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Accuracy assessment of global ocean tide models in the South China Sea using satellite altimeter and tide gauge data 被引量:3
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作者 Yanguang Fu Yikai Feng +3 位作者 dongxu zhou Xinghua zhou Jie Li Qiuhua Tang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第12期1-10,共10页
In this study,to meet the need for accurate tidal prediction,the accuracy of global ocean tide models was assessed in the South China Sea(0°–26°N,99°–121°E).Seven tide models,namely,DTU10,EOT11 a... In this study,to meet the need for accurate tidal prediction,the accuracy of global ocean tide models was assessed in the South China Sea(0°–26°N,99°–121°E).Seven tide models,namely,DTU10,EOT11 a,FES2014,GOT4.8,HAMTIDE12,OSU12 and TPXO8,were considered.The accuracy of eight major tidal constituents(i.e.,Q1,O1,P1,K1,N2,M2,S2 and K2)were assessed for the shallow water and coastal areas based on the tidal constants derived from multi-mission satellite altimetry(TOPEX and Jason series)and tide gauge observations.The root mean square values of each constituent between satellite-derived tidal constants and tide models were found in the range of 0.72–1.90 cm in the deep ocean(depth>200 m)and 1.18–5.63 cm in shallow water area(depth<200 m).Large inter-model discrepancies were noted in the Strait of Malacca and the Taiwan Strait,which could be attributable to the complicated hydrodynamic systems and the paucity of high-quality satellite altimetry data.In coastal regions,an accuracy performance was investigated using tidal results from 37 tide gauge stations.The root sum square values were in the range of 9.35–19.11 cm,with the FES2014 model exhibiting slightly superior performance. 展开更多
关键词 accuracy assessment tide model satellite altimetry tide gauge South China Sea
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Contributions of annual and semiannual tidal constituents to chart datum in the China seas and adjacent waters
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作者 Yikai Feng Yanguang Fu +1 位作者 Long Yang dongxu zhou 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第10期127-136,共10页
Global uniform chart datum(CD)surface construction is the basic upon which to realize various vertical datums transformation,and is of great importance for geospatial data expression under the same vertical datum.Gene... Global uniform chart datum(CD)surface construction is the basic upon which to realize various vertical datums transformation,and is of great importance for geospatial data expression under the same vertical datum.Generally,the CD level is computed by developing the function between tidal constituents’harmonic constants and time,i.e.,the lowest astronomical tide is taken as the lowest predicted tide level by adopting the major constituents over a 19-a period.The CD surface prescribed in China is the theoretical lowest tide(TLT)and is calculated using 13 tidal constituents,i.e.,short-period(Q_(1),O_(1),P_(1),K_(1),N_(2),M_(2),S_(2),K_(2),M_(4),MS_(4)and M_(6))and long-period(Sa and Ssa)tidal constituents.Although the accuracy in determining short-period tidal constituents has improved gradually,the long-period tide has not been studied thoroughly owing to nonstationary and temporal variations.Previous studies have intended to evaluate the effect of Sa and Ssa tides in the determination of the TLT level for the purpose of determining a more accurate CD surface for the China seas and adjacent waters.Here,the parameters of long-period tidal correction and long-period tidal correction rate were treated as the effect of both Sa and Ssa on the TLT,and the TOPEX/Poseidon and Jason series satellite altimetry data ranged from October 1992 to April 2022 were adopted to analyze the contribution of long-period tidal constituents.Results showed that the average long-period correction value is 10.10 cm(range from 8.57 cm to 14.98 cm),and that the average long-period tidal contribution rate is 14.56%(range from 9.09%to 23.97%)in the China seas and adjacent waters.Finally,data from 82 tide gauge station with at least a 1-a record of hourly observations were compared with satellite-derived result.We concluded that the long-period tidal contribution should not be neglected in TLT construction.Furthermore,to reduce tidal datum uncertainty,accurate extraction of long-period tidal constituents should receive closer attentions. 展开更多
关键词 tidal datum chart datum long-period tidal constituent lowest normal low water China seas and adjacent waters
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Absolute sea level variability of Arctic Ocean in 1993–2018 from satellite altimetry and tide gauge observations
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作者 Yanguang Fu Yikai Feng +1 位作者 dongxu zhou Xinghua zhou 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第10期76-83,共8页
Arctic absolute sea level variations were analyzed based on multi-mission satellite altimetry data and tide gauge observations for the period of 1993–2018.The range of linear absolute sea level trends were found-2.00... Arctic absolute sea level variations were analyzed based on multi-mission satellite altimetry data and tide gauge observations for the period of 1993–2018.The range of linear absolute sea level trends were found-2.00 mm/a to 6.88 mm/a excluding the central Arctic,positive trend rates were predominantly located in shallow water and coastal areas,and negative rates were located in high-latitude areas and Baffin Bay.Satellite-derived results show that the average secular absolute sea level trend was(2.53±0.42)mm/a in the Arctic region.Large differences were presented between satellite-derived and tide gauge results,which are mainly due to low satellite data coverage,uncertainties in tidal height processing and vertical land movement(VLM).The VLM rates at 11 global navigation satellite system stations around the Arctic Ocean were analyzed,among which 6 stations were tide gauge colocated,the results indicate that the absolute sea level trends after VLM corrected were of the same magnitude as satellite altimetry results.Accurately calculating VLM is the primary uncertainty in interpreting tide gauge measurements such that differences between tide gauge and satellite altimetry data are attributable generally to VLM. 展开更多
