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31.
辽宁省潜在蒸散发量及其敏感性规律分析 总被引:2,自引:0,他引:2
采用Penman-Monteith法和敏感系数法对辽宁省1965~2014年潜在蒸散发量及影响潜在蒸散发的气象因子敏感性进行分析,探讨气候变化下影响辽宁省潜在蒸散发量变化的主导因子及潜在蒸散发对气候变化的定量响应。结果表明:① 近50 a辽宁省潜在蒸散发呈现显著减少趋势,在空间上由西向东递减;② 潜在蒸散发对气象因子的敏感性在年尺度上表现为,水汽压最为敏感,其次为太阳辐射、风速、平均气温;在季节尺度上,春季和秋季对平均气温最不敏感,夏季对风速最不敏感,冬季对太阳辐射最不敏感;③ 空间分布上,气象因素的敏感系数与气象因子空间变化规律相吻合,潜在蒸散发对气温的敏感性由北部向南部递增,对水汽压、太阳辐射的敏感性由东部向西部递减,而风速与之变化趋势相反。④ 风速的显著降低是辽宁省潜在蒸散发量下降的主要原因,太阳辐射的下降及水汽压的升高也促使了潜在蒸散发量的下降。 相似文献
32.
Abstract We consider the growth of disturbances to large-scale zonally-asymmetric steady states in a truncated spectral model for forced and dissipated barotropic flow. A variant of the energy method is developed to optimize the instantaneous disturbance energy growth rate. The method involves solving a matrix eigenvalue problem amenable to standard numerical techniques. Two applications are discussed. (1) The global stability of a family of steady states is assessed in terms of the Ekman damping coefficient r. It is shown that monotonic global stability (i.e., every disturbances energy monotonically decays to zero) prevails when r≥rc . (2) Initially fastest-growing disturbances are constructed in the r<rc regime. Particular attention is paid to a subregion of the r<rc regime where initially-growing disturbances exist despite stability with respect to normal modes. Nonlinear time-dependent simulations are performed in order to appraise the time evolution of various disturbances. 相似文献
33.
A box model of the interhemispheric thermohaline circulation (THC) in atmosphere-ocean for global climate is considered. By using the multi-scales method, the asymptotic solution of a simplified weakly nonlinear model is discussed. Firstly, by introducing first scale, the zeroth order approximate solution of the model is obtained. Secondly, by using the multi-scales, the first order approximate equation of the model is found. Finally, second order approximate equation is formed to eliminate the secular terms, and a uniformly valid asymptotic expansion of solution is decided. The multi-scales solving method is an analytic method which can be used to analyze operation sequentially. And then we can also study the diversified qualitative and quantitative behaviors for corresponding physical quantities. This paper aims at providing a valid method for solving a box model of the nonlinear equation. 相似文献
34.
大黄鱼皮肤溃烂病病原的研究 总被引:3,自引:0,他引:3
从福建省厦门西海域某渔排养殖大黄鱼(Pseudosciaena cyogga)患皮肤溃烂病的肝脏、肌肉分离到2株优势菌。人工感染试验证实其中1株为致病菌。该菌的主要生理生化特性为革兰氏阴性,短杆状,极生单鞭毛,发酵葡萄糖,氧化酶阳性,赖氨酸脱羧酶、鸟氨酸脱羧酶阳性,精氨酸脱羧酶、水杨素、枸橼酸盐阴性,不产生H2S,利用葡萄糖、甘露醇产酸,对O/129(10μg)不敏感。在含0%,10%NaCl的普通培养基上不生长;在含2%,4%,6%,8%NaCl的普通培养基中生长;在温度30,35,40℃下生长良好,但4℃不生长。初步鉴定该病原菌为副溶血弧菌(Vibrio parahaemolyticus)。药敏试验表明,该菌对卡那霉素、复方新诺明、链霉素等10种药物敏感,对青霉素G、氨苄青霉素、利福平等6种药物不敏感。 相似文献
35.
