1960～2017年汉江流域气象干旱时空特征分析

基于汉江流域13个站点1960～2017年的逐月降水和平均气温资料,计算不同时间尺度下的标准化降水蒸散指数(SPEI),分析汉江流域气象干旱时空特征,并结合大气环流指数讨论该流域气象干旱成因.结果表明:(1)汉江流域SPEI数值具有3～4年的主周期,表现出干湿交替的状态.(2)年尺度下,轻旱和中旱发生频率在5％～24％,且西部地区较高.春季,多轻旱和中旱发生且频率在6％～19％;夏季,轻旱频率中部高于四周,最高地区频率在20％～28％;秋季,中部地区干旱频率较高;冬季干旱频率普遍高于10％但以轻旱和中旱为主.(3)年尺度下,汉江流域SPEI值以0.0021/a的速度降低,说明全球变暖对流域年际干旱情况影响很小;春季和秋季SPEI值与MEI、SOI显著相关,相关系数绝对值在0.271～0.422之间;夏季SPEI值与EASM显著相关,相关系数绝对值在0.261～0.498之间;冬季SPEI值与AO、NAO显著相关,相关系数绝对值在0.220～0.281之间.     

气候变化下SPEI指数在嘉陵江流域的干旱评估应用

基于嘉陵江流域1962~2010年实测月降水和月平均气温数据,利用不同时间尺度(3、6、9、12个月)的SPI和SPEI指数分析了近50a来流域干旱趋势的时空演变规律。对不同时间尺度的SPI及SPEI指数分析表明,1962~2010年嘉陵江流域整体呈干旱增加趋势,特别是流域西部和北部呈现出明显的干旱增加趋势,而流域东部的干旱增加趋势并不明显,个别站点附近还呈现出微弱的干旱减少趋势。SPI及SPEI指数的变化还表明,嘉陵江流域在大时间尺度上的干旱增加趋势更为明显,大时间尺度的干旱事件主要由降雨量决定,而气温变化对干旱趋势的影响则在小时间尺度上更为显著。此外,对于相同的时间尺度,SPEI指数相较于SPI指数检验出更为明显的干旱增加趋势,表明考虑气温影响的SPEI干旱指数更能够检测干旱事件的变化规律,因此SPEI干旱指数更适用于气候变化条件下流域干旱演变特征分析。     

基于CHIRPS卫星降水的雅砻江流域干湿时空演变分析

雅砻江流域是我国水电开发的重点区域之一，在全球气候变化背景下探究流域干湿时空演变规律有利于合理规划和充分利用水资源，为流域内农业生产活动提供科学指导。基于1981~2017年雅砻江流域内及周边16个气象站月气象数据，采用Penman-Monteith（PM）公式计算各站逐月潜在蒸散量ET0，基于气象站降水校正CHIRPS卫星降水产品，从而获得更高空间分辨率的降水数据，以此计算标准化降水蒸散SPEI指数，采用云模型、Mann-Kendall（MK）趋势检验法分析流域年代际、年、季尺度的干湿时空分布特征与变化趋势。结果表明：（1）对CHIRPS卫星降水产品进行偏差校正不但提高了精度，而且能够获得更高空间分辨率的降水；（2）流域春季呈湿润化趋势，其余时间尺度均呈现干旱化趋势，以冬季干旱化速率最快。年尺度下干湿变化不均匀度的稳定性最差，秋季稳定性相对最好。春、冬两季SPEI空间分布的不均匀度弱于时间分布；（3）同一时间尺度下的流域各级别干湿相对面积近似呈正态分布，流域干湿变化趋势空间分布差异较大；（4）流域各级别干旱与湿润高发区无明显区域分布规律，发生干旱与湿润的最高频率在20%左右，且随着干湿程度的加重，频率变化范围逐渐缩小；（5）不同年代干湿频率差异较为显著，年平均干旱频率变化趋势为减-增-减，湿润频率变化趋势为增-减-减，湿润频率高值区呈现由下游向上游转移的趋势。     

