Showing papers on "Longitude published in 2008"

Titan's rotation reveals an internal ocean and changing zonal winds.

Abstract: Cassini radar observations of Saturn9s moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of ∼0.36° per year in apparent longitude and is consistent with seasonal exchange of angular momentum between the surface and Titan9s dense superrotating atmosphere, but only if Titan9s crust is decoupled from the core by an internal water ocean like that on Europa.

An update to a Saturnian longitude system based on kilometric radio emissions

Abstract: [1] The period of Saturn kilometric radiation modulation as determined by Voyager forms the basis for a longitude system (SLS) recognized by the International Astronomical Union However, Ulysses and Cassini observations have shown that this modulation period varies by the order of one percent on timescales of a few years and, hence, does not represent the internal rotation period of the planet A new longitude system was proposed based on ∼2 years of Cassini observations of the kilometric radio emissions and accounts for the variable radio period (SLS2) valid over the time interval from day 001, 2004 through day 240, 2006 Early uses of this longitude system have revealed a number of magnetospheric phenomena which appear to be locked to the radio period, such as variations in the external magnetic field, the plasma density in the inner magnetosphere, and enhanced intensities of energetic ions Analysis of the radio emissions since the new system was proposed revealed that the radio period continued to evolve, even showing a second, shorter period at times The subsolar longitude of the peak of Saturn kilometric radio emissions begins to deviate from that given by the SLS2 system almost immediately after the previous analysis interval Here, we provide a definition for SLS3, an extension to the longitude system valid over the interval from day 001, 2004 through day 222, 2007 based on variable period radio emissions

The Morphology of Northern Hemisphere Blocking

Abstract: The morphology of regional blocking in the Northern Hemisphere is discussed using the 40-yr ECMWF Re-Analysis (ERA-40) dataset and a measure of blocking based on the reversal at storm-track latitudes of meridional θ contrasts on a potential vorticity (PV) surface representative of the tropopause. The focus is on cyclonic and anticyclonic Rossby wave breaking that is inherent to the blocking development, and the extent to which this is determined by the climatological jet position and the ambient shears. More generally, the importance of the climatological planetary scale is discussed. The approach is mainly through composite behavior, but informed by consideration of many individual events. A diversity of behavior is found with longitude in both winter and summer, and there is a striking reversal of the sense of the wave breaking between the two seasons that is generally consistent with the difference in the jet locations. Preferred behaviors are found in various regions and seasons, and retrogre...

Statistical analysis of injection/dispersion events in Saturn's inner magnetosphere

Abstract: [1] In the inner magnetosphere of a rapidly rotating planet such as Jupiter and Saturn, radial transport of plasma mainly comprises hot, tenuous plasma moving inward and cold, denser plasma moving outward. A distinctive phenomenon resulting from the drift dispersion of injecting hot plasma provides direct evidence for this convective motion. Particle instruments aboard the Cassini spacecraft, including the Magnetospheric Imaging Instrument (MIMI) and the Cassini Plasma Spectrometer (CAPS), have made numerous observations of such signatures. The statistics of the properties of such events are studied in this paper by analyzing CAPS data from 26 Cassini orbits. A statistical picture of their major characteristics is developed, including the distributions of ages, longitudinal widths, radial distances, and longitudes and local times of injection. An unexpected longitude modulation of these events appears in the old SLS longitude system, which is based on the Saturn kilometric radiation (SKR) observations by Voyager around 1980, while no such modulation seems to exist in the new SKR longitude system of the Cassini era. A Lomb periodogram analysis, however, reveals no significant periodic modulation of these events. The injection structures are found to occupy a small fraction (∼5–10) of the available longitude space.

