Showing papers on "Longitude published in 2000"

Propagation characteristics of extratropical planetary waves observed in the ATSR global sea surface temperature record

Abstract: This paper examines the characteristics of planetary wave signatures that have been found in the Along Track Scanning Radiometer averaged sea surface temperature (ASST) record for 1991–1996. Longitude-time plots for every latitude between 5° and 50°, north and south, reveal westward propagating wave-like patterns at many locations, whose speed decreases with latitude like baroclinic Rossby waves. A two-dimensional Radon transform method is used to measure the wave speed and its variation with location and time, which broadly matches the Rossby wave speeds predicted by the most recent theory and those measured by TOPEX altimetry, although there are some discrepancies. At low latitudes the thermally detected speeds are slower than expected, a possible consequence of sampling limitations. Wave signatures are clearest between 25° and 40°S, where the meridional temperature gradient is strongest. Here observed speeds are 20–30% greater than theoretical predictions. Planetary wave speed varies considerably with longitude. In general, it increases toward the west of ocean basins, and distinct differences between ocean basins are evident. The propagation characteristics of the waves appear to change abruptly at locations consistent with latitudinal variations in seafloor bathymetry, particularly midocean ridges. In addition, eastward propagating signatures are found in the Southern Ocean. The results demonstrate the value of the ASST data set as a tool for studying basin-scale wave processes as a complement to the use of altimetry. By observing the thermal signature of Rossby waves the method has the potential to clarify their influence on air-sea interaction processes and to contribute to climate modeling studies.

Satellite observations of upwelling on the continental shelf south of Madagascar

Abstract: We report on upwelling seen in satellite AVHRR sea surface temperature imagery over the continental slope and shelf of southern Madagascar during February and March 2000. The upwelling is concurrent with anomalously high pseudo wind-stress over the region during this period. However, the western boundary East Madagascar Current, which is seen over the continental slope region, may contribute to the upwelling effect. The upwelling covers an area of 2° longitude by 1° latitude and at its peak is about 3–5°C cooler than the local ambient sea surface temperature. The paucity of in situ wind and current data in the region, however, prohibit a quantitative assessment of the relative forcing.

The Western Boundary of the Equatorial Pacific Upwelling: Some Consequences of Climatic Variability on Hydrological and Planktonic Properties

Abstract: The longitude of the western limit of the equatorial Pacific upwelling is a key parameter for studies of carbon budget and pelagic fisheries variability. Although it is well defined at the surface on the equator by a salinity front and a sharp variation of the partial pressure of CO2, data from two equatorial cruises make it clear that this hydrological limit does not necessarily coincide with the boundary of the nitrate and chlorophyll enriched area. In January-February 1991 during a non-El Nino period, when trade winds and the South Equatorial current (SEC) were favorable to upwelling, the two limits were at the same longitude. Conversely, in September-October 1994 during El Nino conditions, when the equatorial upwelling had stopped, the nitrate and chlorophyll enriched zone was found a few degrees of longitude east of the hydrological boundary (5.5° at the surface and 2.5° for the 50 m upper layer), whereas no such offset was observed for zooplankton biomass. A simple model, based on the HNLC (High Nutrient - Low Chlorophyll) ecosystem functioning, was initialized with nitrate uptake measurements and estimates of upwelling break duration. The model results support the hypothesis that zonal separation of the limits arises from biological processes (i.e. nitrate uptake and phytoplankton grazing) achieved during that upwelling break.

Interhemispheric plasma flows in the equatorial topside ionosphere

Abstract: Latitudinal, longitudinal, and seasonal variations in the field-aligned and perpendicular flows measured at an altitude near 830 km, by the Defense Meteorological Satellite Program F10 satellite are examined. These profiles are studied during the nighttime (2100 magnetic local time) for solstice periods in 1991 when the solar activity is high. Latitude and longitude variations show the influence of F region winds in modulating the observed field-aligned flows. At night, large downward field-aligned flows of the order 400-600/ ms are observed in the winter hemisphere and coincide in longitude with the location of previously identified adiabatic heating effects studied by Venkatraman and Heelis. Interhemispheric flows at 2100 hours local time are seen to extend up to apex heights of approx. 1000 km during times of high solar activity. Perpendicular drifts, however are relatively invariant with latitude as expected.

