Significance of cytochrome P450 system responses and levels of bile fluorescent aromatic compounds in marine wildlife following oil spills

The relationships among cytochrome P450 induction in marine wildlife species, levels of fluorescent aromatic compounds (FAC) in their bile, the chemical composition of the inducing compounds, the significance of the exposure pathway, and any resulting injury, as a consequence of exposure to crude oil following a spill, are reviewed. Fish collected after oil spills often show increases in cytochrome P450 system activity, cytochrome P4501A (CYP1A) and bile fluorescent aromatic compounds (FAC), that are correlated with exposure to polycyclic aromatic hydrocarbons (PAH) in the oil. There is also some evidence for increases in bile FAC and induction of cytochrome P450 in marine birds and mammals after oil spills. However, when observed, increases in these exposure indicators are transitory and generally decrease to background levels within one year after the exposure. Laboratory studies have shown induction of cytochrome P450 systems occurs after exposure of fish to crude oil in water, sediment or food. Most of the PAH found in crude oil (dominantly 2- and 3-ring PAH) are not strong inducers of cytochrome P450. Exposure to the 4-ring chrysenes or the photooxidized products of the PAH may account for the cytochrome P450 responses in fish collected from oil-spill sites. The contribution of non-spill background PAH, particularly combustion-derived (pyrogenic) PAH, to bile FAC and cytochrome P450 system responses can be confounding and needs to be considered when evaluating oil spill effects. The ubiquity of pyrogenic PAH makes it important to fully characterize all sources of PAH, including PAH from natural resources, e.g. retene, in oil spill studies. In addition, such parameters as species, sex, age, ambient temperature and season need to be taken into account. While increases in fish bile FAC and cytochrome P450 system responses, can together, be sensitive general indicators of PAH exposure after an oil spill, there is little unequivocal evidence to suggest a linkage to higher order biological effects, e.g. toxicity, lesions, reproductive failure.     

Studies of a contaminated brackish marsh in the Hackensack Meadowlands of northeastern New Jersey: an assessment of natural recovery

Eight-Day Swamp is known to be contaminated with heavy metals, especially mercury. Sediment cores were collected to approximately 32 cm at 17 sites on four transects and analyzed at 1 or 2 cm intervals for seven metals and organic matter. Very high metal levels were found throughout the site. Long and Morgan's "effects range-median" (ER-M) was exceeded in more than 50% of slices for all elements except As. Hg had the highest concentration relative to ER-M; median Hg concentration was 72 times its ER-M. On the marsh plain, all metals showed enrichment at 14-20 cm depth of 10-40X over surficial sediments. 137Cs analysis showed sedimentation rates ranging from 0.33 to 0.50 cm yr(-1) over the last approximately 40 yr. These rates indicate that metal contamination peaks occurred in sediments deposited in the early 1960s. Thus, newer, less contaminated sediments are burying older, more contaminated layers and peak levels of contaminants are becoming less available to benthos.     

2004年夏季的天气及预测试验

简要介绍了2004年夏季的主要天气过程和中国科学院大气物理研究所2004年汛期预测的结果.总体上看,2004年夏季江淮流域的降雨分布较均匀,没有造成大江大河及大范围的洪涝,中高纬度典型的梅雨环流形势没有完全建立,西风槽活动频繁.夏季最强的一次降雨过程(7月15～20日)是高空低压槽前的持续性暴雨.2004年夏季华北大部分地区降雨偏多,多为低槽冷锋造成;影响我国的热带气旋明显偏多,8月登陆浙江、福建的2个台风破坏力较大;江南和西北都出现了较强的高温天气,江南和新疆的高温分别为副高和大陆高压造成;9月2～5日川东和重庆的降雨与低涡在该地区的稳定维持有关.从汛期实时降水预测结果看,预测系统对6～8月江淮雨带及其暴雨中心的预测较为准确,对大范围的雨带无漏报和空报.而对华北地区降雨而言,预测评分要低于江淮梅雨,这可能是因为模式中的物理过程,特别是降水的物理过程未能完全准确反映华北地区的情况.要提高华北地区降雨的预测水平,今后应继续开展深入的研究.     

