辐射收支对降水数值预报的影响

将辐射参数化子程序与中国科学院大气物理研究所降水有限区域模式结合 ,进行数值模拟 ,所得结果合理。辐射子程序能模拟并提供各高度及地面的辐射收支、温度、湿度日变化。对于大尺度降水过程 ,辐射使夜间降水量显著增加 ,是夜间降水多的原因之一。而辐射使白天降水有小量增加。     

合肥市降水化学组成成分分析

为研究合肥市降水的化学组成成分,于2010年4—9月在合肥市国家基本气象站设立了采样点,进行降水的采集,对降水化学组成成分进行了测定,并系统分析了化学组成成分的特点。结果表明:合肥降水中阴离子主要为SO24-,阳离子主要为NH4+和Ca2+,[SO24-]/[NO3-]当量浓度比值范围为1.23～6.33,大部分样本的比值<3,说明酸雨类型以硝硫混合型为主。降水的酸度与单一离子当量浓度的相关性并不明显,应该是受多种离子综合影响的结果,SO24-与NO3-,Ca2+与Mg2+,NH4+与SO24-,NH4+与NO3-均表现出较好的相关性。     

我国酸沉降地区硫源的硫同位素组成研究

我国同世界大部分地区的酸雨类型一致,均为典型的硫酸型酸雨,因此硫同位素组成是示踪酸雨来源的重要手段。在前人研究的基础上,对酸雨硫同位素组成研究的思路和实验方法进行综述,重点介绍燃煤过程中硫同位素的分馏效应和大气SO2、气溶胶、大气降水、苔藓和小麦等植物中的硫同位素组成等,对环境地球化学的研究具有重要意义。     

大同市酸雨变化特征及其与气象要素的关系

利用2007—2009年大同市酸雨资料,应用《酸雨观测规范》方法对大同市酸雨变化及其与气象要素的关系进行分析。结果表明：大同市酸雨发生频率为25.0%—36.36%,10月酸雨频率最高,达到75%;其他月份酸雨频率较低。大同市夏季酸雨强度为弱酸雨程度,而秋季酸雨频率则为最高。大同市小雨时酸雨发生频率为33.33%;中雨时酸雨发生频率为19.23%;大雨时酸雨发生频率为60.00%;暴雨时酸雨发生频率为0。由此可见,大同市在大雨天气时,酸雨出现的概率较高。随着风速的增大,降水的酸雨频率逐渐增大。大同市在S风向下的酸雨频率最高为18.60%,ESE和NNW风向下的酸雨频率较高为13.95%。通过分析大同市酸雨变化规律、气象气候条件等因素对酸雨的影响,探讨影响大同市酸雨形成的主要因素,从而为大同市酸雨污染控制提供科学依据。     

Effect of Resuspension on the Release of Heavy Metals and Water Chemistry in Anoxic and Oxic Sediments

Two types of river sediments with contrasting characteristics (anoxic or oxic) were resuspended and the release of heavy metals and changes in water chemistry were investigated. During resuspension of the anoxic sediment, the dissolved oxygen (DO) concentration and redox potential of the water layer decreased abruptly within the first 1 min, followed by increases toward the end of the resuspension period. Heavy metals were released rapidly in the first 6 h, probably due to the oxidation of acid volatile sulfide (AVS) of the anoxic sediment, and then the aqueous phase concentrations of the heavy metals decreased due to resorption onto the sediment until the 12‐h point. During resuspension of the oxic sediment, the DO concentration and redox potential remained relatively constant in the oxic ranges. The heavy metals were released from the oxic sediment gradually during a 24‐h resuspension period. The temporal maximum concentrations of Ni, Cu, Zn, and Cd in the aqueous phases in both experiments frequently exceeded the USEPA water quality criteria or the water quality guidelines of Australia and New Zealand. This suggests that a resuspension event could bring about temporal water quality deterioration in the two sediment environments.     

