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[en] Natural gas resources in China are abundant. The undiscovered recoverable natural gas resources in China are estimated to be 19.27×1012 m3. Natural gas is mainly distributed in the middle and west China and offshore areas of China. The Tarim Basin, Sichuan Basin, Ordos Basin, East China Sea Basin, Tsaidam Basin, Yinggehai Basin, and Qiongdongnan Basin are the main gas-bearing basins. The natural gas resources are not distributed evenly and are under-explored in China. The deeper horizons in east China, foreland basins and craton paleo-uplifts in the middle and west China, and the offshore basins are the main exploration areas in the future.
[en] A geoacoustic inversion method is proposed based on the modal dispersion curve of two-wideband explosive signals for range-dependent environment. It is applied to the wideband explosive sound source data from the South China Sea in 2012. The travel time differences of different modes at various frequencies and distances are extracted by warping transform. The mean bottom acoustic parameters are inverted by matching the theoretical modal time differences to that of the experimental data. The inversion results are validated by using other explosive signals at different distances. (paper)
[en] Currently, Some Chinese nuclear power plants have been built and operating near the Vietnamese border such as the Fangchenggang, Yangjiang, and Changjiang nuclear power plants. Therefore, the building and conduct regular monitoring, continuity and online all developments in the radiation situation in the environment, step by step building the environmental radiation database is important and necessary. Especially in regions that are likely to be affected early when a nuclear incident occurs. Viet Nam online monitoring network and warning of environmental radiation has started operation since the end of 2015. The number of monitoring stations is gradually increasing through investment projects, aid and through domestic research topics. Currently, these devices have been installed and tested in some provinces: Quang Ninh, Lao Cai, Lang Son and Hai Phong. These devices have provided data on the Operations Center located at the Institute for Nuclear Science and Technology. Initially these data are being studied processing and evaluation. (author)
[en] Highlights: • Land-sourced nutrients have caused severe eutrophication in coastal China. • Coastal eutrophication worsened rapidly from the end of the 1980s to the mid-2000s. • Control measures have curbed the worsening trend in the last decade. • Coastal eutrophication should slightly decrease in the China Seas in the near future. - Abstract: China's rapid economic and social development has led to an acceleration in nutrient inputs to coastal waters, which, in turn, has resulted in severe coastal eutrophication. On the occasion of the 40th anniversary of China's reform and opening up, the evolution of the causative factors and the state as well as future prospects for coastal eutrophication in the China Seas are analyzed and summarized. Results showed that the coastal eutrophication situation was not so serious at the beginning of reform and opening up, but it worsened rapidly from the end of the 1980s to the mid-2000s. In the last decade, the worsening trend has been curbed but the status of coastal eutrophication has not been substantially improved. Much work is still needed to be able control the total amount of nutrients entering coastal waters and enable comprehensive treatment of coastal eutrophication in the China Seas.
[en] The South China Sea (SCS) summer monsoon onset has been regarded as the beginning of the East Asian summer monsoon. In this study, we investigated the impacts of the SCS monsoon onset on the transition from the spring persistent rainfall to the summer Meiyu in the middle and lower reaches of the Yangtze River basin (MLYZB). It is found that rainfall in the MLYZB reduces after the SCS monsoon onset. This reduction in rainfall persists until the onset of the Meiyu and is accompanied by a weakening of southwesterlies to the south of the MLYZB. These features exist in both climatology and interannual variability. Rainfall increases significantly over the SCS and the subtropical western North Pacific after the SCS monsoon onset. The latent heating of the increased rainfall can excite an anomalous cyclone over the western North Pacific, which weakens the mean southwesterlies to the south of the MLYZB and decreases water vapor entering the MLYZB. It also generates descending motion over southeastern China. Thus, the SCS monsoon onset could suppress rainfall over the MLYZB by the latent heating induced changes in circulation. Compared to increased rainfall over the SCS, the latent heating of increase rainfall over the subtropical western North Pacific plays a more important role in the reduction of rainfall over the MLYZB. As the SCS monsoon onset affects the timing of the reduction of rainfall in the MLYZB, an early SCS monsoon onset is accompanied by below-normal May rainfall in the MLYZB, while a late SCS monsoon onset is accompanied by above-normal May rainfall.
