A grain-size record from Beijing region in Northern China: Late Quaternary paleoclimate oscillation in response to global change

Numerous samples taken from one core at the Beijing plain were utilized to characterize the paleoclimatic configuration of the study area and its possible relation to global control since the last interglaciation. We presented here a detailed grain-size record for the full length of Late Pleistocene, along with the optical simulated luminescence (OSL) dating. Our findings revealed that Late Pleistocene of the study area started approximately at 110 ka B.P. represented by the thick sediments of 31 m in Changping depression. Four sedimentary cycles were outlined in the core during Late Pleistocene, corresponding to marine isotope stage (MIS) 5 to 2. Controlled by regional geology and global climatic setting, eight paleoclimatic periods were identified simultaneously in the study area on the time scale of 10⁴ year, with the warm and moist climate being found at 110 — 96, 92 — 76, 67 — 56, and 28 — 18 ka B.P.. The climatic instabilities on a millennial scale in Late Pleistocene were characterized largely by the occurrence of 6 strong Heinrich events shown by comparatively coarse groups. These variations correlate well with those documented in the GRIP Greenland and in the Northern Atlantic Ocean, though more complex features may exist on the long time scale.     

上海地区第四承压含水层沉积环境及结构特征

上海地区第四承压含水层是地下水开发利用的主要层次,对其沉积环境、成因、结构特征进行深入研究有利于更好地开展地下水资源开发利用及地质环境保护工作.本文在对上海地区大量钻孔资料深入分析的基础上,对第四承压含水层形成时期即早更新世中、晚期沉积环境及含水层的成因进行了深入剖析,对含水层结构特征进行了详细刻画,为三维地质结构的建立奠定了基础.     

麻黄山西区延长组长4+5至长6储层成岩作用及成岩演化史研究

麻黄山西区长4＋5至长6储层为一套三角洲前缘亚相的细砂岩,研究证明砂岩目前处于中成岩A期。机械压实与胶结作用是孔隙减少的主要作用,也是本区原生孔隙少、储集物性差的直接原因;而大气淡水的淋滤作用及有机酸溶蚀作用,尤其是有机酸溶蚀作用,是产生次生孔隙的主要作用,使局部储层物性有所改善,因此次生孔隙是本区油气的主要储集空间,下一步油气勘探开发应注重对有利次生孔隙空间的预测。     

东营凹陷沙四段碳酸盐岩稀土元素地球化学特征

东营凹陷古近系沙河街组碳酸盐岩的成因一直存在湖相与海相之争。沙四段碳酸盐岩呈厚薄不等的夹层赋于陆相碎屑岩中。本文对研究区代表性碳酸盐岩样品稀土元素地球化学特征的分析表明：东营凹陷古近系沙四段碳酸盐岩的∑LREE〉∑MREE〉∑HREE,MREE相对于HREE富集;不具备Ce／Ce＊负异常特征;Y／Ho值为25．5～34．1,La／La＊值为0．99～1．21;Y／Ho—La／La＊呈负相关关系。所有这些特征均与湖相成因碳酸盐岩一致,沙四段碳酸盐岩的形成应为湖相成因。     

芦山“4·20”地震后宝兴县城打水沟泥石流发育趋势及防治方案

打水沟为宝兴河右岸的一级支流,位于宝兴县城城区,流域面积1.01 km2,主沟长度1.85 km,主沟比降640‰.受芦山“4·20”地震的影响,流域中下游直接引发了大量的崩滑体,加之地形陡峻,且位于青衣江-鹿头山暴雨区边缘,极容易发生泥石流.一旦发生泥石流,将会对沟口建筑和人员的安全造成巨大危害.通过对打水沟地震前后遥感影像的解译,结合野外考察,综合判定该沟为地震触发的潜在性泥石流沟.进一步分析估算,由于地震震动导致流域内发育6处崩塌体,总面积20375 m2,松散固体物质总量为15.20×l04m3.在分析泥石流形成条件与发展趋势的基础上,提出了打水沟泥石流减灾方案,并对泥石流排导槽梯形最佳过流横断面进行了设计.通过计算分析得到,在排泄设计标准的泥石流时,排导槽的最佳过流断面宽度为2.38 m,深度为2.23 m.     

Dynamique et modélisation des crues dans le bassin du Mono à Nangbéto (Togo/Bénin)

Résumé

Les inondations des dernières années en Afrique de l’Ouest rendent nécessaire la prévision hydrologique pour réduire la vulnérabilité des populations. Nous avons étudié la dynamique des crues dans le bassin du Mono en amont du barrage de Nangbéto (Togo et Bénin) par des méthodes statistiques et déterministes. L’augmentation des précipitations au cours de la décennie 1990 et la mise en eau du barrage de Nangbéto en 1988 ont modifié le régime du Mono, dont les débits d’étiages ont augmenté. Les débits entrants et sortants du barrage sont équivalents, même lors des crues. Les maximums annuels des débits entrants peuvent être modélisés par une distribution des valeurs extrêmes (GEV) de type Fréchet, tandis que ceux des débits sortants, suivent une loi GEV de type Weibull (bornée). Le mécanisme dominant de génération des crues dans le bassin est la montée progressive des eaux associée à l’augmentation de la saturation des sols. L’analyse des débits de crue entre 1988 et 2010 n’a pas montré d’augmentation de la magnitude ou de la fréquence des crues. Le modèle GR4J reproduit bien les débits de crues en période calage, mais ces critères de performance se dégradent lorsque l’on s’en éloigne. Dans ces conditions, l’utilisation de ce modèle pour évaluer les risques futurs de crues serait hasardeuse et il est nécessaire d’envisager d’autres types d’approches.     

