Germination and growth effects of hexavalent chromium in Orocol TL (a corrosion inhibitor) on Phaseolus vulgaris

This research was designed to address the potential for germination and growth effects in bush beans (Phaseolus vulgaris L. var. Bush Blue Lake) from hexavalent chromium in Orocol TL, a proprietary chromated, zinc-phosphate compound added to DOE cooling water systems for corrosion inhibition. Studies were conducted at low and high Orocol TL concentrations in the soil by adjusting soil pH and the percent of organic matter. Germination effects were determined for seeds germinated in soils adjusted to differing pH ranges (4–4.5, 5–5.5, and 6.5–7), levels of organic matter (1.8%, 3%, and 5%), and Orocol TL amendments (control of 0, 10, and 500 μg/g chromium). Growth responses (effects) were determined from plants cultured in the same soil treatment combinations as described for the germination study. High levels (500 μg/g) of hexavalent chromium in soil (as Orocol TL) affected germination and growth, while a high level of organic matter significantly reduced chromium toxicity on germination. At lower chromium concentrations there was significant uptake by all plant parts, with a corresponding reduction in biomass of leaves. Consequently, adjustments of soil pH from 4.0 to 7.0 appear to have no significant effect on chromium uptake in plants. Increasing the organic matter level to 5%, while decreasing the toxicity of high chromium levels to germinating seed, did not affect chromium uptake.     

长江中游城市群PM2.5时空特征及影响因素研究

近年来，伴随着工业化和城市化进程的加快，长江中游城市群灰霾天气持续增多，空气污染问题日益突出。基于2015年1月至2016年2月长江中游城市群189个空气质量监测站点的PM2.5逐时监测数据，采用普通克里金插值、探索性空间数据分析法和相关系数法，从年、季、月尺度上分析了PM2.5的空间分布格局及其影响因素。结果表明：（1）在年尺度上，长江中游城市群PM2.5浓度空间分布总体呈现出明显的北部高南部低，局部地区略有突出的特征，该区PM2.5浓度年均值为55.28 μg/m3，其中湖北省PM2.5的年均值为三省市最高，为68.17 μg/m3；其次为湖南省，年均值为53.66 μg/m3；江西省PM2.5的年均值较小，为44.01 μg/m3。（2）在季节尺度上，长江中游城市群PM2.5浓度表现出冬春季高，夏秋季低的现势性，这与区域内夏季高温多雨、冬季低温少雨的气候条件密切相关。（3）长江中游城市群PM2.5月浓度变化大致呈U形分布，1月份PM2.5浓度最高， 1~6月份，PM2.5浓度呈逐步下降趋势， 6~8月份，区域PM2.5浓度处于“U”字的谷底。（4）NO2、CO是影响PM2.5浓度的两项主控大气污染物，而降水量和相对湿度则是影响PM2.5浓度的两个重要气象因素。 关键词： PM2.5浓度；时空特征；气象因素；长江中游城市群     

Effect of cigarette smoking on residential NO2 levels

Two studies evaluating the levels and sources of nitrogen dioxide in approximately 90 employee homes in the Richmond area with continuous sampling during the weeks of August 5, 1980, and February 9, 1981, were performed using samplers in the living room, bedroom, kitchen, and outdoors. Additional data were collected concerning appliance usage, heating/cooling plant, ventilation and cigarette smoking. Results were analyzed using BMDP routines. The largest contributor to NO₂ concentration was found to be gas-fired kitchen appliances. The mean kitchen level for homes with gas appliances during the winter study was 188 μg/m³. Excluding participants with gas kitchens, incremental influence due to cigarette smoking was detected. The 7-day, 3-room average level of NO₂ in the homes of nonsmokers and smokers without gas-fired appliances was 12 and 15 μg/m³, respectively, in the summer. The corresponding winter values were 19 and 22 μg/m³. Furthermore, the individual levels of NO₂ in the homes of smokers were generally below both the adjacent outdoor level and the National Ambient Air Quality Standard limit for annual exposure.     

