河南省春季降水与温度变化的时空分布——基于地理信息系统的分析

春季的气候条件异常一直是制约河南省小麦生产的瓶颈之一,春旱作为河南省主要的气象灾害,严重影响了小麦的生长。近几十年来,极端天气事件随着全球气候变暖的加快而越发频繁。春季干旱发生的主要因子降水和温度的变异性显著变大。基于GIS及和河南省30年的气候整编资料,对河南省春季降水、温度及降水温度比的变化趋势及时空变化分布进行了研究。结果表明:豫南春季降水减少最为严重(南阳盆地除外),豫中次之,豫北春季降水稍有增加;从温度的变化分布来看,河南全省春季温度都呈上升趋势,其中,豫南的信阳、驻马店,豫西北的济源、焦作、洛阳、郑州及平顶山地区温度上升趋势较大,南阳盆地、豫东平原及豫北平原地带温度变化相对较小;反应春季气候异常的降水温度比豫南为负向变化最大,豫北为正向变化最大,空间分布与春季降水基本吻合。综合分析说明未来河南地区的气候变化将会更加不稳定。     

Spatial distribution of perfluoroalkyl acids in the Pearl River of Southern China

An intensive campaign was conducted in September 2012 to collect surface water samples along the tributaries of the Pearl River in southern China. Thirteen perfluoroalkyl acids (PFAAs), including perfluorocarboxylates (PFCAs, C4–C11) and perfluorosulfonates (PFSAs, C4, C6–C8, and C10), were determined using high-performance liquid chromatography/negative electrospray ionization–tandem mass spectrometry (HPLC/(-)ESI–MS/MS). The concentrations of total PFAAs (ΣPFAAs) ranged from 3.0 to 52 ng L⁻¹, with an average of 19 ± 12 ng L⁻¹. The highest concentrations of ΣPFAAs were detected in the surface water of the Dong Jiang tributary (17–52 ng L⁻¹), followed by the main stream (13–26 ng L⁻¹) and the Sha Wan stream (3.0–4.5 ng L⁻¹). Perfluorooctanoate (PFOA), perfluorobutane sulfonate (PFBS), and perfluorooctane sulfonate (PFOS) were the three most abundant PFAAs and on average accounted for 20%, 24%, and 19% of ΣPFAAs, respectively. PFBS was the most abundant PFAA in the Dong Jiang tributary, and PFOA was the highest PFAA in the samples from the main stream of the Pearl River. A correlation was found between PFBS and PFOA, which suggests that both of these PFAAs originate from common source(s) in the region. Nevertheless, the slope of PFBS/PFOA was different in the different tributaries sampled, which indicates a spatial difference in the source profiles of the PFAAs.     

Spatio-temporal characteristics of PM10 concentration across Malaysia

The recurrence of forest fires in Southeast Asia and associated biomass burning, has contributed markedly to the problem of trans-boundary haze and the long-range movement of pollutants in the region. Air pollutants, specifically particulate matter in the atmosphere, have received extensive attention, mainly because of their adverse effect on people's health. In this study, the spatial and temporal variability of the PM10 concentration across Malaysia was analyzed by means of the rotated principal component analysis. The results suggest that the variability of the PM10 concentration can be decomposed into four dominant modes, each characterizing different spatial and temporal variations. The first mode characterizes the southwest coastal region of the Malaysian Peninsular with the PM10 showing a peak concentration during the summer monsoon i.e. when the winds are predominantly southerlies or southwesterlies, and a minimal concentration during the winter monsoon. The second mode features the region of western Borneo with the PM10 exhibiting a concentration surge in August–September, which is likely to be the result of the northward shift of the Inter Tropical Convergence Zone (ITCZ) and the subsequent rapid arrival of the rainy season. The third mode delineates the northern region of the Malaysian Peninsular with strong bimodality in the PM10 concentration. Seasonally, this component exhibits two concentration maxima during the late winter and summer monsoons, as well as two minima during the inter-monsoon periods. The fourth dominant mode characterizes the northern Borneo region which exhibits weaker seasonality of the PM10 concentration. Generally, the seasonal fluctuation of the PM10 concentration is largely associated with the seasonal variation of rainfall in the country. However, in addition to this, the PM10 concentration also fluctuates markedly in two timescale bands i.e. 10–20 days quasi-biweekly (QBW) and 30–60 days lower frequency (LF) band of the intra-seasonal timescales. These intra-seasonal fluctuations show strong seasonality with the largest fraction of variance occurring during the boreal summer and the weakest variance during the winter. Generally, the LF intra-seasonal oscillation is stronger compared to the QBW intra-seasonal band.     

