基于KZ滤波的京津冀2013～2018年大气污染治理效果分析

通过国务院“大气十条”等严格的大气污染治理措施的实施,近年来我国空气质量得到全面改善。对大气污染治理效果开展科学分析研究,可为后续空气质量持续改善、污染科学精准治理提供有效科技支撑。由于气象条件是影响污染物浓度分布的重要因素,治理效果分析的一个重要问题是区分气象条件和减排措施对污染物浓度变化的具体贡献。本文利用京津冀地区13个城市2013～2018年86个监测站点逐日PM2.5浓度以及欧洲中期气象预报中心（ECMWF）气象再分析资料,采用KZ（Kolmogorov–Zurbenko）滤波分析PM2.5浓度观测序列的时频特性,将其分解为短期天气影响分量、中期季节变化分量以及长期趋势分量3个部分,针对分解浓度序列建立气象因子回归模型,实现定量评估气象和减排对治理效果的具体贡献。在研究时间段内,京津冀地区13个城市PM2.5浓度的长期分量显著下降（22.2%～58.0%）,其中邢台市下降幅度最大（58.0%）。整体分析表明,气象条件和排放源均有利于大气污染的改善,但减排措施是空气质量显著改善的决定性原因,具体贡献为气象条件的影响占18.5%,排放源的影响占81.5%。逐城分析表明,唐山市的气象条件最有利于PM2.5浓度的减小（29.2%）,而衡水市的减排措施最有利于PM2.5浓度的减小（92.0%）。     

Seasonal variation in carbon exchange and its ecological analysis over <Emphasis Type="Italic">Leymus chinensis</Emphasis> steppe in Inner Mongolia

Eddy covariance technique was used to measure carbon flux during two growing seasons in 2003 and 2004 over typical steppe in the Inner Mongolia Plateau, China. The results showed that there were two different CO₂ flux diurnal patterns at the grassland ecosystem. One had a dual peak in diurnal course of CO₂ fluxes with a depression of CO₂ flux after noon, and the other had a single peak. In 2003, the maximum diurnal uptake and emitting value of CO₂ were ?7.4 and 5.4 g·m^?2·d^?1 respectively and both occurred in July. While in 2004, the maximum diurnal uptake and release of CO₂ were ?12.8 and 5.8 g·m^?2·d^?1 and occurred both in August. The grassland fixed 294.66 and 467.46 g CO₂·m^?2 in 2003 and 2004, and released 333.14 and 437.17 g CO₂·m^?2 in 2003 and 2004, respectively from May to September. Water availability and photosynthetic active radiation (PAR) are two important factors of controlling CO₂ flux. Consecutive precipitation can cause reduction in the ability of ecosystem carbon exchange. Under favorable soil water conditions, daytime CO₂ flux is dependent on PAR. CO₂ flux, under soil water stress conditions, is obviously less than those under favorable soil water conditions, and there is a light saturation phenomena at PAR=1200 μmol·m^?2·s^?1. Soil respiration was temperature dependent when there was no soil water stress; otherwise, this response became accumulatively decoupled from soil temperature.     

Effect of water stress on ecosystem photosynthesis and respiration of a <Emphasis Type="Italic">Leymus chinensis</Emphasis> steppe in Inner Mongolia

Many studies on global climate have forecast major changes in the amounts and spatial patterns of precipitation that may significantly affect temperate grasslands in arid and semi-arid regions. As a part of ChinaFLUX, eddy covariance flux measurements were made at a semi-arid Leymus chinensis steppe in Inner Mongolia, China during 2003–2004 to quantify the response of carbon exchange to environmental changes. Results showed that gross ecosystem production (F _GEP) and ecosystem respiration (R _eco) of the steppe were significantly depressed by water stress due to lack of precipitation during the growing season. Temperature was the dominant factor affecting F _GEP and R _eco in 2003, whereas soil moisture imposed a significant influence on both R _eco and F _GEP in 2004. Under wet conditions, R _eco showed an exponentially increasing trend with temperature (Q ₁₀ = 2.0), but an apparent reduction in the value of R _eco and its temperature sensitivity were observed during the periods of water stress (Q ₁₀=1.6). Both heat and water stress can cause decrease in F _GEP. The seasonality of ecosystem carbon exchange was strongly correlated with the variation of precipitation. With less precipitation in 2003, the steppe sequestrated carbon in June and July, and went into a senescence in early August due to water stress. As compared to 2003, the severe drought during the spring of 2004 delayed the growth of the steppe until late June, and the steppe became a CO₂ sink from early July until mid-September, with ample precipitation in August. The semi-arid steppe released a total of 9.7 g C·m^?2 from May 16 to the end of September 2003, whereas the net carbon budget during the same period in 2004 was close to zero. Long-term measurements over various grasslands are needed to quantify carbon balance in temperate grasslands.     