鄱阳湖流域1960～2018年极端气温变化及其与大气环流的关系

为进一步揭示鄱阳湖流域极端气温事件变化及其影响因素,基于鄱阳湖流域24个气象站点连续59年观测资料,选取8个极端气温指数,分析鄱阳湖流域极端气温动态变化,并探讨了大气环流与极端气温变化的联系.结果表明:(1)鄱阳湖流域极端气温暖指数(暖昼天数、暖夜天数和夏日天数)及极值指数(日最低气温最小值和日最高气温最大值)均呈增加趋势;冷指数(冷昼天数、冷夜天数和霜冻天数)均呈逐渐减少趋势.(2)从空间分布来看,极端气温空间变化趋势与年际变化一致,极端气温暖指数和极值指数呈增加趋势,冷指数均呈减少趋势,但在不同地区变化趋势存在差异.流域各站点霜冻天数和冷昼天数均呈显著下降趋势,但在赣北地区下降趋势最显著.大部分站点(23/24)暖夜天数、夏日天数和日最低气温最小值均呈显著增加趋势;(3)鄱阳湖流域极端气温指数的变化与大气环流的变化存在相关性,其中西太平洋副高强度指数、夏季东亚季风指数、亚洲区极涡强度指数和北极涛动指数对极端气温事件影响显著.研究结果可为极端气候风险评估、灾害预警提供参考.     

汉江流域1961～2018年多尺度气象干旱时空演变特征

干旱是一种最常见的自然灾害,随着人类活动和气候变化的加剧,干旱事件的发生愈发频繁,对人类的生产生活产生了巨大影响.基于1961～2018年汉江流域0.25°×0.25°格点降水资料,选用标准化降水指数(SPI)定量分析了汉江流域的月尺度、季尺度、年尺度气象干旱的干旱趋势、干旱频率及干旱强度,揭示了汉江流域气象干旱发生的时空演变特征.结果表明:(1)SPI值能较好的反映汉江流域气象干旱变化特征,随着时间尺度的增加,SPI值波动幅度减小,稳定性增强.月、季、年尺度SPI序列的突变年份分别为1980、1988、1994年,季尺度和年尺度SPI序列分别表现出2和4年的显著周期性特征.(2)汉江流域自20世纪90年代以来呈现中部地区干旱化、东部和西部地区湿润化的趋势,干旱发生频率总体呈上升趋势,干旱强度呈现中部高,东西低的特征.其中丹江口水库附近区域和唐白河下游段呈显著干旱化趋势,丹江口以上区域干旱频率最高,干旱强度最大,轻旱、中旱事件频发.(3)各地区的季节性气象干旱特征具有一定差异性.丹江口以下地区秋旱趋势最显著,唐白河地区夏旱发生频率最高,且以轻旱、中旱事件为主,丹江口以上地区秋旱强度最高.     

基于SPEI的云南中部区域干旱时空变化特征分析

利用云南中部地区1961~2010年逐月降水和气温资料,采用降水距平百分率和历史旱情资料验证了标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index,SPEI)在该地区的适用性,并采用Mann-kendall突变检验、Morlet小波和经验正交函数(Empirical Orthogonal Function,EOF)等方法,分析了该地区干旱的时空演变特征,结果表明:(1)SPEI与降水距平百分率在时空上具有很好的相关性,验证了SPEI对降水变化的敏感性;(2)SPEI指数与历史旱情资料比较吻合,能够有效地反映云南中部区域的干旱特征;(3)年均SPEI呈波动下降趋势,干季SPEI降低趋势明显。年均SPEI存在着24a的主周期和9a的次周期,并于1977年发生了突变,此后开始降低,在整体上呈现出干旱化的趋势;(4)从SPEI的空间分布特征来看,其在整体上受大尺度气候系统的影响表现出一致的下降趋势,而在区域内部则表现出东南-西北(干热河谷)的反向结构差异。     