Seasonal modulation of sex-related differences in hippocampus size and spatial behavior in bank voles, Clethrionomys glareolus (Rodentia, Cricetidae)

Male and female bank voles (Clethrionomys glareolus) were compared with respect to seasonal variation in hippocampus size and dynamics of spatial behavior during the annual population cycle. The winter decrease in the size of the hippocampus (the brain region involved in the processing of spatial information about the environment) in young autumn-born voles coincided in time with reduction of their home ranges and did not differ significantly between males and females. The growth of the hippocampus in spring, after winter regression, was higher in males (19–28% in different populations) than in females (8–20%) and coincided with an increase in spatial activity, which was also more distinct in males. A significantly greater hippocampus size in males during the breeding period correlated with their higher mobility (reflected in capture rate) and greater size of home ranges. Thus, parallel seasonal modulation of sex-related differences in hippocampus size and spatial behavior was revealed: sexual dimorphism in these characters was insignificant among young voles in autumn; disappeared in winter; manifested itself again, synchronously in both characters, in early spring (with the onset of puberty); and reached a peak in summer.     

The molecular properties of humic substances isolated from a UK upland peat system: a temporal investigation.

The study concerns the possible changes in the molecular characteristics of humic materials isolated from the same source as a function of time. A great deal of data has been reported concerning the contrast in molecular characteristics of humic substances isolated from different environments. This has primarily been an attempt to identify source-specific molecular characteristics. However, data presented in this paper suggests that humic substances isolated from a single catchment have significant changes in molecular characteristics over time. Two naturally occurring peat pools (X and Y) situated upon a small organic catchment on Great Dun Fell, Cumbria, UK were sampled monthly between November 1994 and November 1996. Dissolved organic matter (DOM) from the pool water samples was fractionated using macroporous nonionic resins (XAD8 and 4), and the humic, fulvic and hydrophilic acids were collected. These fractions were analysed for elemental composition (C, H and N), weight average molecular weight, functional group content and adsorption (340 nm) of a 1 g l(-1) solution measured in a 1-cm spectrophotometer cell. The molecular characteristics were compared to those of natural DOM described by Scott et al. (1998). Scott et al. reported that drought conditions and seasonal climatic changes could have appreciable effects upon molecular characteristics of natural DOM. Results showed that the atomic H/C ratio of the humic substances increased immediately after strong drought conditions experienced in the summer of 1995. This change was temporary with atomic H/C ratio decreasing gradually over the following months. A similar decrease was observed in the carboxyl group content of the isolated compounds. The data set suggested that atomic H/C ratio in the fulvic and hydrophilic fractions exhibited seasonal characteristics of higher ratios during the late summer/early autumn months. This was not observed in the humic fraction. Humic acids exhibited a seasonal pattern of higher weight average molecular weight during the summer months. These trends were explained in terms of summer production of DOM in the catchment soils, their sequestering in the soil due to limited soil water movement during the summer months and their relative ease of dissolution when rainfall and soil water movement increased during the late summer/early autumn period. The results were found to support seasonal and long-term patterns observed in natural DOM as reported by Scott et al. (1998).     

