The Natural Vegetation Responses to the Groundwater Change Resulting from Ecological Water Conveyances to the Lower Tarim River

This paper takes the ecological water conveyance project (EWCP) that transfers water from the Bosten Lake, to Daxihaizi Reservoir, and finally to the Taitema Lake as a case study to analyze the dynamic change of the groundwater depth, the vegetation responses to the elevation of the groundwater depth as well as the relationship between the groundwater depth and the natural vegetation. The results from many years’ monitoring in field indicate: (1) the groundwater depth has been elevating gradually with the increase in the times of watering and the elevation range has been expanding continuously in the lower reaches of Tarim River. Correspondingly, the natural vegetation has a favorable response to the elevation of the groundwater depth. The change of the natural vegetation has accordance with that of the groundwater depth. Such facts not only show that groundwater is a key factor to the growth of the native vegetation but also prove it is feasible that the degraded ecosystem can be restored and protected by the EWCP; (2) the results of analysis of the spatial-temporal response of the natural vegetation to watering reveals that the beneficial influence of the EWCP on the ecosystem in the lower Tarim River is a long-term process; (3) in terms of the function and structure of ecosystem after watering in the lower reaches of Tarim River, the EWCP does not still reach the goal of ecological restoration at a large spatial scale at present. Based on such monitoring results, some countermeasures and suggestions for the future restoration strategy are proposed so as to provide a theoretical basis for restoring and protecting the ecosystem in Tarim River, and meanwhile it can also provide some scientific references for implementing the similar ecological projects in other areas.     

基于光学遥测技术的合肥市气溶胶参数观测

为了解合肥市气溶胶光学特性参数,采用太阳光度计CE318对雾霾期间气溶胶进行监测并分析了气溶胶光学厚度(AOD)、Angstorm波长指数(α)、体积谱函数等气溶胶光学特性参数。同时采用多轴差分吸收光谱技术(MAX-DOAS)反演了雾霾期间二次气溶胶前体物NO2柱浓度并和固定点测量的颗粒物(PM)浓度进行了对比。分析表明,雾霾期间的气溶胶光学厚度比晴天高,且随波长的增加而减少。Angstorm波长指数在雾霾天气时平均值较高,表明合肥雾霾天气期间气溶胶粒子以细粒子为主。气溶胶前体物NO2浓度变化与雾霾天气空气中颗粒物含量(PM10、PM2.5等)变化一致性较好,表明二次气溶胶可能对气溶胶颗粒浓度有一定影响。     

Application and evaluation of kriging and cokriging methods on groundwater depth mapping

Groundwater and water resources management play a key role in conserving the sustainable conditions in arid and semi-arid regions. Applying some techniques that can reveal the critical and hot conditions of water resources seem necessary. In this study, kriging and cokriging methods were evaluated for mapping the groundwater depth across a plain in which has experienced different climatic conditions (dry, wet, and normal) and consequently high variations in groundwater depth in a 12 year led in maximum, minimum, and mean depths. During this period groundwater depth has considerable fluctuations. Results obtained from geostatistical analysis showed that groundwater depth varies spatially in different climatic conditions. Furthermore, the calculated RMSE showed that cokriging approach was more accurate than kriging in mapping the groundwater depth though there was not a distinct difference. As a whole, kriging underestimated the real groundwater depth for dry, wet, and normal conditions by 5.5, 2.2, and 5.3%, while cokriging underestimations were 3.3, 2, and 2.2%, respectively; which showed the unbiasedness in estimations. Results implied that in the study area farming and cultivation in dry conditions needs more attention due to higher variability in groundwater depth in short distances compared to the other climate conditions. It is believed that geostatistical approaches are reliable tools for water resources managers and water authorities to allocate groundwater resources in different environmental conditions.     

云南省气溶胶光学厚度时空变化特征的遥感研究

利用中分辨率成像光谱仪(MODIS)的气溶胶产品研究云南省气溶胶光学厚度(AOT)的时空变化特征。研究结果表明:在长时间尺度上,区域月平均AOT没有明显的增长趋势,年平均值大约为0.19,反映了人为活动排放进入大气的气溶胶没有明显的增加;月平均AOT的变化呈双峰分布特征,2个峰值分别出现在3、8月,AOT大约为0.35±0.08和0.31±0.05,5月出现明显的谷值(0.20±0.03),AOT减少的原因可能是该地区降水增多,大量的降水可以清除大气中的气溶胶粒子,最小值常出现在1月或12月,AOT大约为0.09±0.02。在空间上,云南省AOT普遍较低,年平均值的空间分布为0~0.4,低值区出现在西北部的迪庆州、怒江州和丽江市;AOT高值区分布在云南省的南部和东北部地区,3月AOT值最大可达0.80以上,南部和北部差值达到0.60以上,8月AOT的高值区主要出现在中部的玉溪市红河州北部、玉溪市和昆明市。云南省AOT北高南低分布格局的原因主要是北部地区人为气溶胶排放较少,另外,由于地形的影响,北部地区风速较大,气溶胶停留在大气中的时间较短,AOT较小。     

远程监控城乡管网饮用水的低量色度

选用480 nm单色光及长光程技术进行吸光光度分析,测定水质色度。通过对比普通分光光度法可知,吸光光度测试的光程长度增加10倍,测试灵敏度显著提高,从而保证低色度饮用水(30度)的测定精准度。监测的色度数据利用GSM无线通信传输系统,可实现对水质色度监测结果的远程实时动态遥传,为预警突发性水污染事故提供数据支撑。     