On determining the noon polar cap boundary from SuperDARN HF radar backscatter characteristics

Abstract: Previous work has shown that ionospheric HF radar backscatter in the noon sector can be used to locate the footprint of the magnetospheric cusp particle precipitation. This has enabled the radar data to be used as a proxy for the location of the polar cap boundary, and hence measure the flow of plasma across it to derive the reconnection electric field in the ionosphere. This work used only single radar data sets with a field of view limited to ∼2 h of local time. In this case study using four of the SuperDARN radars, we examine the boundary determined over 6 h of magnetic local time around the noon sector and its relationship to the convection pattern. The variation with longitude of the latitude of the radar scatter with cusp characteristics shows a bay-like feature. It is shown that this feature is shaped by the variation with longitude of the poleward flow component of the ionospheric plasma and may be understood in terms of cusp ion time-of-flight effects. Using this interpretation, we derive the time-of-flight of the cusp ions and find that it is consistent with approximately 1 keV ions injected from a subsolar reconnection site. A method for deriving a more accurate estimate of the location of the open-closed field line boundary from HF radar data is described.

Lamination Frequencies as a Diagnostic for Horizontal Mixing in a 3D Transport Model

Abstract: Ozone simulations are performed in an attempt to simulate laminar events with the frequency observed in balloon ozone sondes. The winds are taken from the Goddard Earth Observing System Data Assimilation System (GEOS DAS); the importance of horizontal and vertical resolution to production of lamina are investigated. A simulation with a high horizontal reolution (grid spacing 1° latitude by 1.25° longitude) and high vertical resolution (∼300 m grid spacing) isentropic model produces lamination frequencies close to the balloon sonde climatology near the polar vortex edge but exhibits too much lamination in the subtropics. This indicates that the GEOS DAS winds contain the information to produce laminar events, although such small-scale features are not manifest in the more commonly used 2° latitude by 2.5° longitude transport model, which uses the hybrid sigma-pressure vertical coordinate. The zonal average ozone tendencies due to horizontal mixing in the lamina-producing models are similar to the ...

System and method of measuring three-dimensional shape of road

Abstract: PROBLEM TO BE SOLVED: To accurately determine the three-dimensional shape of a road. SOLUTION: During running of an observation car 10 on a road, a car-carried hybrid position measuring unit 64 measures the latitude, the longitude and the height of a running trace of the car 10. In parallel, a car-carried video camera 20 takes images of the road and a picture processor 66 extracts white lines at both sides of the road to obtain the distance between the position of the car 10 and the center point of the road, based on the white lines, and calculates the latitude, the longitude and the height of the load center point, using the latitude, the longitude and the height of the travel trace, the distance between the observation car position and the road center point, and the yaw angle and the roll angle from a car-carried three-axis angle sensor 40. It obtains a three- dimensional shape of the road center line from the result and obtains a gradient in the road width direction from the roll angle to determine the latitude, the longitude and the height of an optional position on the road. COPYRIGHT: (C)2002,JPO

Automobile navigation system

Abstract: PROBLEM TO BE SOLVED: To provide an automobile navigation system which can guide three dimensionally. SOLUTION: In this automobile navigation system, an information-processing part 1 obtains three-dimensional position information of a user from electric waves received from the outside based on the operation result of a position- detecting part 5 which operates coordinate values in a longitude direction and in a latitude direction of the present position of the user and on the detection result of a height detector 6 which detects height information of the present position of the user. Moreover, the information-processing part 1 reads out map data including the obtained three-dimensional present position from a storage 2 which stores map data including the longitude direction, the latitude direction and the height information. An output unit 4 displays the three- dimensional present position obtained by the information-processing part 1 and the map data read out from the storage 2. COPYRIGHT: (C)2001,JPO

