Suitable region of dynamic optimal interpolation for efficiently altimetry sea surface height mapping

The dynamic optimal interpolation(DOI)method is a technique based on quasi-geostrophic dynamics for merging multi-satellite altimeter along-track observations to generate gridded absolute dynamic topography(ADT).Compared with the linear optimal interpolation(LOI)method,the DOI method can improve the accuracy of gridded ADT locally but with low computational efficiency.Consequently,considering both computational efficiency and accuracy,the DOI method is more suitable to be used only for regional applications.In this study,we propose to evaluate the suitable region for applying the DOI method based on the correlation between the absolute value of the Jacobian operator of the geostrophic stream function and the improvement achieved by the DOI method.After verifying the LOI and DOI methods,the suitable region was investigated in three typical areas:the Gulf Stream(25°N-50°N,55°W-80°W),the Japanese Kuroshio(25°N-45°N,135°E-155°E),and the South China Sea(5°N-25°N,100°E-125°E).We propose to use the DOI method only in regions outside the equatorial region and where the absolute value of the Jacobian operator of the geostrophic stream function is higher than1×10^(-11).

A hydraulic fracture height mathematical model considering the influence of plastic region at fracture tip

To predict fracture height in hydraulic fracturing, we developed and solved a hydraulic fracture height mathematical model aiming at high stress and multi-layered complex formations based on studying the effect of plastic region generated by stress concentration at fracture tip on the growth of fracture height. Moreover, we compared the results from this model with results from two other fracture height prediction models(MFEH, Frac Pro) to verify the accuracy of the model. Sensitivity analysis by case computation of the model shows that the hydraulic fracture growth in ladder pattern, and the larger the fracture height, the more obvious the ladder growth pattern is. Fracture height growth is mainly influenced by the in-situ stresses. Fracture toughness of rock can prohibit the growth of fracture height to some extent. Moreover, the increase of fracturing fluid density can facilitate the propagation of the lower fracture tip.

ON THE KEY REGIONS OF 500 hPa GEOPOTENTIAL HEIGHTS OVER NORTHERN HEMISPHERE IN WINTER

Variance analysis, correlation analysis and regression analysis methods are applied to analyze the variation of circulation at 500 hPa. In winter, there are three regions (180°E – 150°W, 45°N – 60°N, 70°W – 100 °W,45°N – 75°N, 60°E – 100°E, 65°N – 80°N) whose variations are strong. Those regions are the key regions in which atmospheric circulation can change. Those regions are correlated to some teleconnections and can present a part of variations of 500 hPa to some degree. The linear contemporary correlation between those regions and the height at 500 hPa is significant. Those regions can account for 88 % of variations of concurrent height at 500 hPa. Those regions can present and forecast some variations to some degree in March and April. The longer the time interval, the worse the forecast effect will be. The interannual variations of Q1, Q2 and the SST are weak in the western Pacific.

The automatic height extraction of buildings from shadow region

Height extraction for buildings is a fundamental step of 3D scene reconstruction in many virtual reality applications. In this paper, we propose an automatic method to extract the height of buildings in high resolution satellite imagery based on the length of shadow. Taking into account the limitation of traditional algorithms, we make use of the boundary information of a building to facilitate detecting and matching the shadow regions with higher accuracy. Then, we introduce a shadow-cast model to correct the shadow location in our system. The experimental result shows that when extracting the height of buildings from complex urban regions, our method has better accuracy.

A Spiral History of the Development of Ways to Identify the Correct Position of the Injection Needle in Relation to the Peripheral Nerve: A Brief Historical Essay

The first way to identify the needle in relation to the peripheral nerve W. Halsted and R. Hall in 1884 performed the first regional blockade (using direct visualization). However, Vassily von Anrep was a few months earlier described the blockade of the peripheral nerve by anatomical landmarks. In 1912, the blockade of the brachial plexus was first performed using electrical stimulation, but this technique has been widely used only since 1962. The most popular way to identify the needle relative to the nerve at the moment remains US guidance. A promising direction may be optical coherence tomography. But this method is under development. In the last decade, a method for determining the pressure of a local anesthetic has been introduced into practice to determine the position of the needle relative to the nerve.

