North-south Direction Research Articles

Analysis of Peak Ground Acceleration Attenuation Characteristics in the Pazarcik Earthquake, Türkiye

This study collected acceleration records and station reports from 379 strong-motion stations triggered by the Mw7.7 earthquake in Pazarcik, Türkiye, on 6 February 2023. A total of 451 horizontal and 194 vertical strong-motion acceleration records with complete waveforms and reasonable data were selected to establish appropriate equations for predicting seismic parameters. Two iterative algorithms, specifically the optimization algorithm and orthogonal distance regression, were employed to formulate prediction equations for PGA and EPA in the NS (north–south), EW (east–west), and vertical directions. Furthermore, a comparative analysis of the attenuation curves for PGA and EPA was conducted within the vertical and horizontal directions. The results indicated that the observed and predicted values of vertical PGA and EPA at the same fault distance were approximately 0.577–0.673 times those of horizontal PGA and EPA. The ratio range calculated in our study aligns closely with previous research results, slightly more than 2/3 only in the vicinity of fault zones. The analysis demonstrated that the horizontal PGA value of the soil site at the same fault distance was approximately 1.46 times that of the bedrock site, while the vertical PGA value was only 1.12 times. The comparison of attenuation relationships revealed that within the fault distance range of 20 km to 100 km, the horizontal PGA of the Wenchuan earthquake was approximately 1.26–2.16 times that of the Pazarcik earthquake, and the ratio increased with an increasing fault distance.

Periodic oscillations of Doppler frequency excited by the traveling ionospheric disturbances associated with the Tonga eruption in 2022

The explosive eruption of the Hunga Tonga-Hunga Ha’apai volcano on 15 January 2022 generated atmospheric waves traveling around the Earth, which caused ionospheric disturbances on various spatio-temporal scales. A HF Doppler sounding system in Japan detected characteristic ionospheric disturbances showing periodic oscillations in the Doppler frequency with a period of ~ 4 min. In this study, such periodic oscillations were examined by comparing Doppler frequency data with Total Electron Content data obtained by Global Navigation Satellite System. The observed periodic oscillations in the Doppler frequency were characterized by a sawtooth or S-letter shaped variation, implying the passage of the traveling ionospheric disturbances through the reflection points of the HF Doppler sounding system. It was also found that the periodic oscillations occurred prior to the arrival of the tropospheric Lamb wave excited by the Tonga eruption. From the total electron content data, the traveling ionospheric disturbances causing the periodic oscillations were excited by the tropospheric Lamb waves at the conjugate point in the southern hemisphere, namely, the electric field perturbations due to the Lamb waves in the southern hemisphere mapped onto the sensing area of the HF Doppler sounding system in the northern hemisphere along the magnetic field lines. The periodic oscillations were observed only in the path between Chofu transmitter and Sarobetsu receiver, whose the radio propagation path is almost aligned in the north–south direction. This suggests that the traveling ionospheric disturbance has a structure elongating in the meridional direction. The variation in the Doppler frequency was reproduced by using a simple model of the propagation of the traveling ionospheric disturbances and the resultant motion of the reflection point. As a result, the vertical motion of the reflection point associated with the periodic oscillations was estimated to be about 1 km. It is known that 4-min period variations are sometimes observed in association with earthquakes, which is due to resonances of acoustic mode waves propagating between the ground and the lower ionosphere. Therefore, a similar resonance structure in the southern hemisphere is a plausible source of the traveling ionospheric disturbances detected in the northern hemisphere.Graphical

A Parallax Shift Effect Correction Based on Cloud Top Height for FY-4A Lightning Mapping Imager (LMI)