华南“94·6”特大暴雨的中尺度对流系统及其环境场研究 Ⅰ.引发暴雨的β中尺度对流系统的数值模拟研究

选取1994年6月12日~13日的过程,在确定云雨、垂直运动的模拟基本正确的基础上,利用模式输出资料对β中尺度对流系统的结构进行分析研究。结果表明:低层的水汽辐合很强,并且出现在对流发展前2~3h,有利于对流的启动;随着对流系统的发展,最大的垂直运动向上扩展,饱和层和中性层也不断向上伸展,对流层中层的中性层结既是对流发展的结果,也可能是其维持机制之一;强对流系统发展较强时,低层(600hPa以下)是辐合,而中高层为高压辐散气流,高层的辐散气流对对流系统的发展、维持有一定的作用;系统发展最强时垂直方向是两个模态,发展和衰减阶段一般为多个模态;强对流系统发展的环境风场为低层有西南、东南和北风三支气流辐合,而高层以偏北风为主;切变线上对流系统的降雨量有3h左右的周期变化。     

Statistical characteristics of environmental parameters for warm season short-duration heavy rainfall over central and eastern China

Water vapor content,instability,and convergence conditions are the key to short-duration heavy rainfall forecasting.It is necessary to understand the large-scale atmospheric environment characteristics of shortduration heavy rainfall by investigating the distribution of physical parameters for different hourly rainfall intensities.The observed hourly rainfall data in China and the NCEP final analysis（FNL）data during 1May and 30 September from 2002 to 2009 are used.NCEP FNL data are 6-hourly,resulting in sample sizes of 1573370,355346,and 11401 for three categories of hourly rainfall（P）of no precipitation(P<0.1 mm h^-1),ordinary precipitation(0.1≤P<20 mm h^-1),and short-duration heavy rainfall(P≥20.0 mm h^-1),respectively,by adopting a temporal matching method.The results show that the total precipitable water（PWAT）is the best parameter indicating the hourly rainfall intensity.A PWAT of 28 mm is necessary for any short-duration heavy rainfall.The possibility of short-duration heavy rainfall occurrence increases with PWAT,and a PWAT of 59 mm is nearly sufficient.The specific humidity is a better indicator than relative humidity.Both 700-and 850-hPa relative humidity greater than 80%could be used to determine whether or not it is going to rain,but could not be used to estimate the rainfall intensity.Temperature and potential pseudo-equivalent temperature are also reasonable indicators of short-duration heavy rainfall.Among the atmospheric instability parameters,the best lifted index（BLI）performs best on the shortduration rainfall discrimination;the next best is the K index（KI）.The three rainfall categories are not well recognized by total totals（TT）or the temperature difference between 850 and 500 hPa（DT85）.Threequarters of short-duration heavy rainfall occurred with BLI less than-0.9,while no short-duration heavy rainfall occurred when BLI was greater than 2.6.The minimum threshold of KI was 28.1 for short-duration heavy rainfall.The importance of dynamic conditions was well demonstrated by the 925-and 850-hPa divergence.The representativeness of 925-hPa divergence is stronger than that of 850 hPa.Three-quarters of short-duration heavy rainfall occurred under a negative divergence environment.However,both the best convective potential energy（BCAPE）and vertical wind shear were unable to discriminate the hourly rainfall intensities.     

