Current shipping,tourism,and resource development requirements call for more accurate predictions of the Arctic sea-ice concentration(SIC).However,due to the complex physical processes involved,predicting the spatiote...Current shipping,tourism,and resource development requirements call for more accurate predictions of the Arctic sea-ice concentration(SIC).However,due to the complex physical processes involved,predicting the spatiotemporal distribution of Arctic SIC is more challenging than predicting its total extent.In this study,spatiotemporal prediction models for monthly Arctic SIC at 1-to 3-month leads are developed based on U-Net-an effective convolutional deep-learning approach.Based on explicit Arctic sea-ice-atmosphere interactions,11 variables associated with Arctic sea-ice variations are selected as predictors,including observed Arctic SIC,atmospheric,oceanic,and heat flux variables at 1-to 3-month leads.The prediction skills for the monthly Arctic SIC of the test set(from January 2018 to December 2022)are evaluated by examining the mean absolute error(MAE)and binary accuracy(BA).Results showed that the U-Net model had lower MAE and higher BA for Arctic SIC compared to two dynamic climate prediction systems(CFSv2 and NorCPM).By analyzing the relative importance of each predictor,the prediction accuracy relies more on the SIC at the 1-month lead,but on the surface net solar radiation flux at 2-to 3-month leads.However,dynamic models show limited prediction skills for surface net solar radiation flux and other physical processes,especially in autumn.Therefore,the U-Net model can be used to capture the connections among these key physical processes associated with Arctic sea ice and thus offers a significant advantage in predicting Arctic SIC.展开更多
[ Objective] The study aimed at discussing the purification effect of constructed wetlands for treating river water flowing from phosphate mine areas into Fuxian Lake. [Method] The running parameters of the constructe...[ Objective] The study aimed at discussing the purification effect of constructed wetlands for treating river water flowing from phosphate mine areas into Fuxian Lake. [Method] The running parameters of the constructed wetlands were investigated for one year, and the purification effect of the constructed wetlands for treating the sewage from phosphate mine areas was analyzed. [Result] With the aid of the constructed wet- land, the average removal rates of total nitrogen （TN）, total phosphorus （TP） and CODcr were 52%, 32% and 54%, and the removal effects were best when the designed hydraulic load was 0.67 m3/（ m2 · d）. Running stably for six years, the constructed wetlands had advantages of no power, low resistance and high removal rate. [ Conclusion] The constructed wetlands reduced the load of pollutants from phosphate mine areas into Fuxian Lake effectivelv, which Dlaved important roles in the Drotection of water aualitv of Fuxian Lake.展开更多
Based on a normalized difference vegetation index(NDVI)dataset for 1982-2021,this work investigates the principal modes of interannual variability in summer NDVI over eastern Siberia using the year-to-year increment m...Based on a normalized difference vegetation index(NDVI)dataset for 1982-2021,this work investigates the principal modes of interannual variability in summer NDVI over eastern Siberia using the year-to-year increment method and empirical orthogonal function(EOF)analysis.The first three principal modes(EOF1-3)of the year-to-year increment of summer NDVI(NDVI_DY)exhibit a regionally consistent mode,a western-eastern dipole mode,and a northern-southern dipole mode,respectively.Further analysis shows that sea surface temperature(SST)in the tropical Indian Ocean in February-March and western Siberian soil moisture in April could influence EOF1.EOF2 is modulated by April Northwest Pacific SST and western Siberian soil moisture in May.May North Atlantic SST and sea ice in the Kara Sea in the preceding October significantly affect EOF3.Using the year-to-year increment method and multiple linear regression analysis,prediction schemes for EOF1-3 are developed based on these predictors.To assess the predictive skill of these schemes,one-year-out cross-validation and independent hindcast methods are employed.The temporal correlation coefficients between observed EOF1-3 and the cross-validation results are 0.62,0.46,and 0.37,respectively,exceeding the 95%confidence level.In addition,reconstructed schemes for summer NDVI are developed using predicted NDVI_DY and the observed principal modes of NDVI_DY.Independent hindcasts of NDVI anomalies during 2019-2021 also present consistent distributions with the observed results.展开更多