Low-low satellite-to-satellite tracking: a comparison between analytical linear orbit perturbation theory and numerical integration 总被引:1,自引:0,他引:1
P.N.A.M. Visser 《Journal of Geodesy》2005,79(1-3):160-166
Low-low satellite-to-satellite tracking (ll-SST) range-rate observations have been predicted by two methods: one based on a linear perturbation theory in combination with the Hill equations, and one based on solving the equations of motion of two low-flying satellites by numerical integration. The two methods produce almost equivalent Fourier spectra of the range-rate observations after properly taking into account a few resonant terms. For a typical GRACE-type configuration, where the two satellites trail each other at a distance of 300 km at an altitude of 460 km, and in the presence of the EGM96 gravity field model, complete to spherical harmonic degree and order 70, the agreement between the Fourier spectra is about 1 mm/s compared to a root-mean-square (RMS) value of more than 220 mm/s for the range-rate signal. The discrepancy of 1 mm/s can be reduced significantly when not taking into account perturbations caused by the J2 term. Excluding the J2 term, the agreement between the two methods improves to 0.4 mm/s compared to a RMS value of 6 mm/s for the range-rate signal. These values are 0.01 and 2.3 mm/s when ignoring the spectrum for frequencies below two cycles per orbital revolution, reducing the discrepancy even further to about 0.5% of the signal. The selected linear perturbation theory is thus capable of modeling gravity field induced range-rate observations with very high precision for a large part of the spectrum. 相似文献
36.
计算机仿真模型的灵敏度分析,是仿真建模中的重要研究内容,对实际系统的建立和优化具有重要意义。本文主要研究了在用蒙特卡洛方法仿真随机系统时,其仿真模型(输出)的灵敏度(导数、梯度、Hessian矩阵等),对系统性能函数和灵敏度的参数估计进行了探讨,并结合实际应用系统,对结论进行了分析比较。 相似文献
37.
本文主要就分级布设的变形监测网的灵敏度问题进行讨论,并就在实际工作中如何直接、有效地改善监测网的灵敏度提出了有益的建议. 相似文献
38.
Reliability testing, namely receiver autonomous integrity monitoring (RAIM), consists of statistical testing of least-squares residuals of observations, e.g., on an epoch-by-epoch basis aiming towards reliable navigation fault detection and exclusion (FDE). In this paper, classic RAIM and FDE methods are extended with testing of range-rate residuals to find inconsistent velocity solutions in order to contribute to the reliability of the system with special focus on degraded signal environments. Reliability enhancement efforts discussed include a Backward-FDE scheme based on statistical outlier detection and an iteratively reweighted robust estimation technique, a modified Danish method. In addition, measurement weighting assigned to code and Doppler observations is assessed in the paper in order to allow fitting a priori variance models to the estimation processes. The schemes discussed are also suitable in terms of computational convenience for a combined GPS/Galileo system. The objective of this paper is to assess position and velocity reliability testing and enhancement in urban and indoor conditions and to analyze the navigation accuracy conditions with high sensitivity GPS (HSGPS) tests. The results show the necessity of weighted estimation and FDE for reliability enhancement in degraded signal-environment navigation. 相似文献
39.
变形监测网的质量测度 总被引:2,自引:0,他引:2
对变形监测网络的质量测度-精度、灵敏度和可区分度进行了讨论,重点论述了它们之间的关系及应用的条件,并以算例加以论证。 相似文献
40.
Simulation of soil moisture content requires effective soil hydraulic parameters that are valid at the modelling scale. This study investigates how these parameters can be estimated by inverse modelling using soil moisture measurements at 25 locations at three different depths (at the surface, at 30 and 60 cm depth) on an 80 by 20 m hillslope. The study presents two global sensitivity analyses to investigate the sensitivity in simulated soil moisture content of the different hydraulic parameters used in a one‐dimensional unsaturated zone model based on Richards' equation. For estimation of the effective parameters the shuffled complex evolution algorithm is applied. These estimated parameters are compared to their measured laboratory and in situ equivalents. Soil hydraulic functions were estimated in the laboratory on 100 cm3 undisturbed soil cores collected at 115 locations situated in two horizons in three profile pits along the hillslope. Furthermore, in situ field saturated hydraulic conductivity was estimated at 120 locations using single‐ring pressure infiltrometer measurements. The sensitivity analysis of 13 soil physical parameters (saturated hydraulic conductivity (Ks), saturated moisture content (θs), residual moisture content (θr), inverse of the air‐entry value (α), van Genuchten shape parameter (n), Averjanov shape parameter (N) for both horizons, and depth (d) from surface to B horizon) in a two‐layer single column model showed that the parameter N is the least sensitive parameter. Ks of both horizons, θs of the A horizon and d were found to be the most sensitive parameters. Distributions over all locations of the effective parameters and the distributions of the estimated soil physical parameters from the undisturbed soil samples and the single‐ring pressure infiltrometer estimates were found significantly different at a 5% level for all parameters except for α of the A horizon and Ks and θs of the B horizon. Different reasons are discussed to explain these large differences. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献