精河流域近56年气候特征分析

通过精河县气象站近56年观测的降水、气温、日照总量数据,分析了近56年来精河地区的气候变化特征.得出如下结论:①精河流域的降水有明显上升的趋势;气温也呈明显上升的总趋势,年、代际有较大起伏;年日照总量呈下降趋势,表明阴雨天增多,反应了新疆气候逐步向暖湿气候转型.②精河流域降水量年际变化的周期性振荡特征比较明显;气温年际变化的周期性振荡特征不太明显;日照总量周期性震荡比较明显.③精河流域全年的气温、降水和日照总量的相关程度并不高,随气温升高降水增加,降水升高日照总量降低.④气候的暖湿转型减少了研究区内沙尘暴天气的发生次数.     

2001—2021年黑龙江省森林植被生态质量变化分析

通过统计分析及空间插值等方法,使用气象和遥感数据,分析2001—2021年黑龙江省林区主要植被生长季的气候条件及植被生态质量变化特征。结果表明：2001—2021年黑龙江省林区生长季降水量、平均气温和日照时数分别呈增加、增加和减少趋势。在水分、热量整体逐步增加的背景下,气候条件有利于改善植被生态质量。2021年生长季大部分林区植被生态质量为优和良等级;与多年平均比较,85%以上的林区呈偏好趋势,尤其是中部、东南部部分林区呈很好趋势。植被生态质量指数平均每10 a增大43,99%以上的林区呈提高趋势,特别是北部、东南部及中部部分林区改善明显。     

近40年洞庭湖区地表景观演变及气候潜在响应特征

通过耦合多源遥感数据,研究1980—2015年洞庭湖区地表景观格局演变及其潜在气候响应特征。结果表明,洞庭湖区土地利用类型以耕地为主,占总面积63.67%;水体次之,占23.75%;草地最少,占0.15%。1980年以来耕地面积剧烈减少,减少342.71 km2;建设用地和水体面积呈上升趋势,分别增加278.16 km2和132.55 km2;土地利用转化方式以耕地向建设用地转化为主,转化面积232.70 km2;区域地表景观进一步破碎与复杂化。相关性分析表明,土地利用变化与降水相关性较弱,而与气温呈较显著的相关关系。此外,区域景观格局演变与气温上升呈较强的正相关关系。     

兰州城市大气颗粒物污染浓度的变化特征

通过对兰州市冬季不同高度大气气溶胶的监测数据的分析,得出不同高度气溶胶浓度分布,进而分析TSP和PM10与气象要素之间的相关性,以及近20年气溶胶浓度变化。结果表明,高度16m和9m处的TSP浓度比高度625m处的TSP浓度高,高度50m处的PM10比9m和625m处的PM10浓度高;16m高度的TSP浓度与日最高气温呈正相关,9m高度的TSP浓度和日最低气压、日最低气温、平均气温、平均风速都呈负相关,625m高度的TSP浓度与平均本站气压和日最低本站气压都呈负相关。同时9m高度处PM10浓度与日最高气温呈正相关,625m高度处PM10浓度与平均气温呈正相关。近20年的对比分析表明,兰州城市空气质量得到明显改善,"冬防"举措对于改善市区空气污染状况很有成效。     

重庆市北碚区空气质量改善效果评估分析

基于2014—2020年重庆市中心城区北碚区环境监测数据及地面观测气象要素，分析了北碚区大气污染特征，利用KNN算法建立大气污染的评估模型，对空气质量改善效果进行评估。结果表明，重庆市中心城区北碚区的PM_2.5浓度逐年呈明显下降趋势，O₃浓度除夏季有一个弱的下降趋势外，其余3个季节和年平均值整体均呈上升趋势。全年以优良天气为主且呈增加趋势。O₃与气温、日照时间呈正相关，与相对湿度呈负相关性，PM_2.5与气温、降水及风速呈负相关。基于KNN算法对空气质量改善状况评估表明，减排对O₃污染平均贡献率在-4.7%左右，对PM_2.5污染平均贡献率为-52%,气象条件对O₃污染的平均贡献率在17%左右，对PM_2.5污染的平均贡献率在-7%左右。该大气污染评估模型能够有效地评估空气改善效果。     

