赤峰市黄花甸子流域土壤有机碳含量的空间变异特征研究

选择内蒙古赤峰市敖汉旗黄花甸子流域为研究对象,运用地统计学和ArcGIS空间分析工具相结合的方法研究流域内土壤有机碳含量的空间变异特征以及土地利用方式对其的影响.结果表明,研究区0~10 cm土层范围有机碳含量具有中等空间相关关系,10~100 cm土层范围有机碳含量具有强烈空间相关关系,由随机性因素所引起的空间变异随土壤深度增加而降低.土地利用方式对土壤有机碳含量的影响随土壤深度的变化而发生改变,主要受植物根系分布特征的影响,各土层土壤有机碳平均含量由高到低表现为林地天然草地农地.     

Chemical and optical properties of aerosols and their interrelationship in winter in the megacity Shanghai of China

A field campaign on air quality was carried out in Shanghai in winter of 2012. The concentrations of NO, NO₂, NO_x, SO₂, CO, and PM_2.5 increased during haze formation. The average masses of SO₄^2-, NO₃^- and NH₄⁺ were 10.3, 11.7 and 6.7 μg/m³ during the haze episodes, which exceeded the average (9.2, 7.9, and 3.4 μg/m³) of these components in the non-haze days. The mean values for the aerosol scattering coefficient (b_sp), aerosol absorption coefficient (b_ap) and single scattering albedo (SSA) were 288.7, 27.7 and 0.91 Mm^-1, respectively. A bi-peak distribution was observed for the mass concentrations of CO, NO, NO₂, and NO_x. More sulfate was produced during daytime than that in the evening due to photochemical reactions. The mass concentration of NH₄⁺ achieved a small peak at noontime. NO₃^- showed lower concentrations in the afternoon and higher concentrations in the early morning. There were obvious bi-peak diurnal patterns for bsp and bap as well as SSA. bsp and bap showed a positive correlation with PM_2.5 mass concentration. (NH₄)₂SO₄, NH₄NO₃, organic mass, elemental carbon and coarse mass accounted for 21.7%, 19.3%, 31.0%, 9.3% and 12.3% of the total extinction coefficient during non-haze days, and 25.6%, 24.3%, 30.1%, 8.1% and 8.2% during hazy days. Organic matter was the largest contributor to light extinction. The contribution proportions of ammonium sulfate and ammonium nitrate to light extinction were significantly higher during the hazy time than during the non-haze days.     

安徽及周边地区气溶胶时空特征及成因分析

利用AERONET数据对2013年6月—2014年5月Aqua/MOIDS气溶胶产品在安徽及周边地区的适用性进行了验证,分析了气溶胶时空分布特征并讨论其影响因素.结果表明:MODIS AOD与AERONET数据在研究区具有很好的一致性,满足美国国家宇航局(NASA)的误差要求.时间上,安徽北部及中部春季、冬季AOD值较高,合肥-南京一带在冬季AOD值甚至高于0.9;研究区域整体在秋季达到AOD最低值.空间上,皖西、皖南山区和庐山等高海拔地区AOD较低,而处于山区间的沿江平原的AOD却明显升高,形成一个以沿江平原为高值中心的环形分布区.研究区域内AOD与能见度、相对湿度的相关性显著,风速对AOD有着先促进后抑制的影响,经济发展和人口分布对气溶胶的分布也有着明显的影响.     

黄土高塬沟壑区氮素流失的时空变异特征

为了探讨黄土高塬沟壑区水体氮污染的时空变化情况,选取黑河流域(泾河支流)为研究区域,测定2013—2014年枯水期和汛期流域地表水和地下水中主要离子及NO_3~--N和NH+4-N的浓度并进行分析.结果表明,黑河流域枯水期水化学主要为Na+K-Cl-SO_4型,汛期主要为CaMg-HCO_3型.枯水期及汛期阳离子均主要为Na+,阴离子在枯水期主要为SO_4~(2-)而汛期则转变为HCO_3~-.汛期NO_3~--N浓度普遍大于枯水期,平均值分别为2.37和1.63 mg·L~(-1);且空间分布不均衡,地表水中的浓度为:上游(1.35 mg·L~(-1))中游(1.05 mg·L~(-1))下游(0.93 mg·L~(-1)),而地下水中的浓度为:下游(3.84 mg·L~(-1))中游(2.54 mg·L~(-1))上游(2.35 mg·L~(-1)).NH_4~+-N在时间分布上没有明显的规律,汛期及枯水期变化不大,空间分布特征与NO_3~--N类似,但其整体浓度较低,在0.11 mg·L~(-1)左右波动,较为稳定均且未超过IV类水标准.水体中NO_3~--N不仅来自于农田氮肥的施入等人类活动,还可能来自于酸性降雨.地表水的NO_3~--N污染程度存在空间差异,上游污染程度大于中、下游,而超过70%的地下水水质属于良好,对当地饮用水安全暂不造成威胁.     