Acidic-stable oxygen evolution reaction(OER)catalysts based on earth-abundant materials are important but rare for the proton exchange membrane-based water electrolysis.In this study,a metal-containing hydrogen-bonded...Acidic-stable oxygen evolution reaction(OER)catalysts based on earth-abundant materials are important but rare for the proton exchange membrane-based water electrolysis.In this study,a metal-containing hydrogen-bonded organic framework(HOF)of manganese coordinated with 2,2'-bipyridine-6,6'-dicarboxylate ligands,Mn(bda),interconnected through hydrogen bonding and π-π stacking is used as a heterogeneous OER catalyst(Mn(bda)-HOF)for acidic water oxidation and exhibits a considerable OER performance.Electrochemical results show that Mn(bda)-HOF displays a turn of frequency of 1 s^(-1) at an overpotential of 870 mV.Meanwhile,this Mn(bda)-HOF shows an unusual pH dependence on performance,where the reaction rate increases with the decrease of pH.A comprehensive mechanistic study reveals that the charge transfer triggered coupling of two metal-oxo species Mn^(5+)(O)is the rate-determining step,which leads to this unusual pH dependence on the OER performance.展开更多
The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate incr...The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate increases.Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations,indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction.The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics.However,the excessively high heating rate aggravates the Li+/Ni2+mixing in the Ni-rich cathode.The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.展开更多
作为东亚冬季风的关键系统,西伯利亚高压的变化对欧亚大陆冬季天气及气候异常产生重要影响。本文系统地评估了美国国家环境预测中心第二代气候预测系统(NCEP-CFSv2,National Center for Environment Prediction-Climate Forecast System...作为东亚冬季风的关键系统,西伯利亚高压的变化对欧亚大陆冬季天气及气候异常产生重要影响。本文系统地评估了美国国家环境预测中心第二代气候预测系统(NCEP-CFSv2,National Center for Environment Prediction-Climate Forecast System,version 2)对冬半年(11~2月)及逐月西伯利亚高压强度的预测效能。结果表明,NCEP-CFSv2模式仅对11月西伯利亚高压强度的预测效能较好,研究其成因发现11月西伯利亚高压强度主要受该地区热力、动力过程以及西伯利亚地区积雪状况的影响。在热力过程方面,NCEP-CFSv2模式可以较好地再现11月西伯利亚高压强度及其相联的该地区表层土壤温度、对外长波辐射等热力因素;在动力过程方面,模式能较好地再现11月西伯利亚高压强度及其相联的该地区对流层低层辐散环流、中高层下沉运动;同时,模式也能较好地再现11月西伯利亚高压强度与该地区积雪覆盖率之间的相互作用。因此,与11月西伯利亚高压相联的热力、动力过程和该地区积雪状况可能是11月西伯利亚高压强度的可预测来源,且NCEP-CFSv2模式能较好地再现这些可预测来源。展开更多
基金supported by the National Key Research and Development Program of China[grant number 2022YFE0106800]an Innovation Group Project of the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)[grant number 311024001]+3 种基金a project supported by the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)[grant number SML2023SP209]a Research Council of Norway funded project(MAPARC)[grant number 328943]a Nansen Center´s basic institutional funding[grant number 342624]the high-performance computing support from the School of Atmospheric Science at Sun Yat-sen University。
文摘Current shipping,tourism,and resource development requirements call for more accurate predictions of the Arctic sea-ice concentration(SIC).However,due to the complex physical processes involved,predicting the spatiotemporal distribution of Arctic SIC is more challenging than predicting its total extent.In this study,spatiotemporal prediction models for monthly Arctic SIC at 1-to 3-month leads are developed based on U-Net-an effective convolutional deep-learning approach.Based on explicit Arctic sea-ice-atmosphere interactions,11 variables associated with Arctic sea-ice variations are selected as predictors,including observed Arctic SIC,atmospheric,oceanic,and heat flux variables at 1-to 3-month leads.The prediction skills for the monthly Arctic SIC of the test set(from January 2018 to December 2022)are evaluated by examining the mean absolute error(MAE)and binary accuracy(BA).Results showed that the U-Net model had lower MAE and higher BA for Arctic SIC compared to two dynamic climate prediction systems(CFSv2 and NorCPM).By analyzing the relative importance of each predictor,the prediction accuracy relies more on the SIC at the 1-month lead,but on the surface net solar radiation flux at 2-to 3-month leads.However,dynamic models show limited prediction skills for surface net solar radiation flux and other physical processes,especially in autumn.Therefore,the U-Net model can be used to capture the connections among these key physical processes associated with Arctic sea ice and thus offers a significant advantage in predicting Arctic SIC.
基金Supported by Key Project of Social Development Basic Research of Yunnan Provincial Science and Technology Department(2009cc025)
文摘[ Objective] The study aimed at discussing the purification effect of constructed wetlands for treating river water flowing from phosphate mine areas into Fuxian Lake. [Method] The running parameters of the constructed wetlands were investigated for one year, and the purification effect of the constructed wetlands for treating the sewage from phosphate mine areas was analyzed. [Result] With the aid of the constructed wet- land, the average removal rates of total nitrogen （TN）, total phosphorus （TP） and CODcr were 52%, 32% and 54%, and the removal effects were best when the designed hydraulic load was 0.67 m3/（ m2 · d）. Running stably for six years, the constructed wetlands had advantages of no power, low resistance and high removal rate. [ Conclusion] The constructed wetlands reduced the load of pollutants from phosphate mine areas into Fuxian Lake effectivelv, which Dlaved important roles in the Drotection of water aualitv of Fuxian Lake.
