Assessment of Seasonal Variation of Rainfall Over Tropical Monsoon Zone of Nigeria

Abstract

This study was aimed at investigating the seasonal variation of rainfall in Port-Harcourt (tropical monsoon climate). Specifically, it also aims at investigating the rainfall pattern in Port-Harcourt Nigeria, August break trend in the study area, the season's dominant in the area, and to estimate the rainfall rates. This investigation was carried out using atmospheric data of rainfall and temperature from Nigerian Meteorological agency (NIMET), for a period of 10 years (2009-2018). Results from the analysis shows that there is seasonal variation of rainfall in the study area, and August break was experienced in all the years except in 2009, 2014 and 2016. Rainfall was observed to be maximum in June for four years (from 2013-2015 and in 2018 respectively. In 2009 and 2017, the maximum rainfall were observed in July with average amount of (439mm and 521.1mm) respectively. In 2010 and 2012, the maximum rainfall were observed in September with average value of (454.1mm and 409.4mm); however it was observed in 2011 and 2016 that maximum rainfall occurred in May with average rainfall of 322.8mm and in August with average rainfall amount of 428mm, respectively. Also for the dry season, minimum temperature was observed mostly in December with 0mm rainfall. Thus raining season begins in March till November in the study area, while dry season is observed in December, January and February. The season dominant in the study area is the rainy season; from calculation rain rate is maximum in 2018 with 158.2mm/hr, and minimum in 2011 with 107.6mm/hr.