上海崇明岛近三年PM_(2.5)浓度变化特征与气象条件的关系

利用2011年1月~2014年2月上海崇明岛地区颗粒物(PM_(2.5)、PM_(10))的连续监测资料,研究了PM_(2.5)总体分布、季节变化、日变化及浓度频率分布规律,初步分析了逆温、相对湿度、风向风速等气象要素对颗粒物浓度的影响。结果表明:2011~2013年该地区PM_(2.5)平均值分别为24.7,33.6和28.3μg/m~3,均低于PM2.5的年平均浓度限值35μg/m~3,细粒子污染程度较轻。PM_(2.5)浓度日变化幅度不大,呈微弱的单峰型分布,9∶00左右达到一天中的最大值,15∶00左右达到最小值。PM_(2.5)浓度的季节分布特征明显,呈现出冬季春季秋季夏季,一般情况下5月份PM_(2.5)月均浓度值最高,8月份浓度最低。PM_(2.5)日平均浓度有57.9%达到国家空气质量一级标准,有93.4%达到国家空气质量二级标准,超标率为6.6%。对PM_(2.5)与各气象要素进行分析后发现:PM_(2.5)质量浓度在逆温层结稳定、风速小、高湿以及近地面盛行西北到西风这样的静稳天气条件配合高空西北方向上的外来污染物输送,容易造成高浓度的PM_(2.5)污染。     

2015年长三角地区城市PM2.5时空格局及影响因素分析

PM_2.5浓度值增加对大气能见度、人体健康和气候变化有着重要影响。采用2015年长三角地区监测数据，运用探索性空间数据分析法和相关系数法，分析长三角地区城市PM_2.5污染的时空格局和影响因素，结果表明：（1）2015年长三角地区城市PM_2.5年均浓度值为54.54 μg/m³，季节变化总体呈现春冬高夏秋低的季节性周期变化规律，1月和12月为一年中PM_2.5污染最严重的月份，污染范围最广，5~9月是PM_2.5浓度值优良时段，日均值春季和冬季的波动周期较短而剧烈，夏季和秋季波动周期相对较长而平缓。（2）2015年长三角地区城市PM_2.5年均浓度值整体上从江苏到浙江呈减少趋势，具有北高南低，局部突出的特征。（3）长三角地区城市PM_2.5浓度空间上存在集聚现象，低值集聚主要分布在浙江沿海地区，高值集聚主要分布在苏南地区。（4）燃烧排放的烟尘和前体物的二次转化对长三角地区PM_2.5浓度有显著影响。风速和降水量是影响PM_2.5浓度的两个重要气象因素。     

近50年来鄱阳湖流域降雨多时间尺度变化规律研究

利用鄱阳湖流域16个气象站1960~2008年共49 a的月降雨资料，采用Morlet小波函数，对该流域降雨季节变化、年际和年代际时间序列进行小波分析，揭示了流域降雨变化的多时间尺度特征，分析了不同时间尺度下降雨序列变化的周期和突变点。研究表明：①1960~1990年，年降雨量呈明显年际和代际振荡，并无显著趋势；进入90年代以后，年降雨呈现显著上升趋势；进入21世纪，尤其从2002年开始，年降雨量开始减少；②流域季节降雨和年降雨都存在多时间尺度特征，夏季降雨、冬季降雨和年降雨都存在18 a的第一主周期；春季、冬季和年降雨存在6 a次主周期；此外，春季、秋季、冬季和年降雨均存在3 a次主周期；③夏季降雨在18 a时间尺度上与年降雨变化具有相同的趋势和相位，春季降雨在3 a和6 a时间尺度上与年降雨变化具有相似趋势和相位变化     

Nutrient chemistry of River Pinios (Thessalia, Greece)

The impact of human activities with 3-year monitoring on the fluctuation of nutrients along the Pinios River and its tributaries were studied. Their seasonal variations throughout the years 1996-1998 were also presented. High temperatures, from June to August, cause a restriction of the water flow, an enhancement of nutrient concentration with the subsequent increase of eutrophication. High concentrations of nutrients were observed first in winter (wet period), caused by leaching of fertilizers from terrestrial systems after heavy rainfall, later during the warm months due to low water flow of the river, and at last in autumn when plant organisms began to decompose. The intensive algal and macrophyte growth (spring, summer) resulted in severe depletion of nutrients. Organic carbon showed no seasonal trend but its values were high near the estuaries. Nitrate fluxes were high at the initial station (sources) and the Titarisios tributary, whereas nitrites and ammonium were low. In contrary, the Kalentzis tributary with relatively low nitrate values showed increased values of nitrite ammonium or total nitrogen. On the other hand, the Enipeas tributary showed high SO4 values. Phosphates are remarkably present mainly after the city of Larissa, where sewage and industrial discharges occur. None of the nutrients measured in the Pinios River and its tributaries showed a clear seasonal cycle of concentration. Concentrations of nutrients and organic carbon increased as a consequence of anthropogenic inputs, particularly point discharges from sewage treatment plants (i.e. showing distinct, but variable, concentration peaks), as well as diffuse urban and/or agricultural runoff over long areas during storm events. The agricultural management, the urban pollution, mainly from Larissa City, and the climate conditions in the catchment basin (Thessalia Plain) of Pinios River and its tributaries greatly affect the chemical composition of their waters.     

