Showing papers on "Longitude published in 2017"

Mapping Global Shipping Density from AIS Data

Abstract: Mapping global shipping density, including vessel density and traffic density, is important to reveal the distribution of ships and traffic. The Automatic Identification System (AIS) is an automatic reporting system widely installed on ships initially for collision avoidance by reporting their kinematic and identity information continuously. An algorithm was created to account for errors in the data when ship tracks seem to ‘jump’ large distances, an artefact resulting from the use of duplicate identities. The shipping density maps, including the vessel and traffic density maps, as well as AIS receiving frequency maps, were derived based on around 20 billion distinct records during the period from August 2012 to April 2015. Map outputs were created in three different spatial resolutions: 1° latitude by 1° longitude, 10 minutes latitude by 10 minutes longitude, and 1 minute latitude by 1 minute longitude. The results show that it takes only 56 hours to process these records to derive the density maps, 1·7 hours per month on average, including data retrieval, computation and updating of the database.

Statistical analysis of 26 yr of observations of decametric radio emissions from Jupiter

Abstract: Jupiter is a complex and at the same time very powerful radio source in the decameter wavelength range The emission is anisotropic, intrinsically variable at millisecond to hour timescales, and also modulated by various external processes at much longer periods, ranging from similar to 10 h to months or years (including Jovian day and year, solar activity and solar wind variations, and for ground-based observations, terrestrial day and year) As a consequence, long-term observations and their statistical study have proved to be necessary for disentangling and understanding the observed phenomena We have built a database from the available 26 yr of systematic, daily observations conducted at the Nancay Decameter Array and recorded in digital format This database contains all observed Jovian decametric emissions, classified with respect to the time-frequency morphology, their dominant circular polarization, and maximum frequency We present the results of the first statistical analysis of this database We confirm the earlier classification of Jovian decameter emissions in Io-A, -A', -B, -C, -D and non-Io-A, -B, -C types, but we also introduce new emission types (Io-A '' and Io-B') and precise and characterize the non-Io-D type We determine the contours of all emission types in the CML Phi(Io) plane (Central Meridian Longitude in Jupiter's System III coordinates versus Io Phase), provide representative examples of their typical time-frequency patterns, and the distribution of emission's maximum frequency as a function of Lambda(Io) (Io's Longitude) Finally, we present a statistical analysis of the distributions of the occurrence rate, duration, intensity and polarization for each emission type non-Io-DAM appears to be related to small-scale, possibly bursty auroral structures

Equatorial plasma bubbles: Variations of occurrence and spatial scale in local time, longitude, season, and solar activity

Abstract: We examine the location and structure of equatorial topside depletions referred to here as equatorial plasma bubbles (EPBs) The Coupled Ion Neutral Dynamics Investigation (CINDI) Ion Velocity Meter (IVM) instrument onboard the Communication/Navigation Outage Forecasting System (C/NOFS) is used to measure the ion density from August 2008 to December 2014, a time period in which solar activity transitioned from solar minimum conditions to more moderate solar activity conditions EPB data is divided into four longitude sectors to determine seasonal and solar cycle variability In the early phase of the mission, during solar minimum, EPBs occur late in local time, primarily after midnight in all longitude sectors In the later phase of the mission EPB occurrence after midnight diminishes in all seasons and longitude sectors with the exception of the sector extending from −15∘ to 60∘ An examination of the widths of bubbles indicates that all longitudes show similar distributions between 115 km and 460 km with a prominent peak near 200 km Among these widths is a distinct width that belongs to discrete individual bubbles with no sub-structure We suggest that many bubbles are actually combinations of these individual bubbles, however in the later phase of the mission there is a population of bubbles that do not conform to this description; perhaps due to the influence of large-scale plasma motions affecting the background density in which they are embedded