Intra-annual variability of the low-latitude ionosphere due to nonmigrating tides

Abstract: [1] In-situ plasma density measurements from the CHAMP satellite between about 350–420 km altitude are used to delineate intra-annual variations in the longitudinal structure of the F-region ionosphere. It is shown that the longitude structures during mid-day local times are dominated by the space-based longitudinal wavenumbers ks = 2, 4 and 3 in January, July and December, respectively. These conform to the same dominating ks-values characterizing solar thermal tide zonal winds in the dynamo region, namely the westward-propagating semidiurnal tide with planetary-fixed zonal wavenumber s = 4 (SW4), and the eastward-propagating diurnal tides with s = −3 (DE3) and s = −2 (DE2), respectively. DE3 is the dominating tide during the other months. The results presented indicate that nonmigrating tides other than DE3 may significantly impact the longitudinal structure of the low-latitude ionosphere during certain months.

Reduction of electron temperature in low‐latitude ionosphere at 600 km before and after large earthquakes

Abstract: [1] We examine ionospheric electron temperatures (Te) observed by HINOTORI satellite during three earthquakes; M6.6 occurred in November 1981, M7.4 and M6.6 in January 1982 over Philippine, respectively. It is found that T e around the epicenters significantly decreases in the afternoon periods within 5 days before and after the three earthquakes. The region of ionosphere disturbance extends to 80-120 degrees in longitude. A tendency exists that duration of the disturbance becomes longer as the increase of earthquake magnitude. F 2 peak frequency, f o F 2 and virtual height, h'F from a chain of 4 ionosonde stations located in the longitude zone of 120°E-130°E are used together with electron density(N e ), that is observed simultaneously onboard HINOTORI satellite to find possible cause mechanisms of the abnormal reduction of electron temperatures. Behavior of HINOTORI T e /N e and ionosonde f o F 2 /h'F implies the existence of westward electric field over epicentre. Our finding suggests that simple two plasma instruments might be able to play a fundamental role to study ionosphere disturbance associated with earthquake, if the constellation of small/mini satellites is organized and the orbits are properly chosen.

Technical Note: A new global database of trace gases and aerosols from multiple sources of high vertical resolution measurements

Abstract: A new database of trace gases and aerosols with global coverage, derived from high vertical resolution profile measurements, has been assembled as a collection of binary data files; hereafter referred to as the "Binary DataBase of Profiles" (BDBP). Version 1.0 of the BDBP, described here, includes measurements from different satellite- (HALOE, POAM II and III, SAGE I and II) and ground-based measurement systems (ozonesondes). In addition to the primary product of ozone, secondary measurements of other trace gases, aerosol extinction, and temperature are included. All data are subjected to very strict quality control and for every measurement a percentage error on the measurement is included. To facilitate analyses, each measurement is added to 3 different instances (3 different grids) of the database where measurements are indexed by: (1) geographic latitude, longitude, altitude (in 1 km steps) and time, (2) geographic latitude, longitude, pressure (at levels ~1 km apart) and time, (3) equivalent latitude, potential temperature (8 levels from 300 K to 650 K) and time. In contrast to existing zonal mean databases, by including a wider range of measurement sources (both satellite and ozonesondes), the BDBP is sufficiently dense to permit calculation of changes in ozone by latitude, longitude and altitude. In addition, by including other trace gases such as water vapour, this database can be used for comprehensive radiative transfer calculations. By providing the original measurements rather than derived monthly means, the BDBP is applicable to a wider range of applications than databases containing only monthly mean data. Monthly mean zonal mean ozone concentrations calculated from the BDBP are compared with the database of Randel and Wu, which has been used in many earlier analyses. As opposed to that database which is generated from regression model fits, the BDBP uses the original (quality controlled) measurements with no smoothing applied in any way and as a result displays higher natural variability.

