八宝河流域土壤温度波动的时空分异

The Babao River Basin is the "water tower" of the Heihe River Basin.The combination of vulnerable ecosystems and inhospitable natural environments substantially restricts the existence of humans and the sustainable development of society and environment in the Heihe River Basin.Soil temperature(ST) is a critical soil variable that could affect a series of physical,chemical and biological soil processes,which is the guarantee of water conservation and vegetation growth in this region.To measure the temporal variation and spatial pattern of ST fluctuation in the Babao River Basin,fluctuation of ST at various depths were analyzed with ST data at depths of 4,10 and 20 cm using classical statistical methods and permutation entropy.The study results show the following: 1) There are variations of ST at different depths,although ST followed an obvious seasonal law.ST at shallower depths is higher than at deeper depths in summer,and vice versa in winter.The difference of ST between different depths is close to zero when ST is near 5℃ in March or –5℃ in September.2) In spring,ST at the shallower depths becomes higher than at deeper depths as soon as ST is above –5℃;this is reversed in autumn when ST is below 5℃.ST at a soil depth of 4 cm is the first to change,followed by ST at 10 and 20 cm,and the time that ST reaches the same level is delayed for 10–15 days.In chilling and warming seasons,September and February are,respectively,the months when ST at various depths are similar.3) The average PE values of ST for 17 sites at 4 cm are 0.765 in spring > 0.764 in summer > 0.735 in autumn > 0.723 in winter,which implies the complicated degree of fluctuations of ST.4) For the variation of ST at different depths,it appears that Max,Ranges,Average and the Standard Deviation of ST decrease by depth increments in soil.Surface soil is more complicated because ST fluctuation at shallower depths is more pronounced and random.The average PE value of ST for 17sites are 0.863 at a depth of 4 cm > 0.818 at 10 cm > 0.744 at 20 cm.5) For the variation of ST at different elevations,it appears that Max,Ranges,Average,Standard Deviation and ST fluctuation decrease with increasing elevation at the same soil depth.And with the increase of elevation,the decrease rates of Max,Range,Average,Standard Deviation at 4 cm are –0.89℃/100 m,–0.94℃/100 m,–0.43℃/100 m,and –0.25℃/100 m,respectively.In addition,this correlation decreased with the increase of soil depth.6) Significant correlation between PE values of ST at depths of 4,10 and 20 cm can easily be found.This finding implies that temperature can easily be transmitted within soil at depths between 4 and 20 cm.7) For the variation of ST on shady slope and sunny slope sides,it appears that the PE values of ST at 4,10 and 20 cm for 8 sites located on shady slope side are 0.868,0.824 and 0.776,respectively,whereas they are 0.858,0.810 and 0.716 for 9 sites located on sunny slope side.     

北京千灵山生态修复边坡稳定性研究

开采形成的矿山岩质高陡边坡,造成山体缺损、水土流失、生态破坏,容易产生边坡失稳、崩塌滑落等地质灾害,急需进行生态修复治理。本文以北京市西郊千灵山生态修复岩质高陡边坡为例,根据地质雷达实测剖面分析及室内试验得到的岩体内部结构信息和岩石力学参数,建立了生态边坡的地质力学模型,并用有限元强度折减法对千灵山岩质高陡边坡生态修复前后的稳定性进行了模拟计算。结果表明,非降雨、降雨（饱水）条件下自然岩石边坡和生态修复后的边坡其安全系数分别为17、12.5、5、2;边坡变形以坡脚和生态带区域的中下部位最大,边坡潜在滑动面主要沿坡脚45＆#176;方向上扩展。因此,岩石边坡坡脚和生态带区域的中下部位应是重点加固区,需通过锚杆加固和有效排水对之进行处理。     

基于深度学习的航海通告命名实体识别方法

为进一步提高识别、提取和应用航海通告信息的效率和准确性,基于对深度学习的自然语言处理技术及中文电子航海通告文本特点的研究,通过语料标注、搭建、调参、训练与评价了5种命名实体识别模型,得出CNN-BiLSTM-CRF模型的识别精确率、召回率等主要指标达到70%以上,能够适应复杂的通告内容及其语境干扰,是目前最优的航海通告命名实体识别模型的结论。应用该模型可为航海通告内容的自动化、智能化提取,高效编制及快速与准确应用提供一种新的技术方法。     

地电阻率变化成因分析 ——以宝昌台为例

中国地震台网地电观测以对称四极装置的地电阻率观测为主,其观测曲线通常存在长期变化、年变、日变和阶跃等,文中以宝昌台为例,通过反演、数值模拟等方法分析上述变化成因.宝昌台地电布极区地下的电阻率基本呈现水平分布,电测深曲线类型属于KH型.该台NS、EW测向的地电阻率自1993年至今一直存在长期下降变化,且变化速率存在显著的...     

