Global Solar Radiation Annual Profile, Causes and Seasonal Effects, at Ilorin, Nigeria

The data of short-wave global (total) solar radiation of 4 years (1995-1998) at Ilorin (8˚ 34′ N, 4˚ 34′ E), Nigeria was used to study the characteristic behavior of SW- global solar radiation in the tropics. To do this, its weekly average was plotted and analyzed with respect to the atmospheric constituents responsible for the behavior. On the profile obtained, two “Wells” of unequal size and depth were identified; a “hill” and a “plateau” representing the potentials of the radiation were also identified in a 52 - week year. These features were associated with seasons of the year and the radiation potentials obtainable in the region. The size of the Wells indicates the time prevalence of the atmospheric constituents causing the Wells and the length of the respective season, while the depth indicates the amount and severity of the constituents. The “Wells” and the “Plateau” constitute 3 seasons in a 52- week year

Seasonal Variation in Rates of Dust Fall at Motor Parks of University of Ilorin, Ilorin, Nigeria

The enormous vehicular activities on the commercial motor parks of University of Ilorin, Nigeria called for concern as a result of noticeable level of particulate matter in the atmosphere of the area.  This study was carried out to indicate the seasonal variation in the rate of dust fall at three motor parks in the permanent site of the University campus by using the single bucket sampling method. The study was carried out for five months each of wet and dry season periods. The sampling sites were First Motor Park (PK1), New Motor Park (PK2) and Clinic Area (Cl). Gravimetric method was used to quantify the soluble, insoluble, volatile matter and ash content of the dust. Volatile matter and ash were the component of insoluble dust and the highest rate of insoluble dust deposition was observed in January (2043.12 ± 41.4 and 284.1 ± 35.5 mg/m2/day) for PK2 and Cl and in November (1282.7 ± 64.9 mg/m2/day) for PK1 when their respective traffic density (1509.5 ±72.1, 29.8 ± 1.2 and 1000.8 ± 48.3 vehicles per hour) was highest. The highest (32713.0 ± 1290.1 mg/m2/day) and lowest (70.6 ± 6.9 mg/m2/day) rate of soluble dust deposition in the study were observed at PK1 for September and February respectively which was suspected to be due to increase and decrease in the amount of rain fall. The Pearson Correlation showed that increases in traffic density were correlated with increases in the rate of insoluble dust fall at various sites and the relationship was in the stronger order of PK2 > PK1 > Cl. The motor parks ambient air was highly contaminated with soluble dust in the wet season and insoluble dust in the dry season their being values are more than the recommended 133 mg/m2/day

Diurnal and Interannual Variability of Rainfall in Nigeria Climatic Zones as Seen from In-situ and Satellite Measurements

Rainfall has been considered as a key indicator of changes in the climate and important factor of flood. Its measurements are important for climate change assessment on the water cycle and water balance of the world while her intensities monitoring are necessary for flood predictions. This study investigated the variation of Rainfall Intensity and Rainfall depth in Nigeria climatic zones and to predict the reoccurrence of such type of rainfall for planning purposes. The climatic zones of Nigeria were grouped into four; Coastal, Rain forest, Savannah and Sahel. The Rainfall data used in this study were collected in five minutes average for rainfall intensity for years 2007 to 2015 from Centre for Atmospheric Research (CAR-NASRDA) using Automatic Weather Stations and Tropical Rain Measuring Mission (TRMM) of NASA while monthly rainfall depth of 1980 to 2010 from Nigeria Meteorological Agency (NiMet). The Intensity was converted from mm/5mins to mm/h followed by diurnal values over the months and annual rainfall amounts were derived from the monthly rainfall depth for variability and probability analysis. Statistical analyses were performed using SPSS package to further ascertain the deviations from normal rainfall pattern. The Result shows that short and violent rain (> 50mm/h) are more frequent in the Savannah and Sahel zones compared to Rain forest and Coastal zones where prolonged and light rain (< 2.5mm/h) persist. The Coastal zone experience the highest precipitation of 2823.50 mm while the least precipitation of 925.70 mm occurred in the Sahel during the period considered with some fluctuations within the zones. The decadal wetter trend zone is the Sahel with an increment in rainy of more than 200mm and other zones rainfall increase by nothing less than 50mm of rain since 1980s. The occurrence of yearly rainfall like these could be predicted using the probability curve generated from the annual rainfall values. Keywords: rainfall, climatic zones, intensity, depth, probabilit