Investigation of the Acceleration Region in a Gas-Solid Co-current Down-flow Circulating Fluidized Bed

In this work, a mathematical model is established to describe the axial variation of the characteristic flow parameters (particle velocity, solid holdup and pressure gradient) in a downer. An empirical correlation is developed to estimate the particle velocity at the constant velocity section. Experimental investigations are made to validate the downer model. The model simulations have a good agreement with experimental data. Moreover, a formula is derived to predict the first acceleration section length and the whole acceleration section length.

Planting Performance of Pennisetum purpureum Schumab cv.Purple in the Southern Region of China

[Objective] The present experiment was conducted to investigate the yield,adaptability and quality characteristics of Pennisetum purpureum Schumach cv. Purple to provide reference for the certification and development of new varieties.[Method] With P. purpureum Schumab cv. Purple as experimental material, the variety comparison tests were conducted in Nanning, Lingyun, and Tiandeng in Guangxi from 2007 to 2009, and variety regional trials were conducted in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Its comprehensive characters of plant height, hay yield, stem-leaf ratio and nutritional components were determined, and were compared with those of P. purpureum × P.americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin. [Result] The average height of P. purpureum Schumach cv. Purple was 706.54 cm, which was5.92% and 8.44% lower than that of P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv. Guiminyin, respectively. The average hay yield of P. purpureum Schumach cv. Purple was 32.74 t/ha in Nanning, Lingyun, and Tiandeng of Guangxi from 2007 to 2009, and 22.41 t/ha in Danzhou of Hainan, Fuzhou of Fujian and Zhanjiang of Guangdong from 2011 to 2013. Although its hay yield was lower than two control varieties, the difference was not significant（P 0.05）.The stem-leaf ratio of P. purpureum Schumach cv. Purple was 0.98：1. Moreover,the analysis on the nutritional components of dry matter showed that compared with P. purpureum × P. americanum cv. Reyan No.4 and P. purpureum Schum cv.Guiminvin, the crude fiber of P. purpureum Schumab cv. Purple was decreased by4.76% and 2.78%, respectively; the neutral detergent fiber decreased by 5.07% and2.22%, respectively; the acid detergent fiber was decreased by 2.54% and 1.99%,respectively; the crude fat was increased by 64.29% and 43.75%, respectively; the calcium content was increased by 28.00% and 33.33%, respectively; the phosphorus content was increased by 9.68% and 22.73%, respectively; the total content of amino acid was increased by 43.23% and 68.41%, respectively; the anthocyanin content of leaf was increased by 400.00% and 216.90%, respectively（P 0.05）.[Conclusion] P. purpureum Schumach cv. Purple is a new high-quality forage variety with wide adaptability, high yield, rich nutrient and good palatability, which is appropriate for comprehensive exploitation and application in the southern region of China.

Preliminary Study on the Linear Relationship between the Internal Pressure Head of Rubber Dam Bags and Real-time Dam Height

The design operating conditions of rubber dams were analyzed,and it is found that the operating conditions are similar to the actual operating conditions of changes in the internal pressure ratio of a specific rubber dam bag in the process of filling and draining. Based on this,the linear relationship curve between the internal pressure head H0 and the real-time dam height H and its approximate analytical formula can be obtained,which can be used as a supplement and correction method for the measurement method of real-time dam height during rubber dam operation,and provides reference for rubber dam project managers.

