西宁市近三十多年来大气能见度变化特征分析

利用青海省西宁站1981年1月—2016年12月间各月地面能见度等资料,对比分析了该站大气能见度的日、季节及年际变化特征,并指出了两种不同观测方法之间的差异。分析表明:人工观测较仪器观测值平均高近66%;人工观测和仪器观测值日变化曲线基本一致,均表现为单峰单谷型,即为明显的正弦波型日变化特征;人工观测和仪器观测各月能见度均值同样均表现为单峰单谷型,夏初前后为全年高值时段,12月前后为全年低值时段;西宁近三十多年来能见度总体呈下降的趋势,有明显的高低值段区分;当出现天气现象特别是霾、雾、浮尘、扬沙、尘卷风、沙尘暴、雨、雪等时会降低大气的能见度;能见度受相对湿度的影响是显而易见的,两者呈明显的负相关。     

河北海岸带大雾特征分析及天气概念模型

利用2001—2010年乐亭、秦皇岛大雾监测的252个个例及Micaps3．0常规资料,分析了河北海岸带大雾的时空尺度分布特征,初步建立大雾天气概念模型。研究结果显示：2001—2010年大雾年际变化不大,2005年达到日数最少为17次,2006年达到最多为34次;大雾日具有明显的月变化,一年当中各月均有大雾出现,其中以11~12月大雾日数最多,8~9月次之,其他各月较少;南到东南风、弱的均压场、适宜的海温均有利于产生大雾天气。     

秦皇岛雷暴天气的时空尺度分布与雷电灾害分析

利用2003-2012年3～10月秦皇岛地区5个气象站雷暴监测和雷电灾害资料,采用数理统计、天气综合分析方法,得出秦皇岛地区雷暴天气的时空尺度分布特征为：全区年雷暴发生频次总体上呈递减趋势,其中,2005年35次,2008年33次,2012年20次;6月份为全年雷暴发生的峰值时段,7月、8月次之,且与秦皇岛本地主汛期相吻合;在海岸带地区由于受海洋条件影响,个别年份雷暴最早出现在2月份,最晚出现在11月中旬;雷暴天气的日时段主要出现在下午至傍晚,占70%,夜间占20%,其他时段为10%;北部山区的雷电频次大于沿海地区,对应电力、化工等行业雷电灾害呈下降趋势,但是通讯、计算机、家电等弱电系统雷击事件呈递增趋势。     

基于测点空间加密的青海省大通河流域汛期降水分布特征分析

利用大通河流域及其周边附近地区地面2017年6～9月汛期国家基本站、国家天气站和国家区域站降水资料,分析总结了大通河流域汛期降水时空分布特征。得到大通河流域自动气象站点加密后,最大降水中心和降水量发生了明显的变化;流域汛期逐月降水空间分布特征地区差异明显;降水随着海拔高度的变化,汛期旬降水量的变化不同,旬降水开始时间、结束时间和持续时间也不同;流域降水中心均出现在国家天气站和国家区域站中。通过分析大通河流域汛期测点加密后降水分布特征,可为大通河流域降水精细化预报服务提供有价值的参考指示意义。     

青藏高原东北部地区大气臭氧变化特征

利用TOMS资料分析了青藏高原东北部共和地区大气臭氧近十几年的变化特征。结果表明：1979－1992年期间,共和地区臭氧总量呈现出不断下降趋势,平均气候倾向率为－0．65DU／a,各月臭氧总量均为减少趋势,各月臭氧总量的气候倾向率具有明显的季节变化;冬春季最大,秋季次之,夏季最小,春、夏、秋和冬季臭氧总量的气候倾向率分别平均为－1．00DU／a、－0．33DU／a、－0．38DU/a和－1．03DU／a;夏季出现臭氧总量低于280DU的天数在30d以上,1986年臭氧低值持续时间达81d左右,是持续时间最长的。     

鹤望兰生态适应性及塑棚保温效果计算模式

根据鹤望兰生态条件,用5日滑动平均法普查成都气候资料,得出适宜时段为4月下旬～7月中旬和8月下旬～10月下旬,冬季低温和夏季中午高温为不宜时段,提出了塑料大棚热效应和增温比计算模式,对不同棚型、不同天气的保温效果进行了比较.     