Seasonal variations of aerosol residence time in the lower atmospheric boundary layer

During a one year period, from Jan. 2002 up to Dec. 2002, approximately 130 air samples were analyzed to determine the atmospheric air activity concentrations of short- and long-lived (222Rn) decay products 214Pb and 210Pb. The samples were taken by using a single-filter technique and gamma-spectrometry was applied to determine the activity concentrations. A seasonal fluctuation in the concentration of 214Pb and 210Pb in surface air was observed. The activity concentrations of both radionuclides were observed to be relatively higher during the winter/autumn season than in spring/summer season. The mean activity concentration of 214Pb and 210Pb within the whole year was found to be 1.4+/-0.27 Bq m(-3) and 1.2+/-0.15 mBq m(-3), respectively. Different 210Pb:214Pb activity ratios during the year varied between 1.78 x 10(-4) and 1.6 x 10(-3) with a mean value of 8.9 x 10(-4) +/- 7.6 x 10(-5). From the ratio between the activity concentrations of the radon decay products 214Pb and 210Pb a mean residence time (MRT) of aerosol particles in the atmosphere of about 10.5+/-0.91 d could be estimated. The seasonal variation pattern shows relatively higher values of MRT in spring/summer season than in winter/autumn season. The MRT data together with relative humidity (RH), air temperature (T) and wind speed (WS), were used for a comprehensive regression analysis of its seasonal variation in the atmospheric air.     

基于地面监测数据的2013~2015年长三角地区PM2.5时空特征

近年来,长三角地区灰霾天气持续增多,空气细颗粒物污染问题日益突出。基于2013年1月至2015年5月长三角地区及周边缓冲区内共214个空气质量监测站点PM_2.5逐时监测数据,运用普通克里金插值方法,从年、季、月尺度上分析了PM_2.5的空间分布格局和时间动态变化。结果表明:(1)2 a来,长三角地区PM_2.5浓度空间分布明显呈现整体北部高南部低,局部地区略有突出的分布特征;长三角地区PM_2.5浓度年均值为57.08μg/m³;其中,江苏省PM_2.5的年均值为三省市最高,为65.84μg/m³;其次为上海市,年均值为53.87μg/m³;浙江省PM_2.5的年均值较小,为51.53μg/m³。(2)从季节尺度分析,长三角地区PM_2.5浓度变化表现出冬春季高,夏秋季低的变化趋势;这与区域内冬季风向来源、降水稀少、气象扩散条件差有着密切的关系; (3)长三角地区月浓度变化大致呈U形分布; 12月份PM_2.5浓度最高; 3月份以后, PM_2.5浓度开始呈逐步下降趋势;在5~9月份,区域PM_2.5处于"U"字的谷底,其中6月份夏收时期秸秆焚烧、气象等因素导致PM_2.5浓度有略微升高;进入10月份后迅速攀升,且11、12月份呈现持续升高态势。     

Seasonal assessment of environmental tobacco smoke and respirable suspended particle exposures for nonsmokers in Bremen using personal monitoring

