To address key research problems posed for the land-surface atmosphere energy exchange process (and its balance) for the tropical Nigeria, a micrometeorological field study was organized between 15th February and 10th March, 2004, by the Atmospheric Research Group (ARG). The location chosen for the project was an agricultural farmland at the Teaching and Research farm of the Faculty of Agriculture. The field project which is termed NIMEX-1, an acronym for the Nigerian Micrometeorological Experiment (Phase I). The project is managed by a collective of scientists from the following universities: Obafemi Awolowo University (OAU), University of Ibadan (UI), Federal University of Technology Akure (FUTA) and the University of Bayreuth, Germany (UBT). The field experiment is sponsored by the following institutions: International Programmes in the Physical Sciences of Uppsala University, Sweden (IPPS), African Regional Centre for Space Science Education (ARCSSTE), Alexander von Humboldt foundation (AvH), and the University of Bayreuth, Germany (UBT).

Going by climatology of the south-western Nigeria, it has been anticipated that the period of observation for the NIMEX-1 field study will fall somewhat within a transition between the dry and wet seasons in Ile-Ife (7.55oN, 4.56oE). Thus enabling the investigation to compare and contrast the surface mass, momentum, and energy exchanges of the two contrasting weather phenomena that is typical of the tropical area. At the commencement of the NIMEX-1 field measurements on the 16th of February, 2004, three measurement positions had been established within the study domain. Two of those, that is, M1 and M2, comprise of slow response sensors (making up mast measurements of the near surface wind, temperature, humidity, pressure, global and net radiation, etc.). A third system, that is M3, was established for use with the fast response sensors, representing the eddy covariance determination of the turbulence fluxes. These well established measurement positions (together with their lat./long. coordinates and elevation) are shown in the Figure 1. The slow systems were sampled every 1sec. and stored subsequently as 1 min. averages for all the measured parameters. The fast response system was made up of an ultrasonic anemometer (USA-1 manufactured by METEK, Germany) and a krypton hygrometer (KH20 manufactured by Campbell Scientific). The sonic anemometer was placed at height of 2.48m and sampled at a frequency of 16Hz, while the krypton hygrometer used for the measurements of turbulent fluctuations of humidity was sampled at 8Hz. Both fast response systems were logged with laptop computers while the slow systems were logged with Campbell Scientific dataloggers (model CR10X). The data acquisition/reduction processing programs were developed by OAU/UBT scientists.

A total of 26 scientists/students participated in the conduct of NIMEX-1. With available internet facilities at OAU campus, it was possible regularly to receive updates/consultations and data exchange with the partners from UBT. All the field measurements ran uninterrupted from 19th February till 10th of March when the intensive phase of data collection for NIMEX-1 study was ended. The data capture was excellent (above 90%) for both slow and fast response systems, except for some days when the datalogging for the fast systems were stopped at the nighttimes. A first look at the dataset is promising and these are being processed as the initial results from the NIMEX-1 project. A followup workshop is scheduled to hold by the third week of May 2004 at Ile-Ife to look at the scientific results and the experiences acquired from the running of the NIMEX-1 project. It is logical that this activity will lead the micrometeorology project, NIMEX-1, into a second phase, which is, NIMEX-2.