Spatial Modeling of Mean Annual Temperature in Iran: Comparing Cokriging and Geographically Weighted Regression

Mapping spatial distribution of climatological parameters with a good degree of accuracy is crucial in environmental modeling and planning. Nowadays, there are various models to estimate and predict spatial variables in an area but some such as cokriging and geographically weighted regression (GWR) have got more attention from experts in this field. The objectives of this study are to evaluate and compare GWR with ordinary cokriging (OCK) techniques for estimating the mean annual air temperature (MAT) of Iran using European Centre for Medium-Range Weather Forecasts (ECMWF) data and auxiliary variables (e.g., longitude, latitude and altitude). The MAT-gridded data for Iran was collected in pixels during the time interval of 1987–2015 from the ERA-Interim re-analysis version of ECMWF. Validation results indicate that cokriging model with latitude and altitude for estimating MAT has the lowest MAE (0.0155), MBE (0.00085), RMSE (0.0251), and the highest NS (0.9999) in relation to other cokriging methods. On the other hand, GWR with altitude has better results than those of GWR with other auxiliary variables because of its MAE (0.1271), MBE (0.0124), RMSE (0.1760), and NS (0.9969). By comparing two mentioned methods, cokriging with latitude and altitude has provided the best performance in relation to GWR for prediction of MAT in Iran. To obtain accurate estimation of the spatial distribution of MAT, local residuals were analyzed. Results concluded that residuals of the OCK model have high spatial adaptations between the observed and predicted MAT data compared to the GWR model. Hence, OCK was a relatively optimum method for the estimation of MAT compared with GWR.

     

北京市水生态监测评价方法构建及应用

根据北京市多年水生态监测的经验,确立了典型地表水体水生态监测的水文地貌、理化指标和生物要素。其中,生物要素评价因子主要包括浮游植物、浮游动物和底栖动物。并依据2014年监测结果进行了分析评价,将水生态状态等级分为5级。评价结果表明：北京市典型地表水体水生态状态综合评价结果中处于"中等"级别的监测断面数量为7个,占监测总数的41.2%,生物要素对最终评价结果影响略大。     

Long Term Fire Scar Monitoring with Remote Sensing in Northern Namibia: Relations Between Fire Frequency, Rainfall, Land Cover, Fire Management and Trees

A cost-effective method was developed to map fire scars on Quicklooks of Landat TM imagery. The method was compared with a full resolution Landsat image using visual interpretation and supervised classification using the Maximum Likelihood procedure, resulting in a high degree of agreement between methods. A long time series of fire scars was developed using all available Landsat Quicklooks between 1989 and 2001 for an area of 63000 sq km in north-east Namibia. Between 27 and 51% of the study area burned annually, while only 10% of the area did not burn between 1989 and 2001. Not-burned areas were mainly settled areas and permanent wetlands. 33% of the area burned between 5 and 7 times during the 13 years indicating a high frequency overall. Rainfall and livestock had little influence on burned areas. In 1996 formal fire management started in a portion of the study area consisting of building firebreaks and holding awareness programs. A comparison of burned areas before and after the intervention started allowed evaluating its effectiveness. The area where the formal fire management program was undertaken showed a significant decrease in burned area. It is suggested that awareness campaigns rather than firebreaks contributed to this decrease. Selected tree population data were compared with fire frequencies. Differences in tree occurrence, regeneration, and stem diameter distributions between low and high fire frequencies could be detected and explained with known responses of the species to fire. This suggests that the observed time series is representative of a long-term fire regime in the area.     

Varying Stable Nitrogen Isotope Ratios of Different Coastal Marsh Plants and Their Relationships with Wastewater Nitrogen and Land Use in New England, USA

The stable nitrogen isotope ratios of some biota have been used as indicators of sources of anthropogenic nitrogen. In this study the relationships of the stable nitrogen isotope ratios of marsh plants, Iva frutescens (L.), Phragmites australis (Cav.) Trin ex Steud, Spartina patens (Ait.) Muhl, Spartina alterniflora Loisel, Ulva lactuca (L.), and Enteromorpha intestinalis (L.) with wastewater nitrogen and land development in New England are described. Five of the six plant species (all but U. lactuca) showed significant relationships of increasing δ ¹⁵N values with increasing wastewater nitrogen. There was a significant (P < 0.0001) downward shift in the δ ¹⁵N of S. patens (6.0 ± 0.48‰) which is mycorrhizal compared with S. alterniflora (8.5 ± 0.41‰). The downward shift in δ ¹⁵N may be caused by the assimilation of fixed nitrogen in the roots of S. patens. P. australis within sites had wide ranges of δ ¹⁵N values, evidently influenced by the type of shoreline development or buffer at the upland border. In residential areas, the presence of a vegetated buffer (n = 24 locations) significantly (P < 0.001) reduced the δ ¹⁵N (mean = 7.4 ± 0.43‰) of the P. australis compared to stands where there was no buffer (mean = 10.9 ± 1.0‰; n = 15). Among the plant species, I. frutescens located near the upland border showed the most significant (R ² = 0.64; P = 0.006) inverse relationship with the percent agricultural land in the watershed. The δ ¹⁵N of P. australis and I. frustescens is apparently an indicator of local inputs near the upland border, while the δ ¹⁵N of Spartina relates with the integrated, watershed-sea nitrogen inputs.     