The study was designed to determine seasonal differences in personal exposures to respirable suspended particles (RSP) and environmental tobacco smoke (ETS) for nonsmokers in Bremen, Germany. The subjects were office workers, either living and working in smoking locations or living and working in nonsmoking locations. One hundred and twenty four randomly selected nonsmoking subjects collected air samples close to their breathing zone by wearing personal monitors for 24 h or, in some cases, for 7-day periods during the winter of 1999. The investigation was repeated in the summer with 126 subjects, comprised of as many of the studied winter population (89 subjects) as possible. Saliva cotinine analyses were undertaken to verify the nonsmoking status of the subjects. Subjects wore one personal monitor while at work and one while away from the workplace on weekdays, and a third monitor at the weekend. Collected air samples were analysed for RSP, nicotine, 3-ethenylpyridine (3-EP) and ETS particles. The latter were estimated using ultraviolet absorbance (UVPM), fluorescence (FPM) and solanesol (SolPM) measurements. ETS exposure was consistently higher in the winter than in the summer, this pattern being particularly evident for subjects both living and working with smokers. The highest median 24-h time weighted average (TWA) concentrations of ETS particles (SolPM, 25 microg m(-3)) and nicotine (1.3 microg m(-3)) were recorded for subjects performing weekday monitoring during the winter. These were significantly higher than equivalent levels of ETS particles (SolPM, 2.4 microg m(-3)) and nicotine (0.26 microg m(-3)) determined during the summer. There were no appreciable differences between winter and summer percent workplace contributions to median TWA ETS particle and nicotine weekday concentrations, the workplace in Bremen, in general, contributing between 35% and 61% of reported median concentrations. Workers, on average, spent one-third of their time at work during a weekday, indicating that concentrations were either comparable or higher in the workplace than in the home and other locations outside the workplace. Median 24-h weekend ETS particle and nicotine concentrations for smoking locations were not significantly different from equivalent weekday levels during the winter, but were significantly lower during the summer. Based upon median 24-h TWA SolPM and nicotine concentrations for the winter, extrapolated to 1 year's ETS exposure, those subjects both living and working in smoking locations (the most highly exposed group) would potentially inhale 13 cigarette equivalents/year (CEs/y). However, based on a similar extrapolation of summer measurements, the same group of subjects would potentially inhale between 1.3 and 1.9 CEs/y. The most highly exposed subjects in this study, based upon 90th percentile concentrations for those both living and working in smoking locations during the winter, would potentially inhale up to 67 CEs/y in the winter and up to 22 CEs/y in the summer. This clearly demonstrates that seasonal effects should be taken into account in the design and interpretation of ETS exposure studies. Air sampling over a 7-day period was shown to be technically feasible, and subsequent RSP, ETS particle and nicotine levels determined by 7-day monitoring were not found to be significantly different from equivalent levels determined by 24-h monitoring. However, the longer sampling period resulted in the collection of an increased quantity of analytes, which improved the limits of quantitation (LOQ) and allowed a more accurate determination of low level ETS exposure. This was reflected by a reduced percentage of data falling below the LOQ for 7-day monitoring compared with 24-h monitoring. The use of a liquid chromatographic method with tandem mass spectrometric detection for saliva cotinine measurement afforded a greatly improved LOQ and greater accuracy at low concentrations compared with the radioimmunoassay (RIA) method used in previous studies by these authors. In this study, 17 subjects out of 180 tested (9.4%) were found to have saliva cotinine levels exceeding the selected threshold of 25 ng ml(-1) used to discriminate between smokers and nonsmokers.     