Longitudinal structures in Mars’ upper atmosphere as observed by MAVEN/NGIMS

Abstract: Here we report the first comprehensive study of longitudinal structures in Mars' neutral upper atmosphere associated with atmospheric tides in composition, density and temperature using the Mars Atmosphere and Volatile Evolution Mission/Neutral Gas Ion Mass Spectrometer observations during 2015. These are in situ measurements of number densities of atmospheric species (including CO2, Ar, N2, and CO) in the altitude range from 120 to 200 km above the areoid (corresponding to a total density range from ~108–1011 cm−3), providing a data set that is larger than all previous measurements of these waves combined. These observations span from ±70° latitude and cover a wide range of local times and solar longitudes (Ls), allowing for the study of longitudinal structures under various conditions. Furthermore, the data in May and November 2015 are at similar latitudes and local times but different Ls (~340° in May, close to northern spring equinox, and 70° in November, close to northern summer solstice and aphelion), ideal for studying the seasonal effects of tides. Our analysis shows that in each month the Ar density varies with longitude having a large wave structure. It is dominated by wave 2 and 3, accounting for 8–16% of the change of the mean density. Comparison shows that the longitudinal structures at a constant CO2 density level have different amplitudes at different seasons, although their patterns are similar. The temperature structure has a phase difference from the density variation, indicating the dissipation of tides in this altitude region. The longitudinal structure is seen in all species, including major and minor species, consistent with the tidal signatures.

Study of the effect of 17-18 March 2015 geomagnetic storm on the Indian longitudes using GPS and C/NOFS

Abstract: The largest geomagnetic storm in solar cycle 24 occurred during March 17-18, 2015 where the main phase of the storm commenced from 07:00 UT of March 17, 2015 and reached the Dst negative minimum at 22:00 UT. The present paper reports observations of TEC, amplitude and phase scintillations from different GPS stations of India during the storm of March 17 and highlights its effects on GPS. It also presents the global ESF occurrence during the storm using total ion density drift measurements from C/NOFS satellite. TEC enhancements were noted from stations along 77oE meridian around 10:00 UT on March 17 compared to March 16 and 18 indicating positive storm effects arising out of equatorward neutral wind in the local morning-noon sector of the main phase. Intense scintillation observations from Calcutta were most extensive during 15:00-16:00 UT, March 17 and the receiver recorded a longitude deviation of 5.2 m during this time. Cycle slips of the order of 8 s could be observed during periods of intense phase scintillations on the same night. Intense scintillation observation from Palampur is an exceptional phenomenon attributed to the dramatic enhancement of the electric field due to PPEF leading to a very high upward ion velocity over the magnetic equator as recorded by C/NOFS. The total ion density measured globally by C/NOFS reveals two distinct longitude regions of ESF occurrence during the storm: i) East Pacific sector and ii) Indian longitude during the storm. The time and longitude of ESF occurrence could be predicted using the time of southward turning of IMF Bz.

Longitudinal Variation of the Lunar Tide in the Equatorial Electrojet

Abstract: The atmospheric lunar tide is one known source of ionospheric variability. The subject received renewed attention as recent studies found a link between stratospheric sudden warmings and amplified lunar tidal perturbations in the equatorial ionosphere. There is increasing evidence from ground observations that the lunar tidal influence on the ionosphere depends on longitude. We use magnetic field measurements from the CHAMP satellite during July 2000–September 2010 and from the two Swarm satellites during November 2013–February 2017 to determine, for the first time, the complete seasonal-longitudinal climatology of the semidiurnal lunar tidal variation in the equatorial electrojet intensity. Significant longitudinal variability is found in the amplitude of the lunar tidal variation, while the longitudinal variability in the phase is small. The amplitude peaks in the Peruvian sector (∼285∘E) during the Northern-Hemisphere winter and equinoxes, and in the Brazilian sector (∼325∘E) during the Northern-Hemisphere summer. There are also local amplitude maxima at ∼55∘E and ∼120∘E. The longitudinal variation is partly due to the modulation of ionospheric conductivities by the inhomogeneous geomagnetic field. Another possible cause of the longitudinal variability is neutral wind forcing by nonmigrating lunar tides. A tidal spectrum analysis of the semidiurnal lunar tidal variation in the equatorial electrojet reveals the dominance of the westward-propagating mode with zonal wavenumber 2 (SW2), with secondary contributions by westward-propagating modes with zonal wavenumber 3 (SW3) and 4 (SW4). Eastward-propagating waves are largely absent from the tidal spectrum. Further study will be required for the relative importance of ionopsheric conductivities and nonmigrating lunar tides.

