TITLE:
Assessment of Meteorological Drought in Climate Variability Context within the Comoe River Transboundary Watershed
AUTHORS:
Ismaïla Ouattara, Léréyaha Coulibaly, Koffi Abdelaziz Kouakou, Amidou Dao, Dabissi Djibril Noufé, Bamory Kamagaté, Issiaka Savané
KEYWORDS:
Climate Variability, Drought, SPI.3-Index, Sen’s Slope, Comoe River Basin
JOURNAL NAME:
Atmospheric and Climate Sciences,
Vol.12 No.1,
November
8,
2021
ABSTRACT: In the context of climate variability resulting in a
decrease in rainfall with a severe drought, a spatio-temporal study of this
phenomenon remains imperative for the efficient management of water resources.
This paper aims to assess the long-term rainfall drought trend and breakpoints
within the Comoe River watershed. From monthly rainfall data series
(1960-2000), Standardized Precipitation Index (SPI) values were calculated for
a time scale of 3 months (SPI.3). Statistical tests for breaks (CUSUM, and
t-Student) and trends (Man-Kendall and Linear Regression) as well as the Sen’
slope method for estimating the magnitude of trends was applied. The breaks dates observed are mostly
located after the 1970s. Based on SPI.3 values below the threshold of 0.84
chosen as an indicator of drought, rarely has more than half of the catchment
area been affected by drought. The average watershed affected is about 20% over
the study period (1960-2000). The most representative years, in terms of
spatial expansion of the drought, in decreasing order of importance are: 1983,
1992, 1972 and 1982. The years 1982 and 1983 stand out for their exceptional
condition, as the drought-affected 50% to 90% of the total catchment area.
SPI.3 series from 1960 to the various break dates recorded slopes between -0.01 and 0.00 with a slight drought trend for most of the catchment.
After the break periods, almost the entire northern part of the basin is
characterized by slight moisture with Sen’s slopes between 0.000 and 0.005. The
southern part will remain slightly subject to normal rainfall conditions.