SPARTAN: a global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications

Ground-based observations have insufficient spatial coverage to assess long-term human exposure to fine particulate matter (PM2.5) at the global scale. Satellite remote sensing offers a promising approach to provide information on both short-and long-term exposure to PM2.5 at local-to-global scales, but there are limitations and outstanding questions about the accuracy and precision with which ground-level aerosol mass concentrations can be inferred from satellite remote sensing alone. A key source of uncertainty is the global distribution of the relationship between annual average PM2.5 and discontinuous satellite observations of columnar aerosol optical depth (AOD). We have initiated a global network of ground-level monitoring stations designed to evaluate and enhance satellite remote sensing estimates for application in health-effects research and risk assessment. This Surface PARTiculate mAtter Network (SPARTAN) includes a global federation of ground-level monitors of hourly PM2.5 situated primarily in highly populated regions and collocated with existing ground-based sun photometers that measure AOD. The instruments, a three-wavelength nephelometer and impaction filter sampler for both PM2.5 and PM10, are highly autonomous. Hourly PM2.5 concentrations are inferred from the combination of weighed filters and nephelometer data. Data from existing networks were used to develop and evaluate network sampling characteristics. SPARTAN filters are analyzed for mass, black carbon, water-soluble ions, and metals. These measurements provide, in a variety of regions around the world, the key data required to evaluate and enhance satellite-based PM2.5 estimates used for assessing the health effects of aerosols. Mean PM2.5 concentrations across sites vary by more than 1 order of magnitude. Our initial measurements indicate that the ratio of AOD to ground-level PM2.5 is driven temporally and spatially by the vertical profile in aerosol scattering. Spatially this ratio is also strongly influenced by the mass scattering efficiency.Fil: Snider, G.. Dalhousie University Halifax; CanadáFil: Weagle, C. L.. Dalhousie University Halifax; CanadáFil: Martin, R. V.. Dalhousie University Halifax; Canadá. University of Cambridge; Reino UnidoFil: van Donkelaar, A.. Dalhousie University Halifax; CanadáFil: Conrad, K.. Dalhousie University Halifax; CanadáFil: Cunningham, D.. Dalhousie University Halifax; CanadáFil: Gordon, C.. Dalhousie University Halifax; CanadáFil: Zwicker, M.. Dalhousie University Halifax; CanadáFil: Akoshile, C.. University of Ilorin; NigeriaFil: Artaxo, P.. Governo Do Estado de Sao Paulo; BrasilFil: Anh, N. X.. Vietnam Academy of Science and Technology. Institute of Geophysics; VietnamFil: Brook, J.. University of Toronto; CanadáFil: Dong, J.. Tsinghua University; ChinaFil: Garland, R. M.. North-West University; SudáfricaFil: Greenwald, R.. Rollins School of Public Health; Estados UnidosFil: Griffith, D.. Council for Scientific and Industrial Research; SudáfricaFil: He, K.. Tsinghua University; ChinaFil: Holben, B. N.. NASA Goddard Space Flight Center; Estados UnidosFil: Kahn, R.. NASA Goddard Space Flight Center; Estados UnidosFil: Koren, I.. Weizmann Institute Of Science Israel; IsraelFil: Lagrosas, N.. Manila Observatory, Ateneo de Manila University campus; FilipinasFil: Lestari, P.. Institut Teknologi Bandung; IndonesiaFil: Ma, Z.. Rollins School of Public Health; Estados UnidosFil: Vanderlei Martins, J.. University of Maryland; Estados UnidosFil: Quel, Eduardo Jaime. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rudich, Y.. Weizmann Institute Of Science Israel; IsraelFil: Salam, A.. University Of Dhaka; BangladeshFil: Tripathi, S. N.. Indian Institute Of Technology, Kanpur; IndiaFil: Yu, C.. Rollins School of Public Health; Estados UnidosFil: Zhang, Q.. Tsinghua University; ChinaFil: Zhang, Y.. Tsinghua University; ChinaFil: Brauer, M.. University of British Columbia; CanadáFil: Cohen, A.. Health Effects Institute; Estados UnidosFil: Gibson, M. D.. Dalhousie University Halifax; CanadáFil: Liu, Y.. Rollins School of Public Health; Estados Unido

Bound state solutions of the Dirac-Rosen-Morse potential with spin and pseudospin symmetry

The energy spectra and the corresponding two- component spinor wavefunctions of the Dirac equation for the Rosen-Morse potential with spin and pseudospin symmetry are obtained. The $s-$wave ($\kappa = 0$ state) solutions for this problem are obtained by using the basic concept of the supersymmetric quantum mechanics approach and function analysis (standard approach) in the calculations. Under the spin symmetry and pseudospin symmetry, the energy equation and the corresponding two-component spinor wavefunctions for this potential and other special types of this potential are obtained. Extension of this result to $\kappa \neq 0$ state is suggested.Comment: 18 page