F3 layer during penetration electric field

Abstract: [1] The occurrence of an additional layer, called F3 layer, in the equatorial ionosphere at American, Indian, and Australian longitudes during the super double geomagnetic storm of 7–11 November 2004 is presented using observations and modeling. The observations show the occurrence, reoccurrence, and quick ascent to the topside ionosphere of unusually strong F3 layer in Australian longitude during the first super storm (8 November) and in Indian longitude during the second super storm (10 November), all with large reductions in peak electron density (Nmax) and total electron content (GPS-TEC). The unusual F3 layers can arise mainly from unusually strong fluctuations in the daytime vertical E × B drift as indicated by the observations and modeling in American longitude. The strongest upward E × B drift (or eastward prompt penetration electric field, PPEF) ever recorded (at Jicamarca) produces unusually strong F3 layer in the afternoon hours (≈1400–1600 LT) of PPEF, with large reductions in Nmax and TEC; the layer also reappears in the following evening (≈1700–1800 LT) owing to an unusually large downward drift. At night, when the drift is unusually upward and strong, the F region splits into two layers.

Some new data on modern tectonic deformation and active faulting in azerbaijan (according to global positioning system measurements)

Abstract: Global Positioning System (GPS) observations in Azerbaijan and surrounding areas of the Caucasus region are providing quantitative constraints of the geometry of active fault systems, and rates of present-day deformation. West of 48° E longitude, the Main Caucasus Trust Fault (MCT) follows the sharp change in slope along the south side of the Greater Caucasus as is well known from prior seismic, geophysical, and geologic studies. However, east of this longitude the MCT turns sharply to the south, crossing the Kura Depression and extending along the western side of the Caspian Sea (here called the West Caspian Fault; WCF). While the MCT is predominantly a thrust fault west of 48°E longitude, the WCF is a pure rightlateral, strike slip fault with a slip rate of 11 ± 1 mm/yr south of the Absheron Peninsula. We also document shortening of 4 ± 1 mm/yr along the northern side of the Greater Caucasus in Dagestan on a roughly E-W striking fault that turns to the south inland of the north Caspian shoreline. This fault configuration implies that the Baku area is at the junction of four fault systems, the MCT, the West Caspian Fault, the North Caspian Fault, and the Central Caspian Seismic Zone. The rate of convergence on the MCT decreases from east to west from 10 ± 1 mm/yr at 48° E longitude to 4 ± 1 mm/yr in northwestern Azerbaijan (~46°E longitude). In eastern Azerbaijan, there is no evidence of active shortening in the Lesser Caucasus or Kura Depression, indicating that any deformation in this area is below present velocity uncertainties (± 0.5 mm/yr). The present-day pattern of horizontal motions in aggregate suggests that the Lesser Caucasus and Kura Depression are rotating coherently (i.e., little or no internal deformation) in a counterclockwise sense about a pole located near the NE corner of the Black Sea, resulting in the observed W to E increase in the rate of convergence along the MCT. These new, quantitative constraints on fault activity provide an improved physical basis for estimating earthquake hazards in Azerbaijan.

Atmosphere-ocean conditions jointly guide convection of the Boreal Summer Intraseasonal Oscillation: Satellite observations

Abstract: The water-vapor and air-temperature profiles from the Atmospheric Infrared Sounder (AIRS), in combination with surface wind from Quick Scatterometer (QuikSCAT) and rainfall and sea surface temperature (SST) from Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI), are used to document surface conditions and vertical moist thermodynamic structures of the 2003-2006 Boreal Summer Intraseasonal Oscillation (BSISO) over the Indo-Pacific warm pool. The composite based on Wheeler and Hendon's intraseasonal oscillation index reveals that Convective Available Potential Energy (CAPE), SST, and surface convergence lead convection in both northward and eastward directions. The preconditioning of CAPE is much earlier than that of SST, implying that the atmosphere internal processes precondition CAPE. On the other hand, the ocean positively feeds back to the atmosphere from bottom up, forming a smooth transition from boundary layer moistening, shallow convection at lower or middle level, to the deep convection all through the troposphere. The preconditioning of the boundary layer moist (dry) anomalies to the subsequent positive (negative) rainfall maximum is as far as 60-90 degrees in longitude (15 degrees in latitude) and quarter-to-half cycle in time. In contrast, this boundary layer preconditioning is virtually undetected from conventional NCEP reanalysis. Finally, the implications of these new findings on the frictional "convective interaction with dynamics'' (CID) theory of intraseasonal oscillation are also discussed.