[en] The instrumental observations of dust storm (DS) in China and in most countries of the world have only a history of 50–60 years, and the DS variability beyond this timescale cannot be understood properly. Here, we show that the DS frequency can be reconstructed using the coral reef environment records as a proxy. Based on the high-resolution sea surface temperature (SST) records previously reconstructed by Liu et al. (2008) and Sun et al. (2004), we reconstructed the variations of DS frequency and strong wind frequency in China from 1908 to 1959, using the 5-year moving average of the longitudinal SST gradient (GX-H,SST,5m) in the northern South China Sea (SCS) as an indicator. The calibration equation shows that GX-H,SST,5m explains 66% of the variation in the 5-year average of the DS frequency (FDS,5m) and 86% of the variation in the 5-year moving average of strong wind (FSW,5m) in China, respectively. A comparison between the reconstructed long series (1908–1990) and the observed short series (1960–1990) FDS,5m indicates that the mean, maximum, and minimum of the latter series is 10.8, 20.9, and 36.1% smaller than that of the former, demonstrating that the DS frequency strongly depends on timescales; the statistical characteristics over short timescales are quite different from those over long timescales.
[en] Polybrominated diphenyl ethers (PBDEs) of sixty-three sediment samples from the coastal East China Sea (ECS), extending ∼1000 km from the Yangtze River Estuary to the south, were measured. The levels of BDE-209 and ∑PBDE7 (sum of BDE-28, 47, 99, 100, 153, 154, 183) were 0.3–44.6 ng/g (dry weight) and nd-8.0 ng/g, respectively. BDE-209 was the predominant congener, followed by BDE-99/100. This was consistent with the historical and current usage of PBDE mixtures in China. The compositions and distribution of PBDEs suggest that the PBDEs in this area could be mainly from the coastal electronic waste dismantling/recycling and Yangtze River input. The poor correlations between TOC, grain size of sediments with PBDEs imply that the PBDE distribution is more related to their land-based inputs rather than the sediment characters in the area. The coastal ECS is an important sink of PBDEs (7.5 t/yr) in the world. - Highlights: ► First report on the levels, distribution and inventory of PBDEs in the inner shelf of the ECS. ► PBDEs were mainly from the coastal electronic waste dismantling/recycling and Yangtze River. ► PBDE distribution was related to the land-based inputs rather than the sediment characters. ► The coastal East China Sea is an important sink of the PBDEs in the world. - The levels, distribution, potential sources and mass inventory of PBDEs in sediments of the coastal East China Sea were revealed.
[en] The landfall activity of typhoons (TYs) along the coast of China during July–August–September (JAS) shows significant interdecadal variation during 1965–2010. We identify three sub-periods of TY landfall activity in JAS along the China coast in this period, with more TY landfall during 1965–1978 (Period I) and 1998–2010 (Period III), and less during 1982–1995 (Period II). We find that the interdecadal variation might be related to the combined effects of Pacific Decadal Oscillation (PDO) phase changes and sea surface temperature (SST) variation in the tropical Indian Ocean and Western Pacific (IO–WP). During the negative PDO phase in Periods I and III, a cyclonic anomaly is located in the western North Pacific (WNP), inducing easterly flow in its northern part, which favors TY landfall along the eastern China coast. Warm SST anomalies over the tropical IO–WP during Period III induce an anomalous anticyclonic circulation in the WNP through both the Gill-pattern response to the warm SST in the tropical IO and the anomalous meridional circulation induced by the warm SST in the tropical WNP. As a result, the northern South China Sea and WNP (10°–20° N) are dominated by southeasterly flow, which favors TYs making landfall on both the southern and eastern China coast. With both landfalling-favorable conditions satisfied, there are significantly more TYs making landfall along the China coast during Period III than during Period I, which shows cool SST anomalies in the tropical IO–WP.
[en] A large portion of polychlorinated biphenyls (PCBs) from e-waste released into the coastal areas may be the potential source of PCBs to the global oceans. The paper presents data of PCBs concentrations in fifty surface sediment samples and a dated sediment core in Yangtze River Delta (YRE) and adjacent East China Sea (ECS). The total PCBs levels varied from 5.08 to 19.64 ng/g dry weight, with the highest concentrations situate within the river-sea boundary zone which is so-called “marginal filter”. Concurrent with the operation of e-waste recycling over the last two decades, PCB fluxes started to rise again after 1980s and reached a maximum in this century. The full data set was used to estimate the burden of PCBs in YRE and adjacent ECS. A total sediment burdens were 192.8 tons, with the spatial density of 364 ng/cm2 which accounts for 1.9% of all the PCBs in China. - Highlights: ► PCBs residues remained widespread in Yangtze River Delta and adjacent East China Sea. ► Highest PCBs concentrations situate within the river-sea boundary zone. ► Congener profiles and PCA highlight the influence of e-waste recycling. ► Temporal distributions indicated PCB fluxes reached a maximum in this century. ► Total sediment burdens accounts for 1.9 % of all the PCBs in China. - Spatial and temporal distributions of polychlorinated biphenyls have been delineated in sediments from Yangtze River Estuary and adjacent East China Sea.