“低纬高原”上南北低涡结合的强暴雨过程分析

利用天气图、卫星云图、雷达回波图、物理量图及实时资料计算,综合分析了云南省1988年6月18日出现的一次强暴雨过程。初步确定,这次过程是在“滇黔辐合区”的强烈作用下,南北两个低涡在辐合区内结合,发展而产生的低纬高原上的一次典型降水天气过程。     

东南亚地区夏季风异常对云南2005年初夏干旱的影响

2005年春末夏初云南大部地区出现了50年一遇的高温干旱天气，通过对东南亚地区的水汽及对流进行诊断分析，发现中南半岛地区夏季风爆发的早迟与云南雨季开始的早迟有显著的正相关关系；前期4月孟加拉湾水汽向北输送强（弱）以及苏门答腊岛附近的对流活动强（弱），则云南雨季开始早（迟）。分析表明造成云南2005年初夏干旱的主要原因是中南半岛地区的夏季风爆发较常年偏晚，前期孟加拉湾地区的经向水汽输送以及苏门答腊岛附近的对流活动较常年偏弱。     

DIAGNOSES OF THE SEVERE DROUGHT OVER YUNNAN AREA IN THE EARLY SUMMER OF 2005

High temperature and drought occurred in Yunnan province during the late spring and early summer in 2005, which was the most severe event in this region since 1950’s. Based on the observational data and relevant diagnoses, this extreme weather event was studied and discussed. The results show that the occurrence of this event could be due to the following observational facts that happened in 2005. (1) The seasonal adjustment of middle-high-leveled atmospheric circulation was delayed. (2) The cold air activity center was deviated north. (3) The onset of summer monsoon over South China Sea was delayed. (4) The tropical convection activity was much weaker than usual. (5) The subtropical high over the western Pacific was located southwestwards and relatively strong.     

云南雨季开始期与热带OLR的联系

利用NCEP 1979—2003年1~12月再分析的OLR逐日、月平均资料及同期云南雨季开始期资料,通过相关统计、对比合成等方法,重点分析了南海和孟湾海区的OLR场变化对云南雨季开始期的影响。结果表明,南海和孟湾海区OLR在云南雨季开始偏早年与偏晚年之间差异明显,南海海区前期的对流活动对云南雨季开始期有更显著的指示性,但孟湾海区对流的强弱仍是影响云南雨季开始期的重要因素之一。     

春末初夏异常环流对云南雨季开始期的影响

通过小波分析表明云南目前处于雨季开始期偏早的年代际变化中。2006(2005)年是云南雨季开始特早(晚)的异常年,把这2个雨季开始期相反的极端异常年进行对比分析,发现云南雨季偏早(晚)的4月主要环流特征差异是:200 hPa对流层东西风交界线比多年平均偏北(南);500 hPa中高纬环流有(不)利于冷空气南下;850 hPa北印度洋赤道纬向西风较常年偏强(弱),孟加拉湾南部苏门答腊岛附近的对流较常年偏强(弱)。     

基于“双行裂隙”模型的两淮矿区高承压厚松散层突水机理

两淮矿区高承压厚松散含水层覆盖下煤炭储量巨大,在提高上限开采过程中常发生松散层突水事故,采用传统“上三带”理论难以合理解释此类事故发生的机理。本文在分析两淮矿区高承压松散层水文工程地质条件的基础上,建立近高承压松散层开采“双行裂隙”模型,采用室内实验、数值模拟、理论分析和工程应用检验等方法,研究“双行裂隙”发育规律,揭示两淮矿区高承压厚松散层突水致灾机理,结果显示:祁东煤矿松散层第四含水层（简称四含）水压与裂采比呈线性关系;在水压作用下,覆岩“上行裂隙”发育高度增大;利用裂隙受力分析推导的基岩风化带原生裂隙扩展渗透深度计算公式,表明高承压松散含水层对风化裂隙产生劈裂作用,是“下行裂隙”形成的主要因素。“双行裂隙”的综合作用使工作面更易发生松散层水突水事故,研究成果为近松散层煤层开采安全煤（岩）柱的合理留设提供科学依据。      

青山水库轮虫群落结构特征的时空差异对水质变化的影响

为研究青山水库轮虫群落结构特征的时空差异对水质变化的影响,对其进行了四个季度的采样调查。结果共发现轮虫物种30种,分属于9个科,其中优势种为长肢多肢轮虫和针簇多肢轮虫,后者是一种污染指示种,表明水质处于中度污染状态。轮虫平均密度为171 ind./L,平均生物量为0.0158 mg/L。通过对水库理化因子与轮虫群落生物指数进行相关性分析,初步确定水温和溶解氧是青山水库轮虫群落演替的主要影响因子。根据轮虫群落结构聚类分析表明,青山水库分为四大区域。另外,主成分分析结果表明水质的下降可能与营养盐的的增加有关,特别是氮的输入。综合理化指标、营养状态指数、轮虫多样性指数以及优势种指示种等多种评价方法,结果表明2012—2013年青山水库水质属于中度—重度污染之间,营养程度为中度富营养状态,青山水库水环境污染严重。依据理化指标和轮虫群落结构特征来评价水质状况,得到的结果基本一致,因此轮虫可以作为青山水库一个较为理想的检测指标。     

Polybrominated diphenyl ethers (PBDEs) in sediments and mussel tissues from Hong Kong marine waters

Sediments and green-lipped mussels, Perna viridis, were used to investigate concentrations of polybrominated diphenyl ethers (PBDEs) in Hong Kong's marine environment. PBDEs have been used extensively over the past two decades as flame retardants in polymer additives for a variety of plastics, computers, furniture, building materials, and fabrics. Many measurements of PBDEs in various environmental matrices have been reported from Belgium, Holland, Japan, Europe and North America, but few measurements are available for the southeast Asian region and Hong Kong. PBDE congeners (n=15) were measured in 13 sediments and nine mussel samples, taken from Hong Kong marine waters. The Sigma15PBDEs in sediments ranged between 1.7 and 53.6 ng g(-1) dry wt, with the highest concentrations located around the most heavily populated areas of Victoria Harbour and Sai Kung, while the lowest concentrations of Sigma15PBDEs were found at more remote locations of Sha Tau Kok, Wong Chuk Bay, Castle Peak Bay, and Gold Coast. Sigma15PBDEs ranged from 27.0 to 83.7 ng g(-1) dry wt of mussel tissues. Although not identical, most of the congeners in sediments were found in mussel tissues, with BDE-47, BDE-99, BDE-153 and BDE-183 being the most prominent in both matrices. On the basis of a literature survey, the concentrations of PBDEs reported in Hong Kong sediments and mussel tissues are amongst the highest in the world.