The directivity of solar type III bursts at hectometer and kilometer wavelengths: Wind-Ulysses observations

Abstract: We investigate the directivity of solar type III radio bursts at hectometer and kilometer wavelengths using radio data recorded simultaneously by the Wind and Ulysses spacecraft which are widely separated in heliocentric longitude and latitude. From the positions of the associated flares and the solar wind speed and plasma density measured aboard the spacecraft, we estimate the location of the type III radio sources along the approximately spiral magnetic field lines connected to the flare sites. Using the ratios of the radio flux densities measured from 1995 to 2005 at the same frequencies (940–80 kHz) on these spacecraft, we have for the first time derive the average directivity diagram of type III bursts in two dimensions, longitude and latitude relative to the emission source. This diagram is found to exhibit no significant variation with the solar activity. The diagram in longitude is found to shift east of the local magnetic field direction at the source. The angular width and eastward shift of the diagram are observed to increase with decreasing frequencies; around 800 kHz, its full width at maximum/10 level is about 190 ◦ and its eastward shift 23 ◦ . The diagram in latitude, obtained uniquely thanks to the out-of-ecliptic orbit of Ulysses, shows no significant variation with latitude.

Small scale hot upwelling near the North Yellow Sea of eastern China

Abstract: [1] In order to image the structure of the upper-mantle discontinuity beneath Eastern China, we have applied a common conversion point (CCP) stacking method of receiver function (RF). Both the 410-km and the 660-km discontinuities (hereafter called the 410 and the 660) clearly show continuous positive phases along the selected profile. The 410 shows depression, whereas the 660 shows uplift, in the eastern section of the study profile. The transition zone (TZ) to the west of longitude 122 is thicker than the global average, though the TZ is thinner to the east of that longitude. The thinnest part of the TZ, with 10� 15 km of thinning (an increase in temperature of up to 100C), is located at the North Yellow Sea. We suggest that either the small-scale convection associated with the deep penetration of the sinking slab into the lower mantle, or a small plume from lower mantle, has generated hot upwelling in this region. Citation: Ai, Y., T. Zheng, W. Xu, and Q. Li (2008), Small scale hot upwelling near the North Yellow Sea of eastern China, Geophys. Res. Lett., 35, L20305, doi:10.1029/ 2008GL035269.

The warped plane of the classical kuiper belt

Abstract: By numerically integrating the orbits of the giant planets and of test particles over a period of four billion years, we follow the evolution of the location of the midplane of the Kuiper belt. The Classical Kuiper belt conforms to a warped sheet that precesses with a 1.9 Myr period. The present-day location of the Kuiper belt plane can be computed using linear secular perturbation theory: the local normal to the plane is given by the theory's forced inclination vector, which is specific to every semimajor axis. The Kuiper belt plane does not coincide with the invariable plane, but deviates from it by up to a few degrees in stable zones. For example, at a semimajor axis of 38 AU, the local Kuiper belt plane has an inclination of 1.9 degrees and a longitude of ascending node of 149.9 degrees when referred to the mean ecliptic and equinox of J2000. At a semimajor axis of 43 AU, the local plane has an inclination of 1.9 degrees and a nodal longitude of 78.3 degrees. Only at infinite semimajor axis does the Kuiper belt plane merge with the invariable plane, whose inclination is 1.6 degrees and nodal longitude is 107.7 degrees. A Classical Kuiper belt object keeps its inclination relative to the Kuiper belt plane nearly constant, even while the plane departs from the trajectory predicted by linear theory. The constancy of relative inclination reflects the undamped amplitude of free oscillation; that is, the homogeneous solution to the forced harmonic oscillator equation retains constant amplitude, even while the inhomogeneous solution cannot be written down accurately because the planetary forcing terms are chaotic. Current observations of Classical Kuiper belt objects are consistent with the plane being warped by the giant planets alone, but the sample size will need to increase by a few times before confirmation exceeds 3σ in confidence. In principle, differences between the theoretically expected plane and the observed plane could be used to infer as yet unseen masses orbiting the Sun, but carrying out such a program would be challenging.