The Lightning Mapping Imager (LMI) onboard the Fengyun-4A (FY-4A) satellite is the first independently developed satellite-borne lightning imager in China. It enables continuous lightning detection in China and surrounding areas, regardless of weather conditions. The FY-4A LMI uses a Charge-Coupled Device (CCD) array for lightning detection, and the accuracy of lightning positioning is influenced by cloud top height (CTH). In this study, we proposed an ellipsoid CTH parallax correction (ECPC) model for lightning positioning applicable to FY-4A LMI. The model utilizes CTH data from the Advanced Geosynchronous Radiation Imager (AGRI) on FY-4A to correct the lightning positioning data. According to the model, when the CTH is 12 km, the maximum deviation in lightning positioning caused by CTH in Beijing is approximately 0.1177° in the east–west direction and 0.0530° in the north–south direction, corresponding to a horizontal deviation of 13.1558 km, which exceeds the size of a single ground detection unit of the geostationary satellite lightning imager. Therefore, it is necessary to be corrected. A comparison with data from the Beijing Broadband Lightning Network (BLNET) and radar data shows that the corrected LMI data exhibit spatial distribution that is closer to the simultaneous BLNET lightning positioning data. The coordinate differences between the two datasets are significantly reduced, indicating higher consistency with radar data. The correction algorithm decreases the LMI lightning location deviation caused by CTH, thereby improving the accuracy and reliability of satellite lightning positioning data. The proposed ECPC model can be used for the real-time correction of lightning data when CTH is obtained at the same time, and it can be also used for the post-correction of space-based lightning detection with other cloud top height data.

Ataköy Gözlem Kuyusunda Saha Tepki Tahminleri

Site response analyses are seen to be the reliable way of reproducing and predicting earthquake input motions. The analyses are generally performed by adopting equivalent linear or nonlinear approaches solving the problem in time or frequency domains. Instrumented geotechnical downhole arrays, in this regard, are very important as to obtaining earthquake data through the soil deposits. This data can eventually be used to verify the approaches developed for site response analyses. In this study, the input motions of the 24.05.2014 (Aegean) earthquake event recorded at relatively recently installed Atakoy geotechnical downhole array are assessed. Moreover, the recorded input motions at the bottom bedrock level of the downhole array are simulated in the East-West and North-South directions. The site response analyses are conducted based on frequency domain equivalent linear approach. The peak ground acceleration and the spectral accelerations of the predicted input motions are compared with the recorded ones at 70 m, 50 m, 25 m and at the ground surface. The results indicate that the spectral acceleration predictions can be simulated well until the depth of 50 m. At 25 m and at ground surface, the predictions are always greater than the recorded one. However, the predictions still exhibits good indication of actual values in the North-South direction. In terms of peak ground acceleration and shear strain profiles, the predictions display the soil layers featured with different soil properties. The equivalent linear approach appears to be suited reasonably well in site response analysis.

Variations and causes of in-situ stress orientations in the Dibei-Tuziluoke Gas Field in the Kuqa Foreland Basin, western China

The Kuqa Foreland Basin, adjacent to the southern Tianshan Mountains, is an important gas-producing basin in northwestern China. The development of the basin is dominated by a regional stress field with orientations of the maximum horizontal stress (SHmax) in the north-south direction, as a result of the collision between the Indian and Eurasian Plates. Previous studies have noted variations in the stress state in the Kuqa Foreland Basin; however, little attention has been paid to understanding the mechanisms causing such variations. In this study, a systematic analysis of in-situ SHmax orientations and fractures has been carried out using image logs from eight wells and XMAC/DSI logs from five wells. These wells are located in an East-West (E-W) trending fold-thrust in the foreland basin. The SHmax orientations (having quality ranked between A and D) obtained from borehole breakouts and drilling-induced fractures are highly variable and occur as two evidently different stress patterns on a scale of less than 10 km. The first stress pattern with SHmax orientations between NNW and NNE (165.08 and 188.59 °N) is broadly comparable to the regional stress field inferred from earthquake focal mechanism solutions in northwestern China from the World Stress Map (WSM). The stress pattern is interpreted to be controlled by plate boundary forces related to the collision between the Indian and Eurasian Plates. The SHmax orientations for the second stress pattern, however, ranging from NNE to ENE (26.65–57.77 °N), are clearly inconsistent with the regional stress filed and have been influenced by local geological factors. Faults and hinge-parallel fractures (trending in an approximately W-E direction) formed during the syn-folding stage probably resulted in heterogeneity of elastic properties and thus deflected SHmax orientations, both laterally and vertically, to generate the second stress pattern. The NE-striking hinge-oblique fractures are interpreted to have formed in response to the stress reorientation. Observations in this study suggest that there may exist a close relationship between fracturing (faulting) and stress variations, and pre-existing faults and fractures can influence subsequent fracturing by regulating local stress fields on a scale of several kilometers. The coupling between fracturing or faulting and stress produced fracture swarms, which can significantly enhance fluid flow and hence petroleum production.

