The Influence of Gravity Waves on the Climate Change Over Upper Blue Nile Basin in Ethiopia

Abstract

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.