THE MECHANISM OF THICKNESS OF GEOPOTENTIAL HEIGHT DIPOLE AND ITS RELATION WITH CLIMATE VARIABILITY IN ASIA-AUSTRALIA IN BOREAL WINTER

With the EOF of reanalysis data being analyzed, a northern-southern dipole is found in the upper troposphere geopotential height field of over the Asian-Australian monsoon region in the winter of the Northern Hemisphere(NH),which is defined as Asian-Australian dipole(AAD) in this study. Its intensity index is defined as AADI. Correlation and synthetic analysis illustrate that AADI is closely related to the weather and climate of Asian-Australian region in boreal winter. The index can reflect the simultaneous anomalies of temperature and precipitation on interannual and decadal scales in the boreal winter of Asian-Australian region. The superposition of the decadal and interannual signals is significant for the relationship between the AADI and climate change. The index can be used as an indicator of intensity of the Asian-Australian monsoon. In the years of strong AADI, the East Asia major deep trough is stronger,the Subtropical High is weaker and the Alaska ridge and the westerly jet are stronger than those in normal years.Enhanced meridional circulation between high and low latitudes exists in the years of strong AADI. These relationships reflect the intrinsic link between the anomalies in the upper troposphere geopotential height and climate in the Asian-Australian region.

A STUDY ON FLOW RESISTANCE IN THE ENTRANCE REGION OF ISOSCELES TRIANGULAR DUCTS

In the present paper the variational solution of velocity profile for an incompressible laminar and fully developed flow in isosceles triangular ducts is derived by applying the Kantovorich method. The theoretical and experimental results of pressure loss are also given. The velocity distribution model, additional pressure loss coefficient and calculating method of inlet length in the entrance region of isosceles triangular ducts are also derived, which are suitable for various kinds of vertex angles. The calculations and experiments are also performed for two models: the isosceles triangular channels with vertex angles 2a=45.1 and 2a= 60 . Comparisons are made between the theoretical analysis in this paper and those of the other authors. It can be seen that the present analytical result is of high. accuracy and wide practicability, and agrees well with the authors' experiment.

Analysis of water vapour flux between alpine wetlands underlying surface and atmosphere in the source region of the Yellow River

An underlying wetland surface comprises soil, water and vegetation and is sensitive to local climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Using data from observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling(Ω factor)between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors(solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows:(1) Due to diurnal variations of solar radiation and wind speed, a trend developed where diurnal variations of the Ω factor were small in the morning and large in the evening. Due to the vegetation growing cycle, seasonal variations of the Ω factor present a reverse "U" trend. These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over latent heat flux. This conforms to the Omega Theory.(2) The values for average absolute atmospheric factor(surface factor or total) control exercised by solar radiation and water vapour pressure are 0.20(0.02 or 0.22) and 0.005(-0.07 or-0.06) W/(m2·Pa), respectively. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on latent heat flux.(3) At the underlying alpine wetland surface, solar radiation primarily influences latent heat flux through its direct effects(atmospheric factor controls). Water vapour pressure deficit primarily influences latent heat flux through its indirect effects(surface factor controls) on changing the surface resistance.(4) The average Ω factor in the underlying alpine wetland surface is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between alpine wetland surface and atmosphere system is low. The actual measurements agree with the Omega Theory. The latent heat flux is mainly influenced by solar radiation.

Metasomatic Origin of Some of the Eclogite Bearing Carbonate Rocks in the Dabie Mountain Region, China

Carbonate rocks are one of the major hosts to eclogite in the Mt. Dabie region. Eclogite bodies enclosed in the carbonate rocks occur mostly as knobs, ovoids and lenses measuring centimeters to tens of centimeters in size. The bodies have been intensely carbonatized and usually have transitional contacts with their carbonate hosts. The carbonate rocks have abundant relics of eclogite minerals and their retrogressive derivatives. The REE patterns of the carbonate rocks are characterized by the absence of negative Ce anomaly. These features suggest that a considerable portion of the eclogite bearing carbonate rocks in the Mt. Dabie region was produced by carbonatization of eclogites and their retrogressive derivatives. These carbonate rocks suffered deformation and recrystallization after their formation.

