2013-2018年天山北坡短时强降水中小尺度特征

利用常规观测、自动站逐时雨量、新一代多普勒天气雷达和ERA-interim再分析等资料， 对2013-2018年6-8月天山北坡73次短时强降水过程的中尺度影响系统、对流风暴特征进行分析研究。结果表明：天山北坡短时强降水过程主要中尺度系统为低空急流、低空切变线或辐合线及地面中尺度高压前的辐合线；雷达回波形态分为合并加强型（占33.9%）、列车效应型（占39.0%）及孤立对流型（占27.1%）3类，其垂直剖面有“低质心”和“高质心”2种结构，且前者占多数；径向速度图上有81%的过程有逆风区。以集合箱线图25%百分位作为最低阈值，天山北坡短时强降水阈值为最大反射率因子强度≥46.5 dBZ、强回波中心（40 dBZ）顶高≥4.0 km、回波顶高ET≥8.6 km及垂直累积液态水含量VIL≥7.0 kg?m-2，并以典型个例进行分析。     

Quality of rainwater: A geochemical process of water-air-rock-life interaction

This paper discusses the quality of rainwater from a chemical-physical viewpoint, linking the acquisition of solutes to the interaction processes among different geochemical spheres. The role played by dust in the formation of raindrops and their stability is highlighted. Emphasis is also placed on the solubilization mechanisms of gases and solids responsible for the mineralization and acidity of atmospheric precipitation. The quantitative relationship between the pH of rainwater and its chemical composition is defined by the formulation of a geochemical model, which allows the initial pH of rainwater to be identified before that contamination, such as the addition of substances with high buffering capacity, changed their hydrogen ion composition.     

Influence of 850 mb trajectories on acid precipitation in southwestern British Columbia

Precipitation chemistry in southwestern British Columbia has been examined to determine if the shutdown of the ASARCO smelter in Tacoma, Washington in March of 1985 had a significant effect.The smelter emitted about 300 tonnes/day of sulphur dioxide and about one tonne/day of arsenic. The smelter had a supplementary control system (SCS) which was implemented during adverse meteorological conditions to meet ambient air standards. The SCS was in operation in October 1984.Five storms from October 1984, before the shutdown, that produced precipitation over the eight-station network in southwestern British Columbia, were considered. The 850 mb back trajectories and ionic loadings in the collected precipitation samples were compared. A similar comparison was made for three storms in October 1985, after the shutdown of the smelter. An examination of cases whose trajectories passed over the smelter before and after the shutdown indicated an over 50% decrease in volume weighted average sulphate concentration in precipitation over the Gulf Islands (islands in the southern Strait of Georgia). However, when the trajectory from the northwest passes over British Columbia coastal sources, higher excess SO₄ concentrations were observed in the precipitation over the Gulf Islands, indicating a linkage between these concentrations and the British Columbia coastal sources. There was no apparent change in values at stations farthest from the Strait of Georgia with one exception. It was also noted that there was reduction in arsenic in precipitation, which could be considered as a tracer, after the shutdown of the ASARCO smelter. This paper enlarges on the above observation with comparisons of the major meteorological and chemical characteristics related to eight storms.     

应用GIS进行生态系统对酸雨的相对敏感性分析

对我国东部７省１市进行了生态系统对酸雨的相对敏感性分析。采用ＧＩＳ作为空间分析的工具，综合分析了基岩类型、土壤缓冲能力、植被和土地利用方式，以及土壤水分盈余量等多种要素对酸雨的敏感性。     

Fuzzy modelling of acid mine drainage environments using geochemical,ecological and mineralogical indicators

Fuzzy logic was applied to model acid mine drainage (AMD) and to obtain a classification index of the environmental impact in a contaminated riverine system. The data set used to develop this fuzzy model (a fuzzy classifier) concerns an abandoned mine in Northern Portugal—Valdarcas mining site. Here, distinctive drainage environments (spatial patterns) can be observed based on the AMD formed in the sulphide-rich waste-dumps. Such environments were established, as the effluent flows through the mining area, using several kinds of indicators. These are physical–chemical, ecological and mineralogical parameters, being expressed in a quantitative or qualitative basis. The fuzzy classifier proposed in this paper is a min–max fuzzy inference system, representing the spatial behaviour of those indicators, using the AMD environments as patterns. As they represent different levels (classes) of contamination, the fuzzy classifier can be used as a tool, allowing a more reasonable approach, compared with classical models, to characterize the environmental impact caused by AMD. In a general way it can be applied to other sites where sulphide-rich waste-dumps are promoting the pollution of superficial water through the generation of AMD. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Analysis of rainfall-induced infinite slope failure during typhoon using a hydrological–geotechnical model