Planetary perturbations on Mercury’s libration in longitude

Abstract: Two space missions dedicated to Mercury (MESSENGER and BepiColombo) aim at understanding its rotation and confirming the existence of a liquid core. This double challenge requires much more accurate models for the spin-orbit resonant rotation of Mercury. The purpose of this paper is to introduce planetary perturbations on Mercury’s rotation using an analytical method and to analyse the influence of the perturbations on the libration in longitude. Applying a perturbation theory based on the Lie triangle, we were able to re-introduce short periodic terms into the averaged Hamiltonian and to compute the evolution of the rotational variables. The perturbations on Mercury’s forced libration in longitude mainly come from the orbital motion of Mercury (with an amplitude around 41 arcsec that depends on the momenta of inertia). It is completed by various effects from Jupiter (11.86 and 5.93 year-periods), Venus (with a 5.66 year-period), Saturn (14.73 year-period), and the Earth (6.58 year-period). The amplitudes of the oscillations due to Jupiter and Venus are approximately 33% and 10% of those from the orbital motion of Mercury and the amplitudes of the oscillations due to Saturn and the Earth are approximately 3% and 2%. We compare the analytical results with the solution obtained from the spin-orbit numerical model SONYR.

Further experiments on distance navigation in the adelie penguin pygoscelzs adelzae

Abstract: Summary Further experiments confirm our recently reported findings that Adelie Penguins Pygoscelis adeliae, transported from rookeries on the coasts of Antarctica to remote release points, consistently select a departure direction to the N.N.E. with respect to their home meridian. New releases were made at the South Pole where sun altitude is constant and in the offshore pack ice where the initial N.N.E. departure direction led the birds directly away from their home. Birds imported from the Mirnyy coast, 85° of longitude to the west of Cape Crozier selected a departure direction to the N.W. After being held in an open pen at the new position for three weeks, however, Mirnyy birds revised their orientation to match the N.N.E. departures of a comparably held group of Crozier birds. Juvenile penguins taken from creches and from the beach at Cape Crozier selected the same departure direction as adults. Several lines of evidence suggest that the mechanism used in initial direction selection may be different from that used in course maintenance. The consistent northward or outward departure orientation is discussed in terms of escape to offshore feeding grounds. The easterly component of this orientation is discussed in terms of compensation for a westward drift imposed on outward-moving birds by coastal currents. A circadian rhythm in phase with conditions at the longitude of the home rookery is regarded as serving to guide a displaced bird back to its home coast. A circadian rhythm reset to the solar cycle of a new longitude is regarded as serving to guide a displaced bird to the nearest coast. The return of displaced birds to their home rookery, after initial orientation in other directions, emphasizes the fact that the departure response observed in these studies is only one part of a complex navigational mechanism, which guides the Adelie Penguin through its seasonal migrations.

Australian winter anticyclonicity, 1850–2006

Abstract: [1] The latitude, longitude, and longitudinal extent of Australian winter anticyclonicity are reconstructed for the period 1850–2006 using the gridded mean sea level pressure data set of the Met Office (HadSLP2r). The latitude of the system has varied about 29°S, with no long-term trend evident, while the longitudinal extent has expanded by some 17° and the center pressure increased by some 1.5 hPa.