Lake Floor Morphology and Sediment Architecture of Lake Torneträsk,Northern Sweden

Here we present datasets from a hydroacoustic survey in July 2011 at Lake Torneträsk, northern Sweden. Our hydroacoustic data exhibit lake floor morphologies formed by glacial erosion and accumulation processes, insights into lacustrine sediment accumulation since the beginning of deglaciation, and information on seismic activity along the Pärvie Fault. Features of glacial scouring with a high‐energy relief, steep slopes, and relative reliefs of more than 50 m are observed in the large W‐basin. The remainder of the lacustrine subsurface appears to host a broad variety of well preserved formations from glacial accumulation related to the last retreat of the Fennoscandian ice sheet. Deposition of glaciolacustrine and lacustrine sediments is focused in areas situated in proximity to major inlets. Sediment accumulation in distal areas of the lake seldom exceeds 2 m or is not observable. We assume that lack of sediment deposition in the lake is a result of different factors, including low rates of erosion in the catchment, a previously high lake level leading to deposition of sediments in higher elevated paleodeltas, tributaries carrying low suspension loads as a result of sedimentation in upstream lakes, and an overall low productivity in the lake. A clear off‐shore trace of the Pärvie Fault could not be detected from our hydroacoustic data. However, an absence of sediment disturbance in close proximity to the presumed fault trace implies minimal seismic activity since deposition of the glaciolacustrine and lacustrine sediments.     

From data to decision-making – experiences in Integrated Earth Observation (IEO)

Within the confines of Earth Observation Scientific Knowledge and Technology Transfer in Hungary (EKAT) titled ESA PECS project we gained forum for utilization of our earth observation (EO) knowledge and possibility for further development of experiences. The project aims the horizontal preparation of Hungary for ESA membership – for a dynamically developing sphere in the common part of science, technology and business. For the efficient transfer and dissemination, we preconceived target groups and principles to reach main take-up points and to open new forums of information exchange. Nowadays, user-friendly service, complex supply and real-validation process all have great importance. Joining units of suitable data choice, entire ingestion–processing chains and ergonomic interfaces can only offer a timely and professional solution for the challenges of industry and business sectors. It has to be clearly seen, that information and communication technologies (ICT) and information control becomes a more and more significant part of EO services.     

Fengyun-4 Geostationary Satellite-Based Solar Energy Nowcasting System and Its Application in North China

Surface solar irradiance (SSI) nowcasting (0–3 h) is an effective way to overcome the intermittency of solar energy and to ensure the safe operation of grid-connected solar power plants. In this study, an SSI estimate and nowcasting system was established using the near-infrared channel of Fengyun-4A (FY-4A) geostationary satellite. The system is composed of two key components: The first is a hybrid SSI estimation method combining a physical clear-sky model and an empirical cloudy-sky model. The second component is the SSI nowcasting model, the core of which is the derivation of the cloud motion vector (CMV) using the block-matching method. The goal of simultaneous estimation and nowcasting of global horizontal irradiance (GHI) and direct normal irradiance (DNI) is fulfilled. The system was evaluated under different sky conditions using SSI measurements at Xianghe, a radiation station in the North China Plain. The results show that the accuracy of GHI estimation is higher than that of DNI estimation, with a normalized root-mean-square error (nRMSE) of 22.4% relative to 45.4%. The nRMSE of forecasting GHI and DNI at 30–180 min ahead varied within 25.1%–30.8% and 48.1%–53.4%, respectively. The discrepancy of SSI estimation depends on cloud occurrence frequency and shows a seasonal pattern, being lower in spring–summer and higher in autumn–winter. The FY-4A has great potential in supporting SSI nowcasting, which promotes the development of photovoltaic energy and the reduction of carbon emissions in China. The system can be improved further if calibration of the empirical method is improved.     

The Synergism between Methanogens and Methanotrophs and the Nature of their Contributions to the Seasonal Variation of Methane Fluxes in a Wetland: The Case of Dajiuhu Subalpine Peatland

Wetland ecosystems are the most important natural methane (CH₄) sources, whose fluxes periodically fluctuate. Methanogens (methane producers) and methanotrophs (methane consumers) are considered key factors affecting CH₄ fluxes in wetlands. However, the symbiotic relationship between methanogens and methanotrophs remains unclear. To help close this research gap, we collected and analyzed samples from four soil depths in the Dajiuhu subalpine peatland in January, April, July, and October 2019 and acquired seasonal methane flux data from an eddy covariance (EC) system, and investigated relationships. A phylogenetic molecular ecological networks (pMENs) analysis was used to identify keystone species and the seasonal variations of the co-occurrence patterns of methanogenic and methanotrophic communities. The results indicate that the seasonal variations of the interactions between methanogenic and methanotrophic communities contributed to CH₄ emissions in wetlands. The keystone species discerned by the network analysis also showed their importance in mediating CH₄ fluxes. Methane (CH₄) emissions in wetlands were lowest in spring; during this period, the most complex interactions between microbes were observed, with intense competition among methanogens while methanotrophs demonstrated better cooperation. Reverse patterns manifested themselves in summer when the highest CH₄ flux was observed. Methanoregula formicica was negatively correlated with CH₄ fluxes and occupied the largest ecological niches in the spring network. In contrast, both Methanocella arvoryzae and Methylocystaceae demonstrated positive correlations with CH₄ fluxes and were better adapted to the microbial community in the summer. In addition, soil temperature and nitrogen were regarded as significant environmental factors to CH₄ fluxes. This study was successful in explaining the seasonal patterns and microbial driving mechanisms of CH₄ emissions in wetlands.