基于GIS和RUSLE的三峡库区小流域土壤侵蚀量估算研究

本研究以三峡库区菱角塘小流域为研究对象,在GIS技术的支持下,通过遥感技术和野外调查进行信息采集,对修正的通用土壤流失方程(RUSLE)各因子进行量化分析,从而对三峡库区菱角塘小流域土壤侵蚀量进行定量评价,并对土壤侵蚀强度进行分级;在此基础上分析不同坡度和土地利用类型的土壤侵蚀空间分布特征。结果表明,菱角塘小流域年土壤侵蚀量为208.32t/a,土壤侵蚀模数为1 987.75t/(km2·a),属于轻度侵蚀。28.62%的区域为中度、强度或极强度侵蚀,但是其侵蚀量却占总侵蚀量的82.36%,是预防和加强水土流失治理的重点区域。土壤侵蚀主要发生在坡度为15°~35°的区域,其中15°~25°的坡度土壤侵蚀属于中度侵蚀;坡耕地侵蚀最为严重,15°~25°的坡耕地侵蚀量占总侵蚀量的57.15%,表明坡耕地是该小流域水土流失的主要策源地。同时用137 Cs核素示踪技术测定的坡耕地和林地土壤侵蚀模数证实了RUSLE模型具有较高的准确性和可靠性,该模型在库区地块尺度具有一定的推广价值。     

京津冀PM2.5浓度控制目标可达性分析

雾霾污染已成为京津冀地区最突出的环境问题,国务院颁布了《大气污染防治行动计划》,明确提出了京津冀地区雾霾治理的浓度目标和减排措施。但是这些减排措施能否够实现PM2.5的浓度目标呢?本文基于数据分析方法,量化了2013—2014年京津冀地区PM2.5浓度与污染物排放量的关系,预测了现有减排措施可以达到的PM2.5浓度以及实现既定的PM2.5浓度目标的大气污染物减排要求,对"大气十条"减排政策的有效性进行了科学评估。结果显示,现有的减排措施难以实现PM2.5浓度控制目标,天津和河北的大多数地市需要进一步加大污染物减排力度。河北的部分地市即使实现了PM2.5浓度下降25%的目标,PM2.5浓度仍然过高,应改下降百分比为绝对值目标。北京的污染物减排率过高,减排难度较大,可以考虑一个现实合理的PM2.5浓度目标和污染物减排计划。由于污染物减排行动涉及区域经济和民生保障,PM2.5浓度受到风力等自然因素的影响较大,京津冀地区的雾霾治理应确定现实可行的浓度控制目标,并制定相应的污染物排放量管理目标。     

鄂尔多斯采煤损毁土地预测与复垦模式分析

鄂尔多斯地区作为我国的主要储煤区,由于煤炭开采导致的土地损毁问题日趋严峻,探索适宜该区自然条件特点的采煤沉陷损毁规律与土地复垦模式,对于该区土地资源可持续发展具有重要的现实意义。在对生产工艺、土地利用现状分析的基础上,采用MSPS软件对项目区采煤沉陷土地进行损毁范围及程度分析,进而结合损毁预测结果制定复垦措施:对耕地区因地制宜进行梯田整地、灌溉、排水设施建设,林、草地区在尽量减少地表扰动的前提下适时补植,并加强管护。     

庙台子森林风景名胜资源的可持续发展

陕西留坝庙台子风景区属暖温带针阔混交林夏绿叶林带 ,林业用地占 99 5% ,森林覆盖率 92 8% ;有种子植物 1 4 80种 ,其中国家珍稀濒危保护植物 1 8种 ,中国种子植物特有属 2 6属。庙台子集山地森林和风景名胜为一体 ,是秦岭主要的生态旅游地之一 ,建议把庙台子建设为森林生态系统 -风景名胜国家级保护区 ,同时探讨了可持续发展规划。     

宁夏土壤水文参数空间分布及干旱指标改进研究

土壤相对湿度是干旱监测和评估中最常用的指标之一,但这一指标的有效水下限较为模糊,实际应用中会将一部分土壤有效水排出在外,从而高估干旱的程度,因此有必要对其进行改进。利用2016-2019年宁夏回族自治区气象局122个土壤湿度观测站0-50 cm土壤田间持水量(%)和凋萎湿度(%)的测定数据,分析了宁夏境内土壤水文参数空间分布特征,并引入土壤相对凋萎湿度,以改善当前干旱监测评估中最旱等级土壤水下限模糊的问题。结果表明:宁夏0-20 cm和20-50 cm土壤水文参数的空间分布特征较为相似,田间持水量、凋萎湿度、有效水和相对凋萎湿度的波动范围均呈南低北高的特点;数值大小上,田间持水量、凋萎湿度、有效水整体呈南大北小,而相对凋萎湿度南小北大;分布区间上,田间持水量、凋萎湿度、有效水、相对凋萎湿度集中在15.0%-25.0%、3.0%-6.0%、10.0%-20.0%、10.0%-30.0%之间。基于相对凋萎湿度改进的干旱指标,在宁夏除特旱上限对应的土壤相对湿度波动范围较大外,轻旱、中旱和重旱对应的土壤相对湿度空间波动范围均较小;轻旱、中旱、重旱和特旱的上限对应的土壤相对湿度分别主要介于82.1%-90.0%、64.2%-80.0%、46.3%-60.0%、28.4%-50.0%之间。改进后的干旱指标其物理意义更加明确,能客观反映较低土壤水分对植物有效性真实情况,研究对提高干旱监测评估的准确性有一定现实意义。     

