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| 1 | Application of the Conditional Nonlinear Optimal Perturbation Method to the Predictability Study of the Kuroshio Large Meander显示文摘A reduced-gravity barotropic shallow-water model was used to simulate the Kuroshio path variations.The results show that the model was able to capture the essential features of these path variations.We used one simulation of the model as the reference state and investigated the effects of errors in model parameters on the prediction of the transition to the Kuroshio large meander (KLM) state using the conditional nonlinear optimal parameter perturbation (CNOP-P) method.Because of their relatively large uncertainties,three model parameters were considered:the interfacial friction coefficient,the wind-stress amplitude,and the lateral friction coefficient.We determined the CNOP-Ps optimized for each of these three parameters independently,and we optimized all three parameters simultaneously using the Spectral Projected Gradient 2 (SPG2) algorithm.Similarly,the impacts caused by errors in initial conditions were examined using the conditional nonlinear optimal initial perturbation (CNOP-I) method.Both the CNOP-I and CNOP-Ps can result in significant prediction errors of the KLM over a lead time of 240 days.But the prediction error caused by CNOP-I is greater than that caused by CNOP-P.The results of this study indicate not only that initial condition errors have greater effects on the prediction of the KLM than errors in model parameters but also that the latter cannot be ignored.Hence,to enhance the forecast skill of the KLM in this model,the initial conditions should first be improved,the model parameters should use the best possible estimates. | 王强 穆穆 Henk A.DIJKSTRA | 2012 | Advances in Atmospheric Sciences2012，29，1： | 25 |
| 2 | Opposite effects of nitrogen fertilization and plastic film mulching on crop N and P stoichiometry in a temperate agroecosystem显示文摘Aims Crop nitrogen(N)and phosphorus(P)stoichiometry can influence food nutritive quality and many ecosystem processes.However,how and why N and P stoichiometry respond to long-term agricul-tural management practices(e.g.N fertilization and film mulching)are not clearly understood.Methods We collected maize tissues(leaf,stem,root and seed)and soil sam-ples from a temperate cropland under 30-year continuous N fer-tilization and plastic film mulching treatments,measured their C,N and P concentrations(the proportion(%)relative to the sample mass),and used structural equation models to uncover the re-sponding mechanisms for crop N and P contents(the total amount(g/m2)in crop biomass).Important Findings Long-term N fertilization increased N concentrations in all crop tissues but sharply decreased P concentrations in vegetative tis-sues(leaf,stem and root),thereby reducing their C/N ratio and increasing C/P and N/P ratios.The drop in P concentration in vegetative tissues was due to the dilution effect by biomass in-crement and the priority of P supply for seed production.In con-trast,film mulching decreased N concentration but increased P concentrations in most crop tissues,thereby increasing C/N ratio and reducing C/P and N/P ratios.Film mulching increased crop P content by increasing soil temperature and moisture;whereas,mulching showed little effect on crop N content,because a posi-tive effects of soil temperature may have canceled out a negative effect by soil moisture.This indicated a decoupling of P and N uptake by crops under film mulching.In conclusion,N fertiliza-tion and plastic film mulching showed opposite effects of on crop N and P stoichiometry. | Fan Ding Shuangyi Li Xiao-Tao Lü Feike A.Dijkstra Sean Schaeffer Tingting An Jiubo Pei Liangjie Sun Jingkuan Wang | 2019 | Journal of Plant Ecology2019，12，4： | 8 |
| 3 | Synergistic Effects of Biochar and NPK Fertilizer on Soybean Yield in an Alkaline Soil显示文摘Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil. | Fatima Z.METE Shamim MIA Feike A.DIJKSTRA Md.ABUYUSUF A.S.M.Iqbal HOSSAIN | 2015 | Pedosphere2015，25，5： | 7 |
