A Long-Time-Step-Permitting Tracer Transport Model on the Regular Latitude–Longitude Grid

If an explicit time scheme is used in a numerical model, the size of the integration time step is typically limited by the spatial resolution. This study develops a regular latitude–longitude grid-based global three-dimensional tracer transport model that is computationally stable at large time-step sizes. The tracer model employs a finite-volume flux-form semiLagrangian transport scheme in the horizontal and an adaptively implicit algorithm in the vertical. The horizontal and vertical solvers are coupled via a straightforward operator-splitting technique. Both the finite-volume scheme's onedimensional slope-limiter and the adaptively implicit vertical solver's first-order upwind scheme enforce monotonicity. The tracer model permits a large time-step size and is inherently conservative and monotonic. Idealized advection test cases demonstrate that the three-dimensional transport model performs very well in terms of accuracy, stability, and efficiency. It is possible to use this robust transport model in a global atmospheric dynamical core.

Near-optimal cumulative longitude low-thrust orbit transfer

The indirect method for the continuous low-thrust near minimum cumulative longitude orbit transfer problem is addressed.The movement of the satellite is described by the Gauss equation using the modified equinoctial elements and replacing time as the system independent variable by the cumulative longitude.The maximum principle is adapted to design the optimal control in order to minimize the final cumulative longitude, and the twopoint-boundary-value problem is derived from the orbit transfer problem.The single shooting method is applied in a numerical experiment, and the simulations demonstrate that the orbit transfer mission is fulfilled and the product of the maximal thrust and the minimum cumulative longitude is near constant.

Longitude correction method for the field magnetic surveyed diurnal-variation correction

Solar quiet daily variation(Sq)are dependent on local time.Herein,we applied the moving superposition method to separate the Sq component of correction observatory data and performed a time diff erence correction on the Sq component according to the longitudinal diff erence between the correction observatory and the field station while maintaining the time of other data components.The data were then reconstructed and used for diurnal-variation correction to improve the accuracy of the daily variations correction resu;lts The moving superposition method employs data of“nonmagnetic disturbance days”obtained 15 d before and after to perform the superposing average calculation on a daily basis,aiming to obtain the Sq of continuous morphological changes.The effect of longitude correction was tested using the observatory record and field survey data.The average correction distance of the test observatories was 2114 km,and the correction accuracies of the H(horizontal component of geomagnetic field),D(geomagnetic declination),and Z(vertical component of geomagnetic field)were improved by 28.4%,45.0%,and 21.7%,respectively;the average correction distance of the field stations was 2130 km,and the correction accuracies of the F(geomagnetic total intensity),D,I(geomagnetic inclination)components were improved by 35.2%,26.7%,and 13.9%,respectively.The test results also demonstrated that the longitude correction eff ect was greater with an increased correction distance.

ASTRONOMICAL MEASUREMENT OF RATE OF LONGITUDE DIFFERENCE VARIATION BETWEEN NORTH AMERICA AND EURASIA PLATES DURING 1962——1982

Astrometry method is useful in measuring the longitude and latitude variations of an astronomical station. But owing to the limitation of optical technique, progress in this field has not been significaut since a long time ago. The 500,000 measurements of the worldwide 136 optical instruments during 1962-1982 were reduced once again by the author recently in the BIH in order to redetermine the Earth Rotation Parameters for the twenty years. With such a large quantity of data and a new reduction method, the obtained local corrections and their time derivatives (group unknowns G and G) of a star group in time and latitude measurement should be a better source for studying

Analysis of longitude profiled rolling process of Cu/Al cladded sheet and evaluation of outlet warpage

Longitude profiled cladded sheet is obtained by rolling bimetal cladded sheet with variable gauge rolling technology.The longitude profiled rolling process of Cu/Al cladded sheets was studied by finite element method and experiments.The rolling force rises with the increase in reduction,and a sudden change appears at the end of the thickness variation zone.The thickness ratio of copper layer is enlarged after rolling owing to its relatively large deformation resistance and continues to rise with the increase in reduction rate.Lower elongation of copper side leads to the warpage of exit metal to copper side,which further hinders the deformation of copper.The influence of asymmetric rolling parameters indicates that increasing the work roll diameter ratio,speed radio,and friction coefficient on Al side can reduce the warpage when the reduction rate is below a certain value depending on the thickness ratio and other rolling parameters.Comparison of experiments and simulation results showed good agreement and verified the finite element model.

