海岸为例,对宏观尺度下构造对基岩海岸岸线走向、形状与分维大小的影响进行了研究,基本结论为：在宏观尺度下,构造在总体上控制着福建与台湾基岩海岸岸线的基本走向与分维大小,构造分维相对较大则其对该区域海岸线的控制作用相对较强,而区域海岸线分维相对较小;当构造分维相对较小则其对该区域海岸线的控制作用相对较弱,而区域海岸线分维相对较大。     

On the Conversion of Antarctic Ice-Mass Change to Sea Level Equivalent

This technical note aims to provide a quick reference and some computational examples for the conversion between Antarctic ice-mass changes and global sea level equivalent (SLE) changes using a few assumptions that computationally simplify this complex problem and that acknowledge gaps in our knowledge of the Antarctic environment. A number of factors involved in the conversion process are discussed, and the sensitivity of the conversion result to certain aspects is analyzed. It was found that the global ocean area calculated from a recently improved global shoreline dataset has little impact on the uncertainty of the SLE estimation. SLE estimation using satellite gravity observations, such as those by GRACE, are sensitive to glacial isostatic adjustment (GIA) models. One more important result from the computation is that the effective density of the volume that is gained or lost during mass change may greatly affect the outcome of the conversion if it differs greatly from the actual density of the firn/ice layers. Finally, a table of computational examples is provided for reference under some assumptions for simplifying the computation.