基于SPEI的西南农业区气象干旱时空演变特征

干旱已成为西南农业区的具有一定破坏力的自然灾害,研究干旱的时空变化对该区干旱的评估、预测具有重要的现实意义。根据西南农业区1962~2012年月气象资料,利用Penman-Monteith公式计算蒸散发和标准化降水蒸散指数(SPEI)值;采用线性回归、Mann-Kendall方法、小波分析和旋转经验正交函数(REOF)等方法分析了西南农业区干旱时空变化。研究结果表明:(1)西南农业区整体呈干旱化趋势;2000年以来年、四季变干趋势更加明显;秋季变干趋势显著;年均SPEI指数不存在显著突变点;年和四季干湿变化均存在2~8 a左右的振荡周期。(2)根据REOF分解的前6个空间模态,将西南农业区划分成6个干湿特征区域:云南高原东部区、汉中盆地区、东部山地区、云南高原西部区、四川盆地区、贵州高原区;其中云南高原东部区变干趋势显著,汉中盆地区和东部山地区有变湿润趋势,但并不明显;6个分区干湿变化普遍存在2~6 a左右的振荡周期。研究结果可为西南农业区防旱、抗旱提供科学参考。     

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。     

嘉陵江流域降水集中度的时空变异与驱动因素研究

降水的集中分布是引发洪涝灾害和河流高含沙事件的主要因素,对降水集中度时空变异规律的认识及其主要驱动因素的辨析可为区域水资源管理和灾害预警提供依据.以长江上游最大的产沙支流嘉陵江流域为研究区,基于流域内19个气象站点1954～2018年的逐日降水数据,计算年平均降水集中度(ACI)和长期降水集中度(LCI)指数,采用Mann-Kendall趋势检验法、Sen's slope坡度检验法和反距离权重插值法分析降水集中度指数的时空变异规律,基于相关性分析和随机森林算法探讨其主要驱动因素.结果 表明:(1)嘉陵江流域的ACI和LCI值在空间上均呈现北低南高的分布格局,东南部人口密集区降水集中度大,极端降水事件发生的可能性大;而西北部山区降水集中度较小,降水较均匀,发生极端降水的可能性较小.(2)研究期间降水集中度的数值变化范围为0.53～0.83,变幅较大;19个气象站点中,15个站点降水集中度呈现上升趋势(其中8个为显著上升),4个站点呈现下降趋势(其中2个为不显著下降),各站点的趋势性差异亦与地形、气候因素密切相关.(3)通过相关性分析发现,降水集中度与流域高程具有显著的负相关关系(p＜0.01);基于随机森林算法的重要性分析结果表明,对嘉陵江流域内降水集中度影响最大的气候因子为太阳黑子指数SS,重要性为17.24％～20.25％,其次为ENSO指数(MEI和SOI).     

SPEI及SPI指数在滇西南地区干旱演变中的对比分析

以滇西南地区为研究区,计算出近53 a该区及周边44个气象站点标准化降水蒸散指数(SPEI)和标准化降水指数(SPI)。运用M-K突变检测和Morlet小波交换等方法,对滇西南地区两种指数对应下的4种类型季节连旱变化特征进行系统分析。结果表明:近53 a中,两种指数判定的同一时间尺度下的干旱事件次数和发生时间基本统一,4种类型季节连旱事件为12~14次,多存在并发性;4个季节连旱时段上两种指数均存在3 a左右显著周期变化;同一时段上,两种指数在趋势变化格局空间分布和变化程度上均存在着较大差异,4个时段上的干湿变化趋势也表现出SPEI呈变干趋势,SPI则变干、变湿各为一半的明显不同,这主要是由于期间研究区显著增温加剧了"降水量-蒸散"的水分平衡;与SPI相比,SPEI考虑了热量因子对潜在蒸散发的贡献,能较好地对气候变暖背景下研究区干旱进行刻画。     

Formaldehyde in conventional homes in Taiwan

A survey was conducted in the humid environment of Taipei City during April and May of 1991, to investigate the indoor formaldehyde exposure and its health effects on 117 conventional households. The levels of formaldehyde were measured by the pararosaniline method. The details regarding construction, ventilation, combustion of fuel, burning of Chinese incense, and the complaints concerning the respiratory system were obtained by a questionnaire. The results show that the age of the pressed wood used in furniture and indoor decoration, the ventilation rate, the combustion of fuel, and the burning of Chinese incense significantly affect the levels of formaldehyde. The respiratory complaints found in this study were concluded here to be only partially accounted for by exposure to formaldehyde.     

