Journal Article

Estimation de la durée d’humectation des feuilles par seuillage de l’humidité relative dans la zone nord de la Cote d’Ivoire

Kouassi Amani, Guillaume Koffi Kouassi, Kignielman Riflard Luc Coulibaly, Kouame, Christophe, Nicaise Kassi Ette, Wawogninlin Brice Coulibaly, Kouadio, Alex Zilé

2024

Overview

This study investigates the modelling of leaf wetness duration (LWD) using empirical approaches based on relative humidity (RH). Analysis of meteorological data shows marked diurnal variability, with temperatures ranging from 20°C to 32°C and relative humidity often above 90%. These conditions favour prolonged wet spells, particularly observed at night and in the morning. The RH model, with a threshold of 90%, achieved a fraction correct (FC) of 77%, a CSI index of 60%, and a Cohen’s Kappa of 0.54. This model shows a good ability to identify wet spells, although slightly underestimated (bias of 0.91) and with a false alarm rate (FAR) of 22%. On the other hand, the dew point depression (DPD) model, using thresholds of 1.5°C for the onset and 4°C for the cessation of wetness, showed slightly better performance, with a CF of 79%, a Kappa of 0.58, and a FAR of 17%. However, this model showed greater sensitivity to data variations during validation, limiting its operational applicability. Both models exhibit residual errors mainly around zero, with a slightly better accuracy for the DPD model (MAE of 0.21 versus 0.23 for RH). This study concludes that the two approaches are complementary: the RH model is robust for operational applications, while the DPD model offers increased accuracy for specific contexts. These results contribute to the improvement of agroclimatic systems for the management of risks related to prolonged leaf wetness.

• Publisher: EDP Sciences
• Subject: Variables