Reference evapotranspiration is a key parameter in hydrological and meteorological studies and used to determine the actual water use rate for various crops. The objectives of this study were to explore trend in the grass-reference evapotranspiration (ETo) through years 1961–2011 and to identify trend in the aridity index as an indicator of change in climate in Togo. ETo was calculated using the FAO-56 Penman–Monteith method, and trends analyses were performed with non-parametric statistics proposed by Mann–Kendall and the Sen slope estimator. Results showed that annual ETo varied from 1,440 to 1,690 mm at Lomé, from 1,761 to 1,905 mm at Tabligbo, and from 1,839 to 1,990 mm at Sokode. The Mann–Kendall test revealed significant increase in annual ETo at Tabligbo (Z = 2.89) and Sokode (Z = 2.29). Annual ETo is much more stable at Lomé, with non-significant decrease. In Togo, according to the three study sites, the 1961–2011 period annual aridity index varied from 0.26 to 0.99 at Lomé, 0.38 to 0.98 at Tabligbo, and 0.45 to 1.08 at Sokode. The Mann–Kendall test revealed a declining trend in the ratio of precipitation/ETo which adversely implies an increasing severity of the aridity index at all the sites, prejudicial to rainfed agriculture practiced by about 90% of Togolese crop growers.
Skip Nav Destination
Article navigation
Research Article|
April 09 2015
Trend analysis in reference evapotranspiration and aridity index in the context of climate change in Togo
Djaman Koffi;
1Africa Rice Center, Sahel Regional Station, BP 96 St-Louis, Senegal
E-mail: [email protected]
Search for other works by this author on:
Ganyo Komla
Ganyo Komla
2Institut Togolais de la Recherche Agricole (ITRA), BP 2318 Lome, Togo
Search for other works by this author on:
Journal of Water and Climate Change (2015) 6 (4): 848–864.
Article history
Received:
September 13 2014
Accepted:
March 08 2015
Citation
Djaman Koffi, Ganyo Komla; Trend analysis in reference evapotranspiration and aridity index in the context of climate change in Togo. Journal of Water and Climate Change 1 October 2015; 6 (4): 848–864. doi: https://doi.org/10.2166/wcc.2015.111
Download citation file:
Sign in
Don't already have an account? Register
Client Account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.
eBook
Pay-Per-View Access
$38.00