COSTTEC — The electron content monthly median map adopted by COST 251

Abstract: COSTTEC is a monthly median regional map for ionospheric electron content. The data used for the mapping effort are monthly and bi-hourly medians from Differential Doppler observations on the signals of the Navy Navigation Satellites (NNSS) made at Graz/Austria and Lindau/Harz, Germany. COSTTEC uses linear dependences of electron content on the solar activity index R12, on geographic latitude and on geographic longitude. For the local time dependence and for the seasonal dependence it uses Fourier decomposition. The decomposition converts the 12 × 12 time domain medians into 12 × 12 Fourier coefficients. For the maps only 5x5 coefficients are kept (time independent term, diurnal and semi-diurnal variation, annual and semi-annual variations and all combinations). Finally the maps consist of 2 × 3 sets of 5 × 5 Fourier coefficients: 3 sets for high and 3 sets for low solar activity. At each solar activity level one set is for a central point, one for the latitudinal and one for the longitudinal gradients. Since no TEC data could be used to derive the longitude dependence it was necessary to incorporate experience from F2 peak density behaviour. We report on the reasons for the chosen mapping approach, demonstrate the most important map properties and show comparisons between observations and TEC map data.

Interannual Variability of Antarctic Hydrographic Structure and Frontal Zones along Meridional Sections between Syowa Station and Southern Africa

Abstract: Six years of quasi-meridional crossings of the Antarctic Ocean from Antarctica to southern Africa between 4°W and 16°E longitude are analyzed, with emphasis on temperature and salinity distributions Data are sparse, but (particularly in the southern part of the sections) adequate to show significant variations in the latitude/depth distributions and T-S characteristics of the principal water masses In particular, the cross-sectional area occupied by Warm Deep Water (Weddell Deep Water) dropped by about one third in 1968 Positions of major features associated with the Antarctic Divergence varied by up to 5 degrees of latitude The surface temperature gradient often observed at the Antarctic Divergence appears to be the surface expression of a shallow (possibly seasonal) thermocline which sometimes slopes upward to intersect the sea surface There is a clear need for more closely spaced and consistently planned data from Antarctic cruises, particularly those on which physical oceanography is an ancillary activity As a bare minimum, much more closely spaced surface temperature (and if possible also salinity) measurements would be useful

A Synoptic View of the Subphotospheric Horizontal Velocity Flows in the Sun

Abstract: Ring diagram analysis, a technique of local helioseismology, has been applied to 120 regions of 15° × 15° over the solar surface in order to study the mass motions in the upper layers of the convection zone. The horizontal flows from ~0.95 R☉ up to the surface have been investigated in a region spanning 360° in longitude and about 75° in latitude. The regions were tracked in groups of five centered at 0, ±15°, and ±30° in latitude over a timespan of ±768 minutes from central meridian crossing. More than 30,000 full-disk Dopplergrams taken by the Solar Oscillation Investigation/Michelson Doppler Imager (SOI/MDI) on the Solar and Heliospheric Observatory (SOHO) spacecraft have been analyzed to create a synoptic map. The images were taken during the first SOI Dynamics Program in 1996 May and June and have a pixel size of ~2'' allowing coverage in l up to 1200. The p-modes analyzed cover a range of 0 ≤ n ≤ 7 and 183 ≤ l ≤ 999. The estimated velocity vectors provide information on the size and structure of large-scale flows. The flows exhibit markedly meridional behavior between 0.975 and 0.997 R☉. The zonal component is mainly ruled by the differential rotation.

Secular change in the location of the magnetic dip equator in the twentieth century

Abstract: Using the spherical harmonic coefficients defining the International Geomagnetic Reference Field Models for the 21 epochs 1900 to 2000, the geographic locations of the dip equator in different longitudes were computed. It is shown that the migratory trends in the dip equator are widely different in the American, African and Indian sectors. The largest change is seen over 30 °W to 40°W while there is practically no secular movement over 100 years in the 30°E longitude. It is seen that the geographic longitude of the dip equator farthest away from the geographic equator in the American sector shows a westward migration at the rate of ~0.2 °/year which compares favorably with the average westward drift of the non-dipolar field discussed in the literature. The distance between the magnetic center of the eccentric dipole and the Earth’s center, the South Atlantic Geomagnetic Anomaly (SAGA) center and the migration of the local minimum of the dip equatorial longitude in the American center are all linearly related. In addition, the westward drift in the agonic line over the geographic equator in the American sector, indicative of the contributions from non-dipolar terms, is also linearly related to the three parameters. As the observed location of the dip equator in the American sector closely matches the model-based one, it is suggested that identification of the geographic longitude of the dip equator in the American zone based on a survey over a small area can provide useful information on several other parameters of the westward drift of the geomagnetic field.

