Soil erosion changes over the past five decades in the red soil region of Southern China

This paper reports the dynamic changes of soil and water loss in the red soil region of Southern China since the 1950s. The red soil region covers eight provinces: Jiangxi, Zhejiang, Fujian, Anhui, Hubei, Hunan, Guangdong and Hainan. From the 1950s to 1986, the annual rate of soil erosion increased by 3.4%. From 1986 to 1996 and from 1996 to 2000, the annual rates of soil erosion decreased by 2.0% and 0.32%, respectively. Field surveys showed that from 2000 to 2005, the area of soil and water loss decreased annually by 1.2%. This decrease was a result of large-scale erosion control activities across China. Although the eroded soil has been restored, the restoration process is very slow and full restoration will take a long time. Our report suggests that controlling soil and water loss is a challenging task, and additional measures must be taken to effectively control the soil erosion in the red soil region.     

地下工程施工监控地质地理信息系统研究

主要设计与实现了地下工程施工监控地质地理信息系统（MGGIS）。首先分析了系统特点、结构、具有的功能以及采用的平台和相关技术,定义了数据的获取和存储格式。然后在此基础上进行了3个功能独立的子系统的详细设计与实现,分别为工程计划显示子系统、平面时空效应子系统和断面图显示子系统。首次提出在RIA技术支持下,实现B/S架构下的工程地质地理信息系统;提出了反映随施工进度变化地下工程及环境空间信息的显示平台技术方案,充分反应了地下工程施工中空间信息具有时空效应的特点,适合地下工程安全风险管理的需要。该系统与同类型地理信息系统平台相比具有使用简单、交互性强、速度快等优点,研究成果已经在北京轨道交通工程安全风险监控系统和南京地铁工程安全风险监控系统等相关项目中得以应用。     

中国伊犁河流域生态建设战略与互动模式

运用流域生态学和生态恢复学理论与方法,分析伊犁河流域生态环境背景和利弊因素,划分伊犁河流域为河谷次生林封育治理区、伊犁河谷平原农业和农林牧综合生态建设区、沙漠防风固沙林建设区、逆温带生态经济林建设区、山地水源涵养林建设区、高山冰雪及高寒荒漠生态区等生态建设区,以及乌孙山北部山前平原生态建设重点区;通过对各建设区的分析评价以及流域生态环境特点、资源配置结构、生态服务建设功能耦合关系的研究,提出流域垂直立体的生态建设格局、方向、重点等战略措施,以及流域生态与大农业"双赢"互动模式。为实现流域生态良性循环与大农业可持续发展提供依据。     

Population landscape: a geometric approach to studying spatial patterns of the US urban hierarchy

We present a geometric and graphic approach to studying spatial patterns of urban hierarchy in the US. The multiplicatively weighted Voronoi diagram is found to be effective for visualizing theoretical regions delineated by socio‐economic variables. The population landscape of the continental US demonstrates overall and stepwise patterns reflecting population, neighborhood and distance, with overwhelming influence from huge metropolitan areas. Stepwise exploration and cluster analysis of the spatial pattern reveal an urban hierarchy. Attributes and arrangement are the two important factors of urban hierarchy, with attribute having a stronger local influence and arrangement having a stronger global influence. The study also presents a variation of Zipf's law to visualize the rank‐size distribution from tabular and statistical space to map space.     

Estimation and prediction of the spatial occurrence of fish species using Bayesian latent Gaussian models

A methodological approach for modelling the occurrence patterns of species for the purpose of fisheries management is proposed here. The presence/absence of the species is modelled with a hierarchical Bayesian spatial model using the geographical and environmental characteristics of each fishing location. Maps of predicted probabilities of presence are generated using Bayesian kriging. Bayesian inference on the parameters and prediction of presence/absence in new locations (Bayesian kriging) are made by considering the model as a latent Gaussian model, which allows the use of the integrated nested Laplace approximation ( INLA ) software (which has been seen to be quite a bit faster than the well-known MCMC methods). In particular, the spatial effect has been implemented with the stochastic partial differential equation (SPDE) approach. The methodology is evaluated on Mediterranean horse mackerel (Trachurus mediterraneus) in the Western Mediterranean. The analysis shows that environmental and geographical factors can play an important role in directing local distribution and variability in the occurrence of species. Although this approach is used to recognize the habitat of mackerel, it could also be for other different species and life stages in order to improve knowledge of fish populations and communities.     