陕,甘,宁,青干旱序列年表及其气候特征

根据历史文献记载和气象观测资料，事理了近２００年西北上省（区）旱涝连年表，并对近２００年的旱涝进行了气候统计分析，结果表明：近２００年以来出现过三个干旱时期，三个多雨时期，平均１０．３年发生一次大旱，４．３年发生一次一般干旱，１９９１年开始可能进入一个新的干旱时期。     

让所有的生命都欢唱——5月22日国际生物多样性日

如果把地球四十五亿年演化史压缩成一天二十四小时的话，人类出现在那个时段？上午四点钟出现了最简单的单细胞生物，但是在此之后的十六个小时里—直很平静；直到晚上八点三十分，也就是这一天过去了差不多六分之五的时候，才出现了最初的微生物，然后出现了海生植物；二十分钟以后，出现第一批水母；晚上九点零四分，三叶虫登场；快到晚上十点钟的时候，植物开始出现在大地上；     

近50年新疆沙尘暴频率时空变化趋势分析

采用新疆54个气象站近50年的气象资料,分析新疆沙尘暴时空分布特征、年际和年内演变趋势及年际演变的影响因素。结果显示：新疆沙尘暴近50年以来空间分布特征是南疆多于北疆,沙尘暴主要出现在3～10月,其中4～7月为高发时段。年际演变趋势20世纪80年代以来较60、70年代都有所减少;80年代以后沙尘暴发生日数减少。     

吐鲁番防护林的气象效应

前人对吐鲁番农田防护林的防护效益曾有过许多观测研究，但缺少年周期变化的气象效益观测结果。通过利用吐鲁番红族治沙站农田林网内和旷野建立的气象观测站点收采的全年观测资料，分别选择春季、冬季和风季各一个月的气象资料，对有防护林网保护和无防护林网保护的气温、地表温度和风速的变化进行对比分析证明，防护林网改善小气候的作用随季节变化而发生变化。其中，防风效果最为显著，风速为１６．２ｍ／ｓ时，株网内风速可降低６１．８％－７５．４％；风速为２．０ｍ／ｓ时，林网内风速降低９０％左右或无风。林网对气温调节随节发生变化，１月增温，７月降温，而３月风季的前半月有增温作用，下半月却不明显。但各月增降的幅度不大。林网在各月对地表温度普遍都有提高，其中５月提高幅度最大可达２０℃左右。     

新安江-钱塘江流域水环境健康风险评价研究

本文采用美国环境保护署推荐的水环境健康风险评价模型,对新安江—钱塘江流域水体通过饮水途径导致的人体健康风险进行评价。结果表明:水环境质量监测的11项污染物浓度均符合或优于地表水三类标准。对人体有健康风险的有毒污染物主要是化学致癌物Cr(Ⅵ);非致癌物中氨氮的健康风险最大;个人化学致癌物年总风险远大于非致癌物年总风险;2014年新安江—钱塘江流域的三都大桥断面、西区、闸口、七堡断面的水环境健康个人总年风险均超过国际辐射防护委员会推荐的标准,分别超标0.03、0.69、0.20、0.23倍,其主要原因是这些断面的Cr(Ⅵ)的风险略高。因此,加强对化学致癌物Cr(Ⅵ)的管控,是降低水环境健康风险的有效途径。     

沱江上游（绵远河,石亭江）环境水文条件分析

本文对无实测水文资料的平原水网区使用水文比拟法进行环境水文条件分析并提出有效的处理方法及合理的成果。     

拯救母亲河

一条大河波浪宽,风吹稻花香两岸。这是无数长江人对于长江的记忆。那时的感觉是,生活在长江边真幸福。然而,时光轮转,时过境迁,在沿江开发热潮和GDP高歌猛进的冲击下,负重的长江也变脏了。     

River Habitat Quality from River Velocities Measured Using Acoustic Doppler Current Profiler

