长三角城市群冬季一次重污染天气过程分析

利用NCEP/NCAR和FNL再分析资料,并结合长三角城市群地面气象观测数据,探讨了2014年1月18—25日长三角城市群一次重污染天气过程的气象成因以及污染物路径分析。结果表明,污染期间随着相对湿度和PM2.5浓度的升高,大气能见度明显降低。2014年1月影响我国的东亚冬季风势力偏弱,导致重污染期间冷空气活动偏弱;此外,垂直方向上出现逆温,限制垂直运动的发生、发展。上述因素有利于长三角地区污染物在近地面层堆积,导致重污染天气的发生发展。污染物从温度高的地方向温度低的地方扩散。低空气温低时,不易形成对流,促使污染物在长三角地区堆积。HYSPILT模式模拟显示污染物主要来自山西、河北一带,以平流和弱辐散的方式向长三角地区输送。大气化学模式WRF-Chem可较好地模拟出PM2.5浓度的变化过程,可用作长三角城市群重污染天气预报的业务模式。     

Polychlorinated naphthalenes (PCNs) in surface sediments of the Yangtze and Yellow River Estuaries, China

The concentrations and congener profiles of poly-chlorinated naphthalenes (PCNs) in surface sediment samples collected from the Yangtze and Yellow River Estuaries were inves-tigated. PCN congeners (from MoCNs to OCN) were determined by isotope dilution/high-resolution gas chromatography/high-resolution mass spectrometry (HRGC-HRMS). The total concentrations of PCNs were 34.3-303.0 pg/g (dry weight, dw) in the Yangtze Estuary samples and 6.2-408.0 pg/g (dw) in the Yellow River Estuary samples, which were lower compared with that in other sediments reported by previous studies. In addition, the remarkably different homologue or congener profiles of PCNs have been obtained in this study. Samples dominated with MoCNs to TrCNs might be attributed to atmospheric deposition and global fractionation, while in other samples taken from the surrounding industrial areas the enrichment of higher chlorinated homologues suggested that the industrial and human activities should be the main potential sources.     

Impacts of the Fukushima nuclear accident on the China Seas: Evaluation based on anthropogenic radionuclide 137Cs

In order to evaluate the impact of the Fukushima nuclear accident on the China Seas, seawater samples from the South China Sea (SCS), the East China Sea (ECS) and the Yellow Sea (YS) were collected in April–June 2011, and their ¹³⁷Cs activities were measured using low-background γ-spectrometry. ¹³⁷Cs activities in the study area ranged from 0.75±0.07 to 1.43±0.08 Bq m^?3 with an average of 1.12±0.08 Bq m^?3. ¹³⁷Cs activities initially increased from the nearshore to the inner shelf, and subsequently decreased from the inner shelf to the outer shelf. Vertical profiles showed higher ¹³⁷Cs activities at the surface but lower activities at depth in the ECS, suggesting atmospheric input of ¹³⁷Cs. As such, the distribution pattern of ¹³⁷Cs in the region was presumably determined by a combination of atmospheric deposition and subsequent mixing between different water masses including the coastal currents, the Yangtze River plume and the Taiwan Warm Currents. Based on the inventory of 93 Bq m^?2 and the atmospheric deposition flux of ¹³⁷Cs in the ECS of 32.2 mBq m^?2 d^?1 (5.4–42.9 mBq m^?2 d^?1) which we estimated, we derived the residence time of ¹³⁷Cs in the upper water column to be 66 d (45–95 d). We concluded that in terms of ¹³⁷Cs, the ECS was less impacted by the Fukushima accident as compared to the Chernobyl accident. The released amount of ¹³⁷Cs into the ECS from the Fukushima accident was minute.     

