锰胁迫青葙的高光谱变异特征与叶冠金属元素含量的关系模型

针对喜锰植物青葙,在模拟15个浓度级别的锰含量胁迫生长环境下,观测其生长的过程中不同时段的高光谱变异特征,最终测定锰等33种主微量元素的含量,提取11种可见光波段(400～1 200 nm)的波谱特征参量,与选取的13种重金属元素,以及其经过因子分析组成的地球化学因子之间进行偏回归分析,从而建立胁迫植物青葙的光谱特征与叶冠中重金属含量间的反演模型。研究表明:随着锰胁迫浓度的增加,光谱在红边、蓝红谷位移以及吸收深度产生规律变化。同时,绿峰面积等波谱特征参量随着锰胁迫浓度以及生长周期发生了先增后减的律动。对多组波谱特征参量和重金属元素进行多元回归分析,叶冠中Mn、Cr、Co、Cu、Sr、Mo、Sn、Cs、Zr、Hf、Ti、Th、U和地球化学指标因子,与波谱特征参量组的复相关系数大于0. 8,相关性较强。在此基础上,F_1/F_4的地球化学指标组合,可以作为中观层面指示沉积型锰矿的富集指标,此间接模型也可以为高植被覆盖区开展高光谱遥感寻找矿产预测,以及为通过遥感进行生态修复评估提供依据。

Temporal-spatial Changes in Inner Mongolian Grassland Degradation during Past Three Decades

[Objective] This study aimed to analyze the temporal-spatial variation of Inner Mongolian grassland degradation during past three decades. [Method] The dis- tribution characteristics of grassland were described by land use types supervised classification with TM/ETM. Then, temporal-spatial changes of grassland coverage were quantified by the mean of maximum vegetation coverage in last 30 years. Lastly, the grassland degradation reasons were explored through statistic analysis between the grassland coverage and precipitation, temperature and grazing intensity. [Result] The grassland degradation index of Inner Mongolia was increased from 1.38 to 1.68, and the smallest was 1.28 in 2005s. Grassland degradation and improve- ment were concurrent after 1980s, but grassland degradation was the major change trend for Inner Mongolia grassland. The area of grassland degradation was enlarged from 18.08×10^4 km2 in 1980s to 22.47×10^4 km2 in 2010s on the whole and distribu- tion range was shifted from central-eastern to west in Inner Mongolia that mainly distributed on Hulun Buir and Xilin Gol grassland in 1980s and Ordos and Alax grassland in 2010s. The grassland area of degradation had a rising trend form 1980s to 1995s, then reduced to 10.8x104 km2 in 2005s, and decreased in 2010s, which mainly speared in the west of Xilin Gol grassland. [Conclusion] Inner Mongo-lian grassland degradation were become more seriously in last 30 years because that temperature, precipitation and graze intensities change, which not performance on decreasing coverage but grassland areas.

Analysis on the land use and cover change in Tianjin Binhai New Area based on the remote sensing

This paper carries out quantitative analysis on the land use/cover （LU/C） change of 13anjin Binhai New Area in recent 10 years through using land use transition matrix from the three-stage LU/C classification maps of 2000, 2005 and 2010 drafted by means of the National Land Classification System of China based on Landsat TM satellite remote sensing image and the Tianjin Binhai New Area 1：50 000 relief maps. On this basis, the impact of such driving factors as the economy and population on LU/C is further analyzed. The results show that the area of the building land in Binhai New Area has increased significantly over the ten years, and the greenland, wetland, and shoals of high ecological value have been dramatically transformed into the building land and unused land for the development and construction, and the change is more significant in the later five years.

Analysis to the Driving Force Model and Drives Factor on the Utilized Changes of Cultivated Land in Qinghai Lake Area

Using path analysis, correlation analysis, partial correlation analysis and system dynamics method to study the driving force of cultivated land in Qinghai Lake Area, and using gradually regression analysis to establish the driving force model of utilized change of cultivated land. Driving factors, action mechanism and process of utilized change of cultivated land were analyzed, and the differences during all factors were compared. The study provides some decision basis for sustainable utilization and management of land resources in Qinghai Lake Area.

Vertical Crustal Displacements Due to Surface Fluid Changes

Using the model data for surface mass changes of the atmosphere, ocean, soil moisture and snow depth, the vertical crustal displacements of 25 ficual stations in China were calculated according to the loading theory. From the spectral analysis of the results, we can see that the periods of displacements are 12 months and the semi-periods are 6 months. The results also show that the maximum seasonal displacements can reach 20 mm and even larger. The covariance analyses and significance tests show that the coefficients of 96 percent of the stations are significant at the 0.1 significance level. The results show that one of the reasons of the vertical crustal displacements is the changing surface fluid loads.

