Diurnal cycle of temperature and wind fluctuations within an African equatorial rain forest

• Published in: Agricultural and forest meteorology 2001-08, Vol.109 (2), p.135-141
• Main Authors: Bouka Biona, C., Druilhet, A., Benech, B., Lyra, R.
• Format: Article
• Language: English
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Biological and medical sciences; Climatology, meteorology; Fluctuations; Forest canopy; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Techniques. Climatology. Meteorology. Climatic models of plant production; Spectra; Turbulence; Variance
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/S0168-1923(01)00253-2

This paper describes the characteristics of the temperature and wind speed fluctuations measurements inside the north Congo forest during the DECAFE experiment in February 1988. The temperature spectra show a maximum at 0.018 Hz with a slope close to − 2 3 and the scattering increases as the frequency decreases while the nS( n) wind speed spectra has a maximum at 0.02 Hz with a negative slope at higher frequencies. The dynamical or thermal turbulence in the canopy layer is characterized by a maximum variance in the middle of the day and by two singularities during the transition time at sunrise and sunset when variances are small. This behavior could be due to the turbulent kinetic energy which increases turbulence in the upper part of the canopy layer and also to strongly anisotropic motions generated by the non-homogeneity of the temperature and wind fields inside the forest.