GRAIL gravity gradients evidence for a potential lava tube at Marius Hills on the moon

Lunar lava tubes are underground channels formed by volcanic eruptions and lava flow during the Moon's volcanic period. Intact lunar lava tubes have the potential to serve as secure shelters for humans and facilities, as they provide a safe and pristine environment with a constant temperature. In this study, the lunar gravity field model derived from NASA's GRAIL mission data is analyzed for detecting of an empty lava tube in the Marius Hills region. Compared to the classical Hessian matrix, the gravitational gradient method used in this study is capable of detecting anomaly signals both in the north-south and east-west directions. Using this method, we detect a north-south anomaly signal in the Marius Hills region, located at 57.5°W and 14.3°N, indicating a negative density anomaly near the known lunar sinuous rilles and the Marius Hills Hole skylight. This suggests the presence of a potential lava tube, which is confirmed by the results of the forward method and lunar radar echo data. The extent of the lava tube is estimated with the forward method to be ∼60 km in length, ∼9 km in width, ∼605 m in depth, and ∼55 m in height. Furthermore, the gradient features indicate that the skylight located on the eastern side of the lava tube could serve as an entry to the main part of the lava tube.

Revaluorization of the Geotraffic Position of the Republic of Croatia

The paper re-evaluates the traffic-geographical position of the Republic of Croatia after joining the EU and the Schengen area. Croatian strength is in the fact that it can connect several regions within Europe and that it functions as a link between Western Europe and the Western Balkans and Central Europe and the Mediterranean, however, its political-geographical and transport position can and should be further strengthened, as never before in its difficult and long history. Despite the pressures of malicious neighbors and internal opponents of European values, the Republic of Croatia entered the Schengen Area on January 1, 2023. Before that, it entered the European Union, and Croatian borders became the borders for entering Germany, Italy or France. Croatia's neighbors from the EU can no longer unilaterally block the flow of goods and services in the north-south direction, which is of vital importance for the strategic revaluation of Croatia's geotraffic position. The Adriatic-Ionian transport route is also important for the complete Croatian transport revaluation. The paper also analyzes the historical geopolitical position that influenced the Croatian transport policy.

A Simulation of Calibration and Map-making Errors of the Tianlai Cylinder Pathfinder Array

The Tianlai cylinder array is a pathfinder for developing and testing 21 cm intensity mapping techniques. In this paper, we use numerical simulation to assess how its measurement is affected by thermal noise and the errors in calibration and map-making process, and the error in the sky map reconstructed from a drift scan survey. Here we consider only the single frequency, unpolarized case. The beam is modeled by fitting to the electromagnetic simulation of the antenna, and the variations of the complex gains of the array elements are modeled by Gaussian processes. Mock visibility data are generated and run through our data processing pipeline. We find that the accuracy of the current calibration is limited primarily by the absolute calibration, where the error comes mainly from the approximation of a single dominating point source. We then studied the m-mode map-making with the help of Moore–Penrose inverse. We find that discarding modes with singular values smaller than a threshold could generate visible artifacts in the map. The impacts of the residue variation of the complex gain and thermal noise are also investigated. The thermal noise in the map varies with latitude, being minimum at the latitude passing through the zenith of the telescope. The angular power spectrum of the reconstructed map show that the current Tianlai cylinder pathfinder, which has a shorter maximum baseline length in the North–South direction, can measure modes up to l ≲ 2π b NS/λ ∼ 200 very well, but would lose a significant fraction of higher angular modes when noise is present. These results help us to identify the main limiting factors in our current array configuration and data analysis procedure, and suggest that the performance can be improved by reconfiguration of the array feed positions.