内蒙古呼和浩特市沙尘天气变化规律及防治对策

以呼和浩特市30年(1971~2000年)气象资料为基础,运用数理统计理论,分析了呼和浩特市沙尘天气的时间变化特征及其与降水量、气温、风速、相对湿度、蒸发量等气象因子的关系。结果表明,沙尘暴、扬沙、浮尘等沙尘天气在年代际、年际、季节与月变化上具有一致性。20世纪70年代沙尘天气发生的日数最多,从1970年代到1990年代沙尘天气发生日数总体上波动下降。沙尘天气的年际变化均以1972年最高,但不同沙尘天气发生日数最小值出现的年份不同,最小值为0天,2000年略有上升。沙尘天气呈现春冬季节发生日数多,夏秋发生日数少的季节变化趋势,每年的4月份沙尘天气出现最多,7、8或9月份沙尘天气出现最少。沙尘天气的发生与空气相对湿度、降水量呈现极显著或显著的负相关,与风速、蒸发量呈现极显著或显著的正相关,与气温变化关系不明显。在此基础上,提出了完善监测体系、加强生态环境建设等沙尘天气防治对策。     

拉萨市环境空气质量与气象特征分析

分析了拉萨市环境空气质量及其拉萨市的地理位置、地形地貌和气候特征的关系。研究结果表明 ,自然沙尘是拉萨市环境空气质量的主要自然源。月降尘量与降水、大风等有明显的相关关系。加快拉萨地区生态环境建设 ,增加植被覆盖率 ,减少沙源是改善拉萨市环境空气质量的关键     

上海市臭氧污染时空分布及影响因素

分析2006—2016年上海市的监测数据发现,臭氧(O_3)浓度存在逐年上升趋势,污染持续时间有所增加,但除水平风速有下降趋势外,其他相关气象因素的年际变化趋势并不显著。空间分析结果表明,上海市O_3超标主要集中在西南部郊区,但市区O_3超标潜势不容忽视。O_3污染高发季节的污染玫瑰图分析发现,上海市南部地区是影响上海市O_3污染的关键区域;对于NO_2减排的影响分析发现,尽管上海市O_3平均浓度总体处于上升趋势,但在NO_2下降幅度最为明显的内环市区和北部郊区,O_3上升幅度低于NO_2下降幅度较小的内外环区域和西部郊区,表明上海市的O_3污染控制仍需持续推进NOx的减排,并同步推进VOCs的减排。     

新疆气候暖湿化背景下干旱分布与演变特征

新疆是我国降水最少、产水能力最低的地区，自然灾害主要是干旱。本文基于实测降水、径流数据，依据全国第三次水资源调查评价形成的新疆降水、径流等值线图，形成干旱分布图，并构建年尺度面降水、径流系列。采用干旱分布图和系列数据，按不同空间尺度量化分析了研究区干旱状态和演变规律。新疆多年平均降水深为157.7 mm,单位面积产水量48.5 mm, 80%以上的面积属干旱、半干旱区，南疆较北疆干旱、山区相对湿润、平原干旱。在气候变暖的背景下，呈现不同程度湿化趋势，但气象干旱和水文干旱的气候形态并未发生改变。近30 a的相对丰水期，由于经济社会用水量的不断增加，加之高温导致的径流年际波动加剧，使新疆面临更为严峻的干旱形势。     

民勤县近50a来日照时数变化特征分析

利用民勤县气象站1960~2009年的逐月、逐季、逐年的日照时数观测资料,采用气候倾向率分析法对民勤县近50a日照时数的变化特征进行分析,得出民勤县近50a来日照时数的变化特征。结果表明:近50a来民勤县年日照时数总体呈增加趋势,在四季中,春、夏、秋、冬季日照时数均呈增加趋势并以春季和夏季增加幅度最为显著,变化趋势最为明显,对年日照时数的贡献率最大,秋、冬季增加幅度略小。近50a中民勤县年日照时数最多为2006年的3423.5h,最少为1975年的2763h,两者相差达660.5h,说明年日照时数的变化较大。     