Geo-electrical structure of the mantle beneath the Indian region derived from the 27-day variation and its harmonics

Abstract: Estimates of the C-response function were determined by Z: H method to obtain conductivity and depth values for a substitute perfect conductor (conductosphere) beneath the Indian region, utilizing geomagnetic variations at periods of 27-day and its harmonics. Two and half years of continuous geomagnetic data were utilized. These data were recorded during 1975–77, at a chain of 13 stations confined to the 150° geomagnetic longitude band, which extended from the dip-equator at the southern tip of India, to the northern parts of Russia. Complex demodulation technique was employed to determine the electromagnetic (EM) responses. Taking advantage of the dense latitudinal distribution of the observatories, the demodulates of all the stations were tested statistically to check the validity of the P 1 0 approximation for the inducing field. Single-station response estimates, for a 27-day period, computed by a robust method have shown that reliable EM responses (consistent with P 1 0 source dependence and with local 1-D Earth structure) could be obtained for only 6 stations, all situated in the mid-latitude region. The depth estimates at all 6 stations are consistent, including Sabhawala (SAB) which is situated close to the Himalayan collision zone. The negligible differences in the depth estimates of these mid-latitude stations do not show any latitudinal dependence, as against such an observation reported for the European and the North American regions. The mean depth of the conductosphere is found to be 1200 (±200) km, with an average conductivity of 0.7 (±0.3) S/m. Comparison of the mean geo-electrical structure with those of other regional models shows that the presence of a mid-mantle conductor at 850 km depth could be considered to be a global phenomenon.

Method for rectangular parameterization of a geographic area using a geolocation algorithm

Abstract: A method ( 40 ) for parameterizing a predetermined geographic area ( 12 ) serviced by a satellite communication system ( 60 ) into a number of equally shaped sub-partitions ( 22 ) is discloseed. The satellite communication system ( 60 ) has a processor ( 64, 72 )for generating data elements and a memory ( 66, 74 ) for storing the data elements in data structure. The method ( 40 ) includes the step ( 42 ) of determining a total latitude side length dimension and a total longitude side length dimension of the predetermined geographic area ( 12 ) from latitude and longitude values representative of the geographic area. The steps ( 44 ) also include determining the area of a sub-partition based upon the total latitude side length, the total longitude side length, and the number of equally shaped sub-partitions. Each of the sub-partitions ( 22 ) are substantially square and have the same area. The steps also include determining ( 50 ) an actual side latitude dimension ( 26 ) of the sub-partition ( 22 ) and storing the side latitude dimension ( 26 ) in the data structure, and determining ( 52 ) an actual side longitude dimension ( 28 ) of the sub-partition ( 22 ) and storing the side longitude dimension ( 26 ) in the data structure. The satellite communication system ( 60 ) generates a grid from the actual side latitude dimension ( 26 ) and the actual side longitude dimension ( 28 ) and superimposes the grid over the predetermined geographic area ( 12 ).

Geo-electrical structure of the mantle beneath the Indian region derived from the 27-day variation and its harmonics

Abstract: Estimates of the C-response function were determined by Z: H method to obtain conductivity and depth values for a substitute perfect conductor (conductosphere) beneath the Indian region, utilizing geomagnetic variations at periods of 27-day and its harmonics. Two and half years of continuous geomagnetic data were utilized. These data were recorded during 1975–77, at a chain of 13 stations confined to the 150° geomagnetic longitude band, which extended from the dip-equator at the southern tip of India, to the northern parts of Russia. Complex demodulation technique was employed to determine the electromagnetic (EM) responses. Taking advantage of the dense latitudinal distribution of the observatories, the demodulates of all the stations were tested statistically to check the validity of the P 1 0 approximation for the inducing field. Single-station response estimates, for a 27-day period, computed by a robust method have shown that reliable EM responses (consistent with P 1 0 source dependence and with local 1-D Earth structure) could be obtained for only 6 stations, all situated in the mid-latitude region. The depth estimates at all 6 stations are consistent, including Sabhawala (SAB) which is situated close to the Himalayan collision zone. The negligible differences in the depth estimates of these mid-latitude stations do not show any latitudinal dependence, as against such an observation reported for the European and the North American regions. The mean depth of the conductosphere is found to be 1200 (±200) km, with an average conductivity of 0.7 (±0.3) S/m. Comparison of the mean geo-electrical structure with those of other regional models shows that the presence of a mid-mantle conductor at 850 km depth could be considered to be a global phenomenon.

