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| 1 | Distribution, features, and influence factors of the submarine topographic boundaries of the Okinawa Trough显示文摘Based on multiple types of data, the topographical features of the Okinawa Trough(OT) have been characterized and a computation method has been proposed to determine the break point of continental shelf(BOS), foot point of the continental slope(FOS), the central axial point, and the maximum depth point. A total of 48 topographical profiles that crosscut the continental slope have been used to determine the trends of the BOS and FOS(the BOS and FOS lines) in the East China Sea(ECS). The trend of central axial points in the OT has been similarly determined by analyzing 39 topographical profiles across the axis of the trough. The BOS line forms the boundary between the continental shelf and slope. In the ECS, the BOS line roughly follows the 200 m isobath, continuously in the northern and middle parts of the OT, but jumping about somewhat in the south. The FOS line is the boundary between the continental slope and the bottom of the trough. The depth of the FOS increases gradually from north to south in the OT. Intense incisions by canyons into the slope in the southern part of the trough have led to the complex distribution of FOS. Topographical profiles crosscutting the northern, middle, and southern parts of the OT exhibit features that include: a single W-shape, a composite W-shape, and a U-shape, respectively, which suggests that in the middle and northern parts of the trough the central axial points are always located on seamount peaks or ridges associated with linear seamounts, whereas in the south they are found in the center of en echelon depressions. The line formed by the central axial points is the east-west dividing line of the OT, which indicates that the trough is a natural gap that prevents the extension of ECS continental shelf to the east. The distributions of the BOS and FOS lines are influenced by fluctuation of sea levels and submarine canyons, whereas the distribution of axis lines is controlled by tectonics and deposition. | WU ZiYin LI JiaBiao JIN XiangLong SHANG JiHong LI ShouJun JIN XiaoBing | 2014 | Science China Earth Sciences2014，57，8： | 11 |
| 2 | Distribution,formation and evolution of sand ridges on the East China Sea shelf显示文摘Based on the integrated results of multiple data types including MBES (Multi-Beam Echo Sounding) and historical topography maps,the LSR (Linear Sand Ridges) on the ECS (East China Sea) shelf are identified,divided into subareas,and classified.The distribution of sand ridge crests is also established.The strikes of the LSR on the ECS shelf fall in a normal distribution with the center point being 155° azimuth with additional peak points at 125°,130°,140°,and 180° azimuth.The distribution of the ECS shelf sand ridges is congested in the central area,sparse in the south and north ends,divergent and bifurcated in the eastern area,and densely convergent in the western area.The LSR are divided into seven subzones according to the strikes and distribution of the sand ridges;estuary mouth ridges and open shelf sand ridges are identified and marked out.The high amplitude change of sea level resulting from the glacial-interglacial cycle is the main cause of the vast development of sand ridges on the ECS shelf.Abundant sediments on the shelf carried by the PYR (Paleo-Yangtze River) are the material source for the LSR formation,and the negative seafloor topography influences the strikes of LSR.Based on the effects of LSR distribution,change of sea level,and the simulation of ancient tidal currents,the evolution of the LSR on the ECS shelf is divided into four main stages:Stage Ⅰ before 14.5 ka BP,Stage Ⅱ between 12 and 14 ka BP,Stage Ⅲ from 1.5 to 9.5 ka BP,and Stage Ⅳ after 9 ka BP. | WU ZiYin JIN XiangLong CAO ZhenYi LI JiaBiao ZHENG YuLong SHANG JiHong | 2010 | Science China Earth Sciences2010，53，1： | 9 |
| 3 | Data-driven estimates of global nitrous oxide emissions from croplands显示文摘Croplands are the single largest anthropogenic source of nitrous oxide(N2O) globally, yet their estimates remain difficult to verify when using Tier 1 and 3 methods of the Intergovernmental Panel on Climate Change(IPCC). Here, we re-evaluate global cropland-N2O emissions in 1961–2014, using N-rate-dependent emission factors(EFs) upscaled from 1206 field observations in 180 global distributed sites and high-resolution N inputs disaggregated from sub-national surveys covering 15593 administrative units. Our results confirm IPCC Tier 1 default EFs for upland crops in 1990–2014, but give a ~15% lower EF in 1961–1989 and a ~67% larger EF for paddy rice over the full period. Associated emissions(0.82 ±0.34 Tg N yr–1) are probably one-quarter lower than IPCC Tier 1 global inventories but close to Tier 3 estimates. The use of survey-based gridded N-input data contributes 58% of this emission reduction, the rest being explained by the use of observation-based non-linear EFs. We conclude that upscaling N2O emissions from site-level observations to global croplands provides a new benchmark for constraining IPCC Tier 1 and 3 methods. The detailed spatial distribution of emission data is expected to inform advancement towards more realistic and effective mitigation pathways. | Qihui Wang Feng Zhou Ziyin Shang Philippe Ciais Wilfried Winiwarter Robert B.Jackson Francesco N.Tubiello Greet Janssens-Maenhout Hanqin Tian Xiaoqing Cui Josep G.Canadell Shilong Piao Shu Tao | 2020 | National Science Review2020，7，2： | 7 |
