降水酸度和化学组分垂直监测的初步分析

1986年6—9月,在无锡市近郊的锡惠公园内,在三个不同的高度上进行降水的同步采样,并对雨水的酸度、电导率和各种离子的含量作了测定。结果表明:降水酸度随着高度的增加而增强;电导率和雨水中离子的浓度则随着高度的增加而减小;通常上层减小得慢,下层减小得较快。碱性阳离子的结构在不同的高度上有明显的差异。另外,雨水对大气中污染物的冲刷作用,是一个重要的清除过程,下层比上层的冲刷作用更强。     

城市降水酸度分布与气溶胶水冲刷

在湖南省邵阳市工业区测量表明,该区颗粒物含量处于相当高的水平,颗粒物的主要水溶性成分为Ca~(2 )、SO_4~(-)、NO_3~-、NH_4~ 和Na~ 。Ca~(2 )在大颗粒(dp>9.0um)富集度最高,而SO_4~(2-)在小颗粒(dp<2.0um)中最丰富。所有尺度的颗粒都具有中和酸的能力,随粒径增大而提高。讨论表明,颗粒物水冲刷对雨滴化学成分和酸度的影响对直径小于2000um的雨滴是相当灵敏的,这种影响主要由大颗粒提供。讨论结果与降水成分的监测资料相一致。气溶胶水冲刷机制有效地解释了城市酸雨频率的规律分布。     

2006年“珍珠”台风影响期间福建省降水酸度分布特征分析

利用2006年"珍珠"台风影响福建省期间的酸雨监测资料和新一代天气雷达回波资料,对城市降水酸度分布特征及福州市短时段降水酸度进行分析,结果表明:来自海上的台风降水呈偏碱性;登陆后台风对福建省城市降水酸度的影响与其螺旋雨带上降水云团的移动路径及城市周边污染源分布有关;"珍珠"台风的短时段降水酸度并非保持恒定,对福州市降水酸度的影响会随着台风强度、风场结构的变化及螺旋雨带上降水云团途经下垫面城市大气污染排放状况而发生改变.     

福建高山、重点城市春季TSP对降水酸度的影响

利用福建九仙山和福州市两地监测的TSP资料,对高山、重点城市的TSP酸碱特性和酸化缓冲能力进行分析研究。结果表明,九仙山、福州市的TSP均为酸性颗粒物,是福建省春季酸雨的致酸因子之一,福州市的TSP致酸性能比九仙山的弱。     

华南低涡内部流场与降水分布

对有、无暴雨的两次华南低涡的流场与降水分布进行了对比分析。在此基础上，结合对一次相似的带有暴雨的西南涡过程的分析，提出了华南低涡的流场结构特征和暴雨分布形式。     

黑潮海温与我国汛期降水及东亚高空流场的统计分析

本文利用月平均资料对黑潮海表水温与我国汛期(5—8月)降水进行了相关分析,指出前期(1至4月)海温与汛期降水相关场大致呈稳定的纬向分布。对海温与东亚低阶流场谱分析表明,该海域海温对西太平洋副高强度的滞后响应较明显。     

2008年奥运会减排期间北京地区降水酸度监测及成因探讨

奥运会期间北京地区降水酸度分析：2008年7月20日至8月20日减排期间,北京地区3个酸雨监测站（密云的上甸子、北京观象台和昌平）的降水酸度为1993年以来历史同期最强,酸雨频率和强酸雨频率也达到了一个历史高值,酸雨量与总降水量的比值接近100％。仅8月1～20日期间,     

爆炸影响雹云流场实例分析

应用XDR—WRDPS测雨雷达获取的外场防雹作业个例演示的雹云流场,探寻爆炸对雹云流场影响的证据,改进爆炸作业方式。     

夏季我国高原植被气候效应的数值研究Ⅰ：模式及降水,流场…

在颜宏模式中加入植被参数化方案、并针全国植被划分成１０类，模拟了不同土壤湿度条件下７月高原有，无植被的气候场，发现两者差异较大。在土壤湿度正常时，有植被比无植被情况下四川南部，高原及江淮，东北地区日雨量增加１ｍｍ左右，云贵高原为减雨区达－１－２ｍｍ．ｄ＾－１。     

Influence of bottom topography inhomogeneity on the near-surface air layer

A connection between processes in the deep-water zone and in the near-surface air layer is considered. Measurements were carried out under different meteorological conditions in the shallow-water zone and in the area of depth variation from 250 to 2500 m. It is found that the change in bottom topography results in a transformation of the flow field and surface-wave spectrum, which leads to a change in the structure of the near-surface air layer. Measurements showed that the structure of atmospheric turbulence varied in all cases of depth variation. Thus, variations in bottom topography can manifest themselves in characteristics of surface waves and near-surface atmospheric layer.     

