Confirmation of Climate Change in Southwestern Nigeria through Analysis of Rainfall and Temperature Variations over the Region

Understanding the variability of precipitation and temperature of a region over a long period gives one an idea about the climate and climate change of such region. The study investigated rainfall and temperature variability in four meteorological stations, namely, Abeokuta (lat.7.01o N, long.3.2o  E, alt. 67m) , Ibadan (lat.7.43o N, long.3.9o E, alt. 227m), Ikeja (lat.6.58o N, long.3.33o E, alt. 39m )  and Ondo (lat.7.1o N, long.4.83o E , alt. 287m) in the south-western region of Nigeria.Monthly rainfall, minimum temperature and maximum temperature data were obtained from Nigeria Meteorological Agency (NIMET) for the period of thirty one years (1980 to 2010) for the study.Descriptive Statistics were deployed to determine the mean, confidence levels, coefficient of kurtosis, skewness and coefficient of variations. A fairly “M-shaped” pattern was observed in the monthly mean rainfall distribution with bi-modal peaks in June and September, with slight dryness experienced in August, referred to as “August break”. Analyses of annual trends over a long period revealed a sequence of alternately decreasing and increasing trends in mean annual rainfall and air temperature in region. Generally however, gradients of the trend lines are positive. There is a negative relationship between annual total rainfall and annual average temperature

Storm-time variation of the horizontal and vertical components of the geomagnetic fields and rate of induction at different latitudes

The paper presents the hourly mean variation of horizontal (H) and vertical (Z) components of the geomagnetic field and the rate of induction DH/DZ at different latitudes during magnetic storm of 20 March 2001 and 1 October 2001. The results of the analysis revealed that at high latitude stations greater than 60�, the reduction in DH component was noticed after the noon time while other stations less than 60� experienced reduction of H in the morning time during the geomagnetic storm. Large amplitude of DH and DZ were exhibited during the daytime over the equatorial zone, the amplitude decreases from mid latitudes to the dip equator during the nighttime. The daytime enhancement of DH at AAE, BAN and MBO suggest the presence of a strong eastward directed current which comes under the influence of electrojet. There were strong positive and negative correlations between ring current (DR) and horizontal component of the magnetic field DH. The effect of rate of induction is more significant at high latitudes than lower latitudes, during the geomagnetic storm. More enhancement in rate of induction occurred at nighttime than daytime. This result may be from other sources other than the ionosphere that is magnetospheric process significantly contributes toward the variation of induction

Natural Radioactivity and Hazards in Soil Samples in Alade Community, Southwestern Nigeria

The concentrations of natural radionuclides in Alade community, Ado-Odo/Ota Local Government Area were determined using gamma ray spectrometer comprising a 7.6 cm x 7.6 cm Nal(TI) detector coupled to a multichannel analyser for spectral analysis. A total of 20 soil samples were collected from different locations in Alade community, Ado-Odo/Ota Local Government, Ogun state, Nigeria. Data were analysed using descriptive statistics. The activity concentration obtained were in ranges of 45.62 ± 2.53 Bq/kg to 665.25 ± 35.11 Bq/kg with mean value of 352.34 ± 18.67 Bq/kg for 40K, 2.32 ± 0.47 to 54.56 ± 6.20 Bq/kg with mean value of 19.86 ± 2.56 Bq/kg for 238U and 4.34 ± 0.28 Bq/kg to 23.10 ± 1.40 Bq/kg with mean value of 14.22 ± 0.87 Bq/kg for 232Th. The study evaluated radiation hazard indices, the mean values obtained were, 64.55 ± 5.05 Bq/kg for Radium equivalent activity (Raeq), 32.86 ± 2.53 nGyh-1 for Absorbed Dose Rate (D), 40.30 ± 3.10 µSvy-1 for Annual Effective Dose Equivalent (AEDE), 0.18 ± 0.01 for External Hazard Index (Hex) and 0.22 ± 0.02 for Internal Hazard Index (Hin). These calculated hazard indices were well below their permissible limit. The results obtained for the mean activity concentrations values from 20 soil samples from Alade community, revealed that 40K, 238U and 232Th values were below the United Nations Scientific Committee on the Effects of Atomic Radiation recommended international limits of 370Bq/kg and within the tolerance level indicating minimal radiological health burden on the Alade community and its environment

Impact of meteorological parameters over Covenant University, Ota, Nigeria

This study utilized monthly daily values of solar radiation, humidity, ultraviolet dose, temperature, pressure and wind speed obtained at Department of Physics, Covenant University, Ota, Nigeria, for 2013. It was observed that correlation coefficients vary from 0.134 - 0.955 across the months. This was further demonstrated with values of coefficient of determination R2 which vary from 0.018-0.911 for Ota stations. Based on the RMSE, MPE, MBE and p values, we obtained an Equation that produces the best correlation. Our result reveals the models that produce the smallest p values which are considered as the best model for estimating the solar radiation at Ota site with an acceptable error. Also, Wavelet spectrum based approach was employed to analyse the meteorological monthly series in a sequence of monthly scales of January to December 2013

Proximate Composition and Metabolizable Energy of Some Commercial Poultry Feeds Available in Abuja, Nigeria