风暴相对螺旋度在昌吉州大降水中的应用分析

对2007—2011年5—9月昌吉、阜康、天池3个气象站大降水天气过程的风暴螺旋度（基于乌鲁木齐雷达风廓线产品）和雨量随时间的变化进行分析,结果表明：SRH数值与降水量值无明显的线性关系,降水强度的变化普遍滞后于SRH强度的变化,可根据SRH推断降水的生消;SRH正值开始时间超前于降水开始时间,有提前预报量;SRH极大值出现时间大多数超前于降水极大值出现时间,对短时（临近）预报业务有较好的指示意义。     

安顺两次特大暴雨过程的TBB和螺旋度对比分析

利用自动站观测资料、探空资料及NCEP再分析资料,对2010年6月27日夜间和2012年7月12日夜间贵州南部局地大暴雨天气过程进行对比分析。结果表明,安顺的两次特大暴雨天气过程主要是受高空槽和中低层切变共同影响,并配合低空急流,形成了有利于强降水的环流背景。安顺处于假相当位温的高能舌区和K指数、螺旋度的大值区,为特大暴雨的形成提供了很好的能量和动力条件。MCC是造成安顺特大暴雨天气的直接原因,强降水发生在云团的冷核中心内,最强降水均出现在MCC的成熟期。关岭滑坡现场与周围环境明显的海拔高度差和温度差造成的热力差异,为关岭岗乌两次特大暴雨提供了动力源和暖湿气流,并造成了关岭岗乌多次的强降水。     

大连地区酸雨外来源分析

应用Hysplit传输扩散模式计算2008-2009年大连地区酸雨和非酸雨期间的后向气流轨迹,利用条件概率和轨迹聚类法对气流轨迹进行分析,研究大连地区酸雨外来源。结果表明：外来源通过大气输送对大连地区酸沉降的贡献较大。大连地区酸雨主要受中国华东沿海至山东半岛经黄海中北部或经渤海及其西岸的近地面大气污染输送影响,中国华东、华南等南方内陆地区和日本海周边东亚国家对大连地区酸雨均有贡献。海洋性气团或北方大陆气团一般为大连地区非酸雨来源。     

Holocene ochreous lacustrine sediments within the Famatina Belt,NW Argentina: A natural case for fossil damming of an acid drainage system

A 44 m-thick lacustrine succession of silty-clay banded ochres and subordinated sandstones, and conglomerates (known as the Corral Amarillo Formation) is superbly exposed within the Famatina Belt (Central Andes of Argentina) after deep entrenchment by the present-day Amarillo river due to strong recent uplifting and consequent relative drop in base level. The unusual ochreous-rich succession was produced by natural damming (3.48–3.54 ¹⁴C kyr BP) of an acid drainage system linked to the alteration cap of polymetallic deposits. Facies of silty-clay ochre (wet season) and banded ochre (dry season) from the paleolacustrine setting are composed of jarosite + goethite and goethite respectively. Geochemically, these layers record high concentrations of Fe₂O₃ (25–55 wt. %) and trace elements (Cu, Zn, Co, As, and Mo with mean concentrations of 2759; 2467; 109; 375 and 116 ppm, respectively). Their origin is inferred from a comparative analysis with the present-day Amarillo river, which has a pH of ∼3, (SO₄)²⁻ concentrations of ∼5000 mg/l, and jarosite as the dominant phase, in the upper catchments. Waters downstream have pH values of 3–4.5, (SO₄)²⁻ concentrations of ∼3000–480 mg/l, and schwertmannite as the dominant phase. Thus goethite in the paleolake facies is likely related to schwertmannite transformation by an aging process, whereas jarosite is probably transported from the river but could also be associated with post-depositional formation regulated by variations in grain size and the pore fluid chemistry. The Corral Amarillo Formation offers a Natural model, which may be employed to infer the effect on nature of acid drainage of mineralized areas.