Investigation of the causes of the longitudinal variation of the electron density in the Weddell Sea Anomaly

Abstract: This paper investigates and quantifies the causes of the Weddell Sea Anomaly (WSA), a region near the tip of South America extending from approximately 30° to 120°W geographic longitude and 50° to 75°S geographic latitude at solar minimum between 2007 and 2010 This region is unusual because the midnight peak electron density exceeds the midday peak electron density in summer This study is far more quantitative than previous studies because, unlike other models, it assimilates selected data parameters to constrain a physical model in order to investigate other aspects of the data It is shown that the commonly accepted explanation that the WSA is related to the magnetic field declination and inclination effects on the neutral wind does not explain the longitudinal variation of the electron density Rather, longitudinal changes in the neutral winds and neutral densities are the most likely explanation for the WSA These longitudinal wind and density changes are attributed to the varying latitudinal distance from the auroral zone energy input No contributions from the plasmasphere or other sources are required Furthermore, it is shown that a widely used empirical thermosphere density model overestimates the longitudinal changes in the WSA region

Asymmetric space weathering on lunar crater walls

Abstract: Using new topography-corrected spectral data from the SELENE spacecraft, here we report a new lunar crater property produced by space weathering. We find the optical properties of north, south, east, and west walls vary systematically across the Moon; pole-facing walls are brighter and less red (i.e., less mature) than their equator-facing counterparts as latitude increases, which we explain by reduced solar wind flux in pole-facing slopes. On the nearside, we find that east-west differences in crater wall brightness and redness vary with longitude, which we explain by solar wind shielding as the Moon passes through the Earth's magnetosphere. Because micrometeoroids are largely unaffected by magnetosphere passage, the longitudinal effect is used to discriminate between micrometeoroid and solar wind effects. Thus, for the first time we quantify how surface optical properties vary with solar wind flux.

Seasonal Variability in Precipitation in Central and Southern Chile: Modulation by the South Pacific High

Abstract: Monthly precipitation in Chile (30°–55°S) was found to vary by intensity, latitude, and longitude of the South Pacific high (SPH). In austral winter, precipitation was higher when the SPH was weaker and when it was centered farther west. In austral spring, precipitation was higher when the SPH was weaker, similar to winter. However, spring precipitation was not found to be related to SPH longitude, and higher precipitation was found when the SPH was centered farther north. In austral summer, no relationship was found between precipitation and either SPH intensity or longitude, but positive correlations were found between precipitation and latitude of the SPH. In austral autumn, correlation patterns between precipitation and all three SPH metrics more closely resembled those seen in winter. The results of a multiple linear regression confirmed the importance of two SPH metrics (intensity and longitude) and the unimportance of a third SPH metric (latitude) in understanding variability in winter, sum...

Simulating CH 4 and CO 2 over South and East Asia using the zoomed chemistry transport model LMDz-INCA

Abstract: . The increasing availability of atmospheric measurements of greenhouse gases (GHGs) from surface stations can improve the retrieval of their fluxes at higher spatial and temporal resolutions by inversions, provided that transport models are able to properly represent the variability of concentrations observed at different stations. South and East Asia (SEA; the study area in this paper including the regions of South Asia and East Asia) is a region with large and very uncertain emissions of carbon dioxide ( CO2 ) and methane ( CH4 ), the most potent anthropogenic GHGs. Monitoring networks have expanded greatly during the past decade in this region, which should contribute to reducing uncertainties in estimates of regional GHG budgets. In this study, we simulate concentrations of CH4 and CO2 using zoomed versions (abbreviated as “ZAs”) of the global chemistry transport model LMDz-INCA, which have fine horizontal resolutions of ∼0.66 ∘ in longitude and ∼0.51 ∘ in latitude over SEA and coarser resolutions elsewhere. The concentrations of CH4 and CO2 simulated from ZAs are compared to those from the same model but with standard model grids of 2.50 ∘ in longitude and 1.27 ∘ in latitude (abbreviated as “STs”), both prescribed with the same natural and anthropogenic fluxes. Model performance is evaluated for each model version at multi-annual, seasonal, synoptic and diurnal scales, against a unique observation dataset including 39 global and regional stations over SEA and around the world. Results show that ZAs improve the overall representation of CH4 annual gradients between stations in SEA, with reduction of RMSE by 16–20 % compared to STs. The model improvement mainly results from reduction in representation error at finer horizontal resolutions and thus better characterization of the CH4 concentration gradients related to scattered distributed emission sources. However, the performance of ZAs at a specific station as compared to STs is more sensitive to errors in meteorological forcings and surface fluxes, especially when short-term variabilities or stations close to source regions are examined. This highlights the importance of accurate a priori CH4 surface fluxes in high-resolution transport modeling and inverse studies, particularly regarding locations and magnitudes of emission hotspots. Model performance for CO2 suggests that the CO2 surface fluxes have not been prescribed with sufficient accuracy and resolution, especially the spatiotemporally varying carbon exchange between land surface and atmosphere. In addition, the representation of the CH4 and CO2 short-term variabilities is also limited by model's ability to simulate boundary layer mixing and mesoscale transport in complex terrains, emphasizing the need to improve sub-grid physical parameterizations in addition to refinement of model resolutions.

