Abstract:
This work focuses on trend analysis of rainfall, evaporation, temperature, relative humidity,
wind speed, and sunshine duration over the Ouémé Delta in Bénin. Eight temperature based indices
and fifteen rainfall based indices are computed from 1960 to 2016. Moreover, maximum 1, 2, 3, 5,
and 10 days precipitation indices were computed at the monthly scale. Trends are detected at 0.05
confidence level, using a combination of Mann-Kendall and prewhitened Mann-Kendall test. Partial
correlation and stepwise regression are used to detect the set of meteorological variables that influence
pan evaporation in Ouémé Delta. Results showed intensification of heavy rainfall over Ouémé
Delta. Moreover, a significant increasing trend is detected in temperature. As consequence, diurnal
temperature significantly decreases as proof of the global warming. Average pan evaporation showed
a significant slither increasing trend over the area. Change in pan evaporation can be explained by
wind speed and sunshine duration that hold almost 50% of pan evaporation variance. As future
temperature is going to be increasing, pan evaporation may increase considerably. So, adaptation
measures have to be reinforced in the Ouémé Delta area where farmer are used to rainfed agriculture
for food security. Moreover, Ouémé Delta plan have to be developed for it resources sustainability.
