Actual Observation Data Research Articles

Integrodifference model for blowfly invasion

We propose a stage-structured integrodifference model for blowflies’ growth and dispersion taking into account the density dependence of fertility and survival rates and the non-overlap of generations. We assume a discrete-time, stage-structured, model. The spatial dynamics is introduced by means of a redistribution kernel. We treat one and two dimensional cases, the latter on the semi-plane, with a reflexive boundary. We analytically show that the upper bound for the invasion front speed is the same as in the one-dimensional case. Using laboratory data for fertility and survival parameters and dispersal data of a single generation from a capture-recapture experiment in South Africa, we obtain an estimate for the velocity of invasion of blowflies of the species Chrysomya albiceps. This model predicts a speed of invasion which was compared to actual observational data for the invasion of the focal species in the Neotropics. Good agreement was found between model and observations.

Analysis and Study on Space Variation Laws of Rainfall of Yuanyang Hani Terrace

In order to analyze and research the space variation laws of rainfall of Yuanyang Hani terrace, monthly average rainfall in this area which was actually measured from 2001 to 2010 of the four typical meteorological sites, Kakou, Xiaoshuijing, Xinjie and 073, was spatial interpolated and its space mutation law was analyzed by using inverse distance weighted method, ordinary Kriging method, the most neighboring method, radial basis function method, and analyzed results of different interpolation methods through cross validation, drawn rainfall isoline maps by utilizing surfer software, spatial distribution of all kinds of interpolation and the actual observation data were compared. The results show that among several interpolation methods, results of Kriging interpolation method was close to variation laws of actual measured data mostly, and its interpolation effect was the best. Meanwhile, through the interpolation analysis, it showed that rainfall of Hani terrace took on strong spatial variability.

Ready for Gas Injection: Asphaltene Risk Evaluation by Mathematical Modeling of Asphaltene-Precipitation Envelope (APE) With Integration of All Laboratory Deliverables

Summary An offshore carbonate oil field in the Arabian Gulf is exhibiting asphaltene deposition inside the tubing of production wells completed in one of two main producible limestone reservoirs. This problem significantly reduces well profitability because of production loss and frequent asphaltene-removal jobs (solvent soaking). Furthermore, future full-field enhanced-oil-recovery (EOR) development—namely gas injection—is now planned and might have a risk of enhancing the asphaltene problem. Therefore, comprehensive study has been carried out not only to establish a less-frequent and more-effective remedy than the current action but also to evaluate a future risk of gas injection. The study was initiated with careful review of the fundamental measurements of asphaltene properties collected during the 20 years of production history—saturates, aromatics, resins, and asphaltenes (SARA); asphaltene contents; and asphaltene-onset-pressure (AOP). Subsequently, the mathematical modeling analysis using those properties was incorporated into the study for better understanding/predicting of asphaltene-precipitation behavior. This paper describes the integration/optimization of the asphaltene-precipitation-envelope (APE) modeling on the basis of all available laboratory data, and consequently suggests representative APE. The APE-model validity was evaluated by comparison with actual observation data in the problematic reservoir. On the basis of the mathematical models established, several sensitivities (i.e., mixing with injection gas and blending oils produced from the two main producible reservoirs) were investigated to assess impacts of the future EOR on asphaltene risk from the subsurface and surface points of view. Several types of injection gas were examined, and their risks were compared and identified. Consequently, the surface-facility design was adequately modified and optimized in order to minimize asphaltene risk influenced by gas injection.

Relationship between Sea Temperature Change and Tropical Cyclones Based on Argo

The relationship between sea water temperature with depth and the maximum cyclone wind speed was analyzed, the temperature was acquired before 24h of the cyclones occurred by using of data of Argo floats and cyclones in 2005, and taking advantage of inverse distance weighted interpolation method. The results showed that: (1) the Tropical Cyclone’s intensity had a strong correlation with the sea water temperature in the depth of about 42m or so. (2) Under the conditions of similar latitude, according to the energy conservation law, the maximum intensity of cyclones wind was a linear function of sea water temperature, depth, and continuous change in the overall rate, which was verified through the actual observation data.