大气甲醛时空特征与影响因素分析——以中国主要经济区为例

基于2007—2018年臭氧监测仪甲醛数据,探讨了京津冀、长三角、粤港澳3个主要经济区的大气甲醛柱浓度时空分布特征,并对比分析了不同自然条件和人类活动因素对主要经济区大气甲醛浓度演变的影响关系。结果表明:2007—2018年主要经济区大气甲醛年均柱浓度总体呈增长趋势,变化经历了快速增长、缓慢回落、平稳发展和迅速反弹4个阶段,多年甲醛平均浓度表现为粤港澳>长三角>京津冀,甲醛浓度变化有明显的季节性,表现为夏秋高、春冬低。空间分布特征表明,京津冀地区大气甲醛东南高、西北低;长三角中部和西部地区甲醛柱浓度较高,并由内陆向沿海地区递减;粤港澳地区广州、佛山两地大气甲醛柱浓度较高,同样表现为内陆向沿海递减。自然影响因素中,地形是影响大气甲醛空间分布特征的重要影响因素,温度、降水和植被与大气甲醛浓度的季节性变化有较强的关联。影响京津冀、长三角和粤港澳地区大气甲醛变化最主要的人为因素分别为工业活动、交通运输和第二产业发展。     

长江口及其邻近海域洪季悬沙分布特征分析

基于近几年大量的实测资料,对长江口及其邻近海域洪季期间悬沙浓度的时空分布特征进行了分析.结果表明,悬沙浓度空间上以杭州湾测点最高,其次是长江口内、长江口外,舟山海域最低;悬沙平面分布总体态势为近岸高而外海低;长江口纵向上自口内经口门向口外悬沙浓度大致呈“低-高-低”分布,沿杭州湾测点则由西向东逐渐降低;横向比较长江口外海滨四个测点发现其悬沙浓度自北向南顺次升高;悬沙浓度一般由表及底逐渐增大,但在不同水域其主要呈现的垂线结构类型则有所不同.时间上由于潮流的大小潮和潮周期变化,悬沙浓度还存在大小潮和涨落潮周期变化.另外,对长江口及其邻近海域悬沙浓度时空分布特征的原因进行了初步分析.     

Linkage between winter sea surface temperature east of Australia and summer precipitation in the Yangtze River valley and a possible physical mechanism

The relationship between winter sea surface temperature (SST) east of Australia and summer precipitation in the Yangtze River valley and a possibly related physical mechanism were investigated using observation data. It is found that winter SST east of Australia is correlated positively to summer precipitation in the Yangtze River valley. When the SST east of Australia becomes warmer in winter, the western Pacific subtropical high and the East Asian westerly jet tend to shift southward the following summer, concurrent with low-level southwesterly anomalies over eastern China. These conditions favor precipitation increase in the Yangtze River valley, whereas the opposite conditions favor precipitation decrease. The influence of winter SST east of Australia on East Asian summer atmospheric circulations may occur in two ways. First, by an anomalous SST signal east of Australia in winter that persists through the following summer, thus affecting East Asian atmospheric circulations via the inter-hemispheric teleconnection. Second, when the SST east of Australia is warmer in winter, higher SST appears simultaneously in the southwest Indian Ocean and subsequently develops eastward by local air-sea interaction. As a result, the SST in the Maritime Continent increases in summer, which may lead to an anomalous change in East Asian summer atmospheric circulations through its impact on convection.     

基于三阶段DEA模型的长江中游城市群创新效率研究

以长江中游城市群28个地级市为研究对象，运用三阶段数据包络分析（DEA）模型测度并分析长江中游城市群2005—2018年的创新效率及其时空演化特征，采用地理加权回归（GWR）模型揭示创新效率空间差异的影响因子及其空间异质性.结果显示：长江中游城市群创新效率呈现两段式特征，2005—2010年为平稳发展期，2011—2018年为波动变化期；“一圈二群”创新发展趋势尚不明朗，目前还处于创新发展的初级阶段；长江中游城市群2005—2018年创新效率空间分异显著，整体上呈现“发散-聚敛-发散”的特征；经济基础（ECO）、产业结构（INDU）、外商投资（FDI）、政府支持（GOV）以及基础设施建设（BAS）对长江中游城市群创新发展的驱动模式存在较大差异，具有明显的空间分异性.     