国家地表水环境质量评价、分析与表征系统初步构建

随着国家地表水环境质量监测网络的优化调整以及水质自动监测与采测分离手工监测相结合模式的完全确立,每个月产生数百万计的监测数据。为全面支撑海量监测数据的传输、融合、处理、挖掘、分析、表征,构建了国家地表水环境质量评价、分析与表征系统。通过在多源异构数据融合、智能化数据质量控制、多层级水质评价与统计分析、地图动态数据表征等方面的技术创新,构建了包括数据来源层、数据存储层、应用支撑层、业务应用层和表征展示层5个主要部分的系统。形成了"一个融合、两个数据库、三个应用、四个中心",实现了数据集成融合、数据共享互通、数据统计分析、水质报告生成、地图空间表征、综合大屏展示等6个方面主要功能。应用于国家地表水环境监测评价业务工作,能够及时、直观、准确、全面地展现全国地表水环境质量状况,为全国地表水环境质量管理决策、业务处理、科学研究提供有效的信息支撑。     

安徽淮北矿区地表水氮的富营养化特征及来源解析

为探索淮北临涣矿区地表水体中氮的分布和来源,采集研究区河流和沉陷积水区样品,测试分析其水化学指标和氮、氧同位素特征值,并采用IsoSource模型计算不同端源氮的污染贡献率。结果表明:研究区地表水处于中度富营养化状态,矿区地表水中氮的输入源受含氮肥料、土壤有机氮和粪肥污水共同影响,所发生的硝化及反硝化作用微弱;矿区河水中氮的主要输入源为粪肥污水,贡献率达66.6%,沉陷积水区氮主要受含氮肥料输入的影响,贡献率达52.0%。     

地表水环境质量综合评价方法研究与应用进展

水质评价是目前水环境质量管理的重要支撑,水质综合评价方法已经逐渐由断面评价向流域综合评价进行转变与突破。该文对目前的断面水质评价方法进行了归类综述,并且对流域水质综合评价方法及其在各个国家流域的应用进行了重点评述。分析认为中国在流域评价中所使用的"断面比例法"不够准确,缺乏污染物时空分析以及生物评价等问题,并据此提出了未来的研究方向,为未来地表水质评价方法的提升以及水环境管理的完善提供科学的参考依据和建议。     

南京水体中抗抑郁类药物的赋存及风险评估

采集南京不同水体9个点位的水样,经固相萃取后采用LC-MS/MS方法测定样品中10种抗抑郁类药物,结合风险熵值法评估其对不同营养级水生生物的风险。结果表明,南京水体中存在不同程度的抗抑郁类药物污染,质量浓度范围为未检出～9.4 ng/L;舍曲林、氟伏沙明和西酞普兰的检出率为100%,氟西汀的检出率为44.4%。风险评估结果表明,南京水体中抗抑郁类药物对不同营养级水生生物表现出低—中等风险;舍曲林和氟西汀对总风险的贡献率最高,需要重点关注。     

全自动甲基汞分析仪测定水和废水中甲基汞

建立了全自动甲基汞分析仪测定水和废水中甲基汞的方法,对较清洁的地表水和一般废水样品可直接衍生化测定,对基体复杂水样则需蒸馏后再衍生化测定。该法在水样中甲基汞含量为0~1 000 pg范围内线性良好,相关系数r为0.999 7,检出限为0.002 ng/L,标准参考物质测定结果均在参考值范围内,相对标准偏差为1.1%,加标回收率为83.2%~96.6%。该法适用于水及废水中甲基汞的检测。     