Conditional Posterior Cramér–Rao Lower Bounds for Nonlinear Sequential Bayesian Estimation

The posterior CramerRao lower bound (PCRLB) for sequential Bayesian estimators, which was derived by Tichavsky in 1998, provides a performance bound for a general nonlinear filtering problem. However, it is an offline bound whose corresponding Fisher information matrix (FIM) is obtained by taking the expectation with respect to all the random variables, namely the measurements and the system states. As a result, this unconditional PCRLB is not well suited for adaptive resource management for dynamic systems. The new concept of conditional PCRLB is proposed and derived in this paper, which is dependent on the actual observation data up to the current time, and is implicitly dependent on the underlying system state. Therefore, it is adaptive to the particular realization of the underlying system state and provides a more accurate and effective online indication of the estimation performance than the unconditional PCRLB. Both the exact conditional PCRLB and its recursive evaluation approach including an approximation are derived. Further, a general sequential Monte Carlo solution is proposed to compute the conditional PCRLB recursively for nonlinear non-Gaussian sequential Bayesian estimation problems. The differences between this new bound and existing measurement dependent PCRLBs are investigated and discussed. Illustrative examples are also provided to show the performance of the proposed conditional PCRLB.

Dynamic simulation and definition of crop coefficient for typical steppe in Inner Mongolia, China.

Aims Crop coefficients are the key parameters in calculating crop evapotranspiration. There are few reference values for crop coefficients of natural grass in FAO irrigation and drainage papers. Our aim was to define crop coefficients under different water conditions for typical steppe in Inner Mongolia based on actual observation data so as to accurately calculate the water demand and actual evapotranspiration. Methods Data were collected from field experiments at Xilinhot (44°08′03″N, 116°19′43″ E, elevation 990 m), Inner Mongolia in 2008, and meteorological data from 26 years were obtained from four stations. Using the water balance equation, we calculated crop coefficients of typical steppe using statistical analyses and developed the standard crop coefficients of typical steppe and simulated equations through comparison and validation with rec-ommend values by FAO. We established a climatic correction method for the standard crop coefficients and a correction method of crop coefficients under water stress. Important findings Standard crop coefficient values of typical steppe were fitted with trinomial using days after return of the green period of grass and accumulated temperature (≥0 °C), with correlation coefficients 0.94. Crop coefficients of typical steppe were described as an exponential equation with relative leaf area index (LAI) and relative plant cover. Average value of standard crop coefficient of typical steppe for the growing season was 0.60, and the maximum value was 1.02. Typical values of crop coefficients in different growing stages were 0.40 for initial stage, 0.93 for medium stage and 0.80 for later stage, and threshold ranges of three growing stages were 0.35–0.45 for initial stage, 0.85–1.00 for medium stage and 0.70–0.90 for later stage. Compared with measured data from a lysimeter, the simulated values for 10 days of evapotranspiration indicated an average relative error of 20%–24% for whole growing season, and 10% for the active growing stage. The method and results defined here are applicable to typical steppe in Inner Mongolia.

Studies on Ground Environmental Vibration Induced by Urban Rail Transit

In order to offer theoretical basis for the vibration prevention and noise reduction for the area along urban rail traffic line, the propagation laws of environmental vibration are summarized by analyzing observation data in time and frequency domain based on actual field observation data in Beijing. The mathematical statistics method under the criterion of least-squares has been used to study the vibration propagation and to establish the empirical formula of vertical ground vibration. The results obtained from the empirical formulas proposed agree with the results of field observation well. The vertical ground vibration level is much higher than that of horizontal. So the vertical ground vibration level is the most important aspect when evaluating ground environmental vibration level. The field response near the rail depends on the high frequency vibration caused by moving train and that far from the rail is dominated by the natural vibration frequency of train and the field vibration. The response amplitude of environmental vibration would be changed when load changed.

The Society of Cardiovascular Anesthesiologists' FOCUS Initiative: Locating Errors Through Networked Surveillance (LENS) Project Vision

The Society of Cardiovascular Anesthesiologists' FOCUS Initiative: Locating Errors Through Networked Surveillance (LENS) Project Vision

COMPARISON OF INFRARED 11μm WINDOW CHANNELS FOR MEDIUM RESOLUTION SPECTRAL IMAGER AND VISIBLE AND INFRARED RADIOMETER ON FY-3 METEOROLOGY SATELLITE