Mesoscale objective analysis of daily rainfall with satellite and conventional data over Indian summer monsoon region

Abstract: A mesoscale objective analysis scheme for producing daily rainfall analysis on a regular latitude/longitude grid over the Indian monsoon region is described. The Barnes scheme is applied to interpolate irregularly distributed daily rainfall data on to a regular grid. The spatial resolution of the interpolated arrays is 0.25 degrees of latitude by 0.25 degrees of longitude. Daily rainfall derived from INSAT IR radiances and raingauge observations are combined to produce this analysis. Some objectively determined constraints are employed in this study: (i) weights are determined as a function of data spacing, (ii) in order to achieve convergence of the analysed values three passes through the data are considered and there is automatic elimination of wavelengths smaller than twice the average data spacing. The case of a typical westward moving monsoon depression during the 1994 monsoon season is selected to represent the characteristics of the analysed rainfall. Objective analyses of six days (16 to 21 August 1994) have been carried out using Barnes three pass scheme. The weighting function scale length parameter (c, denominator in the exponential Gaussian weight function) is varied from over a range of values and the root mean square (rms) errors are computed to select the appropriate value of c. The value of c depends on the number of correction passes being performed and on the density of the observations. The characteristics of the output field from this analysis system have been examined by comparing the analysed rainfall with the observed values. The heavy rainfall over the Western Ghat of India has been clearly brought out in this analysis.

Estimating Salinity between 25° and 45°S in the Atlantic Ocean Using Local Regression

Abstract: The empirical relationship between salinity and temperature in the South Atlantic is quantified with the aid of local regression. To capture the spatial character of the TS relationship, models are fitted to data for each point on a three-dimensional grid with spacing of 1° in latitude, 2° in longitude, and 25 dbar in the vertical. To ensure sufficient data for statistical reliability each fit is to data from a region extending over several grid points weighted so that more remote data exert less influence than those closer to the target grid point. Both temperature and its square are used as regressors to capture the curvature seen in TS plots, and latitude and longitude are used to capture systematic spatial variations over the fitting regions. In addition to using statistics of residuals to characterize how well the models fit the data, errors for data not used in fitting are examined to verify the models’ abilities to simulate independent data. The best model overall for the entire region at ...

Analysis of the Spatio-temporal Characteristics of UV-B Strength Change over the Yunnan Plateau

Abstract: In this article,the UV-B data from different altitude,longitude and latitude stations on Yunnan low latitude plateau were analysed and the spatio-temporal characteristics of UV-B strength of Yunnan Province were discussed.The results indicate that:(1)The chronometer factors have an effect on the basic change of UV-B strength,the changing characteristics are directly related to the total radiation and have obvious daily and yearly variations.(2)The UV-B strength is affected by the latitude of the survey points.With the increase of latitude,the UV-B strength decreases.When the latitude rises 1o,the UV-B strength decreases 0.679 W/m2 and 0.157 W/m2 respectively in the dry and rainy season in the same longitude and decreases 0.340 W/m2 and 0.306 W/m2 in different longitude.The changing ratio of UV-B strength in dry season is larger than in the rainy season,having obvious dry-rainy season characteristics.(3)UV-B strength is affected by the altitude,with the increase of altitude of survey points,the UV-B strength increases.When the altitude increases 100m,the UV-B strength increases 0.202 W/m2 and 0.090 W/m2 respectively in the dry and rainy season,having also obvious dry-rainy season characteristics.

Average Thickness of Magnetosheath Upstream of Magnetic Clouds at 1 AU versus Solar Longitude of Source

Abstract: Starting with a large number (N = 100) of Wind magnetic clouds (MCs) and applying necessary restrictions, we find a proper set of N = 29 to investigate the average ecliptic plane projection of the upstream magnetosheath thickness as a function of the longi- tude of the solar source of the MCs, for those cases of MCs having upstream shock waves. A few of the obvious restrictions on the full set of MCs are the need for there to exist a driven upstream shock wave, knowledge of the MC's solar source, and restriction to only MCs of low axial latitudes. The analysis required splitting this set into two subsets according to av- erage magnetosheath speed: slow/average (300 - 500 km s −1 ) and fast (500 - 1100 km s −1 ) speeds. Only the fast set gives plausible results, where the estimated magnetosheath thick- ness (�S) goes from 0.042 to 0.079 AU (at 1 AU) over the longitude sector of 0° (adjusted source-center longitude of the average magnetic cloud) to 40° off center (East or West), based on N = 11 appropriate cases. These estimates are well determined with a sigma ( σ) for the fit of 0.0055 AU, where σ is effectively the same as √ (chi-squared) for the appro- priate quadratic fit. The associated linear correlation coefficient forS versus |Longitude| was very good (c.c. = 0.93) for the fast range, andS at 60° longitude is extrapolated to be 2.7 times the value at 0°. For the slower speeds we obtain the surprising result thatS is typically more-or-less constant at 0.040 ± 0.013 AU at all longitudes, indicating that the MC as a driver, when moving close to the normal solar wind speed, has little influence on magnetosheath thickness. In some cases, the correct choice between two candidate solar- source longitudes for a fast MC might be made by noting the value of the observedS just