Variability of the Pacific North Equatorial Current and its implications on Japanese eel (Anguilla japonica) larval migration

Abstract: The zonal velocity produced by a Regional Ocean Modeling System (ROMS)-based Pacific Ocean circulation model was validated against in situ measurements along the 137 degrees E longitude. The Pacific model successfully reproduced the position and the shape of the North Equatorial Current (NEC) as well as the latitude of maximum surface velocity in the NEC region (8-17 degrees N). The flow field produced by the Pacific model was then used to conduct numerical Lagrangian experiments, in which passive particles were released along a transect (142.5 degrees E, 12.5-17 degrees N) that traverses the known Japanese eel spawning area, and the effects of NEC strength and bifurcation latitude on the particle advection in the northwest Pacific were studied. Our results suggest that, in the 20-yr period (1993-2012), the variability of the currents alone can cause interannual variability of one order of magnitude in the Kuroshio Entrance (KE), the percentage of particles entering the Kuroshio, the range of which varies from 43% in 1997 to 6% in 2012. The yearly-averaged KE is not sensitive to the NEC bifurcation latitude. Instead, it is controlled by the average zonal velocity of a fixed domain (125-143 degrees E, 13.5-17 degrees N) and related to a recently-developed climate index, the Philippines-Taiwan Oscillation (PTO). During the positive phase of the PTO, the zonal velocity in the domain, hence the yearly-averaged KE, increases, and the opposite is true in the negative phase of the PTO. Considering only the trajectories, diel vertical migrations (DVM) in the top 400 m do not significantly affect Japanese eel larval transport, as incorporating DVM schemes does not increase the KE.

Longitude-dependent lunar tidal modulation of the equatorial electrojet during stratospheric sudden warmings

Abstract: Comparison of the diurnal variation of the lunar tidal amplitude in the Peruvian and Indian sectors during December solstice. The peak lunar tidal amplitude over the Peruvian sector is 1.31 times greater than over the Indian sector. Strong lunar tidal modulation of EEJ during SSW is seen in both the sectors after the peak day of polar vortex weakening (PVW). The time shifting semi-diurnal perturbation pattern is clearly observed in both the sectors. Day of peak PVW

Dynamics in the vicinity of (101955) Bennu: solar radiation pressure effects in equatorial orbits