The different remote sensors on China new generation meteorology satellite FY-3 have similar thermal infrared channels. For the visible and infrared radiometer (VIRR) infrared 4-channel and medium resolution spectral imager(MERSI) infrared 5-channel,the line-by-line radiative transfer model (LBLRTM),in which the atmospheric profiles adopt global 52 atmospheric profiles generated by ECMWF,was performed to calculate the spectral radiance emitted from the earth-atmosphere between 8μm and 14μm. The radiance received by the satellite was computed combined with the spectral response functions of channels and then the theoretical relationship of the brightness temperatures for the two channels was analyzed. The FY-3 actual observation data at QingHai Lake in September 2008 was used to examine the relationship. The comparison of the results indicates that the brightness temperatures for both channels calculated by LBLRTM agree each other well,but the temperature obtained from MERSI is lower than that from VIRR. The temperature difference between the two channels increases with the increase of temperature. Because FY-3 actual observations are affected by many factors,VIRR temperature is lower than MERSI,which is different from the theoretical result of the model. The matched MODIS data is used to compare with MERSI and VIRR. It is concluded that VIRR might underestimate the temperature. The deviation of MODIS and MERSI temperaturesis within the absolute accuracy of the temperature measurements. The results described here should be valuable for assessing the similarities and differences for the two similar infrared channels of MERSI and VIRR.

Determination of parameters of meteor bodies based on flight observational data

In the present study, an analytical model of the atmospheric entry is calculated using the altitude and the rate of the meteor body deceleration in the atmosphere from the data of actual observations. With this purpose the strict mathematical algorithm to find basic dynamic parameters of the theoretical relationship between the height and the velocity of the body that help to fit observations along the luminous part of the trajectories in the best way is suggested. The detailed review of the existing approaches to the decision of this problem is presented in the related work by the writer [Gritsevich, M.I. Fireballs masses and densities: hypotheses and reality, in: 37th COSPAR Scientific Assembly, Montreal, Canada, 13–20 July 2008, B04-0041-08, 2008a]. The basic goal of the present study mainly consists in the qualitative description of the universal technique for processing of the meteor body flight observational data. The main difference from previous studies [e.g., Gritsevich, M.I., Stulov, V.P. Entry mass for Bolides of the Canadian Network. Dokl. Akad. Nauk 413, 4, 472–477, 2007a (Phys. Dokl. (Engl. Transl.) 52, 4, 219–224); Gritsevich, M.I. Determination of the Extra-atmospheric Bolides Masses of the Canadian Network. Publishing House of the Faculty of Mechanics and Mathematics of the Moscow State University (in Russian), 2007] is that the given observations are approximated using the analytical solution of the fundamental differential equations of the meteor physics. As for today the method allows to determine parameters of meteor bodies with the high accuracy of estimate.

Validity of the photometric formula for estimating the mass of a fireball projectile

The extraterrestrial mass of a meteoroid is conventionally determined using a photometric formula, by integrating the brightness along the entire luminous segment of the trajectory. The extraterrestrial mass can also be estimated using the altitude and rate of meteor deceleration in the atmosphere. The discrepancy of the estimates obtained using these two techniques is usually diminished by selecting “appropriate” values of the meteoroid density. However, this leads to obviously underestimated values of ~0.25 g/cm 3 for this density [1, 2]. In order to eliminate these discrepancies, it was proposed to consider a swarm of similar-size fragments instead of a single meteoroid. In this case, it is the photometric-to-dynamic mass ratio that determines the number of such fragments [3, 4]. In the present paper, the extraterrestrial mass is calculated using the data of actual observations, by selecting the parameters describing deceleration and ablation of meteoroids along the luminous segment of the trajectory. The model is based on the best fitting of the observational data by an analytical solution of the equations of meteor physics. Cases will be presented where the discrepancy between the dynamic and photometric estimates cannot be explained by the above-mentioned reasons. In particular, large fireballs with dynamic masses exceeding the photometric mass by more than an order of magnitude were observed. Photometric observations are conventionally processed within the framework of the commonly accepted assumption that a certain fraction of the kinetic-energy losses of a meteoroid is converted into its brightness, I τ ˜ dM V 2 /2