Comparison of adaptive structural damage identification techniques in nonlinear hysteretic vibration isolation systems

Early structural damage identification to obtain an accurate condition assessment can assist in the reprioritization of structural retrofitting schedules in order to guarantee structural safety. Nowadays, seismic isolation technology has been applied in a wide variety of infrastructure, such as buildings, bridges, etc., and the health conditions of these nonlinear hysteretic vibration isolation systems have received considerable attention. To effectively detect structural damage in vibration isolation systems based on vibration data, three time-domain analysis techniques, referred to as the adaptive extended Kalman filter （AEKF）, adaptive sequential nonlinear least-square estimation （ASNLSE） and adaptive quadratic sum-sqnares error （AQSSE）, have been investigated. In this research, these analysis techniques are compared in terms of accuracy, convergence and efficiency, for structural damage detection using experimental data obtained through a series of laboratory tests based on a base-isolated structural model subjected to E1 Centro and Kobe earthquake excitations. The capability of the AEKF, ASNLSE and AQSSE approaches in tracking structural damage is demonstrated and compared.     

Methods, current status, and prospect of targeted observation

Targeted observation is an observation strategy by which the concerned phenomenon is observed.In geoscience,targeted observation is mainly related to the forecasts of weather events or predictions of climate events.This paper will first review the history of targeted observation,and then introduce the main methods used in targeted observation.The discussion on the theoretical basis of targeted observation includes its advantages and limitations.After presenting the current situation of domestic and international targeted observations in atmospheric and oceanic sciences,the methods used for targeted observation,and their effect evaluation and testing are mainly discussed here.Finally,the author presents his suggestion about the prospect of further development in the field,and how to extend the method of targeted observation to deal with numerical model errors.     

Modeling the morphology of gully cross sections in the Yuanmou Dry-hot Valley

Abstract

Characterizing gully cross sections (GCs) is essential for calculating the volume and erosion rate of the gully. However, little research has focused on modeling the morphology of GCs. This study investigated 456 GCs with a laser distance meter located at the mouth, middle, and head of 152 gullies in the Yuanmou Dry-hot Valley of China; mapped them with AutoCAD software; fitted them with 2nd–6th degree polynomial functions, and discussed the correlation between the coefficients and the morphology of GCs. The results showed that: (1) using a 2nd-degree polynomial function (y = ax² + bx + c) to describe the morphology of GCs produced a better result than other polynomial functions; (2) the coefficient a of 2nd-degree polynomial function was correlated with depth (r = ?0.226, p < 0.01), gradient (r = 0.545, p < 0.01), and activities; and (3) the symmetry axis (?b/2a) of 2nd-degree polynomial function increased with gully change from left-deflection to right-skewed, and the absolute value showed the asymmetrical degree (r = 0.216, p < 0.01). This study will not only help to understand the morphology and evolution of gullies, but will also provide a scientific basis for prevention of gully erosion.     

TIME-SLICE OF THE FLUVIAL EVOLUTION IN THE NORTHERN JINSHAAN GORGE DURING LATE CENOZOIC

晋陕峡谷黄河形成的时代是地学界十分关注的科学问题,长期存在比较大的意见分歧,至今没有得到比较好的解决.山西保德地区发育—套晚中新世-早上新世的河湖相沉积,年代为＞8.3 ～3.7Ma,地貌与地层分析表明,它们是唐县期夷平面的相关沉积.河湖相地层所含砾石层的组构和岩性统计揭示,当时汇入古湖的河流是发源于周围抬升区的短小河流,形成一个局地规模的湖泊水系.晋陕峡谷北段唐县期夷平面之上分布两期红粘土覆盖的河流砾石层,形成年代分别在4.9Ma前和3.7Ma前;砾石组构和岩性统计揭示,它们所指示的河流流向向北,与黄河流向相反,是一个不同于现代黄河的古河流,它将保德古湖水系与河套盆地联系起来.3.7Ma前,强烈的地面上升导致河湖相沉积结束和唐县期夷平面抬升,风成红粘土堆积其上,地形起伏增大,河流溯源侵蚀加剧,水系进入重新组织阶段;1.2Ma前,黄土高原南部的河流将原北流水系袭夺,黄河形成;最近1.2Ma的强烈地面上升,导致黄河不断下切并发育多级阶地,逐渐形成现代壮观的深切峡谷地貌.     

渤海湾西岸全新世地层的分段与划组

本文以岩性地层、气候地层(CaCO3含量、古温度和Rb/Sr比值等)、年代地层、沉积化学地层和生物组合地层等资料为基础,根据地层规范以及建组要求将渤海湾西岸全新世地层划分为3个组:独流镇组( Qh3 dl)、大黄洼组(Qh2dh)和西翟庄组(Qh1xz).其地层埋深界线及测年界线分别为:晚全新世独流镇组(Qh3dl)与...