关键词 Arctic Ocean absolute sea level variability sea level anomaly satellite altimetry tide gauge
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Brain Pathology in COVID-19:Clinical Manifestations and Potential Mechanisms 被引量:1
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作者 Zhixing Xu Hui Wang +5 位作者 Siya Jiang Jiao Teng dongxu zhou Zhong Chen Chengping Wen Zhenghao Xu 《Neuroscience Bulletin》 SCIE CAS CSCD 2024年第3期383-400,共18页
Neurological manifestations of coronavirus disease 2019(COVID-19)are less noticeable than the respiratory symptoms,but they may be associated with disability and mortality in COVID-19.Even though Omicron caused less s... Neurological manifestations of coronavirus disease 2019(COVID-19)are less noticeable than the respiratory symptoms,but they may be associated with disability and mortality in COVID-19.Even though Omicron caused less severe disease than Delta,the incidence of neurological manifestations is similar.More than 30%of patients experienced“brain fog”,delirium,stroke,and cognitive impairment,and over half of these patients presented abnormal neuroimaging outcomes.In this review,we summarize current advances in the clinical findings of neurological manifestations in COVID-19 patients and compare them with those in patients with influenza infection.We also illustrate the structure and cellular invasion mechanisms of SARS-CoV-2 and describe the pathway for central SARS-CoV-2 invasion.In addition,we discuss direct damage and other pathological conditions caused by SARS-CoV-2,such as an aberrant interferon response,cytokine storm,lymphopenia,and hypercoagulation,to provide treatment ideas.This review may offer new insights into preventing or treating brain damage in COVID-19. 展开更多
关键词 COVID-19 SARS-CoV-2 BRAIN Neurological pathology
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Photosensitivity sources of dissolved organic matter from wastewater treatment plants and their mediation effect on 17α-ethinylestradiol photodegradation
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作者 Zhicheng Liao Bei Li +7 位作者 Juhong Zhan Huan He Xiaoxia Yang dongxu zhou Guoxi Yu Chaochao Lai Bin Huan Xuejun Pan 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2023年第6期49-62,共14页
Dissolved organic matter(DOM)from each treatment process of wastewater treatment plants(WWTPs)contains abundant photosensitive substances,which could significantly affect the photodegradation of 17α-ethinylestradiol(... Dissolved organic matter(DOM)from each treatment process of wastewater treatment plants(WWTPs)contains abundant photosensitive substances,which could significantly affect the photodegradation of 17α-ethinylestradiol(EE2).Nevertheless,information about EE2 photodegradation behavior mediated by DOM from diverse WWTPs and the photosensitivity sources of such DOM are inadequate.This study explored the photodegradation behavior of EE2 mediated by four typical WWTPs’DOM solutions and investigated the photosensitivity sources of DOM in the anaerobic-anoxic-oxic(A2/O)process.The parallel factor analysis identified three varying fluorescing components of these DOM,tryptophan-like substances or protein-like substances,microbial humuslike substances,and humic-like components.The photodegradation rate constants of EE2 were positively associated with the humification degree of DOM(P<0.05).The triplet state substances were responsible for the degradation of EE2.DOM extracted from the A2/O process,especially in the secondary treatment process had the fastest EE2 photodegradation rate compared to that of the other three processes.Four types of components(water-soluble organic matter(WSOM),extracellular polymeric substance,humic acid,and fulvic acid)were separated from the A2/O process DOM.WSOM had the highest promotion effect on EE2 photodegradation.Fulvic acid-like components and humic acid-like organic compounds in WSOM were speculated to be important photosensitivity substances that can generate triplet state substances.This research explored the physicochemical properties and photosensitive sources of DOM in WWTPs,and explained the fate of estrogens photodegradation in natural waters. 展开更多
关键词 Photosensitivity sources 17α-ethinylestradiol PHOTODEGRADATION Dissolved organic matter Wastewater treatment plants
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Super-bunched focusing with chirped random-phase gratings
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作者 LU ZHANG dongxu zhou +2 位作者 YIPING LU HONGZHI ZHANG GUOQUAN ZHANG 《Photonics Research》 SCIE EI CSCD 2020年第4期503-510,共8页
Chirped random-phase gratings are designed to produce experimentally a super-bunched focusing effect with a high bunching peak value of g(2)(0)=15.38±0.05 and a high visibility of 92.5%,greatly surpassing the the... Chirped random-phase gratings are designed to produce experimentally a super-bunched focusing effect with a high bunching peak value of g(2)(0)=15.38±0.05 and a high visibility of 92.5%,greatly surpassing the theoretical bunching peak of 2 of thermal light.Both slit-width-chirped and period-chirped random-phase gratings are studied theoretically and experimentally.The full width at half-maximum of the super-bunched curve decreases significantly with an increase in the slit number,focusing the photon pairs within a decreasing spot size.This super-bunched focusing effect can be useful for improving the resolution and the visibility of the correlation image simultaneously. 展开更多
关键词 Super-bunched CHIRPED random-phase GRATINGS
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