SHRIMP Zircon U-Pb Dating of the Tongshi Magmatic Complex in Western Shandong and Its Geological Implications

1 Introduction Since the Guilaizhuang gold deposit was discovered in the 1980s, the Tongshi magmatic complex has attracted attention since it exhibits a spatial-temporal relationship to gold mineralization. In the past ten years, a number of detailed fundamental researches have been carried out on the complex, Guilaizhuang gold deposit and their relationships (Qiu et al., 1994; Lin et al., 1996; Yan et al., 1996; Xu et al., 1999; Kong et al., 2001; Shun et al., 2001). Up to date, some res…     

中天山东段中元古代晚期—古生代构造-热事件:SHRIMP锆石年代学证据

星星峡杂岩是中天山构造带东段出露的最老岩石,主要岩性为斜长角闪岩和各种副变质岩,并被中—新元古代花岗片麻岩和古生代片麻岩所侵位。文中利用SHRIMP定年方法,对星星峡杂岩的一个片岩和侵入其中的一个花岗片麻岩样品进行了锆石U-Pb测年。其中片岩样品中的碎屑锆石给出1800、1530和1200Ma3组大约年龄,表明其源区不仅包括古元古代和中元古代早期还含有中元古代晚期的地壳物质。在这些碎屑锆石中,最年轻的年龄为(1189±65)Ma,与该区中元古代大约1200Ma岛弧岩浆活动相近,可代表其沉积时的最大年龄。同时获得约910和470Ma的两组较年轻年龄;前者解释为变质年龄,后者为岩浆扰动年龄,与花岗质片麻岩样品的侵位时代相一致。中天山构造带东段的中元古代晚期岩浆(大约1200Ma)和变质作用(大约910Ma)的发生时间与华南、南极洲东部、澳大利亚南部和北美西南部所报道的格林维尔期增生-造山事件在时间上接近,表明中天山构造带东段与Rodinia超大陆的汇聚过程密切相关。     

“碧利斯”(Bilis)台风远距离影响河北的数值预报检验

2006年7月14日河北省中南部出现暴雨到大暴雨.是河北省2006年最强的一次降雨天气.其中石家庄市区降雨量80 mm;是该市"96.8"暴雨以来出现的雨量最大、强度最强的降雨过程.本文利用常规气象资料及新一代天气雷达、自动站和加密雨量站资料等,对暴雨过程进行分析.结果表明:这次暴雨天气过程是由于"碧利斯"台风登陆北抬,台风和副高之间的气压梯度加大,700 hPa东南气流加强为低空急流,带来充沛的水汽;近地层的东北风为暴雨开始的触发机制,副热带高压的高温、高湿为这次暴雨提供了充足的能量条件.对基层气象台常用的几种数值模式检验结果表明:数值模式对本次台风和暴雨的预报已经达到较高的准确度,特别是T213模式对此次过程的形势场、风场预报准确,并且层次、时次多,具有较高的参考价值.     

巴丹吉林沙漠湖泊表层硅藻分布的初步研究

硅藻广泛生长于河流、湖泊和海洋中.硅藻对环境的变化极为敏感,可建立硅藻与环境参数之间的转换函数,并应用于古环境的定量重建[1～5].大量的研究表明一些硅藻种类具有很强的耐盐耐碱特征,广泛生长在干旱、半干旱地区的咸水湖中,不过目前尚无极端干旱地区现代湖泊硅藻分布状况的研究.     