Natural radionuclides in bottled water in Austria

Concentration levels of 226Ra, 222Rn and 210Pb were analyzed in domestic bottled waters commercially available in Austria. Concentrations up to 0.23 Bq/l, with a geometric mean of 0.041 Bq/l were found for 226Ra. Concentrations for 222Rn ranged from <0.12-18 Bq/l, the geometric mean being 0.54 Bq/l. Lead-210 was analyzed in selected samples, the concentrations ranging from <2 to 34 mBq/l, with a geometric mean of 4.7 mBq/l. Ingestion doses resulting from consumption of these waters were calculated for the geometric mean and the maximum concentrations of the three radionuclides. The effective dose equivalents for different age groups of the population due to the intake of 226Ra range from 0.001 to 0.22 mSv/y and of 210Pb from 0.0003 to 0.05 mSv/y. Ingestion doses from 222Rn are low compared to those from 226Ra and 210Pb, ranging from 0.0001 to 0.011 mSv/y for adults and children, respectively. The doses are compared to the total ingestion dose from dietary intake of natural radionuclides on an annual basis.     

Precipitation-driven decrease in wildfires in British Columbia

Trends of summer precipitation and summer temperature and their influence on trends in summer drought and area burned in British Columbia (BC) were investigated for the period 1920–2000. The complexity imposed by topography was taken into account by incorporating high spatial resolution climate and fire data. Considerable regional variation in trends and in climate–fire relationships was observed. A weak but significant increase in summer temperature was detected in northeastern and coastal BC, whereas summer precipitation increased significantly in all regions—by up to 45.9 %. A significant decrease in province-wide area burned and at the level of sub-units was strongly related to increasing precipitation, more so than to changing temperature or drought severity. A stronger dependence of area burned on precipitation, a variable difficult to predict, implies that projected changes in future area burned in this region may yield higher uncertainties than in regions where temperature is predominantly the limiting factor for fire activity. We argue that analyses of fire–climate relationships must be undertaken at a sufficiently high resolution such that spatial variability in limiting factors on area burned like precipitation, temperature, and drought is captured within units.     

Radon concentrations in a spa in Serbia

The paper presents the results of indoor radon concentration survey in 201 homes and offices in Niska Banja (the Spa of Nis), a well-known health resort and a spa in the South-East of Serbia. Radon indoor concentrations were determined by active charcoal method, according to standard EPA procedure. The indoor radon concentrations were in the range of up to 200 Bq/m(3) (47%), from 200-600 Bq/m(3) (26%) and over 600 Bq/m(3) (27%). Three areas of extremely high average radon concentrations were found (1,340-4,340 Bq/m(3)), with a maximum above 13,000 Bq/m(3). The content of natural radionuclides ((226)Ra, (214)Pb, (214)Bi, (235)U, (228)Ac, (212)Pb, (212)Bi, (208)Tl, (40)K) and (137)Cs, as well as the content of total uranium, thorium and potassium in mud used in peloidotherapy in the Health Institute "Niska Banja" was determined, too. The activities of the radionuclides were determined on an HPGe detector, by standard gamma spectroscopy. The results indicated considerably high amounts of total uranium and thorium (0.021 g/kg mud and 0.003 g/kg mud, respectively), due to the karsts origin of the soil.     

Trends in lung cancer in London in relation to exposure to diesel fumes

Mortality from lung cancer among males in England and Wales is now beginning to decline, and the urban excess that has persisted for many years is also becoming smaller. There is nothing in these national trends to suggest that pollution from diesel vehicles, which has been increasing in recent decades, would be involved. Some preliminary results are presented from a long-term study of the incidence of lung cancer among London Transport staff, including men who work in bus garages where there are high concentrations of smoke from diesel buses. Over the 25 year period from 1950–1974 the numbers of cases reported in each of the several job categories have been below those expected on the basis of Greater London rates. The absence of data on smoking habits makes it difficult to determine whether the small differences in rates between job categories are of any importance, but the standardised mortality ratios are all well within the range of those found in national studies of lung cancer mortality and smoking in relation to occupation.     