Prior research has demonstrated the utility of metrics based on spatial velocity gradients to characterize and describe stream habitat, with higher gradients generally indicative of higher levels of physical heterogeneity and thus habitat quality. However, detailed velocity data needed to compute these metrics are difficult to obtain. Acoustic Doppler current profilers (ADCP) may be used to rapidly collect detailed representations of river velocity fields. Herein we demonstrate use of ADCP to obtain ecologically relevant data and compute associated metrics. Data were collected from four reaches of the Little Tallahatchie River in northern Mississippi. Sampled reaches were selected to observe velocity regimes associated with three distinctly different conditions: downstream from a major flow obstruction (a low weir), downstream from the apices of each of two bends, and within an extremely long, straight reach created by channelization. Three-dimensional velocity data sets from each site were used to compute metrics of habitat quality proposed by others. A habitat metric based on the presence of rotational flow in the vertical plane proved to be the best discriminator among conditions within the sampled reaches. Two of four habitat quality metrics computed from these measured velocities were greatest for the sharpest meander bend. ADCP hold great potential for study of riverine physical aquatic habitats, particularly at the reach scale. Additional work is needed to develop generally applicable field protocols and data reduction tools. Specifically, guidelines for ADCP settings and configuration appropriate for a range of riverine site conditions must be developed. Advances in instrumentation are needed to allow collection of information in closer proximity to the free surface and solid boundaries.     

Impediments to River Rehabilitation

Rehabilitation of river ecosystems is generally initiated when a river is no longer able to provide benefits to humans and other living beings. The major purposes of river rehabilitation projects are improving water quality, conserving nature, rehabilitating fisheries and riparian habitats, flood mitigation, and creating recreational opportunities. For a river rehabilitation project to be successful, it must have specific and clearly explained objectives, although these objectives will vary for each project depending upon factors such as economics, public demand, ecosystem benefits, and the like. In this article, we provide a critical analysis of the purposes that drive river rehabilitation projects and we identify and discuss impediments that can cause a project to deviate from its intended goals. We also discuss major constraints on rehabilitation efforts that can result in failed projects.     

Establishing a Context for River Rehabilitation, North Fork Gunnison River, Colorado

Initial river rehabilitation efforts along the North Fork Gunnison River in Colorado focused on the use of in-stream structures and channel stabilization to create a single-thread channel with pools along a braided river. These efforts were based on the assumption that the river’s braided planform results primarily from land use during the past century. In order to establish a context for further rehabilitation, we evaluated the possibility that the river might be braided as a result of processes independent of land use. We estimated volume, grain-size distribution, and lithology of sediment sources along the river corridor and evaluated the planform stability of the river during the past century using historical sources, aerial photographs covering 1939–1997, and comparison of bankfull discharge and gradient in the study area to values published for braided and meandering rivers. Our results indicate that the North Fork Gunnison River has been primarily braided in its lower reaches during the past few hundred years, although the channel planform tends toward a single-thread channel during decades of lower precipitation and discharge. Although land use is not the primary cause of braiding along the North Fork Gunnison River, it has decreased channel stability, and rehabilitation efforts should be designed to reduce these effects. Our results illustrate the importance of planning river rehabilitation measures within a historical context that accounts for both catchment-scale and reach-scale controls on channel processes and planform.     

同饮一江水 共护母亲河

2011年7月27日,皖浙青年手牵手“同饮一江水、共护母亲河”活动在黄山市启动,本刊记者随队参加了为期四天的活动。新安江发源于安徽黄山市境内,地跨皖、浙两省,流域总面积达11674平方公里。得天独厚的一江水,养育了一代又一代的两岸人,     

河流污染的生态治理研究——以甘肃省藉河为例

河流污染是我国水资源的突出问题之一。以甘肃省藉河为例,应用植物群落自然净化水质的原理,采取功能分区的方法,对西北地区城市河流的污染提出了具体的治理方案：将藉河城区段主要分为上游生态过滤区、中游生态景观区、下游生态净水区,然后分区进行具体设计。此研究方案是藉河一期改造工程的一部分,目前“一期”工程已完工,取得了较好的生态与经济效益。     

Libya's Great Manmade River Project

When completed, Libya's Great Manmade River Project will transport through a system of pipelines 12–14 million m³ of water per day from the southern region of the country to the northern coastal areas. The system will provide water for municipal, industrial and agricultural users. This paper describes the project, the uses to which its water will be put and the institutional issues which need to be addressed when the Great Manmade River Project delivers vast quantities of water to the coastal areas. The biggest problem for Libya could be finding and training the vast numbers of technical people needed to manage and operate the system.