Experimental Study of Fluorine Transport Rules in Unsaturated Stratified Soil

Abstract With the aid of soil column test models, the transport rules of fluorine contaminants in unsaturated stratified soils are discussed. Curves of F− concentrations at different times and sites in the unsaturated stratified soil were obtained under conditions of continuous injection of fluoride contaminants and water. Based on the analysis of the actual observation data, the values between computed results and observed data were compared. It is shown that the chemical properties of fluorine ions are active. The migration process of fluorine ions in soils is complex. Because of the effect of adsorption and desorption, the curve of the fluorine ion breakthrough curve is not symmetric. Its concentration peak value at each measuring point gradually decays. The tail of the breakthrough curve is long and the process of leaching and purifying using water requires considerable time. Along with the release of OH− in the process of fluorine absorption, the pH value of the soil solution changed from neutral to alkalinity during the test process. The first part of the breakthrough curve fitted better than the second part. The main reason is that fluorine does not always exist in the form of fluorinions in groundwater. Given the long test time, fluorinions possibly react with other ions in the soil solution to form complex water-soluble fluorine compounds. Only the retardation factor and source-sink term have been considered in our numerical model, which may leads to errors of computed values. But as a whole the migration rules of fluorine ions are basically correct, which indicates that the established numerical model can be used to simulate the transport rules of fluorine contaminants in unsaturated stratified soils.

Solar oxygen and calcium in Mercury's exosphere

In situ and remote sensing observations have provided a glimpse of the space environment at Mercury and the interaction of its magnetic field with both the planetary surface and its exosphere. In this work we suggest that O 6 + and Ca 11 + supplied by the solar wind are adequate to explain the observations of emissions from neutral O and Ca in the Mercury environment, or exosphere. The actual observational data for O are sparse with only a single detection by instrumentation on Mariner 10 with no altitude profile. For Ca the observations are more thorough and show Ca to be present at thousands of km off the high latitude limbs of Mercury. We discuss the abundance and distribution of O and Ca in Mercury's exosphere with the solar wind as the sole source and loss exclusively by ionization. Results are compatible with the observed abundances. We present a new model of solar wind Ca and O implantation into Mercury's regolith and suggest observations that could be made by Mercury atmospheric and surface camera spectrograph (MASCS) and the energetic particle and plasma spectrometer (EPPS) on MErcury, Surface, Space ENvironment, GEochemistry, Ranging spacecraft (MESSENGER) to differentiate between solar wind delivery of O and Ca vs. a true crustal source as may be measured by the neutron spectrometer (NS) and gamma-ray spectrometer (GRS) and possibly the X-ray spectrometer (XRS).

Identification of vibration loads on hydro generator by using hybrid genetic algorithm

Vibration dynamic characteristics have been a major issue in the modeling and mechanical analysis of large hydro generators. An algorithm is developed for identifying vibration dynamic characteristics by means of hybrid genetic algorithm. From the measured dynamic responses of a hydro generator, an appropriate estimation algorithm is needed to identify the loading parameters, including the main frequencies and amplitudes of vibrating forces. In order to identify parameters in an efficient and robust manner, an optimization method is proposed that combines genetic algorithm with simulated annealing and elitist strategy. The hybrid genetic algorithm is then used to tackle an ill-posed problem of parameter identification, in which the effectiveness of the proposed optimization method is confirmed by its comparison with actual observation data.

沖合水面変動記録を用いた津波成分即時抽出法に関する研究

This paper introduces a newly developed real time tsunami detection system using offshore water surface elevation data obtained from GPS buoys or seabed installed acoustic/pressure wave gauges. In order to eliminate high frequency components caused by wind waves and swells, shape of the numerical low-pass-filter was determined with consideration of its real-time efficiency. To eliminate lower frequency phenomena caused by astronomical tides and other causes such as water temperature change, 6 days continuous passed data were found to be necessary to obtain harmonic constants of the 4 principal tide components and averaged sea level. Miss-fixed and data-loss phenomena, which may appear in the GPS buoy observation, were also considered to elaborate the automatic system.Proposed system was checked with the actual offshore tsunami observation data caused by the 2004 Tokaido-off and 2005 Miyagi-off earthquake tsunami events, and the applicability was well confirmed with exception during a huge typhoon caused abnormal waves and sea-level events.