雷州半岛桉林-砖红壤水分动态变化特征研究

根据定位观测数据,对雷州半岛浅海沉积物发育的桉林地砖红壤水分状况及其动态变化进行了初步探讨.结果表明,受水分蒸发量大等因素的影响,0～100 cm土层月均贮水量较低;主要受降雨分布的影响,土壤水分呈明显的季节性变化特征且季节性干旱时间较长,8～     

天津市中心城区空气污染物时间变化规律的研究

根据空气质量标准，分析了SO2、NO2和PM103项污染物不同季节，不同时期，不同时段变化规律、达标状况以及为制定相应的防治措施提供参考依据。     

Rapid genetic erosion in pollutant-exposed experimental chironomid populations

Few studies have evaluated how effectively environmental contamination may reduce genetic diversity of a population. Here, we chose a laboratory approach in order to test if tributyltin (TBT) exposure at environmentally relevant concentrations leads to reduced genetic variation in the midge Chironomus riparius. Two TBT-exposed and two unexposed experimental populations were reared simultaneously in the laboratory for 12 generations. We recorded several life-history traits in each generation and monitored genetic variation over time using five variable microsatellite markers. TBT-exposed strains showed increased larval mortality (treatments: 43.8%; controls: 27.8%), slightly reduced reproductive output, and delayed larval development. Reduction of genetic variation was strongest and only significant in the TBT-exposed strains (treatments: −45.9%, controls: −24.4% of initial heterozygosity) after 12 generations. Our findings document that chemical pollution may lead to a rapid decrease in genetic diversity, which has important implications for conservation strategies and ecological management in polluted environments.     

沈阳臭氧污染时空分布特征及变化趋势

以沈阳2013—2015年臭氧(O_3)监测数据为基础,从地域差异及时间变化上分析了沈阳O_3浓度变化特征。结果表明:沈阳城市外围O_3浓度高于城市中心;O_3浓度变化具有明显季节特征,夏季O_3浓度最高,冬季最低;O_3浓度日变化呈单峰分布,谷值出现在06:00,峰值出现在14:00;O_3浓度出现明显"周末效应",周末白天O_3浓度高于工作日O_3浓度,夜间差异不大。     

基于STIRPAT模型的环境压力空间差异分析——以能源消费为例

定量分析区域人文驱动力对环境的影响,对认识我国区域环境压力及其影响因素具有一定的科学意义.利用STIRPAT模型,以人口数量、富裕度为自变量,以能源消费总量为因变量,应用岭回归函数拟合得到环境压力模型.以研究结果为依据.利用Mapinfo7.0 软件分别绘制人口数量和富裕度对环境压力影响的空间差异图.结果显示,不同省份间人口数量和富裕度对环境压力影响存在显著差异.尽管各省份人口数量对环境压力都产生线性正效应影响,但影响强度有明显差异,最大者是最小者的8.079倍.富裕度对环境压力影响,有正效应或者负效应;有线性作用或者弹性作用.30个考察对象中,北京、上海、四川、新疆4个省市的富裕度二次项系数为负,这说明,在数据观测范围内以上4个省市的结果支持富裕度与环境压力间存在倒"U"型环境库兹涅茨曲线的观点;但这4个省市的环境压力并没有出现下降,这是由于各种人文驱动力影响的净效应决定了环境压力变化趋势.人口数量的增长对环境压力的上升存在较强正效应.因此,控制人口数量的速度对改善环境压力将起到关键作用.     

北京市气溶胶的时间变化与空间分布特征

以MODIS气溶胶遥感数据与同期AERONET监测数据为基础,应用统计分析、对比分析、时间序列分析等技术手段,研究了北京地区气溶胶的时间变化和空间分布特征.结果表明,气溶胶MODIS遥感反演数据和同期AERONET监测数据吻合较好,Pearson积矩相关系数为0 789,误差为ΔAOT550 = -0.077AOT 0.03.北京地区气溶胶550 nm光学厚度AOT和细粒比η的时间变化规律性明显:夏季以城市污染气溶胶为主,光学厚度最高,且具细粒特征;春季城市污染气溶胶和春季沙尘共存,光学厚度比较高,且粗粒占一定比例;冬季以采暖燃煤气溶胶为主,光学厚度不高,但是粗粒占较大比例;秋季大气清澈,气溶胶平均光学厚度仅为0.34.空间分布方面,主要受植被覆盖和产业结构等因素影响,位于西部北部山区的延庆、密云、怀柔和门头沟区气溶胶的光学厚度低,位于东南部平原地区的昌平、顺义、通县、大兴和房山区气溶胶光学厚度总体较高.     

贵州红枫湖水体溶解有机质的剖面特征和季节变化

溶解有机氮(dissolved organic nitrogen,DON)与溶解有机碳(dissolved organic carbon,DOC)相结合在湖泊水体溶解有机质(dissolved organic matter,DOM)的研究中少有报道.本研究对贵州喀斯特地区高原性湖泊———红枫湖水体DOC和DON的含量进行了近2a的测定,研究了DOM的剖面特征和季节变化,并探讨了DOM垂向分布和季节变化的影响因素.结果表明,红枫湖DOC的浓度范围为1.60～3.08 mg·L^-1,DON的浓度范围为0.10～0.37 mg·L^-1.在湖水混合期表层和底层的DOC和DON的浓度基本一致,在湖水分层期DOC和DON浓度表现出从表层往底层减小的趋势.表层水体(0～2m或3m)DOC的浓度在春末夏初或夏季达到最大,DON的浓度在春末夏初稍高于其它月份.结合叶绿素和降雨的数据分析认为,藻类活动和陆源输入直接导致了表层水体DOM的季节变化模式.DOM的C/N在一般情况下向下增大,但在夏季南湖的垂向水柱上,DOC和DON的浓度在12m以下增大,C/N从12m的18.1下降为14m的14.9,并向下持续减小,这很有可能是颗粒态有机质发生降解释放出C/N较低的DOM,成为水体内DOM的一个内源.