Long monthly European temperature series and the North Atlantic Oscillation

In this paper the relationship between the surface air temperatures in 28 European cities and towns and the North Atlantic Oscillation (NAO) are modelled using the Vector Seasonal Shifting Mean and Covariance Autoregressive model, extended to contain exogenous variables. The model also incorporates season-specific spatial correlations that are functions of latitudinal, longitudinal, and elevation differences of the various locations. The empirical results, based on long monthly time series, agree with previous ones in the literature in that the NAO is found to have its strongest effect on temperatures during winter months. The transition from the winter to the summer is not monotonic, however. The strength of the error correlations of the model between locations is inversely related to the distance between the locations, with a slower decay in the east–west than north–south direction. Altitude differences also matter but only during the winter half of the year.

Eksplorasi Batuan Andesit Berdasarkan Interpretasi Data Resistivitas Di Desa Petangis, Kecamatan Batu Engau, Kabupaten Paser

Exploration activities are very important before mining andesite rocks. This research was conducted in Petangis Village, Batu Engau District, Paser Regency using the Wenner-Schlumberger geoelectric resistivity method with 10 tracks, where 7 tracks have a length of 705 meters in an East-West direction and 3 tracks have a length of 235 meters in a North-South direction. The purpose of this study is to identify the resistivity value of andesite rocks and determine the 2D and 3D distribution of andesite rocks based on the obtained resistivity values. Based on the 2D resistivity section results, it was found that in the study area, andesite rocks have resistivity values ranging from 212-460 Ωm with varying depths of 1-52 meters and the 3D modeling results indicate that andesite rocks are predominantly distributed on the East side with an estimated volume of 1.34588e+007 m3.
 Keywords: Andesite, Exploration, Resistivity, Wenner-Schlumberger.

Seismic Background Noise Analysis from the Seismic Station Located at the University of Abuja, Northcentral Nigeria

Abstract: In October 2018, the Federal Government of Nigeria established several seismic stations in different places in the country. Three of these stations are located in the Abuja region (the Federal Capital Territory, or FCT) and are managed by the Nigerian Geological Survey Agency. Over the past few years, several low to intermediate earthquakes have been recorded within and around the Abuja region. These occurrences have provided valuable opportunities to study seismic earth noise using the dataset collected from the VolksMeter II seismometer installed at the University of Abuja. The data was processed using the Win QUAKE software to analyze the seismic background noise by identifying its sources. This analysis aimed to examine the seasonal and/or daily noise levels and check the seismometer’s stability through spectral display. The physical examination and/or quantitative observation of the spectrum revealed that there was a distinct area with densely high ranges between 0.08 and 10 s, corresponding to a frequency range of 0.1Hz–12.53Hz. This assessment involved a full Fast Fourier Transform (FFT) calculation. The spectral analysis indicated the presence of noise burbles, primarily attributable to instrumental noise. These noise burbles were prominent in the east-west direction during the months of March, April, May, and June 2019, with frequencies of 0.03Hz, 0.04Hz, 0.03Hz, and 0.03Hz, respectively. A similar pattern was observed in the north-south direction, with noise peaks of 0.07Hz in the months of January, April, and July 2019. The findings from this study of seismic noise amplitude demonstrate a clear correlation with the global seismic noise models. The sources contributing to the station’s noise levels encompass factors such as wind, geological influences, instrumental noise, and human activities including machinery and airport operations as well as vehicular traffic. These observations highlight the potential of using background seismic noise to quantify tremors and monitor their spatial variations, a task that remains difficult with traditional approaches. Keywords: VolksMeter II, Seismic station, Background noise, Spectrum, University of Abuja.