Four-dimensional data assimilation method based on SVD: Theoretical aspect

A new method of four-dimensional data assimilation based on Singular Value Decomposition (SVD) is proposed. In it, a set of atmospheric states is obtained by integrating a numerical weather prediction model and simulated observations are taken and calculated from the model variables. Then the SVD technique is used to create the base vectors from this coupled data set. Finally, the analysis is obtained by projecting actual observation data into a space spanned by the base vectors. Using this approach, the four-dimensional data assimilation becomes a simple linear inverse problem the linearization of the nonlinear forward model is avoided, and the developments of the adjoint and background error covariance matrix are no longer needed. Since the SVD technique is used here, the method is simply called 4DSVD.

Mismatch between X-Ray and Emission-weighted Temperatures in Galaxy Clusters: Cosmological Implications

The thermal properties of hydrodynamical simulations of galaxy clusters are usually compared to observations by relying on the emission-weighted temperature T_ew, instead of on the spectroscopic X-ray temperature T_spec, which is obtained by actual observational data. In a recent paper Mazzotta et al. show that, if the cluster is thermally complex, T_ew fails at reproducing T_spec, and propose a new formula, the spectroscopic-like temperature, T_sl, which approximates T_spec better than a few per cent. By analyzing a set of hydrodynamical simulations of galaxy clusters, we find that T_sl is lower than T_ew by 20-30 per cent. As a consequence, the normalization of the M-T_sl relation from the simulations is larger than the observed one by about 50 per cent. If masses in simulated clusters are estimated by following the same assumptions of hydrostatic equilibrium and \beta--model gas density profile, as often done for observed clusters, then the M-T relation decreases by about 40 per cent, and significantly reduces its scatter. Based on this result, we conclude that using the observed M-T relation to infer the amplitude of the power spectrum from the X-ray temperature function could bias low \sigma_8 by 10-20 per cent. This may alleviate the tension between the value of \sigma_8 inferred from the cluster number density and those from cosmic microwave background and large scale structure.

Energy distribution of precipitating electrons estimated from optical and cosmic noise absorption measurements

Abstract. This study is a statistical analysis on energy distribution of precipitating electrons, based on CNA (cosmic noise absorption) data obtained from the 256-element imaging riometer in Poker Flat, Alaska (65.11° N, 147.42° W), and optical data measured with an MSP (Meridian Scanning Photometer) over 79 days during the winter periods from 1996 to 1998. On the assumption that energy distributions of precipitating electrons represent Maxwellian distributions, CNA is estimated based on the observation data of auroral 427.8-nm and 630.0-nm emissions, as well as the average atmospheric model, and compared with the actual observation data. Although the observation data have a broad distribution, they show systematically larger CNA than the model estimate. CNA determination using kappa or double Maxwellian distributions, instead of Maxwellian distributions, better explains the distribution of observed CNA data. Kappa distributions represent a typical energy distribution of electrons in the plasma sheet of the magnetosphere, the source region of precipitating electrons. Pure kappas are more likely during quiet times – and quiet times are more likely than active times. This result suggests that the energy distribution of precipitating electrons reflects the energy distribution of electrons in the plasma sheet. Key words. Ionosphere (auroral ionosphere; particle precipitation; polar ionosphere)

Construction of an Estimation Method of the Capacity of each Approach at Signalized Intersections which Deals with the Effect of the Right-Turn Traffic

The right-turn traffics, which are forced to keep staying at an intersection due to the opposing traffic, usually obstruct the following vehicles' way if there is not enough width on the road. This research focuses on such a phenomenon called ‘the blocking phenomenon’, and construct new capacity estimation methods for several types of signal intersections. The capacities are estimated using the signal control parameter, the right-turn traffic ratio and the saturation degree of the opposing traffic, etc.In this paper, after estimation methods for three-leg intersection are constructed, the fitness of each method is checked using actual observation data.

Structure and kinematics of waters in the region of the Argentine Islands in the autumn of 1998

On the basis of the data of the complex oceanographic experiment carried out in the course of the second Ukrainian Antarctic expedition in March 1998, we study the structure and kinematics of waters in the region of the archipelago of Argentine Islands. The regularities of thermohaline stratification of waters are discovered. We determine the most important environmental parameters premoting the variability of hydrophysical fields on time scales varying from several days up to a week, analyse the data of actual observations over the currents, and estimate the relative contribtions of diurnal and semidiurnal tidal waves to the total dispersion of hydrophysical parameters of the environment. The residual currents are filtered out. We propose a hypothesis about the mechanism of their formation. Various types of tidal currents are revealed and the directions of propagation of diurnal and semidiurnal tidal waves are determined.