Profiling and geographical distribution of seed oil content of sunflower in Ukraine

The sunflower has the potential to be a highly competitive crop owing to its diversity market and the valuable oil it produces.Nevertheless,the amount of sunflower seed oil-a key factor for the crushing industry-is affected by genotype and environment,which sometimes is difficult to predict.The paper analyzes the theoretical principles of sunflower growth in Ukraine,highlights the current trends in the sowing of this crop,the influence of climatic factors of the environment on the prospects of the oilseed sunflower yield.The results of the research are presented for 3 years(2014-2016),during the authors conducted a grain quality observatory at the regional level,taking into account the climatic conditions of sunflower growth in different natural zones of Ukraine(from 45
to 51
north latitude and from 22
to 37
east longitude).Additionally,the research includes the coefficient of significance of the deviation from long-term climatic indicators,which makes it possible to forecast sunflower yield in the future.The analyzed data was obtained from the commercial fields with a minimum area of 40 ha in all Ukrainian regions except Crimea peninsula,Donetsk and Luhansk regions.The results obtained in research show the great diversity of oil content index as per both latitude and longitude meaning.If we consider the entire country,this survey shows that the seed oil content can change dramatically from year to year:e.g.47.5%in one year versus 45.7%in another year.Regionally,these changes have a completely different dynamic with a gradual decrease in seed oil content in the southern part of the country.The main goal of the research was to identify the best sunflower growing areas in Ukraine according to the oil content index.

A Modified Algorithm for Identifying and Tracking Extratropical Cyclones

In this study, a modified identification and tracking algorithm for extratropical cyclones is developed. This identification scheme is based on triangular-mesh contouring techniques combined with a connected-component labeling method in order to detect the outer boundaries and spatial domain characteristics of individual cyclones. A new tracking method allowing for the identification of cyclone merging and splitting events, as well as short-lived windstorms, is developed to reduce the uncertainty in the tracking of extratropical cyclones. I also show that this method excludes the tracks of open systems that would have been unnecessarily detected using conventional NCP methods. The climatological features of the distribution of cyclone frequencies are substantially larger over the traditional storm track regions compared to those seen in previous studies. Interestingly, a significant increase in the cyclone density in the Arctic occurs during all four seasons（up to 19%in summer） compared to that seen with a latitude-longitude gridded mesh analysis. I develop two new regional intensity indices（depth and vorticity） based on the cyclonic domain to better quantify the cyclonic activity in the Arctic region, and find that the interannual variabilities in these two indices are highly consistent. The results of this analysis may shed light on high-latitude cyclonic behavior studies via the newly detected 2D cyclone atlas derived from this cyclonic-domain-based algorithm.

ZONALITY OF DISTRIBUTION OF PHYSICO-GEOGRAPHICAL ZONES IN CHINA

With the methods of regression analysis and trend surface analysis, taking the bottom and top lines of dark conifer forest, bottom line of permafrost and the snowline of the latest glaciation in China as examples, this paper discusses the zonality regulaties of the distribution of physico-geographical zones in China. (1) Latitude zonality obeys the mathematical model of normal frequency distribution, being approximate to descending straightly within the latitude of China. (2) Longitude zonality shows that the elevation of physico-geographical zone rises straightly with the distance to east coast. (3) The combination of latitude and longitude zonalities appears a plane inclining from SSW to NNE. The decline of physico-geographical zone resembles a semiellipse- sphere inclining from the Qinghai-Xizang (Tibet) Plateau to northeast China, reflecting the effect of relief. (5) Physico-geographical zonation depends on the combination of hydrothermal conditions. Thus the factors influencing the distribution

WIND STRESS FIELD OVER THE BOHAI SEA,THE YELLOW SEA AND THE EAST CHINA SEA

Seasonal and annual wind stress fields over the Bohai Sea , the Yellow Sea and the East China Sea were computed from the wind rose data compiled in the Climatic Atlas of Chinese Offshore Areas and North-west Pacific and published by the Ocean Press in 1982 . 684 wind roses in 2° latitude by 2° longitude boxes constructed from 278 ,815 wind reports are involved in the present study.The computations are principally intended as a data source for further research . Some oceanographic consequences are expounded on .

