Analysis of the diurnal cycles for a better understanding of the mean annual cycle of forests greenness in Central Africa

Philippon Nathalie, De Lapparent B., Gond Valéry, Sèze Geneviève, Martiny N., Camberlin Pierre, Cornu Guillaume, Morel B., Bigot S., Brou T., Dubreuil Vincent. 2016. Analysis of the diurnal cycles for a better understanding of the mean annual cycle of forests greenness in Central Africa. Agricultural and Forest Meteorology, 223 : pp. 81-94.

Journal article ; Article de recherche ; Article de revue à facteur d'impact
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Quartile : Outlier, Sujet : FORESTRY / Quartile : Q1, Sujet : AGRONOMY / Quartile : Q1, Sujet : METEOROLOGY & ATMOSPHERIC SCIENCES

Abstract : Central Africa hosts the world's second largest tropical forest after the Amazonian basin. However, as compared to its Amazonian counterpart, the Central Africa forests receive much less rain (∼1500 mm/year in mean spread over two rainy seasons in March-May and September-November, and two dry seasons). They also experience a slower deforestation rate, so that the main threat for the next decades might come from climate variations. Nonetheless, their response to the annual cycle of solar radiation and rainfall/clouds is still poorly known. Analysing high resolution remote sensing data of Enhanced Vegetation Index, rainfall, cloudiness, and solar radiation for a target region located between 0 and 5°N and 12–19°E, we explore the climatic drivers of the forests greenness mean annual cycle. Three main points emerge; first, the diurnal cycle is a key-scale for understanding the mean annual cycles of rainfall and incoming solar radiation at surface, then how climate shapes the greenness mean annual evolution; second, neither the two dry seasons nor the two rainy seasons resemble each other in terms of cloud cover, solar radiation and rainfall, and their links with greenness levels; third, whereas the first rainy season (March-May) appears optimal for greenness especially because of favorable light conditions, water availability is the main controlling factor during the main dry season and at the start of the first vegetative season (February). Regarding the little dry season (mid-June-mid-August) and the second rainy season (September-October), light availability might be the main limiting factor. These findings pave the way for further studies of the climate interannual variability and change impacts on the Central Africa forests, taking into account time-scale interactions. (Résumé d'auteur)

Mots-clés Agrovoc : forêt tropicale, Couvert forestier, Télédétection, Déboisement, Lumière du jour, Nuage, Pluviométrie, Précipitation, Végétation, Changement climatique, Dynamique des populations, Feuillage, Imagerie multispectrale

Mots-clés géographiques Agrovoc : Afrique centrale, République centrafricaine, Cameroun, République démocratique du Congo

Mots-clés libres : Central Africa, Tropical forests, Enhanced Vegetation Index, Diurnal cycles, Solar radiation, Cloud cover, Rainfall

Classification Agris : K01 - Forestry - General aspects
K70 - Forest injuries and protection
P40 - Meteorology and climatology
F62 - Plant physiology - Growth and development

Champ stratégique Cirad : Axe 6 (2014-2018) - Sociétés, natures et territoires

Auteurs et affiliations

  • Philippon Nathalie, Université de Bourgogne (FRA)
  • De Lapparent B., CRC (FRA)
  • Gond Valéry, CIRAD-ES-UPR BSef (FRA) ORCID: 0000-0002-0080-3140
  • Sèze Geneviève, CNRS (FRA)
  • Martiny N., CRC (FRA)
  • Camberlin Pierre, CRC (FRA)
  • Cornu Guillaume, CIRAD-ES-UPR BSef (FRA) ORCID: 0000-0002-7523-5176
  • Morel B., Université de la Réunion (REU)
  • Bigot S., CNRS (FRA)
  • Brou T., IRD (REU)
  • Dubreuil Vincent, CNRS (FRA)

Source : Cirad-Agritrop (

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