基金supported by the National Key Research and Development Program of China[grant number 2022YFE0106800]the National Natural Science Foundation of China[grant number 42230603]+1 种基金the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)[grant number 311024001]supported by Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)[grant number SML2023SP209].
文摘Based on a normalized difference vegetation index(NDVI)dataset for 1982-2021,this work investigates the principal modes of interannual variability in summer NDVI over eastern Siberia using the year-to-year increment method and empirical orthogonal function(EOF)analysis.The first three principal modes(EOF1-3)of the year-to-year increment of summer NDVI(NDVI_DY)exhibit a regionally consistent mode,a western-eastern dipole mode,and a northern-southern dipole mode,respectively.Further analysis shows that sea surface temperature(SST)in the tropical Indian Ocean in February-March and western Siberian soil moisture in April could influence EOF1.EOF2 is modulated by April Northwest Pacific SST and western Siberian soil moisture in May.May North Atlantic SST and sea ice in the Kara Sea in the preceding October significantly affect EOF3.Using the year-to-year increment method and multiple linear regression analysis,prediction schemes for EOF1-3 are developed based on these predictors.To assess the predictive skill of these schemes,one-year-out cross-validation and independent hindcast methods are employed.The temporal correlation coefficients between observed EOF1-3 and the cross-validation results are 0.62,0.46,and 0.37,respectively,exceeding the 95%confidence level.In addition,reconstructed schemes for summer NDVI are developed using predicted NDVI_DY and the observed principal modes of NDVI_DY.Independent hindcasts of NDVI anomalies during 2019-2021 also present consistent distributions with the observed results.
基金supported by the National Natural Science Foundation of China(Nos.22172011,22088102,and 22301248)the National Key R&D Program of China(2022YFA0911900)the Fundamental Research Funds for the Central Universities(DUT23LAB611).
文摘Acidic-stable oxygen evolution reaction(OER)catalysts based on earth-abundant materials are important but rare for the proton exchange membrane-based water electrolysis.In this study,a metal-containing hydrogen-bonded organic framework(HOF)of manganese coordinated with 2,2'-bipyridine-6,6'-dicarboxylate ligands,Mn(bda),interconnected through hydrogen bonding and π-π stacking is used as a heterogeneous OER catalyst(Mn(bda)-HOF)for acidic water oxidation and exhibits a considerable OER performance.Electrochemical results show that Mn(bda)-HOF displays a turn of frequency of 1 s^(-1) at an overpotential of 870 mV.Meanwhile,this Mn(bda)-HOF shows an unusual pH dependence on performance,where the reaction rate increases with the decrease of pH.A comprehensive mechanistic study reveals that the charge transfer triggered coupling of two metal-oxo species Mn^(5+)(O)is the rate-determining step,which leads to this unusual pH dependence on the OER performance.
基金funded by the National Natural Science Foundation of China(No.22379052)Taishan Scholars of Shandong Province,China(No.tsqnz20221143)。
文摘The effects of synthesis conditions,especially the heating rate,on the reaction kinetics of Ni-rich cathodes were systematically studied.The growth rate of Ni-rich oxide increases continuously as the heating rate increases.Ab initio molecular dynamics simulations demonstrate that a high heating rate induces anabatic oscillations,indicating a decrease in thermodynamic stability and a tendency for the crystal surface to undergo reconstruction.The presence of an intermediate phase at the grain boundary amplifies atomic migration-induced interface fusion and consequently augments crystal growth kinetics.However,the excessively high heating rate aggravates the Li+/Ni2+mixing in the Ni-rich cathode.The single-crystal Ni-rich cathode exhibits enhanced structural/thermal stability but a decreased specific capacity and rate performance compared with its polycrystalline counterpart.
文摘作为东亚冬季风的关键系统,西伯利亚高压的变化对欧亚大陆冬季天气及气候异常产生重要影响。本文系统地评估了美国国家环境预测中心第二代气候预测系统(NCEP-CFSv2,National Center for Environment Prediction-Climate Forecast System,version 2)对冬半年(11~2月)及逐月西伯利亚高压强度的预测效能。结果表明,NCEP-CFSv2模式仅对11月西伯利亚高压强度的预测效能较好,研究其成因发现11月西伯利亚高压强度主要受该地区热力、动力过程以及西伯利亚地区积雪状况的影响。在热力过程方面,NCEP-CFSv2模式可以较好地再现11月西伯利亚高压强度及其相联的该地区表层土壤温度、对外长波辐射等热力因素;在动力过程方面,模式能较好地再现11月西伯利亚高压强度及其相联的该地区对流层低层辐散环流、中高层下沉运动;同时,模式也能较好地再现11月西伯利亚高压强度与该地区积雪覆盖率之间的相互作用。因此,与11月西伯利亚高压相联的热力、动力过程和该地区积雪状况可能是11月西伯利亚高压强度的可预测来源,且NCEP-CFSv2模式能较好地再现这些可预测来源。