Retrieval of Arctic Sea Ice Motion from FY-3D/MWRI Brightness Temperature Data

Sea ice motion (SIM) has significant implications for sea–air interactions, thermohaline circulation, and the development of the Arctic passage. This research proposes an improved SIM retrieval method from Fengyun-3D’s (FY-3D) microwave radiometer imager’s (MWRI) brightness temperature (Tb) data based on the modified classical maximum cross-correlation (MCC) method and the multisource data merging method. This study utilized buoy data to establish the search area range, applied distinct thresholds across various Arctic regions, and merged the buoy data, reanalysis wind data, and SIM retrieved from FY-3D/MWRI Tb data. In 2019, for the final Arctic SIM results retrieved from the MWRI 89 GHz and 36.5 GHz Tb data, the root-mean-square error (RMSE) and the mean average error (MAE) in the east–west direction were 2.07 cm/s and 1.38 cm/s and those in the north–south direction were 1.96 cm/s and 1.15 cm/s, compared to the ice-tethered profiler (ITP) data. Compared with the daily average data of the National Snow and Ice Data Center (NSIDC), the RMSE and MAE of the SIM results obtained in this study were 0.74 cm/s and 0.93 cm/s in the east–west direction, and 0.56 cm/s and 0.72 cm/s in the north–south direction, respectively. The monthly average of the SIM retrieved from the MWRI Tb data in this research also showed a good agreement with the monthly average of the NSIDC SIM product. The comparison showed that the MWRI Tb data could be used to retrieve the Arctic SIM, and the Arctic SIM retrieval method presented in this paper was accurate and general.

A multi-scenario urban resilience simulation study based on the system dynamics model

Scientific quantification of urban resilience can provide a basis for decision-making on the construction of resilient cities to ensure safe and high-quality urban development. This study used text mining and big data statistical analysis to construct an urban resilience evaluation index system from four dimensions: social, economic, infrastructure, and ecological, and constructed an urban resilience evaluation model based on the system dynamics approach to elucidate the interactions among the indicators. Taking 11 cities in the Yangtze River Economic Belt as study cases, four future development scenarios were set under Shared Socio-economic Pathways (SSPs), and the variations in the urban resilience index of each city to 2030 were simulated. The research results show that: (1) The resilience of the 11 cities currently shows an upward trend, but the stratification phenomenon is obvious, and the overall situation is high in the east and low in the west, high in the north and low in the south; (2) The variations of resilience index vary among cities under different scenarios, and in a comprehensive comparison, SSP1 is the optimal development path; (3) The resilience gap among the 11 cities will remain in the future, but the gap in the east-west direction may gradually decrease, while the gap in the north-south direction remains significant.

New Insight on the Active Fault System in the Halmahera Volcanic Arc, Indonesia, Derived from the 2022 Tobelo Earthquakes

Abstract On 9 January 2022, two shallow earthquakes occurred in the east arm of Halmahera, Indonesia, with magnitudes of Mw 5.2 and 5.4 felt at III–V modified Mercalli intensity. The existence of the causative fault for the earthquakes was unknown. One possible explanation is that the earthquakes were caused by the activity of an inactive fault striking in the southeast–northwest direction, and possibly linked to the volcanic activities in Halmahera. Thus, further analysis of their characteristics is crucial to identify the previously an inactive fault. In this study, we relocated the associated earthquake hypocenters using the double-difference method with an updated velocity model, and determined the focal mechanisms by employing full waveform inversion using moment tensor analysis. The focal parameters were used to analyze the static stress changes. The relocated hypocenters show specific hypocenter clusters, aligning in the north–south direction, associated with left-lateral faulting mechanisms. This north–south alignment differs from the northeast–southwest trend of some other active faults in Halmahera. We propose that the newly found Tobelo fault dips at an angle of around 80° to the west. The seismic stress change from the mainshock and the foreshock of the Tobelo earthquakes corresponds with the distribution of the aftershocks. A detailed analysis of unidentified faults in the high seismicity area is essential to comprehend the tectonic study of Halmahera Island and its seismic hazard assessments.