河流沉积物中有机污染物的分析研究进展

总结了近年来河流沉积物中有机污染物的研究进展 ,集中评述了国内有关沉积物中多环芳烃、有机氯农药和多氯联苯的分析研究现状 ,包括样品采集、样品前处理和样品分析 ,并对今后河流、湖泊及水库沉积物中污染物的分析工作作了展望     

Trends in Nitrogen Transport in Swedish Rivers

Concern about nitrogen loads in marine environments has drawn attention to the existence and possible causes of long-term trends in nitrogen transport in rivers. The present study was based on data from the Swedish environmental monitoring programme for surface water quality; the continuity of these data is internationally unique. A recently developed semiparametric method was employed to study the development of relationships between runoff and river transport of nitrogen since 1971; the observed relationships were then used to produce time series of flow-normalised transports for 66 sites in 39 river basins. Subsequent statistical analyses of flow-normalised data revealed only few significant downward trends (p 0.05) during the time period 1971–1994, and the most pronounced of these downward trends were caused by reduced point emissions of nitrogen. The number of significant upward trends was substantially larger (15 for total-N and 18 for NO₃-N). Closer examination of obtained results revealed the following: (i) the most pronounced upward trends were present downstream of lakes, and (ii) observed increases in nitrogen transport coincided in time and space with reduced point emissions of phosphorus or organic matter. This indicated that changes in the retention of nitrogen in lakes were responsible for the upward nitrogen trends. The hypothesis that nitrogen saturation of forest soils has caused a general increase in the riverine export of nitrogen from forested catchments in Sweden was not confirmed. Neither did the results indicate that improved agricultural practices have reduced the export of nitrogen from agricultural catchments.     

Fluoride in groundwater in selected villages in Eritrea (North East Africa)

A study was undertaken to estimate fluoride content in thegroundwater in certain parts of rural Eritrea, North-East Africa,along the River Anseba. Standard procedure was adopted for fluoride detection. Results indicate elevated concentration offluoride in groundwater. The highest concentration was found tobe 3.73 mg L^-1, well above the safety level for consumption.Geological basis for the high concentration of high fluoride hasbeen established; it is presumed to be the pegmatite intrusion hosted by a granitic batholith. Extensive dental fluorosis has been observed in the population exposed to drinking water of highfluoride content.     

HPLC法测定饲料中维生素A、维生素D 3 和维生素E

建立了以w(C2H5OH)=95 %乙醇直接提取,高效液相色谱仪在波长280 nm和254 nm处连续测定饲料中维生素A、维生素D3和维生素E的方法.色谱柱为大连依利特Hypersil ODS C18(25 cm×4.6 mm×5 μm),流动相为甲醇-水,流速为1.2 mL/min.维生素A、维生素D3、维生素E的质量浓度分别在1.0 mg/L～20.0 mg/L、0.5 mg/L～15.0 mg/L 、2.5 mg/L～50.0 mg/L范围内与峰面积呈良好的线性关系,检测限分别为0.3×10-6 μg、0.04×10-6 μg、5.0×10-6 μg,相对标准偏差分别为1.6 %、2.7 %、2.4 %,平均回收率分别为99 %、102 %、98 %.     