Sediment change under climate changes and human activities in the Yuanjiang-Red River Basin

Both the climate change and human activities are the major influence factors to the sediment change in mountainous rivers. Based on the over 40 years’ record, suspended sediment loads (SSL) change at the Manhao gauging station in the lower reaches of Yuanjiang River (upper Red River). In this paper, the variation of the sediment and its drivers were analyzed through different methods such as synchronous data comparison, traditional correlation, linear regression, and Granger causality. The results show that (1) the general trend of the annual average sediment concentration (SSC) and SSL at Manhao station is increasing from the 1960s to the 1990s, and there is a quick change period after 1984; (2) the SSL and SSC at Manhao station, during different periods of the 1960s, 1970s, 1980s and 1990s, are 1.87, 2.49, 3.12, 3.63 kg/m³, and 28.7×10⁶, 40.3×10⁶, 44.1×10⁶, 60.3×10⁶ t/a, respectively; (3) the correlation analysis and the Granger causality test proved that the climate changes in the catchment were the main driving factors to the sediment variation in the period of 1960s and 1990s, but the influence by the mountainous human actions on the sediment change is stronger than that by the local climate changes in the 1970s and 1980s; (4) the correlation between the sediment changes and the forest coverage change is negative, which further proves that the sediment changes are strongly affected by the human activities in the basin.

     

长江中游宜昌至武汉段底栖动物群落结构特征研究

为了解长江中游宜昌至武汉段底栖动物的群落结构特征以及主要影响因素,分别于2014年春季(4月)和秋季(10月)在该江段布设4个断面(共29个采样点)和5个断面(共40个采样点),进行底栖动物群落监测。春季采集到底栖动物34种,秋季采集到32种,均是节肢动物丰度最高,分别为56%和35%。春季物种丰度、密度和生物量均大于秋季,且春、秋季生物量自上而下逐渐减小。功能摄食类群研究结果表明,该江段底栖动物以牧食者占绝对优势,春、秋季牧食者个体数占总个体数的比例分别为40.25%和59.3%。生物耐污能力统计结果表明,该江段以中等敏感类群和耐污类群为主,武汉断面在两个季节中均以耐污类群为主。5种功能摄食类群以及三大门类生物现存量与7个环境因子的相关性分析结果表明,春、秋季生物受环境因子的影响差异较大,总磷、总氮和粒径是影响春季底栖动物群落结构特征的主要环境因子,而秋季底栖动物主要受p H、溶解氧和透明度的影响。该研究从多个方面较全面地分析长江中游江段底栖动物群落特征,为开展长江大河深层次研究提供基础性资料。     

近48年长江源区降水时空变化特征分析

基于1966～2013年长江源区及周边在内7个气象站点的逐日降水资料,采用降水倾向率、Mann-Kendall趋势检验、Morlet小波分析及Hurst指数法等方法,分析了长江源区近48年来降水量时间序列空间分布特征、年际和年内变化趋势以及其周期性变化特征,并对降水未来的演变趋势进行了预测。分析结果表明：(1) 长江源区降水量存在明显的空间变化差异,总体分布趋势为由东南向西北递减;(2) 近48年来长江源区降水量呈现较为明显的增加趋势,增加速率为17 mm/10a,多年平均降水量为351.5 mm;(3) 长江源区降水量年内分配极不均匀,主要集中在汛期,约占全年总降水量的89.6%,而非汛期降水量仅占10.4%,且降水量具有较明显的季节差异,夏季降水最大,秋季次之,其次是春季,冬季降水量最小;(4) 长江源区降水量变化存在28 a左右的第一主周期,第二、三、四主周期分别为21 a、12 a和5 a;(5) 长江源区各气象站点及全流域的Hurst指数均大于0.5,表明降水量未来趋势与过去一致,即其未来仍将延续降水量增加的变化趋势。     

长江重庆主城区段突发水污染事故模拟研究

因重庆山城特殊的地势，主城区沿长江和嘉陵江两岸建有多种形式的排水干管，一旦发生管道破裂将危及下游水厂取水口的水质安全。在三峡水库蓄水至175 m水位后，针对长江重庆主城区段可能发生的突发水污染事故，基于实测地形、水文等数据，构建二维水动力水质耦合模型，采用优化反演法率定河道糙率，借助有限元法分别模拟河流在丰、枯水期管道破裂事故发生后在24 h或48 h完全修复的情况下，各类污染物（五日生化需氧量BOD₅、化学需氧量COD、总氮TN、总磷TP）质量浓度随时间和空间的变化。模拟结果可为重庆主城突发排水干管破裂的应急预案优化提供科学依据。     