U-Pb SHRIMP Dating of Zircon from Quartz Veins of the Yangshan Gold Deposit in Gansu Province and Its Geological Significance

The Yangshan gold deposit is a super-large fine-grained disseminated gold deposit located in southern Gansu Province. Its metallogenic age has been determined by using the cathodoluminescence image and ion probe U-Pb dating techniques. It is found that zircons from quartz veinlet of the fine-grained disseminated gold ore show characters of magmatic origin with prism idiomorphism, oscillatory zoning and dominant Th/U ratios of 0.5-1.5. Three main populations of zircons are obtained, giving average 206Pb/238U ages of 197.6±1.7 Ma, 126.9±3.2 Ma and 51.2±1.3 Ma respectively. The first age corresponds to the K-Ar age of the plagiogranite dike, while the latter two ages indicate that buried Cretaceous and Tertiary intrusives exist in the orefield, suggesting that the Yangshan gold deposit was genetically related to the three magmatic hydrothermal activities. By contrast, zircons from coarse gold-bearing quartz vein in the mining area are much older than the host rock, indicating that the vein was formed ear     

山东省经济增长与环境污染水平关系的计量研究

以经济增长与环境污染水平计量模型——环境库兹涅茨曲线(EKC)为理论基础,选取山东省1981年以来经济与环境数据,建立经济增长与环境污染水平的计量模型,通过分析经济因子与环境因子的相互关系,探究山东省经济增长与环境质量的演替轨迹。结果表明:山东省工业废水与工业固体废弃物的EKC呈"倒U形右侧"曲线特征,SO2与烟尘的EKC呈"N形"曲线特征;研究时段内,污染物排放量均已渡过峰值,其后随人均GDP的增长呈下降趋势,但是2002年以来,下降趋势停止并产生波动。分析表明,山东省EKC特征与工业结构变化、环境保护投资、环境政策取向有显著关系。     

中国半干旱区农田土壤碳、氮、磷含量对玉米生产的影响

中国干旱半干旱区占据陆地大片区域,主体位于内蒙古高原、黄土高原、新疆及青藏高原。半干旱区处于季风和非季风的边缘,降水稀少,生态环境脆弱,对气候变化敏感。探究半干旱区农田生态系统有机碳对作物生产和碳储存的影响机制及固碳潜力,对提高区域作物生产水平和生态安全具有重要意义。本研究区位于中国宁夏南部典型半干旱区,基于2017—2019年主要粮食作物玉米生产对土壤有机碳以及氮磷的响应,运用农田生态系统调查取样的方法,开展耕层土壤有机碳（SOC）、全氮（STN）、全磷（STP）及碳氮比（C/N）对玉米生产水平及有机碳储存的影响研究,分析农田SOC的合理贮存范围。结果表明：（1）SOC、STN、STP含量对玉米产量影响差异显著。一定阈值内SOC、STN、STP含量及土壤C/N对玉米产量表现出积极的正效应,而当SOC、STN、STP以及C/N分别超出10.00 g·kg^-1、1.00 g·kg^-1、0.85 g·kg^-1、8.50的阈值后,玉米产量的增长出现减缓,甚至下降趋势;（2）研究区域SOC含量从3.00 g·kg^-1增加至13.00 g·kg^-1的阈值,对籽粒有机碳、蛋白质、淀粉、粗脂肪、可溶性糖等含量的提升呈现积极的正效应,分别增长43.47%、77.13%、52.16%、56.92%、116.71%,均呈先快速增长,后逐渐趋于平缓趋势。而SOC对籽粒全氮和全磷呈现倒U型变化趋势。STN、STP对玉米品质的影响相对较弱;（3）研究区作物耕层SOC、STN、STP含量与生态系统固碳潜力具有较强的正相关性,而SOC、STN、STP含量过高,作物固碳潜力基本保持稳定。研究结果较好反映了研究时间段内SOC、STN、STP含量与作物生产水平及提高SOC储存的关系。本研究认为宁夏南部半干旱区,农田SOC、STN、STP、C/N的合理阈值分别为10.00—12.00 g·kg^-1、0.80—1.10 g·kg^-1、0.70—0.85 g·kg^-1、8.00—9.00。