The micrometeorological investigation of heat flux and moisture content of the soil as measured at a tropical station in Ibadan, Nigeria

Abstract

The diurnal and seasonal variations of heat flux and the moisture content in the soil at a site for the Nigeria Mesoscale Experiment (NIMEX) in the University of Ibadan, Nigeria (7.38⁰ N and 3.93⁰ E), had been investigated. The study also investigated effects of the atmospheric phenomena on magnitudes of the surface layer parameters. The month of May to August (wet months) had the least soil moisture of about 19% which was beyond the maximum obtained in the dry months. The frequency of this was above 10, and there was a record of soil moisture content above 22% in the month of June when the mean rainfall amount approached 22 mm. The frequency of soil moisture, which was less than 17%, was as high as 16, particularly in the month of November (the peak of the dry month). The month of October was peculiar with the frequency as high as 14 and soil moisture content well above 20%. This was because of the unusual heavy rainfall in the month of October, 2006. The substantial difference recorded for time lag in the same soil layer was attributable to increased wetness. Both soil heat flux and soil moisture content exhibited a similar variation, attained maximum at noon and gradually decreased as it approached the night time. Thus there was a positive association between the soil moisture and soil heat flux. Equally, the disturbed weather phenomena that prevailed clearly established the reason for the large difference in the fluxes.

Keywords: Heat Flux, Micrometeorology, Moisture Content, Soil Disturbance