1990—2020年承德市御道口地区产水与水源涵养功能时空演变

承德市御道口地区作为京津冀水源涵养功能区的组成部分,是区域可持续发展的重要生态支撑。基于生态系统服务和权衡的综合评估模型(InVEST模型)定量分析了1990—2020年御道口地区的产水与水源涵养功能的时空演变,并采用情景模拟法分析评估气候要素与土地利用类型变化对产水量与水源涵养量的影响。结果表明:(1)1990—2020年,御道口地区平均产水深度与水源涵养深度分别为103.26,81.66 mm,产水量与水源涵养量呈现先减小后增加的波动变化趋势;空间均呈现东北高西南低的分布特征,高值区主要集中于东北林、草地区域,低值区则主要集中于未利用地与西南部耕地区域;(2)各气候要素中,产水深度、水源涵养深度与降水量呈正相关关系,与潜在蒸、散发量呈负相关关系;各土地利用类型中,草地的平均产水量贡献率最大(51.23%),林地的平均水源涵养量贡献率最大(50.77%);(3)1990—2020年,气候与土地利用变化对产水量变化的年平均贡献率分别为94.99%和5.01%,对水源涵养量变化的年平均贡献率分别为92.21%和7.79%,气候变化是御道口地区产水、水源涵养功能时空演变的主导因素,而土地利用变化的影响正在逐渐增强。     

美国EPA地表水质监测与评估的点位设计介绍

介绍了美国EPA地表水质监测与评估的点位设计。首先,指导性文件《基本水质监测方案》中的环境监测计划要求建立1个不少于1 000个点位的国家地表水质环境监测网,并提出了点位设计的标准,包括4点基本要求和针对每一类水域的具体要求。其次,另一指导性文件《准备州综合水质评估(305b报告)和电子升级:报告内容的准则》提出了1种新的对水质的综合性评估技术,要求在传统的判断点位设计的基础上增加概率统计点位设计方法。最后,全国一致的概率统计点位设计是相当有效的获知全国范围的水质情况及变化趋势的方法,EPA完全支持通过这种概率统计点位设计的方法来评估更多的水质状况。概率统计点位设计是EPA地表水质监测与评估的点位设计的发展趋势。     

Implications of Seasonal and Regional Abundance Patterns of Daphnia on Surface Water Monitoring and Assessment

The seasonal dynamics of Daphnia populations vary regionally throughout the United States. Within the general pattern, Daphnia increase in abundance after the initiation of the spring algal bloom in all lakes, but their subsequent seasonal patterns differ in various climatic regions. Lakes in regions with cooler summers have large-bodied Daphnia populations that tend to persist throughout the summer, although the species dominance may shift. Regions with warmer summers tend to have large-bodied Daphnia populations that decline or are absent through much of the summer. Still warmer water bodies tend to have medium- to small-bodied species that are abundant during spring, but absent most of the summer. Many central Florida lakes lack Daphnia; if Daphnia species are present, they tend to be small-bodied. Daphnia abundance in these water bodies varies, but seems to be independent of temperature.If surface water (lake, pond) sampling is done in all regions during July and August, the impression will be that Daphnia are absent from large segments of the United States. This would be erroneous, because Daphnia are important earlier during the spring and early summer but are likely to be absent during midsummer in some U.S. regions. Year-to-year variation will be superimposed on this regional pattern. Because there are differences in the dates when spring and summer occur, it would be useful to have an index period that would standardize the start of the growing season. The use of the terrestrial onset of greenness, based on remote sensing of the Normalized Difference Vegetation Index, is suggested as a possible index set point.     

2011—2021年全国地表水环境质量评价与变化分析

根据国家地表水监测网2011—2021年水环境监测数据,从全国、十大流域主要江河、重要湖库3个层面分析了我国地表水环境质量变化趋势及当前存在问题,并提出相关建议。分析结果显示,2011—2021年,我国地表水环境质量逐步改善。其中,2021年Ⅰ~Ⅲ类水质断面比例较2011年提高了35.2个百分点,劣Ⅴ类水质断面比例较2011年降低了11.4个百分点。高锰酸盐指数、氨氮和总磷指标浓度呈现明显的下降趋势;总氮呈现先降后升再降的变化趋势,且目前仍处于较高水平。长江、珠江、浙闽片河流、西北诸河及西南诸河流域水质优于淮河、黄河、海河、辽河及松花江流域。十大流域主要江河水环境质量均有所改善,改善幅度最大的是海河流域。重要湖库水质状况有所好转,但富营养化情况未有明显改善。年内水环境质量方面,夏季水质明显劣于其他季节,表明当前我国面源污染防治存在明显短板。建议在明确当前水环境质量改善取得积极成效的同时,也应当意识到我国水生态环境保护面临的结构性、根源性压力尚未得到根本缓解,不能停留在过去的以水环境质量改善为核心的污染治理思路上,应从生态系统整体性和流域系统性出发,坚持山水林田湖草沙生命共同体理念,从"三水统筹"的角度加强对水域生态系统的整体保护。     