Seasonal changes in radon concentrations in buildings in the region of northeastern Poland

In this study, seasonal observations of radon concentration changes inside buildings carried out in the northeastern region of Poland is presented. One-year measurements of radon concentrations were performed in chosen buildings. The integral method of Cr-39 trace detectors in diffusive chambers was used. Mean values of radon concentrations were determined in monthly, 2-, 3-, 6-month, and annual observations. The fraction of a mean annual concentration of the value obtained in a shorter observation was calculated. Monthly concentration values were from about 0.2 to 14.9 of the annual mean. All buildings revealed seasonal fluctuation of radon concentration. Negative correlation of indoor radon concentration in the buildings and the mean temperature outside was observed in most examined buildings. The lowest coefficient range, determining which part of the annual mean value would be obtained in the 6-month observation, was gained for exposure begun in April or October.     

Participatory approach in vision setting: emerging initiatives in local municipalities in Japan

In this paper, we present the emerging practices in Japanese local municipalities, in which participatory methods are applied to envision sustainable future and relevant target settings. We selected three local cases: Higashiomi city, Kizugawa city and Nagakute city as emerging initiatives. A comparative analysis was carried out to identify commonalities and differences, and to derive lessons for appropriate governance and systems for participatory deliberation in future visioning. We argue that the deliberation processes served as a platform for effective communication, and that installing a mechanism that allows reflexive deliberation processes is the key to make participatory methods fully functional.     

Natural radionuclide content in building materials and gamma dose rate in dwellings in Cuba

An extensive research project to investigate the radioactive properties of Cuban building materials was carried out because there is a lack of information on the radioactivity of such materials in Cuba. In the framework of this project 44 samples of commonly used raw materials and building products were collected in five Cuban provinces. The activity concentrations of natural radionuclides were determined by gamma ray spectrometry using a p-type coaxial high purity germanium detector and their mean values were in the ranges: 9-857Bqkg(-1) for (40)K; 6-57Bqkg(-1) for (226)Ra; and 1.2-22Bqkg(-1) for (232)Th. The radium equivalent activity in the 44 samples varied from 4Bqkg(-1) (wood) to 272Bqkg(-1) (brick). A high pressure ionisation chamber was used to measure the indoor absorbed dose rate in 543 dwellings and workplaces in five Cuban provinces. The average absorbed dose rates in air ranged from 43nGyh(-1) (Holguín) to 73nGyh(-1) (Camagüey) and the corresponding population-weighted annual effective dose due to external gamma radiation was estimated to be 145+/-40microSv. This value is 51% lower than the effective dose due to internal exposure from inhalation of decay products of (222)Rn and (220)Rn and it is 16% higher than the calculated value for the typical room geometry of a Cuban house.     

Lead content in new decorative paints in India

The paint industry in India is broadly classified into two categories: organized sector and unorganized sector. Multinational and big Indian companies form the organized sector, whereas the small- and medium-scale industries which produce paints for the local market form the unorganized sector. The present study was undertaken to determine the level of lead in decorative paints in India. A total of 148 paint samples sourced from four organized sector companies and six unorganized sector companies were analyzed for the total lead content. Results of this study reveal that 39 % of the total paints tested (n = 148) contain lead more than 300 ppm, the voluntary limit prescribed by Bureau of Indian Standards, BIS (IS 15489:2011), and 45 % of the tested paints contain lead more than 90 ppm, the US limit. Further analysis of the data indicates that only 5 % of the tested paints manufactured by organized sector companies contain lead more than 300 ppm (n = 91), whereas 93 % of the tested paints manufactured by unorganized sector companies contain lead more than 300 ppm (n = 57). Comparison with earlier reported data suggests that while organized sector companies are gradually abandoning the use of lead-based compounds in their paints, the unorganized sector companies are still adding lead-based compounds intentionally in their paints despite the potential health hazards associated with it. The maximum concentration of lead obtained was 80,350 ppm in one of the paints manufactured by an unorganized sector company. The presence of high concentration of lead in yellow and green color paints indicates that color can be a predictor of lead content in decorative paints.