降温降水对池塘水环境影响及诱发鳜鱼疾病的研究

探讨气候变化（降水、降温）与养殖鳜鱼（Ｓｉｎｉｐｅｒｃａ ｃｈｕａｓｔｓｉ）池溏主要水生态因子关系问题。结果表明，降水、降温会引起藻类种群的改变，进而溶氧变化，最终影响鱼的健康，低溶氧是诱发鳜鱼疾病的首要水化因子。所以，气侯变化是生态因子变化继而诱发鳜鱼疾病的催化剂。水中营养盐浓度影响藻类生长。     

Acid drainage from sulfides hosting gold mineralization (Furtei, Sardinia)

 The past mining activity for kaolin minerals left several abandoned quarries in the area of Furtei (southern Sardinia). Recently, gold mineralization has been found in association with intensely altered andesitic rocks, and an open-pit gold mine is expected to open in the near future. Twenty-one water samples were analyzed for a wide range of major and trace elements, in order to define the present hydrochemical situation before exploitation starts. Waters interacting with the altered andesitic rocks had higher salinity and metal concentrations than waters in contact with nonaltered rocks. Acid drainage and high concentrations of metals (Al, Fe, Mn, Zn, Cu, As) in solution were observed in waters leaching the mineral deposit. An environmental impact study is urgently called for since the waste material derived from the exploitation is expected to enhance acidification and metal-releasing processes, due to the increase in the specific yield, which favors the oxidation of sufide minerals. Received: 15 February 1995 · Accepted: 10 October 1995     

Partitioning of rainfall in a eucalypt forest and pine plantation in southeastern australia: II stemflow and factors affecting stemflow in a dry sclerophyll eucalypt forest and a pinus radiata plantation

Stemflow of a dry sclerophyll eucalypt forest and a nearby Pinus radiata plantation was studied on a rainfall event basis. The stemflow yields of the forests are quantified, compared, and presented on an annual basis for four years. Yields of the individual eucalypt species are compared and the tree characteristics responsible for the yield differences are discussed. The influence of event size, type, and season on stemflow are also shown. Rainfall angle is shown to have a significant effect on stemflow yield.     

Freshwater mollusc biodiversity and conservation in two stressed Mediterranean basins

This paper reviews the environmental factors that influence biodiversity of freshwater mollusc communities and conservation status of watercourses in two Mediterranean acid mine drainage-impacted basins of the southern Iberian Peninsula. We found 17 mollusc species: 14 gastropods (10 native and 4 introduced) and 3 bivalves. We found five distribution patterns: native headwater (Arganiella wolfi, Stagnicola palustris, Unio delphinus, Pisidium casertanum and Pisidium personatum) and mouth (Hydrobia acuta, Peringia ulvae and Myosotella myosotis) sensitive-stenochoric species, intermediate sensitive-widely distributed species (Planorbarius metidjensis and Radix balthica), insensitive-eurychoric species (Ancylus fluviatilis), and erratic-distribution pattern species (Galba truncatula and Planorbis carinatus). The highest biodiversity indices have been found in non-impacted headwaters and, to a lesser extent, in tidal streams. The biodiversity of the middle reaches, with varying degrees of impact by acid mine drainage and high water deficit, was scarce and dominated by introduced species. Over 30% of the variation in native and introduced species richness is explained by environmental gradients related to heterogeneity (instream macrophytes cover and Fhi and Qbr indices) and acid runoffs (pH, conductivity, turbidity and concentration of sulphides). Severely impacted sites have no mollusc species. The conservation status of watercourses is also very remarkably influenced by the heterogeneity and contamination of the environment. Conservation values are higher in water bodies located in protected northern and southern sites in both basins.     

Metal concentrations in water and sediments from tourist beaches of Acapulco, Mexico

A survey on the metal concentrations (As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, V, Zn) in beach water and sediments is reported from the tourist destination of Acapulco city on the Pacific coast of Mexico. The concentration of dissolved trace metals (DTMs) in beach water and acid leachable trace metals (ALTMs) in sediments indicated that they are anthropogenic in nature due to the increased tourist activities in the crowded beach locations. The statistical analysis indicates Fe and Mn play a major role as metal scavengers in both the medium (water and sediment) and the higher value of other metals is site specific in the study area, indicating that they are transported from the local area. Comparison results suggest that the beach water quality has deteriorated more than the sediments and special care needs to be taken to restore the beach quality.     

Characterization of acid sulfate soils and assessing their impact on a humic boreal lake

Due to acidity and metals from acid sulfate soils (a.s. soils), many watercourses in midwestern Finland have since 1960s regularly experienced short but intensive periods of poor water quality during high water flow. This has led to occasional massive fish kills and a significant decline in fish populations.     