Investigations on indoor radon in Austria, Part 1: Seasonality of indoor radon concentration

In general, indoor radon concentration is subject to seasonal variability. The reasons are to be found (1) in meteorological influence on the transport properties of soil, e.g. through temperature, frozen soil layers and soil water saturation; and (2) in living habits, e.g. the tendency to open windows in summer and keep them closed in winter, which in general leads to higher accumulation of geogenic Rn in closed rooms in winter. If one wants to standardize indoor Rn measurements originally performed at different times of the year, e.g. in order to make them comparable, some correction transform as a function of measurement time which accounts for these effects must be estimated. In this paper, the seasonality of indoor Rn concentration measured in Austria is investigated as a function of other factors that influence indoor Rn. Indoor radon concentration is clearly shown to have seasonal variability, with higher Rn levels in winter. However, it is complicated to quantify the effect because, as a consequence of the history of an Rn survey, the measurement season maybe correlated to geological regions, which may introduce a bias in the estimate of the seasonality amplitude.     

雅鲁藏布江中游河谷气温时序变化的小波分析

通过对雅鲁藏布江中游河谷地区拉萨、日喀则、江孜和泽当等4个气象站1957～2007年逐日气温资料进行等权平均取值，采用气候倾向率和小波分析法，研究了不同时间尺度下近51 a气温变化趋势及周期特征。结果表明：近50 a年平均气温倾向率为0.27℃/10 a，高于西藏地区平均值。气温变化以秋、冬季较显著，夏季气温增长最不明显。年与各季气温变化均存在15～20 a时间尺度上的周期性震荡，突变点在1987年左右，总体表现为1987年前气温偏低，1987年后处于偏高期。春、秋、冬季在1975年左右存在一个升温期，但夏季较明显的升温期却在20世纪80年代中期。
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岷江上游高山森林凋落叶在冬季河流中的质量损失特征

凋落叶在高山森林河流中的分解不仅是生态系统物质循环的重要内容,而且与森林养分流失以及下游水体环境密切相关,并可能受到冬季雪被变化和土壤季节性冻融的影响,但一直缺乏必要的关注。因此,以岷江上游高山森林4种代表性植物康定柳(Salix paraplesia)、高山杜鹃(Rhododendron lapponicum)、方枝柏(Sabina saltuaria)和四川红杉(Larix mastersiana)凋落叶为研究对象,采用凋落叶分解袋法,研究了一个冬季不同冻融时期(冻结初期、冻结期和融化期)的质量损失特征。经过一个冬季(162d)的分解,康定柳、高山杜鹃、方枝柏和四川红杉凋落叶分别完成了初始干重45.5%、18.9%、26.4%和23.8%的分解;除康定柳凋落叶质量损失在融化期最大外,其余3种凋落叶均表现为冻结初期最大;康定柳、方枝柏和四川红杉凋落叶质量损失与河流水环境的平均温度和正积温均表现出显著或极显著的正相关关系,且与河流流速和硝态氮显著正相关,而与河流pH显著负相关;高山杜鹃凋落叶质量损失除与HCO3-含量显著相关外,与河流水温及其它水质特征均无显著相关关系。这些结果表明高山森林河流流速及水环境特征显著影响了凋落叶分解及其相关的物质循环过程,但影响程度受到凋落叶特性的调控。     

太湖介形类动物丰度与生物量

2004年9月~2005年8月对太湖介形类动物进行了季节性调查分析,结果表明：太湖中共有15种介形类动物,其年均丰度为1 590 ind/m2,年均生物量为46 495 μg(dwt)/m2,丰度和生物量在9个湖区的分布状态相似,受介形类自身食性及行为方式的影响,高丰度和高生物量主要出现在夏秋两季的太湖东半部分（包括东太湖、东部沿岸带和贡湖）。9个湖区中,除梅梁湖和贡湖外,其它几个湖区中介形类丰度和生物量的周年变化规律较为一致,而太湖中终年出现物种克氏瘤丽星介（〖WTBX〗Physocypria kraepelini〖WTBZ〗）、豆形豆形玻璃介（〖WTBX〗Fabaeformiscandona〖WTBZ〗 cf. 〖WTBX〗fabaeformis）和塔尔薄丽星介（Dolerocypria taalensis〖WTBZ〗）的自身繁殖力是造成梅梁湖和贡湖中介形类丰度和生物量间存在差异的主要原因,但两湖区中介形类丰度和生物量在整个太湖中所占比重有限,所以不影响太湖总体介形类季节变化趋势,四个季节中介形类的丰度和生物量均值总体呈现出秋＞夏＞冬＞春的规律。在15个物种中克氏瘤丽星介和豆形豆形玻璃介的丰度和生物量最高,所以两者为太湖介形类的建群种。介形类丰度、生物量与环境因子间的相关关系分析结果显示,水体中的植被密度、透明度、温度和溶氧量对介形类丰度和生物量分布和变化的影响较其它环境因子大,但因季节不同而有所变化。     

