This work presents the theoretical investigation of the superconducting and thermodynamic properties of the two-band model high-temperature iron-based superconductor Ba1-xNaxFe2As2. By developing a model Hamiltonian and by employing the well-knownvdouble-time temperature-dependent Green’s function formalism, we have computed the superconducting orderbparameters for the electron and hole intra- and inter-band transitions, superconducting transition temperature, densitiesbof states, and condensation energies. Furthermore, the electronic specific heat and the entropy for electron and hole intra-band transitions have been determined. By using appropriate experimental data and some credible approximations of the parameters in the computed expressions, we have found the phase diagrams of superconducting order parameters versus the temperature, superconducting critical temperature versus the inter-band interaction potential, temperature dependences of the electronic specific heat and entropy for electron and hole intra-band transitions, and densities of states for the electron and hole intra-band transitions as functions of the excitation energy at different values of the temperature. Finally, the phase diagrams of the condensation energy versus the temperature, inter-band pairing potential at T = 0 K versus the condensation energy, and condensation energy versus the superconducting transition temperature (TC) have been drawn. In some of the phase diagrams, the comparison between theoretical and experimental values has been made. The results are in a good agreement with previous findings.

The current research work deals with the theoretical investigation of the interplay between spin density wave (SDW) and superconductivity in a two‐band model high‐temperature iron‐based superconductor by using the double‐time temperature‐dependent Green's function formalism. The superconductivity transition temperature () versus the spin density wave order parameter () for the electron and hole intrabands as well as the interband for the iron‐based superconductor has been plotted. With an increase in of the material, the superconductivity transition temperature decreases. In both intra‐ and interband pairings, the temperature at which the spin density wave transition () rises with increasing . The interplay between superconductivity and spin density wave of the electron and hole intraband interactions for . Furthermore, the phase diagram of the spin density wave parameter () versus temperature has been plotted, and the spin density wave parameter () is observed to decrease as the temperature rises and vanishes at the spin density wave transition temperature ().

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Precipitation and temperature are the most fundamental meteorological/weather parameters with high spatiotemporal variability over any region of the Globe. Over Ethiopia, Upper Blue Nile basin (UBNB) is the major water resources for irrigation and societal needs not only for Ethiopia but also for downstream countries. However, the exact mechanism to study climate change is not yet satisfactory. Climate variability over UBNB is too high due to its variable topographical features. Gravity wave is one of the most influencing factors to climate change. However, there is no study conducted by considering gravity wave activities on the effect of climate change over UBNB. Therefore, the attempt is made the influence of gravity waves on climate change and variability over UBNB. To this end, we inferred different data sources (reanalysis and ground based). Kinetic energy and momentum equations were used in this study. The results indicate that the reanalysis (ECMWF) precipitation and temperature data were well agreed to the ground based data with correlation coefficient of 0.83 and 0.41 respectively. Strong gravity wave takes tropospheric cloud to stratosphere which causes drought events, while weak gravity wave moves lower tropospheric cloud to tropopause which leads to the occurrence floods. Generally, gravity wave activities affected precipitation and temperature distribution during rainy season. Hence, future study is quite useful to investigate the frequency of high gravity wave occurrence in connection to Ethiopian drought events.

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