Rainwater infiltration during typhoons tends to trigger slope instability. This paper presents the results of a study on slope response to rainwater infiltration during heavy rainfall in a mountain area of Taiwan. The Green-Ampt infiltration model is adopted here to study the behavior of rainwater infiltration on slopes. The failure mechanism of infinite slope is chosen to represent the rainfall-induced shallow slope failure. By combining rain infiltration model and infinite slope analysis, the proposed model can estimate the occurrence time of a slope failure. In general, if a slope failure is to happen on a slope covered with low permeability soil, failure tends to happen after the occurrence of the maximum rainfall intensity. In contrast, slope failure tends to occur prior to the occurrence of maximum rainfall intensity if a slope is covered with high-permeability soil. To predict the potential and timing of a landslide, a method is proposed here based on the normalized rainfall intensity (NRI) and normalized accumulated rainfall (NAR). If the actual NAR is higher than the NAR calculated by the proposed method, slope failure is very likely to happen. Otherwise, the slope is unlikely to fail. The applicability of the proposed model to occurrence time and the NAR–NRI relationship is evaluated using landslide cases obtained from the literature. The results of the proposed method are close to that of the selected cases. It verifies the applicability of the proposed method to slopes in different areas of the world. An erratum to this article can be found at     

低空急流对广西热带气旋特大暴雨的影响及概念模式

利用ncep再分析资料,对1990～2003年期间,广西14次热带气旋特大暴雨过程进行850hPa低空急流的合成分析,结果指出:广西热带气旋特大暴雨的产生伴随着中南半岛西南急流的增强,西南急流是暴雨增幅的主要水汽和能量输送系统。另外,结合大尺度环流系统的分析给出广西热带气旋特大暴雨的概念模式。     

Spatiotemporal Continuity of Sequential Rain Suggested by 3-D Variogram

A series of rainfalls observed in central Japan from noon on the 13th to midnight on the 14th, August 1999 (36 h), has been analyzed by spatiotemporal variograms in order to reveal the continuity of rain precipitation in a 3-D space defined by geographic coordinates and time. All instances of zero precipitation are considered, but have been treated as four different cases: case 0 excludes all zero data, case 1 includes a zero datum neighboring to each finite value, case 2 includes a zero neighboring to each finite value and the next neighboring zero, and a fourth case (termed case A) includes all zeros. Hourly precipitation has a statistical distribution best approximated by a Weibull model, and somewhat less well by a normal distribution, in all four cases. A rectangular variogram of measured values of total precipitation shows that the best continuity appears approximately along the N-S direction (the ranges given by directional variograms are 500 and 80 km in the N-S and W-E directions, respectively). In contrast, temporally stacked rectangular variograms of hourly precipitation shows that the best continuity direction is W-E in all cases (the ranges in case A are 50 and 100 km along the N-S and W-E directions, respectively). A spatial variogram gives a spatial range independently of time, whereas a temporal variogram gives a temporal range. When geographic coordinates are normalized by the spatial range (here 80 km given by the temporally stacked omnidirectional variogram in case A), and time is normalized by the temporal range (here 7 h given by the spatially stacked temporal variogram), geographic coordinates and time can be treated as equivalent variables. Consequently, a spatiotemporal variogram can be calculated along a given direction in 3-D space using the normalized coordinates. The continuity direction of a series of rainfalls can be best understood by display on a Wulff net, where each range value is written at a point corresponding to the direction. The direction of the best continuity is N0°W+20° in the normalized space. A rectangular variogram in the normalized space, in which the horizontal and vertical axes represent N-S direction and time, respectively, suggests that the series of heavy rainfalls examined here had a continuity pattern that was elongated from west to east (the range values are 20–30 km and 100 km along N-S and W-E, respectively), and that migrated from south to north with a speed of 30 km/h.     

高原逗点云团与江南暴雨

本文主要是利用水汽图像和ＨＬＡＦＳ数值模式计算方法从定性到定量地研究１９９８年６月１２日￣１４日江南北部的一次大暴雨过程。通过云系路径的分析和发展的定量研究,我们可清楚看到影响江南北部这次大暴雨过程的天气系统,是从青藏高原东移的。其中,特别是该系统（气旋）东移到暖湿的海而时得到了大量第表面水汽蒸发补充,水汽上升凝结潜热释放,促使气旋迅速发展。     

2004—2008年辽宁酸雨时空分布特征研究

根据2004-2008年辽宁22个酸雨监测站的统计资料,对近年辽宁酸雨的时空分布特征进行分析和探讨。结果表明：2004—2008年,pH年平均值范围为5.49—6.62,呈逐年降低、酸雨强度逐年增强的趋势;酸雨主要发生在大连、本溪县和丹东及兴城地区,其中大连酸度最强;建平县最弱;辽宁酸雨有明显的季节变化,pH值以夏季酸度为最强,春季为最弱,酸雨出现频率以秋季为最高,春季为最低。