Poultry feeds are prepared to contain all the nutrients in their right proportions necessary for good health, proper growth and egg production of the chicken. This study was undertaken to determine the proximate composition and variations of nutrient in some commercial poultry feeds sold in Abuja, Nigeria. Seven poultry feed brands in their various ratios were subjected to proximate analysis using standard methods. The results of the analysis revealed that the poultry feeds had proximate composition ranging from 6.58 ± 0.02 - 10.88 ± 0.19 % moisture content, 6.03 ± 0.16 - 14.78 ± 0.73 % ash content, 9.98 ± 0.81 - 20.05 ± 0.08 % crude lipid, 3.57 ± 0.11 - 14.77 ± 0.14 % crude fiber, 16.55 ± 0.07 % - 34.01 ± 0.09 % crude protein, 26.28 ± 1.80 % - 48.21 ± 2.07 % carbohydrate and 2971.48 ± 65.44 - 3686.18 ± 29.08 Kcal/kg metabolizable energy. Generally, there were differences in the proximate composition of the poultry feed brands analyzed, however, the poultry feeds have optimum nutrients in their feeds which meet most of the requirements recommended by SON and NRC. The moisture contents in all the feeds were within the recommended value of not more than 12 % while the mean values obtained in crude lipid were all higher than the maximum recommended requirements in poultry feeds

Observation of the Total Electron Content for 14- GPS stations in Malaysia during the Annular Eclipse of 15th of January 2010

The paper examines the Ionospheric response to the annular eclipse of the sun on January 15, 2010 over eastern and western Malaysia using GPS data measurement from 14- ground station in Malaysia. The GPS sensing technique employs two different approaches to verify the TEC depletion occurrence at the 14-stations. The first approach measures the TEC depletion parameters at the 14 GPS stations during the solar event. The second approach compares the TEC value with the quiet day TEC variation at one of the station 3-days before and 3-days after the solar eclipse event. The GPS observation indicates occurrence of TEC depression at 6 stations where the behaviour varying from one station to another. On the basis of the first and second measurement techniques, the range of TEC depletions at the six stations were 9 to 20 %, while for the other 8-stations 0.4 to 12% respectively. The measurement shows that TEC depression at most GPS stations began on the neck of the first contact of the solar eclipse followed by deeper depressions. This effect was as a result of the hiding of the optical rays during the solar eclipse which causes direct reduction in photo ionization; destroy the previous photo-chemical equilibrium and result in the depletion in electron density

Estimating geomagnetically induced currents at sub-auroral and low latitudes to assess their effects on power systems

During large magnetic storm the geomagnetically induced current has a negative impact on ground conducting technology systems. The time derivative of the horizontal component of the geomagnetic field (dH/dt) is greater than 30nT/min for induced currents causing undesirable consequence in power grids. Multiple regression analyses were developed to predict the level of geomagnetic disturbance using time derivatives of the horizontal geomagnetic field, east and north components of the geoelectric field, auroral electrojet and disturbance storm times from 1994-2007 at low and subauroral latitudes. The statistical test RMSE (Root Mean Square Error) and MBE (Mean Bias Error) were employed to evaluate the accuracy of the geomagnetic disturbance. Different variables have been used to develop different types of models. Values of the correlation coefficient and the coefficient of determination were high, which indicates that the results are good. The equations produced the best correlations at subauroral and low latitudes, and the best correlation was obtained with low values of RMSE and MBE

Variations of time derivatives of the horizontal geomagnetic field and horizontal geomagnetic field along 96-degree magnetic meridian

The  Energetic  particles  are  released  from  the  Sun  by  solar  flares  or  eruptive ejections  interaction  with  geomagnetic  field  producing  geomagnetic  storms  and  more ionization  in  the  ionosphere.  The  geomagnetic  substorms  are  classified  as  one  of  major factor  that  influence  geomagnetically  induced  currents  (GIC)  that  affect  the  operation  of technological system through the geomagnetic field variations. The direct representation of GIC is the time derivative of the horizontal geomagnetic field. 138 substorms onset events were  obtained  from  IMAGE  magnetometer  data  from  Northern  Europe,  using  Dst (Disturbance  storm  time)  to  determine  the  substorm  events  of  varying  strengths,  for  five stations (Addis Ababa, Abisko, Bangui Hermanus and Nurmijarvi). The data used in this study covers the periods from 1999 to 2001. Positive high correlation exhibited between the maximum  value  of  time  derivatives  of  the  horizontal  geomagnetic  field  (dH/dtmax)  and maximum value of horizontal geomagnetic field (max H). Also, Monthly variations of the maximum  value  of  time  derivatives  of  the  horizontal  geomagnetic  field  (dH/dtmax)  and maximum value of the horizontal geomagnetic field (max H) were also investigated

Asymmetry in Seasonal Variation of Geomagnetic Activity

Seasonal variations in geomagnetic activities were studied for the period of 1990-2007 using Dst and AE indices. Over 150 events characterised by increase in geomagnetic activity of varying strength (from -90 up to -1800nT) were statistically analysed. Although Russell- McPherron effect plays a major role in the equinoctial asymmetry of the geomagnetic activity, others may also take place. During this study we found a statistically significant October-November peak in geomagnetic activity for Northern Hemisphere, which is sufficiently larger than March-April peak. Several hypotheses for the cause of such effect are discussed