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Due to the shortage in electricity supply in Nigeria, there is a need to improve the alternative power generation from wind energy by analysing the wind speed data available in some parts of the country, for a better understanding of its underlying dynamics for the purpose of good prediction and modelling. The wind speed data used in this study were collected over a period of two years by National Space Research and Development Agency (NASRDA) from five different stations in the tropics namely; Abuja (7050'02.09"N and 6004'29.97"E), Akungba (6059'05.40"N and 5035'52.23"E), Nsukka (6051'28.14"N and 7024'28.15"E), Port Harcourt (4047'05.41"N and 6059'30.62"E), and Yola (9017'33.58"N and 12023'26.69"E). In this paper, recurrence plot (RP) and recurrence quantification analysis (RQA) are applied to investigate a non-linear deterministic dynamical process and non-stationarity in hourly wind speed data from the study areas. Using RQA for each month of the two years, it is observed that wind speed data for the wet months exhibit higher chaoticity than that of the dry months for all the stations, due to strong and weak monsoonal effect during the wet and dry seasons respectively. The results show that recurrence techniques are able to identify areas and periods for which the harvest of wind energy for power generation is good (high predictability) and poor (low predictability) in the study areas. This work also validates the RQA measures (Lmax, DET and ENT) used and establishes that they are similar/related as they give similar results for the dynamical characterization of the wind speed data. [ABSTRACT FROM AUTHOR]

Supply of potable water in Oghara communities in particular and parts of Ethiope West Local Government Area of Delta State in general is inadequate as a result of increasing population and development activities in the area. This can be resolved and sustained if groundwater resources are effectively managed. This study was carried out to determine the aquifer vulnerability and groundwater quality using geophysical and physiochemical methods in parts of Ethiope West Local Government Area, Delta State. Thirty vertical electrical soundings and four dipole–dipole profiling were administered using Abem Terrameter SAS 1000 AB. The field data were curve matched and iterated using WinResist and Dipro software. The aquiferous zone was found in the fourth layer with resistivity ranging from 159 Ωm to 100234 Ωm, thickness ranging from 12 m to 156 m, and depth ranging from 32 m to 162 m except VES 25, whose aquifer is in the third layer. The dipole–dipole resistivity structure shows low resistivity values along areas where waste dump was sited with resistivity ranging from 300 Ωm to 630 Ωm. This finding suggests that the leachate from the dumpsite is affecting the characteristics possessed by the subsurface close to it. The first order geoelectric and Dar-Zarrouk parameter study of aquifer protective capacity revealed a protection capacity value less than 0.1 for VESs 1–18 and 20–30, while VES 19 revealed a value of 0.24. Thus, Oghara communities are extremely unprotected, and the aquifer is prone to contamination. The physiochemical analysis carried out indicates that groundwater is slightly acidic with a pH value ranging from 5.40 to 6.40 when compared with the WHO permissible limit. The groundwater flow direction is depicted from the east to the west; this will assist policy planners to decide where dumpsites and companies generating waste could be sited to preserve groundwater potential. [ABSTRACT FROM AUTHOR]