Advances in Measurement Techniques and Statistics Features

Rain Drop Size Distribution (DSD) is one of the key parameters to micro physical process and macro dynamical structure of precipitation. It provides useful information for understanding the mechanisms of precipitation formation and development. Conventional measurement techniques include momentum method, flour method, filtering paper, raindrop camera and immersion method. In general, the techniques havelarge measurement error, heavy workload, and low efficiency. Innovation of disdrometer is a remarkable progress in DSD observation. To date, the major techniques are classified into impacting, optical and acoustic disdrometers, which are automated and more convenient and accurate. The impacting disdrometer transforms the momentum of raindrops into electric impulse, which are easy to operate and quality assured but with large errors for extremely large or small raindrops. The optical disdrometer measures rainfall diameter and its velocity in the same time, but cannot distinguish the particles passing through sampling area simultaneously. The acoustic disdrometer determines DSD from the raindrop impacts on water body with a high temporal resolution but easily affected by wind. In addition, the Doppler can provide DSD with polarimetric techniques for large area while it is affected by updrafts, downdrafts and horizontal winds.DSD has meteorological features, which can be described with the Marshall Palmer (M-P), the Gamma, the lognormal or the normalized models. The M P model is suitable for steady rainfall, usually used for weak and moderate rainfall. The gamma model is proposed for DSD at high rain rate. The lognormal model is widely applied for cloud droplet analysis, but not appropriate for DSD with a broad spectrum. The normalized model is free of assumptions about the shape of the DSD. For practical application, statistical comparison is necessary for selection of a most suitable model. Meteorologically, convective rain has a relatively narrow and smooth DSD spectrum usually described by the M P model. Stratiform rain has a broad DSD spectrum described with the Gamma model. Stratocumulus mixed rain has relatively large drop diameter but small mean size usually described by the Gamma model. The continent rainfall is altitude dependent and it differs from the maritime cloud rainfalls in terms of rain rate and drop diameter. Overall, the meteorological features are useful to improve our understanding of precipitation formation but also important to development of precipitation retrieval techniques with a high accuracy.     

松辽盆地营城组两类酸性火山岩地球化学特征与成因

松辽盆地断陷期营城组发育一套厚层火山岩,钻井岩心及薄片观察发现,火山岩以流纹岩、英安岩、流纹质凝灰岩及熔结凝灰岩等酸性火山岩为主,中基性岩相对较少。在对样品精细挑选基础上,开展了岩石主量元素、微量元素及Sr-Nd同位素测试分析。结果显示,该套酸性火山岩依据TiO2含量可明显分为两类,其中高Ti酸性火山岩(TiO2>0.45%),规模较小,SiO2含量介于64.87%～68.79%之间,其主量元素、微量元素与亚碱性中基性岩呈连续变化趋势且具有相似的Sr-Nd同位素组成;低Ti酸性火山岩(TiO2<0.4%)SiO2含量为68.93%～76.69%,该类岩石为营城组酸性火山岩主体,与碱性基性岩呈双峰式组合,元素含量及同位素比值变化范围较大。研究表明,两类酸性火山岩的形成都与晚中生代东北地区受古太平洋板块俯冲引起的岩石圈拆沉减薄软流圈上涌有关。在板块俯冲影响下,被富集的亏损地幔源区发生部分熔融,在岩浆演化过程中经历了一定分离结晶作用形成了少量高Ti酸性火山岩岩浆。与此同时,在底侵作用下新生地壳与下地壳物质发生混合熔融,受上地壳不同程度混染后形成了大规模的低Ti酸性火山岩岩浆。     

伊宁市1991-2011年降雨特征分析

利用1991～2011年5～9月伊宁市气象站逐小时降水资料,分析了伊宁近21a降雨特征。结果表明,21a来伊宁雨日年际变化较为明显,后10a和前10a相比,中雨、大雨和暴雨日数均出现增加,但小雨日数明显减少导致总雨日出现了减少。小雨过程发生最多的时段是7月中旬,中雨和大雨过程最多时段同在5月下旬。前半夜为中雨、大雨、暴雨过程最易发生时段,后半夜为小雨过程最易发生时段。逐小时降水量和降水频次呈现较为一致的日变化特征,夜雨多且雨量集中。伊宁的降水主要以短时性降水（1～4h）为主,多发生在前半夜至后半夜,1h降水频次最多的是量级≤1mm的降水,但1.1～3mm量级的降水贡献率最高。     

沈阳城区一次暴雨过程的水汽条件分析

利用Micaps实况资料、东北区域中尺度数值模式分析场资料和常规观测资料,对2013年8月16日沈阳城区暴雨的水汽条件进行了分析。结果表明：850 hPa以下城区上空水汽含量占整层的80％以上,地面比湿呈现快速增加后减少的变化,比湿峰值对应的并不是强降水的最强时刻。强降水发生前,城区地面周围的湿度分布不均匀,水汽输送主要以南北向为主。比湿的迅速增加主要是由于降水前风向和风速的快速变化,其中主要是南风分量的贡献。城区上空垂直方向上水汽主要是850 hPa向上输送,850 hPa以下输送强度逐渐减弱。伴随着强降水的开始,水汽的垂直输送转为高度层越低,输送强度越大。强降水发生时,地面U、V方向上水汽通量快速减小。强降水发生后,地面和高空水汽输送均发生了变化。大气可降水量与降水量之间具有一定的对应关系,可降水量的大小主要是取决于水平水汽通量辐合的大小,水汽局地变化对可降水量的贡献较小。水汽通量的辐合、辐散的大小主要取决于水平风场引起的辐合、辐散的大小。