Characteristic analysis of wind field and sea wave field in the western part of the n. pacfic ocean

Abstract: The meteorological data for shipping in the The western part of the N. Pacific Ocean during 1950~1995 analyzed taking 5°×5° latiude and longitude as staistical girds.The characteristics and changing laws of the wind, wave and swell are given. This area is representative's monsoon area. In the period of monsoon, the directions of wind, wind wave and swell are roughly consistent. In a year, the direction of wind wave is almost Northeast in equatorial zone. The monsoon in winter is stronger than that one in summer,corresponding, the average wave high is higher, and the frequencies of rough sea and heavy swell are also stronger.Both of North Indian Ocean and this sea area is monsoon area, but characteristic is opposite. This text provide specification data of wind field and wave field and the changing law for ships sailing、 working、 scientist and military active in The western part of the N. Pacific Ocean.

Solar rotation in the subphotospheric layers

Abstract: The solar rotation rate at latitudes 0°, 15° and 30° has been inferred by averaging the results of 120 regions of 15°×15°, which have been studied over a total area of about 75° in latitude and 360° in longitude. A local helioseismology technique, the ring diagram analysis method, has been used to analyse the horizontal velocity vectors from about 0.95 R⊙ up to the surface. Our results are in very good agreement with those of other authors over most of the depth range. However, near the surface we find sharp local features which are not reported in other studies. The independent measurements of the rotation rate in the north and south hemispheres show asymmetries below 0.975 R⊙. The data used are full-disc dopplergrams taken by Solar Oscillation Investigation/Michelson Doppler Imager (SOI/MDI) on board of the SOlar and Heliospheric Observatory (SOHO) during its first Dynamic Program, between 1996 May and June.

Covariance modelling for merging of multi-sensor ocean surface data

Abstract: The problem of estimating the sea surface height from observations made by remote sensing satellites is discussed. The potential for improving altimetric estimates by merging different types of surface data is explored. The focus in this paper is on the modelling of covariance functions of sea surface height and sea surface temperature and identification of the appropriate spatial and temporal correlation scales. It is shown that on the mesoscale, westward propagating planetary waves can be detected in both fields. The dependence of the phase speed on latitude and depth, as well as the local enhancement of variability near ocean fronts, renders the auto and cross covariance functions to be complicated functions of latitude, longitude and time. It is shown how propagating features can be accounted for in the covariance model for the purpose of optimal merging of sea surface height and temperature data.

Analysis of vegetation green wave change in China using NOAA AVHRR data sets

Abstract: This paper provides a preliminary overview of vegetation cover change analysis using a time series remote sensing data in China. A series of 12 monthly average NDVI data, which is derived from NOAA AVHRR data (January 1990 - December 1990), is used in this study. The research result shows that the vegetation cover change is different along the longitude and latitude during the year. Along the same longitude, vegetation index change is closely corresponded to the seasonal change law. The higher the latitude is, the greater the scope of seasonal change. In summer, there is no clear difference in vegetation index between southern and northern region, but in winter this different is much clear. Along the same latitude the vegetation index change is closely related to precipitation change during the year. The result of greenness classification for each monthly NDVI image also shows that in summer, the high greenness classes occupy most area of China; in opposite, lower greenness classes occupy most of territory of China in winter.

The magnetic activity cycle of II Pegasi: results from twenty-five years of wide-band photometry