洞庭湖流域近58年季节性干旱时空分布及大气环流分析

利用洞庭湖流域1960～2017年103个气象站点逐月降水数据、NCEP/NCAR再分析数据以及Z指数,对洞庭湖流域近58年来季节性干旱的时空变化和不同干旱范围等级的大气环流形势进行分析,以加强对季节性干旱的认识。结果表明:近58年洞庭湖流域Z指数存在显著的年际和年代际变化特征,表现为20世纪60年代偏旱,70与80年代干旱呈现出显著的年际旱涝转换,90年代较湿润,进入21世纪出现年代际旱涝转换。春、夏和冬季干旱多发生在1990年之前,且流域的季节性干旱在不同的年代际存在不同的空间分布特征。流域各站点多年平均干旱频率基本在10%～30%之间。从同期大气环流形势来看,EU型遥相关波列对流域各季节干旱均有重要影响,EAP型与Silk Road型遥相关在夏、秋季节对副高强度与位置有重要影响。干旱事件在春、冬季主要受制于北方冷空气的强弱,夏(秋)季在副热带高压偏弱(强)偏北时易发生较大面积干旱。     

青藏高原四季降水变化特征分析

利用青藏高原87个地面气象台站41年（1960～2000年）的月降水资料,并在Arcgis 9.0中通过Kriging插值方法对少数站点的缺测值进行了插补,用线性回归方法研究了高原四季降水量的变化趋势及区域上的差异。为了保证本研究的完整性,对高原年降水也做了相应分析。结果表明：（1）高原冬春两季降水量呈显著增加趋势。冬季雅鲁藏布江下游、春季高原东北部为降水减少区,高原其他区域均表现为增加;夏秋两季降水量基本保持不变,但夏季高原中部和川西降水减少,高原南部和北部降水表现为增加;秋季高原中部、南部降水增加,川西降水减少。（2）高原年降水呈显著增加趋势。在区域上高原南部大致以东经102度为界,该线以东降水减少,以西降水增加,且降水增加区域表现出随纬度的增加而递减的特征。高原中部、北部的年降水基本保持不变或微弱增加。     

On seasonal variations of radiocesium speciation in the surface sediments of Lake Juodis, Lithuania

Data on radiocesium speciation measured seasonally in black silt surface sediments in the shallow terrace and in the deepest southern part of Lake Juodis (Lithuania) in 2004-2005 are presented. It is shown that seasonal variations of radiocesium exchangeable fractions in the sediments in the shallow terrace are mainly related to its redistribution due to the vital cycle of green algae covering bottom surfaces - processes of their growth and decomposition. A seasonal course of those fractions in surface sediments of the deepest bottom areas of the lake follows a distinct pattern and is annually recycling. It is maximum in winter and declines due to stagnant bottom water zone disruption in summer. It is shown that surface sediments in the deepest bottom areas of the lake are not a radiocesium source during the formation of the anaerobic zone in bottom water in winter, and act in that case as its acceptor. The radiocesium remobilization to the bottom water is seasonal and site-specific. It is suggested to be due to three main processes: its diffusion from deeper and more active sediments, its redistribution during decomposition of organics freshly accumulated in surface sediments and a radiocesium flux induced by the mechanism of the seasonal anaerobic zone formation in near-bottom water.