Global Positioning System Measurements of Crustal Deformation in Azerbaijan

Abstract: GPS observations in Azerbaijan and surrounding areas are providing quantitative constraints of the geometry of active fault systems, and rates of present-day deformation. West of 48° E longitude, the Main Caucasus Trust Fault (MCT) follows the sharp change in slope along the south side of the Greater Caucasus as is well known from prior geophysical and geologic studies. However, east of this longitude the MCT turns sharply to the south, crossing the Kura Depression and extending along the western side of the Caspian Sea (West Caspian Fault; WCF). While the MCT is predominantly a thrust fault west of 48°E longitude, the WCF is a pure right-lateral, strike slip fault with a slip rate of 11 ± 1 mm/yr south of the Absheron Peninsula. The rate of convergence on the MCT decreases from east to west from 10 ± 1 mm/yr at 48° E longitude to 4 ± 1 mm/yr. The present-day pattern of horizontal motions in aggregate suggests that the Lesser Caucasus and Kura Depression are rotating coherently in a counterclockwise sense about a pole located near the NE corner of the Black Sea, resulting in the observed W to E increase in the rate of convergence along the MCT.

Re‐examination of MLT Mean Zonal Winds over East Asia by Using WINDII/UARS Dataset

Abstract: In this paper, the monthly mean zonal winds in the MLT region (90~120 km) over Eastern Asian sector that is represented by the meridian of 40° longitude width centering at 120°E, are re-examined by using the WINDII/UARS data winds taken during November 1991 to August 1997 The one year course of the winds in latitude-height cross-section ranging from 0° to 60°N latitude and from 90 to 120 km height are presented Good agreements are seen in the comparison of the yearly course of the current zonal wind estimates and that of an observational estimates using the data taken by the Wuhan (30°N, 114°E) meteor radar Agreement is also seen in the comparison of the two monthly zonal winds derived respectively by WINDII/UARS and HRDI/UARS data Both these agreements suggest that the current results represent the general features of the zonal winds in the meridian Large discrepancies are seen in the comparison between the monthly zonal winds estimated by using the WINDII data and that provided by the CIRA-86 reference atmosphere, in particular in the height range above 100 km And the discrepancy is even larger at low latitudes equatorward, where the CIRA-86 zonal winds often exhibit opposite direction against that of the WINDII winds, which suggests that the reference atmosphere holds significant uncertainty as to the real atmosphere

Ionospheric Responses to the July 15-16, 2000 Magnetic Storm Around Geographic Longitude 121 E

Abstract: This study presents observed behavior of ionospheric responses using vertical total electron contents (VTEC) and NmF2. The data were collected from global positioning system (GPS) networks and ionosondes around the geographic longitude of 121E from mid- to low-latitudes for the severe magnetic storm on 15 July 2000. The results show that the severe magnetic storm caused significant density depletion and a G-condition occurrence in the western Pacific region on 15 - 16 July 2000. The G-condition is observed on the ionograms at Chung-Li station around 2330 UT on July 15. Furthermore, the variation of the F-peak height (HmF2) at Cebu indicates that a zonal electric field produced an upward drift and enhanced the fountain effect from 1000 UT on July 15. The observation of a G-condition indicates that a storm-induced neutral-wind circulation was the main cause of compositional change; i.e., an increase in the N2/O ratio and its associated loss coefficients that produced a negative storm phase along the chain of geographic longitude 121E.