CHARACTERISTICS OF SUNSPOT GROUP 5395

1 INTRODUCTION The sunspot group 5395 was appeared in the east of the solar disc on 6 March anddisappeared in the west of the solar disc on 20 March in 1989. Its heliographiccoordinates were N34, L257. It has been the largest group according to its area since

Geographical location affects size and materials used in the construction of European Pied Flycatcher(Ficedula hypoleuca) nests

Background: Nest construction is a key element of avian reproductive behaviour and the result is often a complex structure that is used for incubation of eggs, which represents an extended phenotype. It is known that nest construction is a plastic behaviour but the extent to which plasticity is observed in a single species with a wide geographical distribution is largely unknown. This study sought to better understand variation in nest size and composition across a very wide geographical area. The hypothesis suggested that location would affect size but not composition of nests of the European Pied Flycatcher (Ficedula hypoleuca). Methods: Nests and reproductive data were collected from seventeen study sites, spread over 6° of latitude and 3.3° of longitude on the island of Great Britain. Dimensions of nests were measured before they were deconstructed to determine the masses and types materials used in the outer nest and the cup lining. Results: Geographical variation was observed in base thickness of nests but not many other dimensions. Nests varied in composition but were mainly made of leaf, moss, bark, grass, root and fern. Moss was used more to the north and east of the study area compared with more leaf mass towards the south and west. The species of leaf and bark used in the nests varied between geographical locations. Additionally, the use of leaves or bark from a particular tree species did not reflect the incidence of the tree species in the immediate territory. Conclusions: This study showed that nest composition was affected by geographical location over a wide area. Variation between nests at each location was high and so it was concluded that differences in nest composition reflect individual selection of materials but evidence is such that it remains unclear whether this is deliberate to fulfil a specific role in the nest, or simply opportunistic with birds simply picking up materials with the appropriate characteristics as they find them outside their nestbox.

Revision of CG Flash Density Based on Lightning Location Data

Using the data of the Lightning Location System( LLS) over Hubei Province,through the analysis of the distribution characteristics of CG( Cloud-to-Ground) flash density in 2015,it was found that the layout of the detection station had influence on the spatial distribution of lightning.Grid CG flash density data were used to characterize the spatial distribution of the CG flash,and station distance factor was used to characterize the detection station layout. The result showed that there existed negative correlation between density and factor,significant correlation between the density component and the factor for the lightning current amplitude of 5 to 30 kA,and insignificant correlation between >30 kA of density component and factor. So it is necessary to revise the density to eliminate the influence of the station layout. On the basis of the linear regression method and its residual theory,the revision model of the grid CG flash density and the statistical model of relative detection efficiency were established. The result consistency of segment and non-segmented revision of the density was verified. Through the contrastive analysis of theoretical detection efficiency and relative detection efficiency,the feasibility for revision method of CG flash density and the statistical method of relative detection efficiency was also verified.

Using Polaris and the Big Dipper to approximate local standard time

In this paper we introduce methods for approximating local standard time in the Northern Hemisphere using Polaris and the Big Dipper as well as alternative reference stars, and describe in detail how to construct a device we call a dipperclock to facilitate this process. An alternative method which does not require a dipperclock is also discussed. Ways of constructing dipperclocks which glow in the dark are presented. The accuracy of dipperclocks is examined, both theoretically and through field testing. A java program is provided for creating dipperclocks customized to a particular year-long time period and place to get improved accuracy. Basic astronomical definitions and justifications of the results are provided. We also discuss the use of dipperclocks to find longitude and latitude.

FY-2G Launched Successfully

The FY-2G meteorological satellite was launched into space by a LM-3A launch vehicle at 09:02(Beijing time)on December 31,2014 from the Xichang Satellite Launch Center.24 minutes after the liftoff,the satellite separated from the rocket and entered its preset orbit.The satellite was positioned in a geosynchronous orbit above

公元1996年为何366天

公元１９９６年为何３６６天１９９６年新的日历公历２月是２９天，全年共有３６６天，比１９９５年多一天。你知道这是怎么会事吗？目前世界上通用的公历是以地球绕太阳公转一周的＂回归年＂为依据的。一＂回归年＂是３６５．２４２２天，即３６５天５小时４８分４６秒。...