多普勒天气雷达资料同化对暴雨模拟的影响

利用我国CINRAD/SA多普勒天气雷达资料与ARPS模式 (Advanced Regional Prediction System) 的资料分析系统ADAS (ARPS Data Analysis System), 对初始场进行调整, 并应用于WRF (Weather Research and Forecasting Model) 模式, 对2003年梅雨期淮河流域两次典型致洪暴雨过程进行模拟试验。对模拟结果的对比分析和检验结果表明:引入雷达资料后, 在雷达观测区的整层风场和水汽场都随之调整, 雷达径向风和反射率因子资料对初始场调整有不同影响, 径向风资料侧重于对风场的调整, 而反射率因子资料侧重于对温、湿量场的调整, 使降雨落区和强度预报都有所提高; 在ADAS系统中, 雷达径向风和反射率因子资料对初始场调整有不同影响, 径向风资料侧重于对风场的调整, 而反射率因子资料侧重于对温、湿量场的调整, 两个个例的试验表明, 加入雷达径向风资料的模拟试验能够得到较好评分, 加入雷达反射率因子资料或同时加入这两种雷达资料也能够在一定程度上提高模拟的准确性。     

我国暴雨机理与预报研究进展及其相关问题思考

为了不断提高对我国暴雨发生发展机理的认识和暴雨预报的准确率,本文对新中国成立70年来我国暴雨机理与预测研究历程与重要成果进行了回顾,首先简要介绍了热带季风及其变异、西太平洋副热带高压及阻塞高压对我国暴雨的影响;然后,概述了我国梅雨期暴雨、华北暴雨与华南前汛期暴雨、登陆台风暴雨与西部地区强降水、青藏高原及不同地形对暴雨影响研究方面的主要进展;最后,探讨了我国发展更精细暴雨定量降水数值预报的前景和存在问题。在此基础上,提出未来我国暴雨研究与预报中值得关注和思考的几个科学问题。     

一个改进的沙尘天气数值预测系统及其模拟试验

在中尺度气象模式最新版本MM5V3.7的基础上,通过与一个起沙模式的耦合,建立了一个新的中国科学院大气物理研究所(IAP/CAS)沙尘天气数值预测系统(IAPS 2.0).该系统与IAP原有的沙尘天气数值预测系统(IAPS 1.0)最主要的差异在于气象模式中陆面过程模式的改进.利用改进前后两个版本的预测系统对2002年4月发生在我国北方地区的两次较强沙尘(暴)过程进行了数值模拟,并与观测实况进行了比较,结果表明改进的系统对沙尘天气的预测能力比改进前的版本有显著的改进,这主要是由于新的陆面模式改善了地表土壤湿度的模拟,进而改进了决定起沙与否的关键因子临界摩擦速度的模拟,从而提高了预测系统对起沙范围和强度的模拟效果.总的说来,采用了更为先进的Noah陆面模式的IAP沙尘(暴)天气数值预测系统对中国北方春季沙尘(暴)天气过程具有更好的模拟能力.     

1998年中国科学院大气物理研究所气候与环境预测研究中心汛期暴雨短期数值预测

对１９９８年夏季汛期（６～８月）天气过程进行了分析;在６～８月期间用ＩＡＰ－ＥＴＡ暴雨数值预报模式进行了每天的２４小时的降水实时预报;首次采用从Ｉｎｔｅｒｎｅｔ网上获取的ＮＣＥＰ资料,作为初值。预报的结果表明,ＥＴＡ坐标有限区域模式对暴雨预报有较好的参考价值;ＮＣＥＰ资料是有用的,尤其是在高原和广大海洋资料稀少地区。     

华北和北京的酷暑天气 Ⅰ. 历史概况及个例分析

如果将日最高气温超过３５ ℃的天气定义为酷暑天气, 则近６０ 年的资料统计表明, 北京出现酷暑天气的年频率高达８１ ％ , 并不少见, 尤以４０ 年代和９０ 年代明显偏多。１９４２ 年６ 月和１９９９ 年７ 月都出现≥４２ ℃的酷暑天气。分析表明, 北京和华北酷暑天气的出现与大环流形势密切相关, 大陆副热带高压维持于华北上空是其主要因素, 空气下沉增温是酷暑的主要机制, 而大城市的热岛效应则可使城区百叶箱气温再增高２ ℃左右。