Abstract: Here we study the dynamical effects of the solar radiation pressure (SRP) on a spacecraft that will survey the near-Earth rotating asteroid (101955) Bennu when the projected shadow is accounted for. The spacecraft's motion near (101955) Bennu is modelled in the rotating frame fixed at the centre of the asteroid, neglecting the sun gravity effects. We calculate the solar radiation pressure at the perihelion, semi-major axis and aphelion distances of the asteroid from the Sun. The goals of this work are to analyse the stability for both homogeneous and inhomogeneous mass distribution and study the effects of the solar radiation pressure in equatorial orbits close to the asteroid (101955) Bennu. As results, we find that the mascon model divided into ten equal layers seems to be the most suitable for this problem. We can highlight that the centre point $E$8, which was linearly stable in the case of the homogeneous mass distribution, becomes unstable in this new model changing its topological structure. For a Sun initial longitude $\psi_0 = -180^o$, starting with the spacecraft longitude $\lambda = 0$, the orbits suffer fewer impacts and some (between 0.4 and 0.5 km), remaining unwavering even if the maximum solar radiation is considered. When we change the initial longitude of the Sun to $\psi_0 = -135^o$, the orbits with initial longitude $\lambda = 90^0 $ appear to be more stable. Finally, when the passage of the spacecraft in the shadow is accounted for, the effects of solar radiation pressure are softened, and we find more stable orbits.

A High Resolution Survey of the Galactic Plane at 408 MHz

Abstract: The interstellar medium is a complex 'ecosystem' with gas constituents in the atomic, molecular, and ionized states, dust, magnetic fields, and relativistic particles. The Canadian Galactic Plane Survey has imaged these constituents with angular resolution of the order of arcminutes. This paper presents radio continuum data at 408 MHz over the area 52 degrees < longitude < 193 degrees, -6.5 degrees < latitude < 8.5 degrees, with an extension to latitude = 21 degrees in the range 97 degrees < longitude < 120 degrees, with angular resolution 2.8' x 2.8' cosec(declination). Observations were made with the Synthesis Telescope at the Dominion Radio Astrophysical Observatory as part of the Canadian Galactic Plane Survey. The calibration of the survey using existing radio source catalogs is described. The accuracy of 408-MHz flux densities from the data is 6%. Information on large structures has been incorporated into the data using the single-antenna survey of Haslam (1982). The paper presents the data, describes how it can be accessed electronically, and gives examples of applications of the data to ISM research.

On the variation in the ionospheric response to geomagnetic storms with time of onset

Abstract: Recent observations from Immel and Mannucci (2013) have indicated that geomagnetic storms cause larger enhancements in the ionospheric plasma density and total electron content (TEC) in the American sector than anywhere else on the planet. This suggests that the presence of a UT storm onset effect is important for correctly understanding the impact, longitudinal structure, and timing of geomagnetic storms. Using the Global Ionosphere-Thermosphere Model (GITM), we conduct a modeling experiment of the August 2011 geomagnetic storm by modifying the storm arrival time (UT) in Earth's daily rotation and examining the subsequent system response. We find that the simulations reflect the recent studies indicating that the strongest enhancements of TEC are in the American and Pacific longitude sectors of storms with onsets between 1600 UT and 2400 UT. The underlying mechanisms of the strong TEC increases during storm times in these longitude sectors are also examined. Some of the resulting TEC structures may be explained by changes in the [O]/[N2] ratio (especially in the high latitudes), but it is unable to explain all of the variability in the equatorial regions. Storm time neutral winds and vertical ion motions coupled to Earth's asymmetrical geomagnetic topology appear to be driving the longitude sector variability due to UT storm onset times.

Annual Fluctuations and Displacements of Inter Tropical Convergence Zone (ITCZ) within the Range of Atlantic Ocean-India