长江三角洲地区旅游资源时空结构分析

根据68处4A级景区所依托的主要旅游资源，将长江三角洲地区旅游资源的时空结构概括为4种类型：周末型——圈层结构、节假日型——多节点结构、四季型——面状结构及其它时闻型——单节点结构；由此提出该地区旅游产品亦构建为具有更加精细市场针对性的4类产品类型：周末型、节假日型、四季型和单节点型；认为通过旅游资源与产品的时空结构分析，可以促进区域旅游资源的集约化开发。改变目前“长三角”地区旅游产品开发租放的现状，推动区域旅游协调发展。     

中国土地资源退化时空变化分析

在GIS技术的支持下,利用土地利用现状变更调查数据(1991～2003年),在辨析土地资源退化定义和分类基础上,将土地资源退化分为沙漠化、石漠化、次生盐渍化、非农建设用地占用、森林砍伐、天然草地退化和湿地萎缩7大过程.通过全面分析这些退化过程的动态变化和空间分布,揭示出中国土地资源退化的整体态势和时空变化规律.结果表明:①我国土地资源退化总体态势较为严重,尽管部分改善,但总体恶化;土地资源总体退化指数呈增加趋势,其中非农建设用地占用和湿地萎缩过程指数变化最为明显,造成土地资源退化程度最为严重.②土地资源退化集中于天然草地退化和非农建设占用过程,占66.27%,土地资源改善主要是沙漠化治理和森林恢复过程,占57.5%.③土地沙漠化和石漠化过程发生了逆转,面积总计减少了约15 578km2,但我国沙漠化治理过程主要分布在生态脆弱的西北部地区,而东部地区,尤其是江河流域沿线地区,沙漠化土地面积正在不断扩大.④约60%的非农建设用地增加来源于耕地占用,其中70%以上分布在东北、华北和沿海地区等高产粮区,严重威胁到我国的粮食安全.⑤耕地的损失必然造成土地开发复垦压力的增加,随之而来的大量生态用地被开垦为农田,如湿地资源退化面积的50%以上转化为耕地.这些分析和评价结果将为我国制定土地资源退化治理和保护对策提供科学依据.     

Monitoring of Seasonal Variation in the Water Quality of Ubu River in Ekwusigo and Nnewi Local Government Areas of Anambra State,Nigeria

Investigation of the water quality of the Ubu river has been carried out. The upstream course of the river is slightly acidic (pH 5.45 ± 0.23), and the acidity decreases along the lower courses of the river. Turbidity, surfactant, and iron content parameters of the river increased during the wet season, and these changes have been attributed to inputs from flood, leachates of soil erosion, and storm water runoff discharged into the river in increased quantities during the season. Concentrations of some metals were found to increase during the dry season because of absence of dilution of the river by storm water runoff. Most water quality parameters are within World Health Organization acceptable limits set for potable water, and they include most of the cationic and anionic constituents. Although there is no hydrocarbon or metal ion pollution, potability is reduced along the mid to downstream courses of the river by unacceptable levels of turbidity, surfactant concentration, and iron content, particularly during the wet season.     

THE EFFECTS OF DIURNAL MIXING ON THERMAL STRATIFICATION OF STATIC IMPOUNDMENTS1

ABSTRACT: The time variation in the temperature distribution of a static water impoundment is predicted. The body of water is modeled as a discrete number of horizontally isothermal layers and the energy equation is solved using an implicit numerical scheme. Vertical energy transport mechanisms included are solar absorption, molecular diffusion, and convective mixing due to nocturnal turnover. The latter mechanism, called diurnal mixing, is found to have a profound effect on the stratification, particularly in the eplimnion patterns for a typical deep static impoundment.     

中国城市居民生活能源碳排放的时空格局及影响因素分析

随着经济社会的发展与人民生活水平的提高,生活用能强度逐年增大,城市居民生活能源碳排放日益成为碳排放的新增长点.本文采用Theil指数、空间自相关分析了我国城市居民生活能源碳排放的时空格局演变特征,并利用STIRPAT模型分析了影响城市居民生活能源碳排放的主要因素.结果表明:12001—2012年我国城市居民生活能源碳排放总量及人均生活能源碳排放量均呈增长趋势,其年增长率分别为9.69%、3.29%;2八大经济区域间城市居民人均生活能源碳排放的差异是构成我国城市居民人均生活能源碳排放总体差异的主要原因,其对总差异的贡献率达到了57.90%;3我国城市居民人均生活能源碳排放具有显著的空间正相关性,2001—2012年间城市居民人均生活能源碳排放的"冷点"区变化较为稳定,主要分布在东部和南部经济区,而"热点"区主要分布在西北、东北和黄河中游经济区;4城市人口规模、城市居民可支配收入、城市居民生活消费支出、城市居民年龄结构均对城市居民生活能源碳排放量具有加剧作用,而城市居民能源消费结构具有减缓作用,且北方城市居民生活能源碳排放量明显高于南方;5现有样本数据支持环境Kuznets曲线假说,即随着经济的发展,城市居民生活能源碳排放量存在转折点.