Impact of atmospheric tides on climate model

Gachari F., Mulati D. M. and Mutuku J. N

We present a predictive rainfall model based on fitting a Generalized Linear Model on monthly rainfall amounts with factors and covariates that determine the occurrence and persistence of the gravitational atmospheric tide state. The model demonstrates high skill while estimating monthly amounts by achieving a correlation coefficient above 0.7 between the estimates and the measurements. Model estimates of annual total for the period 1901 to 2020 indicate that the model may not only be used to estimate historical values of rainfall but also predict monthly rainfall amounts. The advantage of atmospheric tidal factors and their derivatives is that their future values are obtained accurately in advance.

Application of non parametric test for trend detection of rainfall in the largest island of Bangladesh

Md. Arafat Rahman and Monira Begum

This study aims to determine trends of rainfall of largest island Bhola in Bangladesh. This is an effort to analyze one of the most important climatic variable i.e., precipitation, for analyzing the rainfall trend in the area. Rainfall data from 1966 to 2011 has been processed in the study to find out the monthly variability of rainfall for which Mann-Kendall test and Sen’s Slope Estimator for the determination of trend and slope magnitude. Monthly precipitation trend has been identified here to achieve the objective which has been shown with 46 years of data. The application of a trend detection framework resulted in the identification of insignificant trends from January to December. There are rising rates of precipitation in some months and decreasing trend in some other months obtained by these statistical tests suggesting overall insignificant changes in the area.

Impact assessment of solid waste on groundwater: a case study of aarada refuse dumpsite, Nigeria

E. Rotimi Olafisoye, L. Ayobami Sunmonu, T. Aanuoluwa Adagunodo and O. Peter Oladejo

A research on the impact of waste disposal site on groundwater resources was conducted around Aarada refuse dumpsite, Ogbomosho, Oyo State, Nigeria using electrical resistivity (vertical electrical sounding) and hydro-physicochemical methods. A total of seven VES were carried out with length ranging between 80 to 130m. The hydro-physicochemical analysis was conducted at the peak of the dry season on nine water samples taken from nine different hand-dug wells in the research area. The result obtained from the interpreted VES data revealed leachate plumes at the subsurface in the study area. The outcome of the hydro-physicochemical method revealed hazardously high values of Fe²⁺, Pb²⁺, Zn²⁺, Cu²⁺ and NO₃^-.

This study evaluates quality of 26 water and 2 soil samples around Abule Egba and Olushoshun landfill sites in Lagos, Nigeria. This was enhanced through the determination of the major ions and their origin, suitability of well and borehole water for drinking purpose and analysis of geotechnical properties of the underlying soil. Piper’s was used to interpret water suitability for drinking. Results showed that Abule Egba is dominated by Ca-MgCl and CaHCO₃ while Oloshoshun dumpsite is generally dominated by (Na+K)-HCO₃ with few samples as CaSO₄ suggesting incursion of saline water into the fresh aquifer. The mean concentration of Fe²⁺ at Oloshoshun measures above the permissible limits of WHO standard for drinking water. Grain size analysis revealed that the soils are sandyclay with average hydraulic conductivity of 10^-5cm which makes them potential barrier material in modern landfills. Though quality of groundwater shows little anthropogenic influence, pre-treatment due to dominance of Cl^- and SO^-2_4.  is recommended.

Study of mineralogy and swelling of different clay materials

Lamia Bouchhima, Faiçal Turki and Taher Mhiri

The present work focuses on the mineralogical and swelling analysis of clay material samples collected from Tunisia, Egypt and Italy. The samples were selected with the objective of analyzing their characteristics regarding chemical composition, loss on ignition, X-ray diffraction, infra red spectral (IR) analysis and sweling analysis. The sedimentary red clays have low amount of SiO2, high amount of Al2O3, and high loss on ignition. In addition, it was found that the character of the clays is typically kaolinitic. The results obtained show that the clay samples have a variable mineralogical composition. Kaolinite alone constitutes between 15 to 36%, illites varies from 20 to 53%, smectite ranged from 2 to 85% and halloysite ranged from 0 to 100%. Isothermal dehydration established for these six clay samples show that the largest loss of water is at the beginning of the dehydration to p / po between 1 and 0.95. The clay of Egypt (E2) is the most hydrated sample throughout the RH domain, and its isotherm is located above the other five. The clay sample Kasserine is the least hydrated its isotherm is located below the other five.

Bangladesh, a densely populated country in South Asia, is located in the northeastern part of the Indian sub-continent at the head of the Bay of Bengal. Geographical location of Bangladesh makes it ideally suited to earthquake. Bangladesh is surrounded by the regions of high seismicity which include the Himalayan Arc and shillong plateau in the north, the Burmese Arc, Arakan Yoma anticlinorium in the east and complex Naga-Disang-Jaflong thrust zones in the northeast. It is also the site of the Dauki Fault system along with numerous subsurface active faults and a flexure zone called Hinge Zone. These weak regions are believed to provide the necessary zones for movements within the basin area. The historical seismicity data of Bangladesh and adjoining areas indicate that Bangladesh is vulnerable to earthquake hazards. As Bangladesh is the world’s most densely populated area, any future earthquake shall affect more people per unit area than any other seismically active regions of the world. So that proper hazard mitigation measures may be undertaken before it is too late.