Abstract: We present an analysis of a sequence of light curves of the RS CVn-type binary II Pegasi extending from 1974 to 1998. The distribution of the spotted area versus longitude is derived by Maximum Entropy and Tikhonov regularized maps, assuming a constant spot temperature (Lanza et al. 1998a). The spot pattern on the active K2 IV star can be subdivided into a component uniformly distributed in longitude and a second unevenly distributed component, which is responsible for the observed photometric modulation. The uniformly distributed component appears to be possibly modulated with an activity cycle of ∼ 13.5 yr. The unevenly distributed component is mainly concentrated around three major active longitudes. The spot activity appears practically permanent at one longitude, but the spot area changes with a cycle of ∼ 9.5 yr. On the contrary, the spot activity is discontinuous at the other two longitudes, and it switches back and forth between them with a cycle of ∼ 6.8 yr. However, before each switching is completed, a transition phase of ∼ 1.05 yr, during which both longitudes are active, occurs. After this transient phase, spot activity remains localized at one of the two longitudes for ∼ 4.7 yr untill another switching event occurs, which re-establishes spot activity at the other longitude. The longitude separation between the permanent and the switching active longitudes is closest during the switching phases and it varies along the ∼ 6.8 yr cycle. Different time scales characterize the activity at the permanent longitude and at the switching longitudes: a period of ∼ 9.5 yr is related to the activity cycle at the permanent longitude, and a period of ∼ 4.3 yr characterizes the spot life time at the switching longitudes in between switching events. The photometric period of the active star changes from season to season with a relative amplitude of 1.5% and a period of ∼ 4.7 yr. Such a variation of the photometric period may be likely associated with the phase shift of the light curves produced by the switching of spot activity from one active longitude to the other. The permanently active longitude shows a steady migration towards decreasing orbital phases, with an oscillating migration rate along the 9.5 yr cycle period and nearly in phase with the variation of its spotted area. The amplitude of the differential rotation derived from such a behaviour is of the order of ∼ 0.023%, about one order of magnitude smaller than estiSend offprint requests to: S.Messina (sme@sunct.ct.astro.it) mated by Henry et al. (1995). The other two active longitudes migrates also towards decreasing orbital phase, but at a discontinuous rate. There appears to be no correlation between the location of the active longitudes with respect to the line joining the two components of the system and their activity level.

Ip address on internet by latitude and longitude

Abstract: PROBLEM TO BE SOLVED: To allocate IP addresses to host computers on the entire surface of the earth by max digits by combining and using the latitude and longitude of the earth and respective prescribed angles SOLUTION: A method such as 135:56:16:##:35:51:15:## is adopted in the case of a longitude of 135 degrees 56 minutes 16 seconds east and a latitude of 35 degrees 51 minutes 15 seconds north Besides, 135+56/60+16/3600, 35+51/60+15/3600 135927777 of the east longitude and 358541666 of the north latitude or the like can be adopted Moreover, 180 degrees is 648,000 seconds and the 90 degrees is 324,000 seconds 648,000*60=38,880,000=2,514,400h and 324,000*60=19,440,000=128A 180h can be used 135 degrees 56 minutes 16 seconds=489,376seconds*60=1C 00980h and 35 degrees 51 minutes 15 seconds=129,075 seconds*60=762BF 4h A numerical value above the ground is about 25 m/60≈40 cm It is preferable that numerical values are given to the head in order to discriminate the east longitude, west longitude, north latitude and south latitude

Business aiding system and recording medium

Abstract: PROBLEM TO BE SOLVED: To provide a business aiding system capable of providing information for efficiently executing business activity. SOLUTION: The system is provided with an area information storage part 1 previously registering longitude/latitude data in each area specification information. At the time of receiving two area specification information from the external, a longitude/latitude data extraction means 11 extracts longitude/latitude data from the storage part 1 on the basis of the two area specification information. An inter-area distance operation means 12 calculates a distance between two areas from the two longitude/latitude data and multiplies the distance by a time conversion coefficient to find out an access time.

Propagation Characteristics of Low‐Latitude c3 Pulsations in East‐West Direction

Abstract: An east-west chain of three stations was established in north China near geomagnetic latitude 29.6° (L = 1:3) within a geomagnetic longitude span of 40.2°from Oct.10 to Nov.29 in 1996. Propagation and polarization characteristics of low-latitude Pc3 pulsations were studied. It is concluded that the westward propagation of Pc3 pulsations is dominant in the morning and the eastward propagation is dominant in the afternoon. NW-SE of major axis azimuth and right-handed polarization are dominant in the daytime.

Finding space on Earth: The quest for longitude 1500-1800

Abstract: With the increase in exploration, colonization, and trade during the sixteenth and seventeenth centuries that was stimulated by the discoveries of the wealth of the New World, the problems of ocean navigation and in particular finding longitude at sea became of growing concern to the major seafaring nations of Europe. For more than two centuries, many ingenious, but unsuccessful, attempts were made, but not even the most celebrated scientists were able to solve the problem of finding longitude at sea. In the end, the solution came from an unexpected source: a clockmaker. His name was John Harrison. This article describes John Harrison's life and the making of his remarkable timekeepers in the context of the fascinating history of finding longitude at sea.