OCCURRENCE OF SHORT-PERIOD ANOMALY OF RESIDUALS OF ASTRONOMICAL TIME-LATITUDE AT YUNNAN OBSERVATORY PRECEDING THE LUQUAN EARTHQUAKE (M_L=6.3)

It has been found in several cases that short-period anomalies in astronomical time and latitude residuals appeared simultaneously or/and separately preceding the strong earth-quakes occurring nearby the site of the astronomical time and latitude observations made with classical instruments. Before the strong earthquake of M_L≥7.0 at a distance <300 km or that of M_L≥6.0 at a distance <100 km, we notice that the 5-day mean of

EFFECT OF THE CHANGE OF LOCAL VERTICAL LINE DEFLECTION ON ASTRONOMICAL TIME OBSERVATION

The classical time and latitude observations are based on local vertical line. In principle, if the mass distribution around the point of observation and in the earth interior is asymmetric, the local vertical line deflection will be changed, thus affecting the results of time and latitude observations. Referring to a standard system (e.g. BIH, IPMS or the Jiont System), the time and latitude observations of every instrument contain systematical errors, which are represented by (A-O), where A is the adopted value of standard system and O the ob-

Longitudinal distribution of O_2 nightglow brightness observed by TIEMD/SABER satellite

The global distribution of 1.27 ~tm 02 nightglow brightness observed by the TIMED/SABER satellite has been investigated to find the longitudinal structures for different seasons and latitudes. The results show that the 02 airglow is dominated by wave 4 structure at latitudes between equator and 20°S/N in both hemispheres during most seasons. At mid-latitudes around 40°S/N, the wave 1 structure is observed for most seasons with a small contribution of wave 2 during the June solstice. A comparison of the 02 and OH nightglows shows similarity in their global distributions which can be attributed to their similar photochemical mechanisms.

Spatial variation of altitudinal belts as dividing index between warm temperate and subtropical zones in the Qinling-Daba Mountains

To determine the dividing index between warm temperate and subtropical zones based on the spectra of altitudinal belts,this paper collected 33 spectra of altitudinal belts in the Qinling-Daba Mountains from published literatures and then analyzed the structures and the spatial patterns from south to north,from west to east and based on exposure directions.The results show that:1)From south to north,the basal belt gradually changes from subtropical evergreen broadleaf forest to warm temperate deciduous broadleaf forest;the spectra of altitudinal belts change from complex to simple;the dominant belt changes from montane broadleaf-conifer mixed forest and evergreen-deciduous broadleaf mixed forest to deciduous broadleaf forest.2)From west to east,the structures of the altitudinal belt spectra show complexity in the east and west but simplicity in the middle section;the upper limits of both the evergreen-deciduous broadleaf mixed forest belt and montane deciduous broadleaf forest belt present a quadratic curve distribution pattern in the longitudinal direction.However,the upper limit of the montane broadleaf-conifer mixed forest belt exhibits a nearly linear decrease in the west-east direction.3)Both the north and south slopes in the Qinling Mountains have the similar basal belt,whereas it varies greatly between the north and south slopes in the Daba Mountains.Comparably,dominant belts are very similar in the Qinling Mountains and the north slope of the Daba Mountains,but the south slope of the Daba Mountains has its own unique dominant belt:evergreen-deciduous broadleaf mixed forest.This implies that the Daba Mountains are more appropriate than the Qinling Mountains to act as the boundary between subtropical and warm-temperate zones in central China.

A new method of single celestial-body sun positioning based on theory of mechanisms

Considering defects of current single celestial-body positioning methods such as discon- tinuity and long period, a new sun positioning algorithm is herein put forward. Instead of tradi- tional astronomical spherical trigonometry and celestial coordinate system, the proposed new positioning algorithm is built by theory of mechanisms. Based on previously derived solar vector equations （from a C1R2p2 series mechanism）, a further global positioning method is developed by inverse kinematics. The longitude and latitude coordinates expressed by Greenwich mean time （GMT） and solar vector in local coordinate system are formulated. Meanwhile, elimination method of multiple solutions, errors of longitude and latitude calculation are given. In addition, this algo- rithm has been integrated successfully into a mobile phone application to visualize sun positioning process. Results of theoretical verification and smart phone＇s test demonstrate the validity of pre- sented coordinate＇s expressions. Precision is shown as equivalent to current works and is acceptable to civil aviation requirement. This new method solves long-period problem in sun sight running fix- ing and improves applicability of sun positioning. Its methodology can inspire development of new sun positioning device. It would be more applicable to be combined with inertial navigation systems for overcoming discontinuity of celestial navigation systems and accumulative errors of inertial nav- igation systems.