The surface of Mercury from ground-based astronomical observations

Abstract: Recent ground-based astronomical short-exposure observations of Mercury have yielded more than 50000 electronic pictures of the planet at different phases and different positions relative to the Earth. The work was fulfilled in several observatories. The use of available and newly developed processing methods applied to large volumes of electronic frames allowed the images of a considerable portion of Mercury’s surface to be synthesized. We present the images of the 90°–180°W, 215°–280°W, and 50°–90°W sectors containing, among others, the longitudes not covered by spacecraft imaging. Along with the listed images, we present the results of recent observations of Mercury carried out on November 20–24, 2006 during the morning elongation at the Special Astrophysical Observatory of the Russian Academy of Sciences (SAO RAS) (Nizhnii Arkhyz, Karachai-Circassia, the Caucasus). The 265°–350°W longitude sector of Mercury was observed. The observations were made under good weather conditions. Among the main tasks of the new observations was obtaining a complete view of the S Basin. Previously, this basin had been investigated in fragments only by the actual solar illumination conditions. During the period of November 20–24, 2006, the S Basin was on the sunlit side of the planet. The complete image of the basin was obtained from the processing of a large number of electronic frames. The appearance of the S Basin is compared with the data on its relief acquired with radar methods. In this longitude sector, a number of other unusual surface features were found; among them, are a huge “Medallion” crater and other formations. The results considered in the present and earlier published studies are compared with the Mariner 10 data (1974–1975) and with the data received from the Messenger spacecraft during its first flyby of the planet (January 2008).

Computer system for displaying location information on map, and map and coordinate using the same

Abstract: PROBLEM TO BE SOLVED: To provide a method of displaying location information on the earth and on a map, which is not a latitude and longitude expression in the prior art, but a new method of expressing location information, and which facilitates a user to deal with the location information on the earth or on a map efficiently with regard to indication, recognition, input, data processing by a computer, etc. SOLUTION: The numeric values of the latitude and the longitude of an arbitrary location on a map are expressed in the decimal number system as a latitude corresponding numeric value OWP and a longitude corresponding numeric value OWQ on the basis of the following formulae: when the latitude numeric value is P and the longitude numeric value is Q, the latitude corresponding numeric value OWP=0.5+P/360, and the longitude corresponding numeric value OWQ=0.5+Q/360. COPYRIGHT: (C)2010,JPO&INPIT

Communication terminal and area defining program

Abstract: PROBLEM TO BE SOLVED: To provide a communication terminal that defines an area enabling estimation precision of a user's situation to be improved even when positioning precision of position information is low, and also to provide an area defining program. SOLUTION: A positioning part 11 positions a latitude and a longitude of GPS (Global Positioning System). An area defining part 12 defines a user correction HA (Home Area) generated by user's correction input and an error absorption HA including the middle point between the latitude and longitude of GPS and a latitude and a longitude of user correction in the center. An area determining function 161 determines that the user is in an HA when the level of positioning precision is less than a threshold, and the latitude and longitude of GPS is outside the user correction HA and included in the error absorption HA, and also determines that the user is in the HA when the latitude and longitude of GPS is included in the user correction HA. COPYRIGHT: (C)2010,JPO&INPIT

The Rise of Extreme Typhoon Power and Duration over South East Asia Seas

Abstract: The study features an analysis of 40 years of records of longitude, latitude and power (wind speed) of tropical storms and typhoons over South East Asia seas. The results demonstrate the growing intensity of the most severe events. The singular spectrum analysis of wind speed series from 1960 till 2000 identified two sub-periods of roughly similar behavior. Then, the recorded events were classified statistically and the escalating power and duration of the most extreme ones were examined with extreme probability distributions to quantify the resulting climate change consequences in the studied region. Finally, conclusions and suggestions for a potential follow-up research were provided.