丽水市空气中Pb污染调查

为调查丽水市空气中Pb污染现状，在机动车相对集中的市区布设5个测点，测点高度1．2m；监测周期为1a，每星期采样1d或2d，每天采集1个样，每次采样6h；监测项目为TSP、Pb；评价标准采用GB3095—1996《环境空气质量标准》。结果表明，丽水市各测点空气中Pb最大的季均值、年均值均未超标；常规测点和交通路口测点之间TSP、Pb质量浓度值均存在显著的差异性。     

Organochlorines and Mercury in Waterfowl Harvested in Canada

Samples of breast muscle from 32 species of waterfowl collected from 123 sites across Canada were analyzed for chlorobenzenes (CBz), chlordane-related compounds (CHL), hexachlorocyclohexanes (HCH), DDT, mirex, dieldrin, PCBs and mercury. ΣDDT, ΣCBz and ΣPCB were the compounds most frequently found above trace levels. ΣHCH and ΣMirex were detected the least often. Mercury was detected in all of the mergansers, over 50% of dabbling, bay and sea ducks, and in less than 2% of the geese analysed. The highest levels of contaminants were generally found in birds feeding at higher trophic levels such as sea ducks and mergansers. With the exception of a few samples of mergansers and long-tailed ducks from eastern Canada, which contained ΣPCB concentrations of 1.0–2.4 mg kg⁻¹, ΣPCB levels were less than 1 mg kg⁻¹ wet weight. Only one merganser from eastern Canada had a ΣDDT concentration (2.6 mg kg⁻¹ ww) which was greater than 1 mg kg⁻¹ ww. The highest ΣCHL (0.10 mg kg⁻¹ ww) was also found in mergansers from eastern Canada. Levels of total mercury in breast muscle were either low (< 1 mg kg⁻¹ ww) or below detection limits with the exception of a few samples of mergansers from eastern Canada which contained mercury concentrations of 1.0–1.5 mg kg⁻¹ ww. Health Canada determined that the organochlorine and mercury levels found in samples of breast muscle of ducks and geese analysed in this study did not pose a health hazard to human consumers and therefore these waterfowl were safe to eat.     

兰州市冬季和春季PM2.5金属元素浓度水平与分布

为了解兰州市大气PM2.5中金属元素的污染水平和分布,于2013年冬季和春季在兰州市区4个在线监测点进行PM2.5样品采集,利用ICP-MS分析金属元素浓度。结果表明,Pb、B元素含量高于200 ng/m3,V、Fe元素含量在100~200 ng/m3,其余元素含量低于100 ng/m3,其中Pb含量最高,平均含量达到373.8 ng/m3.各监测点元素含量在冬季和春季各有不同,整体上是冬季高于春季。金属元素在兰州市区的空间分布与兰州市工业排放和气象因素有关,工业排放为主导因素。     

中国1998年度环境质量状况

对我国１９９８年度的环境空气质量,酸雨,主要流域水质,近岸域海水水质,地下水水位与水质,城市声环境、射环境质量,典型区域生态环境的状况进行了综述了与分析,指出了我国的环境污染问题主要是城市空气污染,地面水体污染和城市噪声污染。     

Characteristic Air Temperature Distributions Observed in Summer and Winter in Urban Area in Japan

The air temperature distributions in August (summer) and December (winter) were measured in an approximately 15 × 15-km urban area in Hyogo Prefecture, Japan, in order to study the spatial distribution of the air temperature and to propose effective measures against the heat island phenomenon. The air temperature was measured mainly by using thermometer shelters installed in an elementary school and a junior high school. The characteristic air temperature distribution depended on the season. The air temperature was higher inland than in the coastal region in August but was higher in the coastal region in December. The air temperature index indicated that the area where higher air temperatures would most likely appear was 5 to 10 km inland from the coast in August and around the coast in December. The seasonal air temperature distribution was presumably due to the strength of solar radiation and anthropogenic exhaust heat.     

天津市空气颗粒物中酞酸酯的分布特征

采用气相色谱-质谱仪(GC-MS)对天津市空气颗粒物中15种酞酸酯(PAEs)夏季和冬季的浓度进行了分析测定,研究了酞酸酯污染水平的季节变化,不同季节酞酸酯的功能区差异,15种酞酸酯在颗粒物中的分布特征,以及DBP和DEHP在夏冬两季中的污染特点,分析了产生上述结果的原因,基本说明了天津市空气颗粒物中酞酸酯的污染状况和特点。