地表水水质时空变化及其与土地利用响应研究

基于全国水质监测站点数据和Landsat 8 OLI数据,分析各个站点pH值、高锰酸盐指数、溶解氧和氨氮 4项水质参数的时空变化特征,采用冗余分析方法研究不同尺度缓冲区内土地利用类型对水质参数变异的解释能力。结果表明,大部分监测站点水质参数变异程度较小,水质状况良好;不同尺度缓冲区内土地利用类型对水质参数的影响不同,在1 200 m缓冲区内土地利用对水质参数的解释率最大;农业用地在300 m缓冲区内会使水质恶化,可在较大尺度上对水质有净化作用,林地和水域在一定程度上可以起到改善水质的作用,建设用地对水质有较大的负面影响。     

里下河典型区域渔业养殖水质及其对地表水环境质量影响分析

对渔业养殖水体进行监测分析，是评估养殖污染源对地表水环境质量影响的重要依据。选取里下河典型地区兴化市的养殖池塘和地表水断面作为研究对象，采用手工监测、相关性分析、三维荧光指纹和风险商值法等技术和分析方法，对养殖池塘和地表水断面水质开展研究。结果表明：养殖水体水质总体劣于地表水断面，养殖尾水排放达标率为89.7%，主要影响指标为pH值；Y1和Y2池塘对S1断面的高锰酸盐指数具有负面贡献；以养殖尾水为代表的农业源是影响S1断面水质的主要污染来源；地表水和养殖水体中林可酰胺类抗生素检出率均达100%，四环素类和头孢类抗生素在该地区养殖活动中的使用较多。风险商值法评估结果显示，Y2池塘养殖水体受磺胺甲恶唑影响的生态风险较高。     

梁子湖水体和沉积物中邻苯二甲酸酯分布特征及生态健康风险评价

对枯水期、平水期和丰水期梁子湖水体和沉积物中7种邻苯二甲酸酯(PAEs)的污染水平及分布特征进行了研究,并评价了其健康风险和生态风险.结果表明,枯水期、平水期和丰水期梁子湖水体中7种PAEs总量(∑PAEs)分别为0.10～3.56、0.16～1.78、0.57～2.16μg/L,沉积物中∑PAEs分别为0.10～0....     

离子色谱法测定地表水和饮用水中亚氯酸盐、溴酸盐和氯酸盐

采用KOH梯度淋洗离子色谱法测定地表水和饮用水中ClO2-、BrO3-和ClO3-,在试验确定的条件下,3种离子与F-、Cl-、NO2-、NO3-、SO2-4、Br-、I-等7种离子分离度良好。 ClO2-、BrO3-、ClO3-在50．0μg/L～1000μg/L范围内线性良好,检出限分别为5．2μg/L、8．9μg/L、7．6μg/L,环境水样加标平行测定的RSD分别为2．1％～5．4％、4．1％～5．4％、2．5％～4．8％,两个质量浓度水平加标的平均回收率分别为93．7％～96．5％、90．3％～94．8％、98．7％～111％。     

乌梁素海表层水中重金属元素的空间分布及生态风险评估

于2014年4月采集乌梁素海表层水样,利用地统计方法分析重金属元素Cd、Cr、Cu、Hg、Pb、Zn的空间分布特征,并通过计算元素的富集系数来分析其富集水平。结果表明:重金属元素具有相似的空间分布特征,除局部区域外均呈现出随水流方向从北到南递减的趋势,Cu在局部区域存在高值区,Pb在水流经10号采样点后质量浓度逐渐升高。元素的富集系数从高到低依次为HgCdCuZnCrPb,其中Hg富集非常明显,达到高等富集和很高富集水平,Cd在4号采样点达到中等富集水平,其他元素为不足最小富集水平。     

地表水自动与常规监测评价结果一致性对比分析

选择分布在不同流域的15个与自动监测站位置一致性较好的断面,对其进行为期1年的"同时同点位"对比监测.分析数据发现:由于采样时间和位置的偏差,自动监测月均值与常规手工监测数据的可比性并不理想.采用以下4种方法评价水质:自动5项、手动5项、手动21项、自动5项+手动16项.比较第1和第2种方法,水质评价类别相同与变化一类...     

中俄界河--黑龙江水环境分析与评价

采用“有机污染综合评价法”对黑龙江干流上、中游江水水质进行分析评价,分析与评价结果表明,黑龙江总体水质较好,主要污染物为高锰酸盐指数。