Abstract: Inter Tropical Convergence Zone (ITCZ) is one of the major systems in making the general circulation of atmosphere. Many climatologists believe that the starting point of the general circulation of atmosphere is from this system. It seems that the annual displacement of this system is coordinated with the sun. In this study we have tried to investigate the annual and seasonal displacement of this system within the range of Middle East, especially within the range of longitude of Iran in a long period of time (statistical period of 66 years). This is the first study in the field of ITCZ monthly and annual long-term changes in Iran. In this study, not only his exact position on Africa and South West Asia ITCZ is determined, it also shows the change in the period of 66 years. These results can also be used on regional climate changes. For this purpose topographic and surface level pressure maps are 1000 and 850 hpa and they were approximately extracted monthly for 12 months of the year from 1948 to 2013 and also they were extracted from the National Oceanic and Atmospheric Ad-ministration Site in America within the range of 30° west to 110° east, and they were extracted by using the flow map of location (ITCZ). Due to the sudden displacement in the ITCZ bar path in the two seasons of summer and winter, on the Middle East region, the direct impact of this displacement on sudden changes of seasons, the start and end of untimely rains, its impacts on agricultural products and water recourses of the country so all these reasons are essential that this phenomenon should be studied carefully. Studies have shown that ITCZ is not a coordinated solar system and its displacement is not coordinate with the apparent annual displacement of the sun. October is the only month of ITCZ that within the range of 10 northern degrees in all the ranges of longitude 20° west to 110° east has an approximate orbital shape. In 6 months of the year (from November to April) (ITCZ) within the range of 30° east or 110° east, it is entirely located in the Southern Hemisphere and on the contrary in 5 months from May to September (ITCZ) within the range of 30° east to 110° east, it is entirely located in the Northern Hemisphere. And in this period, ITCZ has its highest Northern movement on the Earth. So that at the foot of the Himalayas it moves to 30° north. Within the range of Africa, ITCZ never enters the Southern Hemisphere at any time of the year. And the interesting phenomenon of severe refraction in the way of ITCZ, during the cold period, is within the range of Ethiopia and ITCZ has approximately redirected for Meridian and enters the Southern Hemisphere.

Time and Time Again; Determination of longitude at sea in the 17th Century

Abstract: Determination of one's longitude at sea has perplexed sailors for many centuries. The significant uptake of world trade in the 17th and 18th Centuries rendered the increasingly urgent need to solve the 'longitude problem', an issue of strategic national importance. Historical accounts of these efforts often focus almost exclusively on John Harrison's role in 18th-Century Britain. This book starts instead from Galileo Galilei's late-16th-Century development of an accurate pendulum clock, which was first achieved in practice in the mid-17th-Century by Christiaan Huygens in the Dutch Republic. It is primarily based on collections of letters that have not been combined into a single volume before. Extensive introductory chapters on the history of map making, the establishment of the world's reference meridian at Greenwich Observatory, and the rise of the scientific enterprise provide the appropriate context for non-expert readers to fully engage with the book's main subject matter.

Forecasting scintillation activity and equatorial spread F

Abstract: When transionospheric radio waves propagate through an irregular ionosphere with plasma depletions or “bubbles,” they are subject to sporadic enhancement and fading, which is referred to as scintillation. Communication and navigation systems may be subject to these detrimental effects if the scintillation is strong enough. It is critical to have knowledge of the current ionospheric conditions so that system operators can distinguish between the natural radio environment and system-induced failures. In this paper we briefly describe the Forecasting Ionospheric Real-time Scintillation Tool UHF scintillation forecasting technique, which utilizes the observed characteristic parameter h′F from a ground-based, ionospheric sounder near the magnetic equator. The prereversal enhancement in vertical E × B drift velocity after sunset is the prime driver for creating plasma depletions and bubbles. In addition, there exists a “threshold” in the h′F value at 1930 LT, h′Fthr, such that, on any given evening, if h′F is significantly above h′Fthr, then scintillation activity is likely to occur, and if it is below h′Fthr, scintillation activity is unlikely to occur. We use this technique to explain the lack of scintillation activity prior to the Halloween storm in October 2003 in the Peruvian longitude sector. In addition, we have carried out a study which forecasts the occurrence or nonoccurrence of equatorial spread F (ESF), on a night-to-night basis, in five longitude sectors. The overall forecasting success is greater than 80% for each of the five longitude sectors.

Stability of the interstellar hydrogen inflow longitude from 20 years of SOHO/SWAN observations

Abstract: Aims. A recent debate on the decade-long stability of the interstellar He flow vector, and in particular the flow longitude, has prompted us to check for any variability in the interstellar H flow vector as observed by the SWAN instrument on board SOHO. Methods. We used a simple model-independent method to determine the interstellar H flow longitude, based on the parallax effects induced on the Lyman- α intensity measured by SWAN following the satellite motion around the Sun. Results. Our results show that the interstellar H flow vector longitude does not vary significantly from an average value of 252.9°± 1.4° throughout the 20-year span of the SWAN dataset, further strengthening the arguments for the stability of the interstellar gas flow.