The WKBJ Wavefunctions in the Classically Forbbiden Region: the Connection Formulae

As well known, the WKBJ approximation method provides an approximate solution to the Schrödinger equation of a quantum mechanical system; but the method fails at the classical turning points (classically forbidden region) of the system’s potential energy function. Solutions about these “inaccessible ” regions are derived by the transformation of Schrödinger equation to either the Airy or modified Airy differential equation. The asymptotic expansion of these solutions are appropriately connected (connection formulae) with the WKBJ solutions to provide full range solutions and these are used to derive the standard energy level formula (Semiclassical quantization rule), which is applied to obtain the modified semiclassical quantization rule

Large global variations in measured airborne metal concentrations driven by anthropogenic sources

10.1038/s41598-020-78789-yScientific Reports1012181

Variation in global chemical composition of PM2.5: emerging results from SPARTAN

10.5194/acp-16-9629-2016Atmospheric Chemistry and Physics16159629-965

Variation in global chemical composition of PM_2.5: emerging results from SPARTAN

The Surface PARTiculate mAtter Network (SPARTAN) is a long-term project that includes characterization of chemical and physical attributes of aerosols from filter samples collected worldwide. This paper discusses the ongoing efforts of SPARTAN to define and quantify major ions and trace metals found in fine particulate matter (PM_2.5). Our methods infer the spatial and temporal variability of PM_2.5 in a cost-effective manner. Gravimetrically weighed filters represent multi-day averages of PM_2.5, with a collocated nephelometer sampling air continuously. SPARTAN instruments are paired with AErosol RObotic NETwork (AERONET) sun photometers to better understand the relationship between ground-level PM_2.5 and columnar aerosol optical depth (AOD).<br><br>We have examined the chemical composition of PM_2.5 at 12 globally dispersed, densely populated urban locations and a site at Mammoth Cave (US) National Park used as a background comparison. So far, each SPARTAN location has been active between the years 2013 and 2016 over periods of 2–26 months, with an average period of 12 months per site. These sites have collectively gathered over 10 years of quality aerosol data. The major PM_2.5 constituents across all sites (relative contribution ± SD) are ammoniated sulfate (20 % ± 11 %), crustal material (13.4 % ± 9.9 %), equivalent black carbon (11.9 % ± 8.4 %), ammonium nitrate (4.7 % ± 3.0 %), sea salt (2.3 % ± 1.6 %), trace element oxides (1.0 % ± 1.1 %), water (7.2 % ± 3.3 %) at 35 % RH, and residual matter (40 % ± 24 %).<br><br>Analysis of filter samples reveals that several PM_2.5 chemical components varied by more than an order of magnitude between sites. Ammoniated sulfate ranges from 1.1 µg m⁻³ (Buenos Aires, Argentina) to 17 µg m⁻³ (Kanpur, India in the dry season). Ammonium nitrate ranged from 0.2 µg m⁻³ (Mammoth Cave, in summer) to 6.8  µg m⁻³ (Kanpur, dry season). Equivalent black carbon ranged from 0.7 µg m⁻³ (Mammoth Cave) to over 8 µg m⁻³ (Dhaka, Bangladesh and Kanpur, India). Comparison of SPARTAN vs. coincident measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network at Mammoth Cave yielded a high degree of consistency for daily PM_2.5 (<i>r</i>² = 0.76, slope  =  1.12), daily sulfate (<i>r</i>² = 0.86, slope  =  1.03), and mean fractions of all major PM_2.5 components (within 6 %). Major ions generally agree well with previous studies at the same urban locations (e.g. sulfate fractions agree within 4 % for 8 out of 11 collocation comparisons). Enhanced anthropogenic dust fractions in large urban areas (e.g. Singapore, Kanpur, Hanoi, and Dhaka) are apparent from high Zn : Al ratios.<br><br>The expected water contribution to aerosols is calculated via the hygroscopicity parameter <i>κ</i>_v for each filter. Mean aggregate values ranged from 0.15 (Ilorin) to 0.28 (Rehovot). The all-site parameter mean is 0.20 ± 0.04. Chemical composition and water retention in each filter measurement allows inference of hourly PM_2.5 at 35 % relative humidity by merging with nephelometer measurements. These hourly PM_2.5 estimates compare favourably with a beta attenuation monitor (MetOne) at the nearby US embassy in Beijing, with a coefficient of variation <i>r</i>² =  0.67 (<i>n</i> =  3167), compared to <i>r</i>² = 0.62 when <i>κ</i>_v was not considered. SPARTAN continues to provide an open-access database of PM_2.5 compositional filter information and hourly mass collected from a global federation of instruments