Oceanic Excitation of Polar Motion During 1992-1994

Abstract: Two global ocean general circulation models have been used to compute the angular momentum of nontidal oceanic current and sea level height variations: (1) the Princeton Modular Ocean Model (MOM) having 22 vertical layers and a rigid lid, and (2) the Miami Isopycnic-Coordinate Ocean Model (MICOM) having 11 vertical layers with a mixed layer and a free surface Both models were run on the same 2 degree longitude by 1 degree latitude grid spanning 80 S to 80 N latitude Following a 10-year spin-up with climatological air-sea fluxes, both models were forced during 1992-1994 with daily wind and heat flux from the NCEP operational analysis and sea surface salinity restoring to Levitus climatology After correcting for the effects of mass non-conservation in these models, they are shown to predict similar effects on polar motion excitation of sea level height variations, but the effect of currents predicted by MOM is much larger than that predicted by MICOM

Longitude and Latitude Structure of the Polar Activity of the Sun in the 21st Cycle

Abstract: A catalog of observations of polar faculae by the Mountain Astronomical Station of the Pulkovo Observatory (Kislovodsk) for the 21st polar-activity cycle of the Sun (1972–1976) has been compiled. The mean annual and semiannual longitude distributions of the facular surface density have been constructed for latitude bands from 35 to 85° with steps of 10° in latitude and 30° in longitude in polar (the “wind roses”) and cylindrical projections, using a Bartels coordinate-grid rotation system. Coherent spatial structures in these distributions, which are characteristically elongated in two mutually perpendicular directions (i.e., they have an “X”-like appearance), can be identified. The high-latitude activity in the northern and southern hemispheres tends to be in spatial antiphase. This behavior corresponds to a four-sector global polar-activity structure. This indicates the presence of a magnetic-field source that is not associated with the differential rotation of the sun and modulates the evolution of local magnetic fields.

UV Irradiance Patterns in Italy

Abstract: Since 1992 the two Italian stations of Rome, urban site (latitude 419° N, longitude 125° E, altitude 60 m), and Ispra, semi-rural site (latitude 458° N, longitude 86° E, altitude 240 m), collect regular continuous measurements of spectral UV (290-325 nm) irradiance by means of Brewer Spectrophotometry The measured data are compared with the output of the STAR model (System for Transfer of Atmospheric Radiation) [1] STAR is a multiple scattering radiative transfer model which considers all atmospheric factors modulating UV radiation at ground (ozone, aerosol, clouds, pollutants, albedo, pressure, temperature, humidity) [2] The model involves combination of a radiative transfer code, an initialisation procedure and an integration scheme

Field Interpretation of Latitude and Longitude in Arkansas: A Portable Coordinate Projection

Abstract: Two-and three-dimensionalcoordinate systems are fundamental to most quantitative mapping applications. The Geodetic, Universal TransverseMercator (UTM),and State Plane systems have traditional roles in various science, surveying, and gov- ernment agency engineering applications. The coordinates of three-dimensionalGeodetic system are latitude, longitude, and height above ellipsoid(HAE).Becauseof its abilityto cope with the intrinsically three dimensionalcharacter of the earth's sur- face, the Geodetic system is capable ofsupporting precise relative positioning and veryhigh accuracy computations of distance between any two positions on or near the earth's surface. The two-dimensionalUTM and State Plane systems are extremely useful for the local horizontal positioning and scaling required for paper maps of county-size land areas. In the two plane systems, horizontal distance computation is a very straightforward application of the distance formula (analyticgeometry) based on the Pythagorean theorem. Although precision line- and geodesic- distance formulasbased on geodetic coordinates are more complex,useful horizontal distance estimates are easily derived from the latitudes and longitudes of two positions. This paper examines this premise for Arkansas. The approach to estimatinghorizontal distancesutilizes an application of the distance formulain conjunction withan assumedconstant distance/unit latitude of 30.8 m (arc sec)" 1.A linear regression equa- tion is used to represent distance/unit longitude as a functionof latitude in Arkansas. The approximation math is extremely simple, and the process as a whole is equivalent to a portable coordinate projection.