城市环境地球化学研究新进展

针对目前平原区城市环境地球化学异常评价及查证中出现的问题,通过土壤重矿物研究方法,在位于城镇及其周边的多个土壤Hg等重金属元素异常区内发现了辰砂和磁性"微球粒".这一新的发现不仅意味着城市环境地球化学研究取得重要进展,而且为正在开展的平原区城市环境地球化学质量评价提供了新的思路和研究方法,并将对目前广泛开展的平原区"多目标"地球化学调查工作的健康发展起到积极作用.深入的试验研究正在进行之中.     

面向土地利用分类的HJ-1 CCD影像最佳分形波段选择

环境一号卫星（HJ-1）CCD影像光谱波段较少,地物之间的准确分类识别有一定困难。采用分形纹理辅助地物分类识别是一种有效方法,而波段选择是提高分类识别精度的关键。本文以江西赣州定南县土地利用分类为例,采用双毯覆盖模型对HJ卫星CCD影像6类典型地物的波谱分形特征进行了分析,利用不同地物在不同波段上的分形区分度差异构建了最佳分形波段选择模型,并利用该模型挑选出最佳分形波段来辅助土地利用分类,最后对分类结果进行检验。结果表明：最佳分形波段选择模型能够综合权衡不同地物在不同波段上的分形区分度差异,利用挑选出来的最佳分形波段来辅助分类,其分类总体精度相对于原始影像分类提高了11.77%,相对于第1主成分分形辅助下的分类提高了1.56%。     

矿山安全与环境的多源遥感监测技术

随着我国矿产资源的大力开发,矿山环境问题日趋严重,利用遥感手段进行矿山环境与灾害动态监测成为保护环境和防灾、减灾的重要手段。本文针对单一遥感手段在矿山监测中存在的缺陷,开展了天、空、地多源遥感监测技术在矿山环境监测中的应用研究,分析了该技术的特点和优势,提出了将天基的卫星遥感技术、空基的无人机遥感技术以及地面的热成像、测量机器人等遥感测量方法结合起来,进行矿山生产、安全、环境、灾害的协同观测。     

航海通告自动获取系统的设计与实现

目前,从互联网获取航海通告数据是提高海图产品现势性、保障舰船航行安全的主要途径之一。基于对国内外网站特点、网页结构及网络爬虫技术、数据库技术的研究,提出了自动获取航海通告网页数据的总体方案;通过研发应用系统,实现了通告爬取、数据整理、数据库管理等主要功能。测试结果表明:较之传统工作方式,利用该系统获取的航海通告数据具有准确性、完整性、实时性和高效性,将为海图一体化生产体系提供更高质量的基础数据源支持。     

Comparison of CO2 Effluxes and Their Driving Factors Between Two Temperate Steppes in Inner Mongolia, China

Soil respiration is a key component of the global terrestrial ecosystem carbon cycle. The static opaque chamber method was used to measure the CO2 effluxes from soil of a semiarid Aneurolepidium chinense steppe and a Stipa krylovii steppe in the Xilin River Basin of Inner Mongolia, China from March 2002 to December 2004. The results indicated that the soil respiration rates of the semiarid Aneurolepidium chinense steppe and the Stipa krylovii steppe were both relatively high from mid-May to mid-September of each year and remained low during the rest of the year. The minimum value of soil respiration occurred in December or January and negative effluxes of CO2 appeared for several days during the non-growing season of individual years at the two sampling sites. A high annual variation was found in the two steppes with the coefficients of variance (CV) being over 94%, even high to 131%. The annual sums of soil CO2 efflux of the Aneurolepidium chinense steppe varied between 356.4 gC m?2 yr?1 and 408.8 gC m?2 yr?1, while those of the Stipa krylovii steppe in the three years were in the range of 110.6 gC m?2 yr?1 to 148.6 gC m?2 yr?1. The mean respiration rates of the Aneurolepidium chinense steppe were significantly higher than those of the Stipa krylovii steppe in different statistical periods with the exception of the non-growing season. About 59.9% and 80.6% of the soil respiration variations in both steppes for the whole sampling period were caused by the changes of temperature and soil water content. In the Aneurolepidium chinense steppe, the soil respiration rate has significant or extremely significant positive correlation (r = 0.58 ? 0.85, p < 0.05 or p < 0.01) with air temperature and ground temperature of the topsoil except in 2002; the unique contributions of temperature change to the soil respiration variation of the three years were 53.3%, 81.0% and 58.6%, respectively. But, for the Stipa krylovii steppe in the same time interval, the soil water content (especially that of the 10–20 cm layer) has a greater effect on the change of soil respiration, and the unique contributions of the change of the 10–20 cm soil water content to the variations of soil respiration in 2002 and 2003 were 60.0% and 54.3%, respectively. In 2004, in spite of the higher contribution of temperature than soil water content, the contribution of ground temperature at a depth of 10 cm was only 46.2%, much weaker than that of any single year in the Aneurolepidium chinense steppe.     

Relative importance of wind and buoyancy forcing for interdecadal regime shifts in the Pacific Ocean

Interdecadal variations in the Northern Hemisphere and the North Pacific have been documented in many studies[1 4]. The connection between the subtropical North Pacific and the tropics is regarded as the most important process triggering and maintaining t…