Geochemical characteristics of hydrothermal sediments from Iheya North Knoll in the Okinawa Trough

Thirty sediment subsamples were recovered from the Iheya North hydrothermal field （with an average of 38 m away from the hydrothermal vent） in the middle Okinawa Trough. Samples were obtained by the ROV （Remote Operated Vehicle） Faxian during the virgin cruise of the R/V Kexue in 2014 with the application of push cores. The chemical compositions of the sediments show that the hydrothermal sediments near the hydrothermal vent are mainly composed of SO3, ZnO and Fe203. Moreover, the hydrothermal sediments are also highly enriched in Pb, As, Sb, Hg, Se, Ag, Ba, Mo and Cd comparing with previous analysis results. On the other hand, the concentrations of St, Hg andAg in studied sediments are strongly and positively correlated, these elements can be used as an hydrothermal indicator. In addition, a factor analysis of the sediments suggested that the sediments were mainly influenced by hydrothermal origin, and terrestrial and biogenic input are limited in studied area. It is also suggested that different stages of crystallization were involved in the formation of hydrothermal chimney from factor analysis.

Land Use Changes of Valleys Based on Topographic Factors in Beijing Mountainous Regions of China

Land use changes in mountainous regions were greatly enhanced as the rapid development of economy due to the expanded population in developing countries. Acting geographically as the basic unit of mountainous regions, valleys are the primary sites of economic activities. Therefore optimization of land use policy in valleys is of critical important to the sustainable development in mountainous regions. On the basis of land use data in 1995 and 2012, this study explored the changes of land use according to the assessment of varied topographic factors （i.e., altitude and slope） in typical valleys of the Beijing mountainous regions, China. Our results showed that the valley is an efficiently geographical unit to evaluate land use changes in mountainous regions. We also found that major land use changes in mountainous regions of Beijing from 1995 to 2012 were the dramatic losses of grassland to the cultivated and construction lands, while most of these changes took place at the altitude of 0-400m and the slope of 6-15~. Considering the ever increasing economic development in Beijing mountainous regions, the increases of the construction and cultivated lands are inevitable, however, the great changes at a steeper slope imply the need to tailor land use structure coming into line with topographic factors, and suggesting ecological barriers and water conservation must be exercised in the developments of these areas.

Satellite Image-based Monitoring of Urban Land Use Change and Assessing the Driving Factors in Pokhara and Bharatpur Metropolitan Cities, Gandaki Basin, Nepal

Urban growth is a key indicator of economic development.At the same time,haphazard urban growth creates serious socioeconomic,environmental and urban land management problems.In this context,understanding the process of urban landscape change is important for guiding the sustainable growth of urban areas.This study analyzes the urban land changes during 1990–2018 in two metropolitan cities of Gandaki basin:Pokhara and Bharatpur.Landsat satellite images were analyzed using supervised classification methods.The results revealed that the built-up area has increased significantly by 300%in Pokhara and by nearly 500%in the Bharatpur during the past 28 years.Population growth,migration from surrounding areas due to urban facilities and the easy lifestyle in cities were found to be major determinants of urban growth within the study area.In addition,the changing urban definition and expansion of municipal boundaries are key factors for rapid urban growth.Both cities are likely to grow in the future as they are both located in areas that encompass the high levels of commercial activity and modern service facilities.The haphazard urban growth should be minimized through planning and policies for sustainable urban development.

A Review on the Driving Mechanisms of Ecosystem Services Change

Ecosystem services have rapidly changed at the global and regional scales in recent years. Exploring the driving mechanisms of ecosystem services change and projecting future change are of increasing importance to inform policy and decision-making options for ecosystem conservation and sustainable use. Although some research has analyzed the influences of land use or climate changes on ecosystem services, a systematic review on the mechanisms of ecosystem services change has not been carried out so far. This work elaborated on the mechanisms of ecosystem services change based on a literature review, and reached four main conclusions.(1)Climate change and land use jointly determine the ecosystem services change through complex and interacting pathways.(2) Whereas the present research progresses mainly focus on the identification of a single influencing factor, they fail in the determination of multiple influencing factors.(3) Although multi-scenario simulations based on remote sensing and climate models are the main means used to predict future changes in ecosystem services,clarifying the interactive mechanisms of multiple factors is the precondition for future projection of ecosystem services change;(4) Therefore, future research should strengthen the analysis and simulation of the effects of human activities on ecosystem services, especially the development of technology to detect the dynamic responses of ecosystem services to major ecological projects, which is crucial to the selection of restoration measures and the regional arrangement of ecosystem conservation projects.