| 4 | Resources calculation of cobalt-rich crusts with the grid subdivision and integral method显示文摘On the basis of three geological models and several orebody boundaries,a method of grid subdivision and integral has been proposed to calculate and evaluate the resources of cobalt-rich crusts on the seamounts in the central Pacific Ocean.The formulas of this method are deduced and the interface of program module is designed.The method is carried out in the software 'Auto mapping system of submarine topography and geomorphology MBChart'.This method and program will possibly become a potential tool to calculate the resources of seamounts and determine the target diggings for China's next Five-year Plan. | WU Ziyin CHU Fengyou MA Weilin LI Shoujun SHANG Jlhong | 2007 | Acta Oceanologica Sinica2007，26，5： | 2 |
| 5 | A VGGNet-based correction for satellite altimetry-derived gravity anomalies to improve the accuracy of bathymetry to depths of 6500 m显示文摘Understanding the topographic patterns of the seafloor is a very important part of understanding our planet.Although the science involved in bathymetric surveying has advanced much over the decades,less than 20%of the seafloor has been precisely modeled to date,and there is an urgent need to improve the accuracy and reduce the uncertainty of underwater survey data.In this study,we introduce a pretrained visual geometry group network(VGGNet)method based on deep learning.To apply this method,we input gravity anomaly data derived from ship measurements and satellite altimetry into the model and correct the latter,which has a larger spatial coverage,based on the former,which is considered the true value and is more accurate.After obtaining the corrected high-precision gravity model,it is inverted to the corresponding bathymetric model by applying the gravity-depth correlation.We choose four data pairs collected from different environments,i.e.,the Southern Ocean,Pacific Ocean,Atlantic Ocean and Caribbean Sea,to evaluate the topographic correction results of the model.The experiments show that the coefficient of determination(R~2)reaches 0.834 among the results of the four experimental groups,signifying a high correlation.The standard deviation and normalized root mean square error are also evaluated,and the accuracy of their performance improved by up to 24.2%compared with similar research done in recent years.The evaluation of the R^(2) values at different water depths shows that our model can achieve performance results above 0.90 at certain water depths and can also significantly improve results from mid-water depths when compared to previous research.Finally,the bathymetry corrected by our model is able to show an accuracy improvement level of more than 21%within 1%of the total water depths,which is sufficient to prove that the VGGNet-based method has the ability to perform a gravity-bathymetry correction and achieve outstanding results. | Xiaolun Chen Xiaowen Luo Ziyin Wu Xiaoming Qin Jihong Shang Huajun Xu Bin Li Mingwei Wang Hongyang Wan | 2024 | Acta Oceanologica Sinica2024，43，1： | 0 |
| 6 | Methods and procedures to determine the outer limits of the continental shelf beyond 200 nautical miles显示文摘This paper establishes techniques and methods to determine a variety of boundaries associated with 200nautical miles beyond the continental shelf.The methods,based on topography,slope and second-derivative profile integrated analysis,are now able to identify automatically the foot of the continental slope(FOS).By analyzing the sedimentary profile,the points of 1%sediment thickness are recognized.Through the intersection,cut,deletion and mergence calculation of the extrapolated data set of fixed-point series,the method succeeds in generating automatically the extrapolated boundaries,including the FOS+60 M line,the 350 M line,and the 2 500 m+100 M line.In addition,based on the automatic analysis of the topographic profile,it can be applied to determine rapidly the points of maximum water depth.Taking the northern Okinawa Trough(OT)as an example,these methods are used to calculate and examine the boundaries included in the Submission by the People's Republic of China Concerning the Outer Limits of the Continental Shelf beyond 200 Nautical miles in Part of the East China Sea(ECS);the boundaries thus derived have a solid scientific and rational basis. | WU Ziyin LI Jiabiao JIN Xianglong FANG Yinxia SHANG Jihong LI Shoujun | 2013 | Acta Oceanologica Sinica2013，32，12： | 0 |
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