走马塘拓竣延伸工程对长江水环境影响研究

走马塘拓竣延伸工程是2008年5月国务院批复的《太湖流域水环境综合治理总体方案》安排实施的重要引排工程之一。工程主要是解决望虞河引江济太期间西岸地区的排水出路问题：在望虞河引江济太期间,望虞河西岸地区涝水不入望虞河改由走马塘拓浚延伸工程北排长江。笔者重点分析了走马塘排水对长江水环境的影响。     

主分量分析方法在乌鳢种下分类中的应用

利用采自全国各地的68尾普通乌鳢Ophicephabus argus argus Cantor,采自四川嘉陵江的19尾白乌鳢O.a.kinacran(Shih)和东北地区的14尾黑龙江乌鳢O.a.warpachowska Berg作为研究材料,选取3个计数性状和12个比例性状,对其种下分类进行了主分量分析.结果表明,自乌鳢与普通乌鳢覆盖率为73%.黑龙对乌鳢与前者完全分开,因此由乌鳢亚种不能成立.乌鳢可分为乌鳢指名亚种和黑龙江乌鳢亚种.两亚种可由侧线鳞和吻长与全长的比例区分开.     

Analysis on river sediment changes of the upper reaches of Yantze River

The sediment load and river sedimentation of the upper reaches of Yangtze River has been undergoing constant changes as complex landform, large mountain area and plentiful precipitation make the drainage area of Yangtze River very vulnerable to water erosion and gravity erosion. Through analyzing the hydrological and sediment load statistics recorded by major hydrological stations along Yangtze River since 1950s, and editing the accumulation graph of annual runoff volume and annual sediment load, we find out that the suspended-sediment of Yangtze river has been decreasing year by year in Wulong Hydrological Station on Wujiang River. Beibei Hydrological Station on Jialingjiang River, Lijiawan Hydrological Station on Tuojiang River and Gaochang Hydrological Station on Minjiang River, Yichang Hydrological Station, Cuntan Hydrological Station along Yangtze River mainstream share the same experience too. But the statistics obtained at Pingshan Hydrological Station on Jinshajiang River shows the sediment load there has increased. Taking ecological construction, hydraulic engineering construction and precipitation changes into consideration, the thesis analyses the causes for the sediment load decrease of Jialingjiang River, Tuojiang River, Minjiang River and Wujiang River and provides us both scientific foundation for further study of river sediment changes of the upper reaches of Yangtze River, and measures to control river sedimentation. Foundation item: Supported by the National Natural Science Foundation of China (50099620) Biography: ZHONG Xiang-hao (1942-), male, researcher, research direction: mountain environment and ecology.     

青藏高原积雪异常对亚洲夏季风气候的影响

为了研究青藏高原积雪异常对亚洲夏季风气候的影响,从季风环流和季风降水等方面综合分析了高原积雪异常对气候的影响,并利用IAP 9L AGCM模式,对高原雪量进行了增加和减少的数值试验。从而提出高原多(少)雪年南亚夏季风偏弱(强),东亚夏季风反而偏强(弱)的新观点。高原积雪异常会导致高原上空大气垂直运动的扰动,扰动传播到下游致使我国长江流域和西太副高所在区域大气对流运动发生变化。高原多(少)雪,夏季我国南方的偏南风增强(减弱),有利于水汽从孟加拉湾和南海向我国大陆输送,但到长江流域时,由于偏南风存在较强(弱)的辐合,江淮流域偏涝(旱)。     

大气程辐射遥感图像技术

大气程辐射遥感图像是遥感图像中各点大气程辐射遥感值按顺序排列所形成的、与地面状况无关的、仅与大气状况有关的、无法在自然条件下直接获取的遥感图像.就对地探测而言,大气程辐射是需消除的干扰因素,对于大气传输特性的研究、遥感图像的大气修正、区域大气遥感探测和大气环境质量遥感监测等则是宝贵的信息源.研究利用遥感数字图像和对应地面反射率、逐点分离、提取像元大气程辐射遥感值从而生成大气程辐射遥感数字图像有重要理论和应用价值.     

