Mean Annual Weather Cycles of some Weather Variables over Warri, Delta State, Nigeria during 2009 to 2018

Abstract

The importance of analysing the weather cycles of any region cannot be over emphasized considering the dynamic nature of weather and its undesirable impacts on the environment. This study examines the mean annual cyclic behaviour of some weather variables over Warri, Delta State, Nigeria using recent weather data from NiMet for a period of ten years (2009 to 2018). It was observed from the cyclic behaviours from the various weather variables for the ten years period under consideration, that the annual maximum and minimum temperature, vapour pressure and cloud amount cycles follow similar trends, likewise the undulation of the annual soil heat flux cycles. The annual rainfall, wind speed, maximum and minimum relative humidity cycles were found to fluctuate in different patterns. In periods of limited rainfall, relative humidity is at the threshold of ~ 50.0%. A roughly curvilinear fit was noticed between the annual rainfall and relative humidity. While, rainfall appears insensitive to relative humidity changes during the months with lower relative humidity, which tends to be linear during the months with higher relative humidity. Hence, as the rainfall amount increases, there is an increasing tendency towards a curvilinear relationship. The occurrence of the maximum in temperature preceding that of wind speed indicates that the prevalent winds over Warri could be thermally 23

The Refractive Effect of k-Factor on Radio Propagation over Lokoja, Nigeria

“…In this study h 1 and h 2 are at the surface (12 m) and 100 m Above Ground Level (AGL) respectively. The k-factor can be expressed as indicated in Equations ( 3)-(4) [4,5] .…”

“…Results revealed average values 1.476, 1.940, 1.860 and 1.287 respectively in Akure, Minna, Jos and Sokoto respectively. Ukhurebor and Odesanya [5] investigated k-factor over Auchi area of Edo State, South-South, Nigeria. The work determined k-factor mean value of 1.470 over Auchi which is slightly greater than ITU-R standard.…”

“…If the troposphere is homogenous and turbulent free, any wave propagated into the troposphere parallel to the earth's surface will follow the earth's curvature [4] and be maximally received. However, due to the inhomogeneity of the troposphere, radio wave propagated undergoes bending depending on the tropospheric condition which also depends on the interaction of the radio climatic factors in the environment [5] .…”