Experimental Investigation on the Pressure Characteristics of Cavity Closure Region

The most complicated component in cavitating flow and pressure distribution is the flow in the cavity closure line. The cavitating flow and pressure distribution provide critical aspects of flow field details in the region. The integral of pressure results of the hydrodynamic forces, indicate domination in the design of a supercavitating vehicle. An experiment was performed in a water tunnel to investigate the pressure characteristics of the cavity closure region. Ventilation methods were employed to generate artificial cavity, and the ventilation rate was adjusted accordingly to obtain the desired cavity length. An array of pressure transducers was laid down the cavity closure line to capture pressure distribution in this region. The experimental results show that there is a pressure peak in the cavity closure region, and the rise rate of pressure in space tends to be higher in the upwind side when the flow is non-axisymmetric. The transient pressure variations during the cavity formation procedure were also present. The method of measurement in this paper can be referenced by engineers. The result helps to study the flow pattern of cavity closure region, and it can also be used to analyze the formation of supercavitating vehicle hydrodynamics.

New approach to calculating tree height at the regional scale

Background:Determining the spatial distribution of tree heights at the regional area scale is significant when performing forest above-ground biomass estimates in forest resource management research.The geometric-optical mutual shadowing(GOMS)model can be used to invert the forest canopy structural parameters at the regional scale.However,this method can obtain only the ratios among the horizontal canopy diameter(CD),tree height,clear height,and vertical CD.In this paper,we used a semi-variance model to calculate the CD using high spatial resolution images and expanded this method to the regional scale.We then combined the CD results with the forest canopy structural parameter inversion results from the GOMS model to calculate tree heights at the regional scale.Results:The semi-variance model can be used to calculate the CD at the regional scale that closely matches(mainly with in a range from-1 to 1 m)the CD derived from the canopy height model(CHM)data.The difference between tree heights calculated by the GOMS model and the tree heights derived from the CHM data was small,with a root mean square error(RMSE)of 1.96 for a 500-m area with high fractional vegetation cover(FVC)(i.e.,forest area coverage index values greater than 0.8).Both the inaccuracy of the tree height derived from the CHM data and the unmatched spatial resolution of different datasets will influence the accuracy of the inverted tree height.And the error caused by the unmatched spatial resolution is small in dense forest.Conclusions:The semi-variance model can be used to calculate the CD at the regional scale,together with the canopy structure parameters inverted by the GOMS model,the mean tree height at the regional scale can be obtained.Our study provides a new approach for calculating tree height and provides further directions for the application of the GOMS model.

An analysis on the effect of mining height and floor lithology on pressure relief of upper protective layers

In order to understand the effect of mining height and floor lithology at the upper protective layer face on the pressure relief of protected coal seams, this paper uses a numerical simulation method to model the pressure changes at protected coal seam during mining upper protective layer. The results show that the taller the mining height at the upper protective layer face, the greater the protection on protected coal seam due to the higher level of pressure release; the upper protective layer face with hard rock floor impedes the pressure release at the protected coal seam, which affects the overall effect of the pressure release at protected coal seam using the protective layer mining method.

Study on the characteristics of ground pressure behaviors in working face with great mining height at different advance speeds by similarity model experiment

Presently most of research results on strata behaviors were concluded under the normal （moderate） advance rate conditions. Comparing with normal advance rate, fast advance rate and slow advance rate may cause some new changes of strata behaviors. The characteristics of ground pressure behaviors in working face with great mining height at different forward speeds were studied by similarity model experiment in laboratory. Its conclusion provides a theoretic basis for ground pressure controlling.

Research on the Regional Ecological Environment Evaluation and Application under the Influence of the Severe Earthquake Disaster

To conduct the ecological restoration and reconstruction of disaster areas after the severe earthquake, such as Wenchuan Earthquake and Lushan Earthquake, this article uses region al ecological environment evaluation and ecological footprint to construct a quantitative analysis model on the basis of ecololgical environment indexes in Mianzhu City. Through this model, resource status of the regional environment in Mianzhu is analyzed, as well as the ecological capacity and the ecological security. Based on the evaluation and analysis, this paper provides multi-path development strategies of ecological restoration and sustainable development of human settlements after the earthquake.