Dissipation of terbuthylazine,metolachlor, and mesotrione in soils with contrasting texture

ABSTRACT

This study evaluates the dissipation of terbuthylazine, metolachlor, and mesotrione at different depths in soils with contrasting texture. The field trial was conducted at the Padua University Experimental Farm, north-east Italy. The persistence of three herbicides was studied in three different soil textures (clay soil, sandy soil, and loamy soil) at two depths (0–5 and 5–15 cm). Soil organic carbon content was highest in the clay (1.10%) followed by loam (0.67%) and sandy soil (0.24%); the pH of soils was sub-alkaline. Terbuthylazine, metolachlor, and mesotrione were applied on maize as a formulated product (Lumax®) at a dose of 3.5 L ha^?1. Their dissipation in the treated plots was followed for 2 months after application. The concentrations of herbicides were analyzed by liquid chromatography-mass spectrometry. The dissipation of terbuthylazine, metolachlor, and mesotrione could be described by a pseudo first-order kinetics. Terbuthylazine showed the highest DT50, followed by metolachlor and mesotrione. Considering the tested soil, the highest DT50 value was found in clay soil for terbuthylazine and metolachlor, whereas for mesotrione there was no difference among soils. Significant differences were found between the two soil depths for terbuthylazine and metolachlor, whereas none were found for mesotrione. These results suggest that soil texture and depth have a strong influence on the dissipation of terbuthylazine and metolachlor, whereas no influence was observed on mesotrione because of its chemical and physical properties.     

高突危险水体上煤层开采下限及带压开采分区研究

确定开采下限,对高突危险水体上煤层的安全开采具有十分重要的意义。本文基于肥城矿区地质条件,用FLAC3D软件,对开采煤层下伏岩层移动变形规律进行了深入研究,对煤层底板三带范围进行了初步确定;同时,从不同方面对煤层底板开采破坏深度进行了理论计算。根据突水系数、导水带深度、导升带高度和经验数据,确定出正常条件下带压开采的下限(-720m)以及安全措施条件下(底板预注浆处理等)的带压开采下限(-850m)。依据开采下限,对带压开采条件进行了分析,初步形成了高突危险水体上煤层带压开采的分区分类,划分了"开采相对安全区(安全开采区、次安全开采区、条件安全开采区)、深部突水危险区、构造突水危险区",为确定安全开采技术与工艺奠定了理论基础。     

基于超声脉冲法的火灾损伤后混凝土裂纹深度检测

检测或诊断裂纹深度是火灾后混凝土结构受损综合评判的重要依据。开发一种专用的火灾后混凝土裂纹深度检测仪器,是一项填补国内该领域空白的重要研究课题。在研讨和分析超声脉冲法检测混凝土表面损伤裂纹深度的单面平测法、逐层穿透法和损伤层厚度判定3种测试方法的基础上,笔者设计开发了一种超声测试诊断仪,采用高精度计时电路、传感器驱动电路和自动增益电路,提高了仪器计时精度和抗干扰性。经对多组火灾损伤后的结构混凝土试件的测试,获取了6组共60个声时数据,用给出的方法进行了计算,得出的裂纹深度值与观察结果能较好地吻合。理论与实测表明,提出的裂纹检测方法和开发出的测试仪器具有实用性。     

巢湖水体固有光学特性研究

水体的固有光学特性是描述水体辐射传输的基本光学特性,是建立水质参数遥感模型的基础.黄色物质、非色素悬浮物和浮游植物是影响内陆水体光学特性的3种主要物质,对巢湖水体中这3种物质在波长为400～800 nm的吸收系数进行了测量和分析.结果表明,各组分的吸收系数随其含量的增加而增加;黄色物质和非色素悬浮物的吸收系数随波长的增加呈负指数形式递减;浮游植物吸收光谱的形状与不同藻类的色素组成密切相关.绿色到近红外波段范围是遥感监测内陆水质参数的最佳波段.      

顾及尺度效应的多源遥感数据“源”“汇”景观的大气霾效应

以武汉市为例,利用多源遥感数据研究城市"源""汇"景观格局与大气霾污染的相关关系.首先,基于武汉市Landsat8数据的地表覆盖分类结果,计算不同尺度下地表覆盖的整体异质性景观指数,选择异质性最大的尺度作为"源""汇"景观分析的最优尺度;在此基础上,用MODIS数据的气溶胶光学厚度(AOD)产品作为大气霾污染程度的度量,基于自相关性较小的"类别层"景观指数,使用地理加权回归分析模型对"源""汇"景观与AOD进行局部回归分析,并在工业区、商业区和居民区3种功能区内分析建筑物对大气霾污染影响的差异.结果表明:6 km是本文分析的最优尺度;大气霾污染的"源"景观为建筑物,"汇"景观为灌木和林地;减小"源"景观面积所占比例、增大其破碎化程度、"源""汇"穿插均匀分布,可以有效减小气溶胶光学厚度,降低大气霾污染;对于武汉市来说,其大气霾污染的主要来源为中心城区的商业区和居民区,即来自于市民生活.针对中心城区要发挥其经济、交通等功能,已有的建设用地不宜大面积改动这一现状,可以采取小幅度优化措施,而对于非建成区可采取建前合理规划"源""汇"景观空间分布的措施.