High level of nickel tolerance and metal exclusion identified in silver maple (Acer saccharinum)

Nickel (Ni) and copper (Cu) are the most prevalent metals found in the Greater Sudbury Region ecosystems. The main objectives of this study are to (1) assess silver maple (Acer saccharinum) tolerance to different doses of Ni and (2) determine the translocation pattern of metals in A. sacharinum. This study revealed that A. sacharinum is highly tolerant to high doses of NI (1600 and 9200?mg/kg). Growth chamber screening trials revealed that Ni is stored in roots and does not translocate to other plant parts. Analysis of samples from A. sacharinum growing for >30 years in soil contaminated with metals also showed that the levels of iron (Fe), manganese (Mn), Ni, and zinc (Zn) were significantly higher in roots compared with soils and aerial parts. On the other hand, the amount of Cu was higher in soil compared with roots and other plant parts. In fact, the bioaccumulation factors (BFs) were 0.29, 2.00, 3.6, 1.9, and 4.0 for Cu, Fe, Mn, Ni, and Zn, respectively. The translocation from roots to aerial parts showed an insignificant level of movement of Cu, Fe, and Ni. Hence, A. saccharinum is classified as excluder for Fe, Mn, Ni, and Zn, and avoider for Cu.     

Identifying the European Fossil Fuel Plumes in the Atmosphere Over the Northeast Atlantic Region Through Isotopic Observations and Numerical Modelling

As part of the Danish NEAREX project the origin and variability of anthropogenic atmospheric CO₂ over the Northeast Atlantic Region (NEAR) has been studied. The project consisted of a combination of experimental and modelling activities. Local volunteers operated CO₂ sampling stations, built at University of Copenhagen, for ¹⁴C analysis at four locations (East Denmark, Shetland Isles, Faroe Isles and Iceland). The samples were only collected during winter periods of south-easterly winds in an attempt to trace air enriched in fossil-fuel derived CO₂ due to combustion of fossil fuels within European countries. In order to study the transport and concentration fields over the region in detail, a three-dimensional Eulerian hemispheric air pollution model has been extended to include the main anthropogenic sources for atmospheric CO₂. During the project period (1998–2001) only a few episodes of transport from Central Europe towards NEAR arose, which makes the data set for the evaluation of the method sparse. The analysed samples indicate that the signal for fossil CO₂, as expected, is largest (up to 3.7±0.4% fossil CO₂) at the Danish location closest to the European emissions areas and much weaker (up to ∼1.5±0.6% fossil CO₂) at the most remote location. As the anthropogenic signal is weak in the clean atmosphere over NEAR these numbers will, however, be very sensitive to the assumed background ¹⁴CO₂ activity and the precision of the measurements. The model simulations include the interplay between the driving processes from the emission into the boundary layer and the following horizontal/vertical mixing and atmospheric transport and are used to analyse the meteorological conditions leading to the observed events of high fossil CO₂ over NEAR. This information about the history of the air masses is essential if an observed signal is to be utilised for identifying and quantifying sources for fossil CO₂.     

地形和季节变化对有机氯农药分布特征的影响——以四川省成都经济区为例

在成都经济区典型地貌单元（平原区和丘陵区）采集春季和秋季样品,共计52件农作物样品和100件土壤样品,通过美国EPA8080A方法测试样品中有机氯农药含量,以研究不同地貌单元不同季节有机氯农药污染分布特征。结果表明：土壤中DDT含量高于HCH含量;平原区绵竹市土壤中有机氯农药含量高于丘陵区盐亭县土壤有机氯农药含量;在平原区的绵竹市,秋季采集的土壤中有机氯农药含量高于春季样品中有机氯农药含量;在丘陵区的盐亭县,春季采集的土壤有机氯农药含量高于秋季样品中含量。农作物中有机氯农药的检出率较高,各种作物浓度均未超标,但对人们健康具有潜在危害。油脂含量高的粮食作物中有机氯农药含量高于叶类蔬菜和果实类蔬菜中有机氯农药的含量。地貌类型、土壤有机质含量以及有机氯农药施用是造成两个地区春、秋季土壤含量特征不同的主要原因,而植物的吸收方式、OCP的物理化学性质是影响农作物中OCP含量不同的主要因素.     

近百年云南纵向岭谷区气温的时空变化特征

采用多种统计方法,对近百年来纵向岭谷地区气温的时空变化特征进行了分析.结果表明:纵向岭谷区气温分布具有一致性,且温度、热量分布存在明显的南北差异.自然的阻隔作用使得岭谷地区的年平均、冬季平均温度呈现出西高东低,大致具有经向分布的特征;夏季平均气温表现出南北高,中间低的分布.澜沧江流域是年、冬季气温和热量发生变化的阻隔分水岭.纵向岭谷地区的气温具有明显的年代际变化特征,近百年来以增温趋势为主.