Performance of Twelve Mass Transfer Based Reference Evapotranspiration Models under Humid Climate

Abstract

Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic conditions. However, due to data requirement of the FAO-PM equation, there is a need to investigate the applicability of alternative ETo equations under limited data. The objectives of this study were to evaluate twelve mass transfer based reference evapotranspiration equations and determine the impact of ETo equation on long term water management sustainability in Tanzania and Kenya. The results showed that the Albrecht, Brockamp-Wenner, Dalto, Meyer, Rohwer and Oudin ETo equations systematically overestimated the daily ETo at all weather stations with relative errors that varied from 34% to 94% relative to the FAO-PM ETo estimates. The Penman, Mahringer, Trabert, and the Romanenko equations performed best across Tanzania and the South Western Kenya with root mean squared errors ranging from 0.98 to 1.48 mm/day, which are relatively high and mean bias error (MBE) varying from −0.33 to 0.02 mm/day and the absolute mean error (AME) from 0.79 to 1.16 mm/day. For sustainable water management, the Trabert equation could be adopted at Songea, the Mahringer equation at Tabora, the Dalton and/or the Rohwer equations at Eldoret, the Romanenko equation at Dodoma, Songea and Eldoret. However, regional calibration of the most performing equation could improve water management at regional level.

Genetic diversity in Colocasia esculenta and Xanthosoma mafaffa in Togo, West Africa

“…In the Togo collection, flowering occurred among accessions of both species, but fruiting and seed pro duction were not observed. Togo has a tropical savannah climate, with distinct wet and dry seasons, and annual rainfall ranging from around 800 mm to 1,600 mm (Djaman et al, 2017). In Burkina Faso, in the same general climate zone, but further Northwest, most taro is mostly grown in provinces with annual rainfall ranging from around 700 mm to 1,100 mm, near Togo (Traore, 2013).…”

“…Together, taro and new cocoyam offer a range of cultivars suitable for cultivation in wetland to dryland environments. Agriculture in Togo is predominantly rainfed and often experiences both flooding and drought (Djaman et al, 2017). In seasons and loca tions when water is abundant, the flooding tolerance of dasheen taro (Onwueme, 1999) is a positive attribute that can enhance the food security of farm ers working in riverine flood plains.…”

“…400 mm per year in the main agricul tural districts of Cyprus). Over the last 50 years, cli mate change has been very obvious throughout Togo, with the wet season becoming 12 months shorter (Djaman et al, 2017;GadédjissoTossou, 2018). During the period 19612001, for example, annual precipitation decreased at 80% of weather stations across the country (Djaman et al, 2017).…”

A Study on Characteristics and Comparison of Evaporation Estimation Methods in Bandung

“…For example, in the case of Trabert [13], the original model only calculates evaporation without transpiration, although in later studies it has been used as evapotranspiration e.g. in [35].…”

Evaluation of Empirical and Machine Learning Approaches for Estimating Monthly Reference Evapotranspiration with Limited Meteorological Data in the Jialing River Basin, China

“…The Priestley–Taylor (PT) equation [ 17 ] is energy-driven and presented a good performance in estimating ET 0 . Numerous studies have developed these empirical equations in different climates and regions [ 18 , 19 , 20 ]. However, according to existing studies, the above-mentioned empirical methods may be limited due to the fact that the performance of empirical equations could significantly vary depending on the environment [ 21 ].…”