Spatial pattern of lightning strikes in North Asia

Abstract: The averaged data of observations oflightning strikes in North Asia in 2009-2014 are presented. The pattern is retrieved from the data of World Wide Lightning Location Network (WWLLN); one station of this network is located in Yakutsk. The dependence of thunderstorm activity on latitude, longitude, and altitude is demonstrated.

Roadmat weaving machine

Abstract: The present invention provides a road mat weaving machine which comprises: a longitude line input unit; a longitude line crossing unit vertically crossing a transferred longitude line, and composed of a longitude line crossing module; a latitude line input unit inputting a latitude line by enabling a bobbin bracket to cross between a first group and a second group of the longitude line; and a latitude line discharge unit bonding the latitude line inputted from the latitude line input unit and the longitude line to finish a road mat. Moreover, as a bobbin bracket grip module transmits and receives the bobbin bracket to enable the latitude line to be inputted, crossing of the longitude line can be accurately performed, and traversing of a bobbin does not completely interrupt the crossing of the longitude line. Therefore, a weaving process of a road mat can be automated.

Studies of seismo-ionospheric correlations using anomalies in phase of very low frequency signal

Abstract: We present the results of the statistical analysis of very low frequency (VLF) signal transmitted from NWC transmitter (latitude 21.8° S, longitude 114.15° E) at 19.8 kHz received at Ionospheric and Earthquake Research Centre (IERC) (latitude 22.50° N, longitude 87.79° E). We analyse the phase of VLF signal for the whole year 2011 and compute the sunrise and sunset terminator time from it. We observe unusual shift of these sunrise and sunset terminator time during seismic events for which the earthquake epicentres are in India and its subcontinent region. We calculate the total energy accumulation by all those earthquakes for a single day and compute the effective magnitude of all the earthquakes for that day which behaves as a single quake. We compute a cross correlation between fluctuation in terminator time shifts from the normal value with effective magnitude of earthquake. We found that the unusual fluctuations in terminator time are well correlated with earthquake magnitude and the fluctuati...

Climatology of Guinea: Study of Climate Variability in N’zerekore

Abstract: N'zerekore is a geographical region of Guinea, which houses a weather observatory located at longitude 88°, latitude 77° and altitude 475 m This region is of major socioeconomic interest for the country The climatological study of this region shows the variability of each parameter The objective of this study was to analyze meteorological parameters trends and to assess the space-time evolution of some agro-climatic risks related to the main trends observed in the meteorological parameters regime of this region In this study, programming tools were used for processing and analyzing meteorological parameters data, including temperatures, rains, wind, evaporation and storms measured in this observatory from 1931 to 2014 The interannual, annual and daily variations of these parameters were obtained, as well as temperature, precipitation anomalies and agroclimatic indexes trends The analyzing of these variations explained that September is the rainiest months, and the year 1932, 1957 and 1970 are normal, rainy and dry year, respectively The evaporation increased since 1971 from January to March and November to December A positive temperature anomaly was observed since 1973 with the maximum 26-33 °C and the minimum 16-21 °C A dominant westerly wind with a speed of 26 m/s was determined Agro-climatic parameters in N'zerekore have high variability From 1931 to 2014, three major periods can be distinguished: a wet period from 1931 to 1977, a dry period from 1978 to 1994 and rainfall variability from 1995 to 2014 The trend of these parameters explains the impact of climate change in this part of the world This is exacerbated by human activity (deforestation), thus mitigation measures are necessary It would be useful to extend this study throughout the country

Three-dimensional semi-empirical climate model of water vapor distribution and its implementation to the radiation module of the middle and upper atmosphere model

Abstract: To provide the more accurate simulation of stationary planetary waves and atmospheric tides using the middle and upper atmosphere model (MUAM), the three-dimensional (longitude-latitude-height) semi-empirical climate model of water vapor distribution in the troposphere was developed which takes into account seasonal variations. The modules of radiation heating and cooling in the MUAM model were modified taking into account the dependence of water vapor concentration on longitude. The simulations performed using the modified version of MUAM revealed that the consideration of water vapor concentration variability along the circle of latitude leads to the substantial dependence of solar heating on longitude that affects the amplitudes of stationary planetary waves in the stratosphere.