Effects of Organic Fertilizer on Growth and Yield of Common Bean (Phaseolus vulgaris L)

A field experiment was conducted in Zaqom Khail village, Baraki Barak district of Logar province, Afghanistan, during the summer cropping season in 2020 and 2021. The study focused on organic fertilizers at rates of 300 kg/ha, 450 kg/ha, and 600 kg/ha. The NPK (100:100:50) and zero treatment were served as positive and negative controls, respectively. A dosage (100 and 50%) of organic fertilizer was applied during sowing time, at the last harrowing. The experiment followed a randomized completely block design with three replications and five treatments. Each plot had a size of 2m x 1.5m, resulting in an area of 3m², and the gaps between adjacent plots and blocks were maintained at 0.50 meters and 1 meter, respectively. Bean seeds were sown with a spacing of 0.40 m (row-row) x 0.20 m (plant-plant) and at a depth of 6 cm. The plant lines were arranged in a north-south direction, with a population of 60 plants per plot. Each plot consisted of four lines, with 15 plants in each line. The total experimental area was approximately 110 m2. The results showed that the growth parameters (number of plant branches and plant height) and yield attributes (number of plant pods, number of seeds per pod, dry matter weight per plot, and grain yield per hectare) were highest with the application of 600 kg of organic fertilizer per hectare in both 2020 and 2021. This treatment resulted in a maximum plant height of 51.0 and 49.4 cm, a higher number of plant branches (6.0 and 5.93), the maximum number of pods per plant (8.20 and 8.08), a number of seeds per pod (5.60 and 5.53), dry matter weight (30.77 and 29.30 grams), and grain yield per hectare (2.563 and 2.535 metric tons), respectively, compared to the control group. These findings indicate that the optimal dose of organic fertilizers for promoting the growth and improving the yield of common beans in the field may be a rate of 600 kg of organic fertilizer per hectare under the agro-ecological conditions of Logar.

Effects of Quaternary climatic oscillations over the Chacoan fauna: phylogeographic patterns in the southern three-banded armadillo Tolypeutes matacus (Cingulata: Chlamyphoridae)

Abstract The southern three-banded armadillo, Tolypeutes matacus, is one of the most representative species of the South American Chaco region. The susceptibility of this species to climatic changes and its good number of paleontological records has led to the study of their range dynamics for untangling the effects of Quaternary oscillations. These studies yielded contradictory results, suggesting expansion processes under opposite conditions: some during glacial periods and others during interglacial periods. Here, we assess the population structure of T. matacus in Argentina based on mitochondrial genes, and estimate demographic and spatial dynamics that contribute to unveiling the evolutionary process that moulded its biogeography. We found no clear phylogeographical breaks, although there were differences in the composition and frequency of haplotypes between the northern and southern localities studied. Demographic inferences indicate that the species has undergone population and range expansion processes. The higher diversity found in the north and the spatial diffusion analysis allow us to infer a north–south direction of this expansive process. Our results yield essential evidence for disentangling the evolution of this Chacoan species linked with Quaternary climates and provide genetic information about its populations that should be taken into account for the conservation of this threatened mammal.

A Performance Improvement for Indoor Positioning Systems Using Earth's Magnetic Field.

Although most indoor positioning systems use radio waves, such as Wi-Fi, Bluetooth, or RFID, for application in department stores, exhibition halls, stations, and airports, the accuracy of such technology is easily affected by human shadowing and multipath propagation delay. This study combines the earth's magnetic field strength and Wi-Fi signals to obtain the indoor positioning information with high availability. Wi-Fi signals are first used to identify the user's area under several kinds of environment partitioning methods. Then, the signal pattern comparison is used for positioning calculations using the strength change in the earth's magnetic field among the east-west, north-south, and vertical directions at indoor area. Finally, the k-nearest neighbors (KNN) method and fingerprinting algorithm are used to calculate the fine-grained indoor positioning information. The experiment results show that the average positioning error is 0.57 m in 12-area partitioning, which is almost a 90% improvement in relation to that of one area partitioning. This study also considers the positioning error if the device is held at different angles by hand. A rotation matrix is used to convert the magnetic sensor coordinates from a mobile phone related coordinates into the geographic coordinates. The average positioning error is decreased by 68%, compared to the original coordinates in 12-area partitioning with a 30-degree pitch. In the offline procedure, only the northern direction data are used, which is reduced by 75%, to give an average positioning error of 1.38 m. If the number of reference points is collected every 2 m for reducing 50% of the database requirement, the average positioning error is 1.77 m.