咸潮入侵对上海市水质影响研究

本市地表水资源593.5亿立方米,其中长江径流量占80％故长江径流量是发展上海经济和对外开放的主要限制因素,但近年来长江径流量逐年减少,导致咸潮入侵增强,给国民经济建设和人民身体健康带来威胁。本文分析长江口区咸潮入侵途径和咸潮入侵的变化规律,进而探讨咸潮入侵对上海水资源产生的可能影响,最后提出减轻减潮入侵,改善水质的设想。     

咸潮入侵对上海市水质影响研究

本市地表水资源593.5亿立方米,其中长江径流量占80%故长江径流量是发展上海经济和对外开放的主要限制因素,但近年来长江径流量逐年减少,导致咸潮入侵增强,给国民经济建设和人民身体健康带来威胁.本文分析长江口区咸潮入侵途径和咸潮入侵的变化规律,进而探讨咸潮入侵对上海水资源产生的可能影响,最后提出减轻减潮入侵,改善水质的设想.     

The latest Yanshanian magmatic and metallogenic events in the middle-lower Yangtze River belt: Evidence from the Ningzhen region

The Ningzhen region in Jiangsu Province represents the easternmost magmatic region in the middle-lower Yangtze River belt.The formation of the polymetallic deposits has close genetic relationships with Early Cretaceous intermediate-acid intrusions.In this study,LA-ICP-MS zircon geochronology of two Mesozoic intermediate-acid intrusive rocks(including the Shima porphyritic granodiorite and Gaozi quartz diorite porphyry)in the Ningzhen region were systematically investigated.These new geochronological data demonstrate that the intermediate-acid magmatism in the Ningzhen region dates to approximately between 109 and101 Ma.We present new40Ar-39Ar phlogopite ages for the Cishantou skarn iron deposits that constrain the timing of the mineralisation in the Ningzhen region.The phlogopite in the Cishantou skarn deposits yielded a40Ar-39Ar plateau age of 104±1 Ma.This result coincides with the ages of the Anjishan and Tongshan Cu(Mo)deposits in the Ningzhen region.Our high-precision geochronological data together with recent high-precision geochronological studies(such as zircon LA-ICP-MS U-Pb,zircon SHRIMP U-Pb,molybdenite Re-Os and single-mineral40Ar-39Ar dates)reveal that there were four periods(152-135 Ma,135-127 Ma,127-121 Ma,109-101 Ma)of magmatism and ore formation in the middle-lower Yangtze River metallogenic belt.The Mesozoic intermediate-acid magmatism and mineralisation in the Ningzhen region belong to the latest episode in the middle-lower Yangtze River metallogenic belt.     

A physically-based statistical forecast model for the middle-lower reaches of the Yangtze River Valley summer rainfall

A new approach to forecast the middle-lower reaches of the Yangtze River Valley summer rainfall in June-August （JJA） is proposed in this paper. The year-to-year increment of the middle-lower reaches of the Yangtze River Valley is forecasted and hence the summer precipitation could be predicted. In this paper, DY is defined as the difference of a variable between the current year and the preceding year （year-to-year increment）. YR denotes the seasonal mean precipitation rate of the middle-lower reaches of the Yangtze River Valley summer rainfall. After analyzing the atmospheric circulation anomalies in winter and spring that were associated with the DY of YR, six key predictors for the DY of YR have been identified. Then the forecast model for the DY of YR is established by using the multi-linear regression method. The predictors for the DY of YR are Antarctic Oscillation, the meridional wind shear between 850hPa and 200hPa over the Indo-Australian region, and so on. The prediction model shows a high skill for the hindcast during 1997-2006, with the average relative root mean square error is at 18%. The model can even reproduce the upward and downward trends of YR during 1984--1998 and 1998--2006. Considering that the current operational forecast models of the summer precipitation over the China region have the average forecast scores at 60%--70% and that the prediction skill for the middle-lower reaches of Yangtze River Valley summer precipitation remains quite limited up to now, thus this new approach to predict the year-to-year increment of the summer precipitation over the Yangtze River Valley （and hence the summer precipitation itself） has the potential to significantly increase the operational forecast skill of the summer precipitation.