The influence of the different elements of an organic molecule structure on the main kinetic parameters of its unimolecular reaction in the high-pressure region

The most general dynamic tendencies of the energy redistribution in the high-pressure region are considered. Their influence on the possible deviations from the kinetic conceptions, which is now generally accepted, is examined. In this way, the structural elements of an organic molecule that promote internal energy mobilization in the high-pressure region and, conversely, hamper it, are defined. The first of these elements reduces both the Arrhenius parameters of the unimolecular reactions while the second leads to the opposite results. Some well-known exceptions to existing kinetic theories, which find an explanation in the framework of these proposed concepts, is considered. The proposed concept is very general as distinct from the existing dynamic studies, which investigate more particular details of the separate bond behaviors. The proposed general concept can broaden the study of chemical kinetics.

A new strategy for ionospheric remote sensing using the 130.4/135.6 nm airglow intensity ratios

We demonstrate here that global-scale determination of a key ionospheric parameter,the peak height of the F_(2)region(h_(m)F_(2)),can be obtained by making a simple ratio measurement of the atomic oxygen 130.4 and 135.6 nm emissions in the far-ultraviolet nightglow with a nadir-viewing system such as a pair of photometers suitable for flight on a CubeSat.We further demonstrate that measurements from an altitude that is within the typical range of nighttime h_(m)F_(2)250−450 km can provide the ratios that are needed for retrieval of the h_(m)F_(2).Our study is conducted mostly through numerical simulations by using radiative transfer models of the two emissions coupled with empirical models of the atmosphere and ionosphere.Modeling results show that the relationship between the h_(m)F_(2)and the intensity ratio is sensitive to the altitude from which the emissions are observed,primarily because of the distinctly different degrees of resonant scattering of the two emissions in the atmosphere.A roughly quadratic relationship can be established for observations from an orbit of~400 km,which enables h_(m)F_(2)retrieval.Parametric analysis indicates that the relationship can be affected by the ambient atmospheric conditions through resonant scattering and O2 absorption.For typical nighttime conditions with h_(m)F_(2)250−450 km,retrieval of the h_(m)F_(2)from synthetic observations shows that the typical errors are only a few kilometers(up to~20 km),depending on the accuracy of the ambient conditions predicted by the empirical models.Our findings pave the way for use of the 130.4/135.6 nm intensity ratios for global-scale monitoring of the nighttime ionosphere at mid to low latitudes.

Retrieval of forest canopy height in a mountainous region with ICESat-2 ATLAS

Forest canopy height is one of the important forest parameters for accurately assessing forest biomass or carbon sequestration. ICESat-2 ATLAS provides the potential for retrieval of forest canopy height at global or regional scale, but the current canopy height product (ATL08) has coarse resolution and high uncertainty compared to airborne LiDAR-derived canopy height (hereafter ALCH) in mountainous regions, and is not ready for such applications as biomass modeling at finer scale. The objective of this research was to explore the approach to accurately retrieve canopy height from ATLAS data by incorporating an airborne-derived digital terrain model(DTM) and a data-filtering strategy. By linking ATLAS ATL03 with ATL08 products, the geospatial locations,types, and (absolute) heights of photons were obtained, and canopy heights at different lengths (from 20 to 200 m at 20-m intervals) of segments along a track were computed with the aid of airborne LiDAR DTM. Based on the relationship between the numbers of canopy photons within the segments and accuracy of ATLAS mean canopy height compared to ALCH, a filtering method for excluding a certain portion of unreliable segments was proposed.This method was further applied to different ATLAS ground tracks for retrieval of canopy heights and the results were evaluated using corresponding ALCH. The results show that the incorporation of high-precision DTM and ATLAS products can considerably improve the retrieval accuracy of forest canopy height in mountainous regions.Using the proposed filtering approach, the correlation coefficients (r) between ATLAS canopy height and corresponding ALCH were 0.61–0.91, 0.65–0.92, 0.68–0.94 for segment lengths of 20, 60, and 100 m, respectively;RMSE were 1.90–4.35, 1.55–3.63, and 1.34–3.23 m for the same segment lengths. The results indicate the necessity of using high-precision DTM and using the proposed filtering method to retrieve accurate canopy height from ICESat-2 ATLAS in mountainous regions with dense forest cover and complex terrain conditions.