雨水酸度与降水物理特性的关系

一、引言 酸雨对工农业都有不同程度的危害,为了探讨酸雨的成因及其与降水的关系,我们在安徽芜湖湾里(1982年7月)和浙江宁波(1983年5、8月)进行了雨水pH值的观测,观测点都设在楼顶平台。宁波观测点的位置在市区西南边缘,西边是农田,北边和东北边是市区,有一些污染较严重的工厂,其中尤以北方的电缆厂为甚,东边和南边是民房。     

An evaluation of lightning and corona discharge on thunderstorm air and precipitation chemistry

This study synthesizes literature to provide a best estimate for the integrated effect of cloud-to-ground lightning, intracloud lightning, and corona discharge on air and precipitation chemistry for an idealized thunderstorm. The cloud volume concentration of NO (the predominant chemical species produced by lightning), assuming all flashes occurred simultaneously in an undiluted, idealized storm volume of 1.5×10³ km³, is approximately 0.8 ppbv at STP. Uncertainties are discussed, and assumptions used in this estimate are evaluated and compared to the literature for consistency. Also, NO production values (an average of field, theoretical, and laboratory observations) are used to scale theoretical estimates of other chemical species produced by lightning that can be scavenged by precipitation. The maximum concentrations of these pollutants in rain water are estimated by assuming complete removal of these select, acid rain related species and found to be insignificant.     

关于流场、高度场的一个客观分析方法

本文介绍一个低纬度流场和高度场客观分析方法,这个方法主要依靠当时观测资料而无需预备场。我们曾在上海气象局台风研究协作期间试验过高度场的客观分析方法。本文则在这基础上探讨低纬流场和高度场的客观分析方法,并进一步地考虑了船舶、飞机等非常规报的利用方案。     

影响遵义夏季降水的前期特征因子分析

分析了EI－nino事件、东亚槽、东亚季风、印缅槽、极涡等物理因素，提出影响遵义夏季降水的前期特征。     

上海地区雨水酸度与天气背景的关系

1981—1983年在上海地区11个观测站进行了雨水pH值观测,取到资料2448份.从资料分析得到:(1)雨水pH值与天气背景有关,静止锋天气影响时,酸雨出现几率达44.5％,雨水较酸;暖锋天气时,酸雨出现几率仅9％.(2)台风、高压边缘天气影响下,酸雨的形成主要是受局地污染源的影响;但静止锋、冷锋、低压系统天气时,酸雨的形成不仅受局地污染源的影响,而且还可能受随气流输送来的外来污染物的影响.     

一次积雨云降水过程的宏微观物理特征和雨水酸度的综合观测

1984年7月27日晚,在北京西郊北京大学综合观测了一场积雨云降水的全过程。包括两个降水过程:第一个降水过程持续时间短(33min),平均雨强大(12.9)mm/h),雨滴谱宽且出现多峰,降水pH值7.0左右;第二个降水过程的持续时间长(126min),平均雨强较弱(1.6mm/h),随降水的强烈冲刷,云下空气愈来愈干净,pH值连续下降至6.6,电导率也大大减小。     

An analytical study of diurnal wind-structure variations in the boundary layer and the low-level nocturnal jet

An analytical framework is proposed for studying variations in the diurnal wind structure in the planetary boundary layer (PBL) and the evolution of the low-level nocturnal jet. A time-dependent eddy-diffusivity coefficient corresponding to solar input is proposed, and an appropriate coordinate transformation ensures that mixing height varies continuously with ground heat-flux changes. The solution exhibits the receding character of the daytime PBL as evening approaches, thereby dividing the PBL into two regimes — the one just above the ground, representing the nocturnal boundary layer, and the region above it. It is assumed that inertial oscillations (IO) are triggered in the upper layer at about the time of sunset when the reversal in the direction of ground heat flux is felt in the upper layer. Two approaches are adopted to determine the characteristic features of IO and the evolution of the nocturnal low-level jet. The first one is based on the physical principle that release of horizontal momentum due to deviation from the geostrophic wind gives rise to the IO. The solution captures all the characteristic features of the IO, such as phase shift and decreasing amplitude of the IO with increasing height. According to this analysis the IO is triggered at a level as soon as the top of the receding boundary layer leaves that level. The solution is discontinuous with respect to the vertical coordinate. In the second approach we solve an initial-value problem to determine the solution in the upper layer, assuming that at about the time of sunset there is a rapid collapse of the daytime PBL to the steady, nocturnal boundary layer. The assumption is based on the mixing-height profiles prepared from climatological data collected at Delhi. The solution for the nocturnal boundary-layer regime is then obtained as a boundary-value problem. The solutions so obtained are continuous throughout the domain of interest and exhibit the characteristic features of an IO. The analysis leads to the conditions under which a low-level nocturnal jet is produced and provides quantitative estimates of the parameters, such as length of night, latitude, mixing height at sunset and nocturnal mixing height, that are conducive to the generation of a jet. The nocturnal wind profile produced by this approach compares well both with typical atmospheric data observed at Delhi and with output from a mesoscale numerical model. There is still some uncertainty related to the time of initiation of the IO as a function of latitude.