Efficiency comparison between tracking and optimally fixed flat solar collectors

We investigate the optimal orientation for a fixed flat plate solar collector using the clear sky model. The ground reflection component of irradiation that hits the collector’s surface is ignored due to its relatively small magnitude when compared to the direct beam and sky diffusive components. Analytical calculations demonstrate that regardless of the collector’s latitude, the most effective azimuthal angle, gamma ^*, is 0, which generally corresponds to a North–South direction. However, the optimal tilt angle, beta ^*, is dependent on both the Day of Year (DoY) and the collector’s local latitude. For latitudes typical of mid-altitude climate zones, we can calculate the optimal tilt angle and the maximum energy that the collector can harvest during each DoY. We compare the maximum daily received energy—which is the sum of the direct beam and sky diffusive energies—associated with this optimal orientation to their corresponding values when the flat plate tracks the Sun. The relative increase in total energy due to Sun tracking depends critically on the DoY, with a minimum value of about 17% in early winter and a maximum value of 40% over a large interval.

Collection, distribution, characterization and utilization of Indigofera oblongifolia Forssk.: an important underutilized multi-use leguminous shrub of Indian hot arid region

AbstractIndigofera oblongifolia Forssk. locally known as ‘Goilia or Jhil’, is an important underutilized leguminous browse shrub for small ruminants in hot arid region of India and traditionally utilized for its medicinal value. Its irregular patchy distribution was observed in depression of rocky areas, bunds of farmer fields and along the depression on the road sides in Jaisalmer and Pali district during collection. Soil samples collected from Pali district have high level of pH and electrical conductivity as compared to Jaisalmer which indicates its suitability to saline areas. It exhibited good plant growth under Jodhpur conditions with respect to plant height (171.5 cm), number of branches (47.9) and canopy diameter (100–210 and 115–180 cm in north-south and east-west direction, respectively) after 12 months of planting in fields under protected condition. Morphological characterization showed the presence of high coefficient of variation (%) in the number of raceme per branch (27.3) followed by raceme length (22.9), pod length (21.0) and least in pod width (8.1). Phytochemical results revealed that leaves of I. oblongifolia contained considerable amounts of total phenols (31.44 mg g−1), flavonoids (29.73 mg g−1) and antioxidant capacity (6.26 FRU g−1) which make its suitability as a browse species to ruminants in rangelands. Along with these finding, its traditional knowledge and utilization are detailed in this paper as to hasten further research on its various aspects for its sustainable utilization in rangelands or in alternate land use systems in the Indian hot arid region.

Rotational radial shear in the low solar photosphere

Context. Radial differential rotation is an important physical ingredient in stellar dynamo theory. In the case of the Sun, heliosismology techniques have revealed the existence of a near-surface shear layer covering 15–20% of the upper convection zone. It was recently shown that the rotation velocity gradient is not uniform in this layer and that it displays a steep increase in a shallow layer near the surface. Aims. We report the detection of a rotation velocity depth-gradient in the low photosphere that is not accessible to heliosismology techniques. Methods. We applied differential interferometric methods to spectroscopic data obtained with the solar telescope THEMIS, which is equipped with an efficient adaptative optics system. The detection was based on the measurement of a systematic east-west shift between images of the solar granulation at different depths in the FeI 630.15 nm at the center of the solar disk. The same technique was applied to obtain the depth-difference between the images from their perspective shift when they are observed away from the disk center. Both THEMIS and HINODE/SOT data were used for the height-difference measurement, giving similar results. Results. At the center of the solar disk, we measured a systematic retrograde shift of the photospheric granular structures on the east-west axis and with no shift in the north-south direction. The retrograde shift increases linearly with height. We interpret these findings as a signature of a steep decrease in the angular velocity in the low photosphere. Conclusions. The rotational radial shear in the low solar photosphere is likely related to the dynamics of the subsurface shear layer. Its measurement yields a valuable constraint on the numerical simulations of the solar upper convection zone.