| 4 | Three-Dimensional Structure of Optimal Nonlinear Excitation for Decadal Variability of the Thermohaline Circulation显示文摘The decadal variability of the North Atlantic thermohaline circulation(THC) is investigated within a three-dimensional ocean circulation model using the conditional nonlinear optimal perturbation method. The results show that the optimal initial perturbations of temperature and salinity exciting the strongest decadal THC variations have similar structures: the perturbations are mainly in the northwestern basin at a depth ranging from 1500 to 3000 m. These temperature and salinity perturbations act as the optimal precursors for future modifications of the THC, highlighting the importance of observations in the northwestern basin to monitor the variations of temperature and salinity at depth. The decadal THC variation in the nonlinear model initialized by the optimal salinity perturbations is much stronger than that caused by the optimal temperature perturbations, indicating that salinity variations might play a relatively important role in exciting the decadal THC variability. Moreover, the decadal THC variations in the tangent linear and nonlinear models show remarkably different characteristics, suggesting the importance of nonlinear processes in the decadal variability of the THC. | ZU Zi-Qing MU Mu Henk A.DIJKSTRA | 2013 | Atmospheric and Oceanic Science Letters2013，6，6： | 2 |
| 5 | Optimal nonlinear excitation of decadal variability of the North Atlantic thermohaline circulation显示文摘Nonlinear development of salinity perturbations in the Atlantic thermohaline circulation(THC) is investigated with a three-dimensional ocean circulation model,using the conditional nonlinear optimal perturbation method.The results show two types of optimal initial perturbations of sea surface salinity,one associated with freshwater and the other with salinity.Both types of perturbations excite decadal variability of the THC.Under the same amplitude of initial perturbation,the decadal variation induced by the freshwater perturbation is much stronger than that by the salinity perturbation,suggesting that the THC is more sensitive to freshwater than salinity perturbation.As the amplitude of initial perturbation increases,the decadal variations become stronger for both perturbations.For salinity perturbations,recovery time of the THC to return to steady state gradually saturates with increasing amplitude,whereas this recovery time increases remarkably for freshwater perturbations.A nonlinear(advective) feedback between density and velocity anomalies is proposed to explain these characteristics of decadal variability excitation.The results are consistent with previous ones from simple box models,and highlight the importance of nonlinear feedback in decadal THC variability. | 祖子清 穆穆 Henk A.DIJKSTRA | 2013 | Chinese Journal of Oceanology and Limnology2013，31，6： | 2 |
| 6 | Polymorphisms of the ADAM33 gene are associated with accelerated lung function decline in asthma显示文摘 | H.Jongepier H. M.Boezen A.Dijkstra T. D.Howard J. M.Vonk G. H.Koppelman S. L.Zheng D. A.Meyers E. R.Bleecker D. S.Postma | 2004 | Clinical & Experimental Allergy2004，，5： | 1 |
| 7 | Numerical Bifurcation Methods and their Application to Fluid Dynamics: Analysis beyond Simulation显示文摘We provide an overview of current techniques and typical applications of numerical bifurcation analysis in fluid dynamical problems.Many of these problems are characterized by high-dimensional dynamical systems which undergo transitions as parameters are changed.The computation of the critical conditions associated with these transitions,popularly referred to as‘tipping points’,is important for understanding the transition mechanisms.We describe the two basic classes of methods of numerical bifurcation analysis,which differ in the explicit or implicit use of the Jacobian matrix of the dynamical system.The numerical challenges involved in both methods are mentioned and possible solutions to current bottlenecks are given.To demonstrate that numerical bifurcation techniques are not restricted to relatively low-dimensional dynamical systems,we provide several examples of the application of the modern techniques to a diverse set of fluid mechanical problems. | Henk A.Dijkstra Fred W.Wubs Andrew K.Cliffe Eusebius Doedel Ioana F.Dragomirescu Bruno Eckhardt Alexander Yu.Gelfgat Andrew L.Hazel Valerio Lucarini Andy G.Salinger Erik T.Phipps Juan Sanchez-Umbria Henk Schuttelaars Laurette S.Tuckerman Uwe Thiele | 2014 | Communications in Computational Physics2014，15，1： | 0 |
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